Dorte Drongstrup, Søren Overgaard, David Minguillo
Research and Analysis Section, University Library of Southern Denmark, University of Southern Denmark; Copenhagen University Hospital, Bispebjerg, Department of Orthopaedic Surgery and Traumatology, University of Copenhagen, Department of Clinical Medicine, Faculty of Health and Medical Sciences; PIMS, KTHB, KTH Royal Institute of Technology, Stockholm 100 44, Sweden

Background: he Journal Impact Factor (JIF) is often used as an indicator of research quality by tenure, promotion, and funding assessment committees. Thus, a higher JIF could lead to increased visibility for journals and more publication submissions. This provides incentives for journal editors to optimize in accordance with the JIF formula; the number of citations received in a given year to a journal’s publications from previous two years divided by the number of only articles and reviews from previous two years. However, the use of JIF to assess research quality is highly problematic, since it can easily be manipulated. A strategy to boost the JIF-score is by increasing the rate of Journal-Self-Citations (JSC) to the two previous years (JIF-years), which increases the number of citations (size of the numerator).
Aim: The aim is to investigate to what extent Orthopedic journals might use different strategies to influence and increase their JIF-scores.
Materials and Methods: All journals indexed in the subject category Orthopedics by the Journal Citation Report between 1997 and 2018 were analyzed. The data source was the in-house database version of Web of Science owned by the Royal Institute of Technology (KTH). The study covers 95 journals, 210,528 publications, and 3,990,809 citations. We analyze the publishing and citation patterns of these journals and apply different measures to identify which strategies might be the most frequent in the field to optimize the impact factors and which journals might take most advantage of these strategies to boost their JIF and ranking.
Results: Our first results show that the rate of JSC to JIF-years tend to be as almost double as high than usual. Still, there are large variance in the JSC intensity among journals. If the JSC to the JIF-years are excluded, the impact factor on average decreases 15%. For the 2018 JIF ranking, four journals in the top10 changes position when JCS are excluded.
Interpretation / Conclusion: The study finds a strong tendency for JSC in the JIF- years. It suggests that the inclusion of JSC in the calculation influences the JIF-scores and ranking of journals.

Jens Rithamer Jakobsen, Peter Schjerling, Michael Kjaer, Abigail Mackey, Michael Rindom Krogsgaard
Department of sports traumatology M51, Bispebjerg-Frederiksberg Hospital*; Institute of Sports Medicine, Department of Orthopaedic Surgery M, Bispebjerg Hospital, Copenhagen*; Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, *Departments are part of IOC Research Center Copenhagen.

Background: The connection between the muscle fibers and the tendon, name the myotendinous junction (MTJ), is architecturally constructed to transmit force between muscle and tendon, but at the same time it is vulnerable to strain injury. In order to explain why these injuries occur and suggest how they can be prevented, a better understanding of the composition and cellular components of the MTJ is needed. Previous studies have shown the presence of an unique collagen type at the MTJ, Collagen XXII, which is not demonstrated elsewhere in the skeletal muscle system.
Aim: The aim was to evaluate the gene expression of the MTJ and compare it to the adjacent muscle and tendon. We aimed to find new targets that are unique to the MTJ and of importance for the strength or recovery of the tissue. In addition, we wanted to identify targets that are higher expressed at the MTJ compared to the neighboring muscle and tendon.
Materials and Methods: Samples were collected from the superficial digitorum flexor muscle from 20 horses, frozen and sliced into sections containing muscle, MTJ and tendon tissue before preparation for RT-PCR. Based on the mRNA results a t-stochastic neighboring embedded plot (t-SNE) was made and sets of samples from 5 horses with the clearest separation between tissues were chosen for RNA sequencing. An expected contribution of muscle and tendon was calculated for all targets based on the known expression of 2-300 of the most selective muscle and tendon genes. Any variation between the expected and measured gene expression was regarded as expressed by the MTJ.
Results: No targets were found to be uniquely expressed at the MTJ. Collagen XXIIa1 was expressed 17-fold higher compared to the expected value. Generally, genes involved in remodeling and reformation of skeletal muscle fibers and extracellular matrix were expressed to a larger extent at the MTJ.
Interpretation / Conclusion: Despite the MTJ being a region specialized in force transmission with a highly specialized morphology no genes could be demonstrated as being unique to this region. The genes expressed higher in the MTJ compared to muscle and tendon were related to remodeling activities, and this confirms the previous finding of high rates of remodeling at the MTJ.

Jens Rithamer Jakobsen, Jens Hannibal, Mackey Abigail , Michael Rindom Krogsgaard
Department of sports traumatology M51, Bispebjerg-Frederiksberg Hospital*; Department of Clinical Biochemistry, Bispebjerg - Frederiksberg Hospital, Copenhagen; Institute of Sports Medicine, Department of Orthopaedic Surgery M, Bispebjerg Hospital, Copenhagen*; Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, *Departments are part of IOC Research Center Copenhagen.

Background: Strain injuries occur in the myotendinous junction (MTJ) where muscle and tendon meet. Clinical studies have demonstrated that eccentric exercise is effective to prevent these injuries, and to explain this positive effect, it is relevant to study the ultrastructural adaptations of the MTJ to exercise. Electron microscopy of the MTJ has revealed a very folded interface between muscle and tendon, increasing the surface area of the MTJ. In animals these foldings increase as response to training. However, electron microscopy analyzes only very small segments of the entire MTJ, and results might not be representative for the entire MTJ. In addition muscle fiber types cannot be distinguished by electron microscopy, which would be relevant, as there are indications that the surface area varies between type 1 and 2 fibres.
Aim: To develop a method where the surface area of MTJ in entire muscle fibers can be measured and the muscle fiber type can be established.
Materials and Methods: For this pilot study a sample from one patient scheduled for ACL-surgery was collected from the semitendinosus muscle. Following fixation, the sample was manually dissected into single muscle fibers with intact MTJ. Using immunofluorescent antibody against collagen XXII (a marker of MTJ) and myosin heavy chain I, the MTJ and the muscle fiber type was identified. With a spinning disc confocal microscope each fiber was scanned and a 3-D reconstruction was made from the images. From this 3D-reconstruction the area and volume of the interface could be measured. 28 muscle fibers were analyzed (16 type I and 12 type II fibers)
Results: An average area of 25817 µm2 ± 6095 and volume of 4509 µm3 ± 1236 was found when pooling both fiber types. No significant differences in area or volume were seen between fiber types.
Interpretation / Conclusion: With confocal microscopy it was possible to analyze the interface area between muscle and tendon from a large number of fibers. There was relatively small variance between fibers, and this method is useful to measure the effects of exercise on the interface area of the MTJ.

Anthony Fraisse, Steffen Rasmussen, Sune Lund Sporrring , Jes Bruun Lauritzen
Composites Manufacturing and Testing Section, Department of Wind Energy, Risø Campus Department of Orthopaedic Surgery, Bispebjerg Hospital University of Copenhagen

Background: An intraarticular unconstrained resurfacing HipCap, intended for use in patients with osteoarthritis, have been tested for biomechanical strength analysis. The obtained information of implant wear against the osteoarthritic surface is limited.
Aim: The objective was to characterize the long-term laboratory wear of a harvested osteoarthritic femoral head rotating into a HipCap implant made of BioDur BioDur® Carpenter CCM® Alloy.
Materials and Methods: The experimental test was performed according to ISO14242-1 load pattern using ASTM hip simulator accessory mounted on the FastTrack 8874 axial torsional test system (Instron). The test was kept at 37 degrees Celcius, and run in saline water 0.9 % mixed with Atamon Atamon. The load was chosen as 1 kN for the entire sample life with rotation of the actuator from -90 to 90 degree which is showing a hip rotation corresponding to standard.
Results: The femoral head/cup has been subject to 5.100.000 cycli so far and is still running with the load pattern simulating a body weight of 100 kg. The implant showed no degradation, but may be influenced by failure of the fixture, which is a challenge in these tests. The bone changed colour due to increased load from the implant or influenced by the saline. No bone insufficiency at the femoral head has been observed.
Interpretation / Conclusion: The osteoarthritic femoral head surface, which has undergone condensation of mineral with an eburnated eburnated surface seem rather wear resistant to the HipCap implant with polished surface. The test may approximately correspond to 5 years wear for a person with moderate physical activity. The wear test is still running.

Linda Fernandes, Allan Villadsen, Christina Holm, Michala Skovlund Sørensen, Mette Kreutzfeldt Zebis, Lars Louis Andersen, Michael Mørk Petersen
Department of Midwifery, Physiotherapy, Occupational Therapy and Psychomotor Therapy, University College Copenhagen, Copenhagen, Denmark; Musculoskeletal Tumor Section, Department of Orthopedic Surgery, University Hospital Rigshospitalet, Copenhagen, Denmark; National Research Centre for the Working Environment, Copenhagen, Denmark; Institute of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark

Background: While most patients going through limb-sparing surgery (LSS) due to bone sarcoma are of the working-age population, limited knowledge exist about their work ability and physical demands at work.
Aim: The aim of this study was to assess work ability and work and leisure-time activity in these patients.
Materials and Methods: This cross-sectional study compared 20 patients, receiving LSS and reconstruction in proximal femur (n=9), distal femur (n=7) and proximal tibia (n=4) between 2006 and 2016, with 20 healthy controls. Both patients and controls were employed. The Musculoskeletal Tumour Society Score (MSTS) was used as descriptive information. The Work Ability Index (WAI), The Patient Specific Functional Scale (PSFS), activity monitor and the International Physical Activity Questionnaire (IPAQ) were used to evaluate work ability, work and leisure-time activities. Between group differences were assessed using unadjusted and adjusted (sex, age, BMI, educational level, type of work) general linear models.
Results: The patients were seen 7 (±2.9) years post-surgery, had a mean age of 43 (±13.6) years, BMI 27 (±3.7) and MSTS of 69 (±14.6)%. The adjusted analyses showed differences between patients and controls in general work ability (7.8 vs. 9.1 points, p=0.002) and work ability due to physical demands (3.2 vs. 4.6 points, p<0.001). There were between group differences in PSFS mean score (2.8 vs. 9.5 points, p<0.001). No differences were seen in step counts/day (10.588 vs. 12.239 steps, p=0.144) or the IPAQ (4107 vs. 4035 METs/week, p=0.942).
Interpretation / Conclusion: Most patients experienced difficulties in performing tasks requiring physical demands at work and leisure-time. Although we found no differences in step counts or METs per week, patients reported great difficulties in performing activities. Work ability should be further evaluated in future research. Elements of vocational rehabilitation might be considered in postoperative care for working-age patients following LSS and reconstruction with tumour prosthesis.

Kenneth C. Obionu, Michael R. Krogsgaard, Christian F. Hansen, Jonathan D. Comins
Section for Foot and Ankle Surgery, Department of Orthopedic Surgery M, Bispebjerg and Frederiksberg Hospital, Copenhagen University, Denmark; Section for Sports Traumatology M51, Department of Orthopedic Surgery M, Bispebjerg and Frederiksberg Hospital, Copenhagen University, Denmark

Background: There are numerous patient-reported outcome measures (PROMs) for patients with chronic ankle instability (CAI). However, the Foot and Ankle Ability Measure (FAAM) is the only PROM with adequate content and construct validity for these patients. It was developed with involvement of patients with CAI, and the measurement properties fit a modern test theory (MTT) model. Notwithstanding, FAAM is not available in a Danish version.
Aim: The aim was to translate and culturally adapt the original English version of FAAM into Danish and to assess its measurement properties using Rasch MTT.
Materials and Methods: Translation and adaptation was conducted using the dual panel method. Cultural adaptation was performed by subsequent cognitive interviews with eight patients and face validity was explored by interviews with seven health care professionals. Finally, construct validity was assessed by analyzing completed questionnaires from 206 patients (70%) of the 293 recruited patients with various ankle and foot conditions, using the Rasch Unidimensional Measurement Model (RUMM) software program.
Results: The original 29-item version was translated and culturally adapted to Danish utilizing the Dual Panel process and reviewed by Danish patients who confirmed content relevance, after small adaptations. Face validity was confirmed. Rasch modelling revealed that the scale was not unidimensional, meaning that domain scores could not be aggregated. The 21-item ADL domain showed misfit, but after removing 6 items, the resulting 15-item scale displayed adequate fit to a partial credit Rasch model. The Sports domain also exhibited misfit, but after removing one item and adjusting the scale due to differential item functioning related to age for another item, a 7-item scale showed good fit. This resulted in a 22-item, 2-dimensional Danish version of FAAM with good measurement properties.
Interpretation / Conclusion: The FAAM was successfully translated to Danish and demonstrated relevance for patients with CAI. A Danish 22-item version of FAAM exhibits robust measurement properties for patients with various conditions of the lower leg, ankle and foot, including CAI.

Frederikke Oxenvad Schultz, Stine Rytter Christensen, Brian Elmengaard , Casper Bindzus Foldager
Institute for Clinical Medicine, Aarhus University, Aarhus, Denmark; SANA Medical Systems, Aarhus, Denmark

Background: Intermittent hypoxic therapy (IHT) is a treatment modality that can induce systemic effects by exposing the patient to short-term hypoxic stress by lowering of inspiratory oxygen tension in short intervals followed by normoxic or hyperoxic recovery. This has been shown to induce several systemic effects including a magnitude of changes in inflammatory and anabolic cytokines. SANA (SANA Medical Systems, Aarhus) is a new private institution specializing in research and treatment of pain using data-driven algorithm-based individualized IHT.
Aim: The aim of this study was to investigate the clinical effects of a novel algorithm of IHT on musculoskeletal chronic pain in a prospective consecutive cohort.
Materials and Methods: A consecutive cohort of self-referred patients treated in the SANA clinic with chronic musculoskeletal pain (>3 months) were included. Patients were treated with individualized IHT. They completed a Numeric Rating Scale for pain intensity (NRS) and a 36-Item Short Form Health Survey (SF-36) prior to treatment and 6 weeks after the first treatment. Prior to each treatment session patients also completed NRS. Patients with pre-treatment NRS of =2 were excluded. P-values less than 0.05 were considered significant.
Results: Thirty-six patients were included, and the follow-up rate after 6 weeks were 62%. Mean age was 43 years and mean duration of symptoms was 55 months. The average number of treatments were 5. We found that IHT significantly reduced pain after 6 weeks in both rest (NRS 6.0 to 2.5; P=0.0039(week), NRS 6.0 to 2.0; P=0.0078 (month)) and activity (NRS 7.5 to 3.0; P=0.0001 (week), NRS 7.0 to 3.0; P=0.0004 (month)). Additionally, IHT increased health- related quality of life, an improvement that was significant in five out of eight domains related to pain and function. Lastly, we found that IHT significantly reduced pain on NRS from baseline to the evaluation after 2 treatments in both rest (P=0.009) and activity (P=0.0009).
Interpretation / Conclusion: We conclude that this novel algorithm of individualized IHT is associated with significant pain reduction and improved health-related quality of life in patients with musculoskeletal chronic pain.

Thomas Vedste Aagaard, Sahar Moeni, Søren Thorgaard Skou, Ulla Riis Madsen, Stig Brorson
Department of Physiotherapy and Occupational Therapy, Holbaek Hospital, Holbaek, Denmark; Department of Orthopaedic Surgery, Holbaek Hospital, Holbaek, Denmark; Department of Orthopaedic Surgery, Zealand University Hospital, Koege, Denmark Department of Orthopaedic Surgery, Zealand University Hospital, Koege, Denmark Department of Physiotherapy and Occupational Therapy, Naestved- Slagelse-Ringsted Hospitals, Slagelse, Denmark: Research Unit for Musculoskeletal Function and Physiotherapy, Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark Department of Orthopaedic Surgery, Holbaek Hospital, Holbaek, Denmark; The Danish Knowledge Centre for Rehabilitation and Palliative Care. University of Southern Denmark, Odense, Denmark Department of Orthopaedic Surgery, Zealand University Hospital, Koege, Denmark: Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark

Background: One of the most feared complications of diabetes mellitus is diabetic foot ulcers (DFU), as it can cause severe adverse consequences such as amputation or death. Patients are often required to refrain from bearing weight on their affected limb, leaving some patients immobile for weeks, months or even years. This is in direct contrast to guidelines for diabetes where exercise therapy and physical activity are core elements in the treatment. This leaves patients and caretakers with a paradox. If a DFU evolves, should patients continue following the guidelines for diabetes? Even if these guidelines include recommendations of brisk walking and exercising at high intensity.
Aim: Exercise therapy is a core element in the treatment of diabetes, but the benefits and harms for patients with a diabetic foot ulcer are unknown. We aimed to systematically review the benefits and harms of exercise therapy for patients with DFU.
Materials and Methods: We searched six major databases. We performed citation and reference searches of included studies and contacted authors of ongoing trials. We included randomized controlled trials to assess potential benefits on health-related quality of life (HRQoL) and harms of exercise therapy. Observational studies were included to identify potential harms of exercise therapy.
Results: We included 10 published publications of 9 trials and results from two unpublished trials including a total of 281 individuals with DFUs receiving various forms of exercise therapy. Due to lack of HRQoL measurements and high heterogeneity, it was not possible to perform meta-analyses. Results on HRQoL was present in one unpublished study. Harms reported ranged from musculoskeletal problems, increased wound size, to amputation; however, no safe conclusions could be drawn from the available data due to high heterogeneity and risk of bias in the trials.
Interpretation / Conclusion: Protective strategies are often preferred over therapeutic exercise which might have unforeseen consequences for patients over time. Based on the current literature, no evidence-based recommendations can be provided on the benefits and harms of exercise therapy for patients with DFUs. Well-conducted RCTs are needed to guide rehabilitation.

Christopher Jantzen, Lars B. Ebskov, Kim H. Andersen, Mostafa Benyahia, Peter Bro-Rasmussen, Jens K. Johansen
Department of Orthopedic Surgery, Foot and Ankle Section, Hvidovre University Hospital, Copenhagen, Denmark

Background: Total ankle replacement (TAR) is a rapidly growing treatment for end-stage ankle arthritis. TAR is generally performed as an inpatient procedure with an average length of stay between 2.5-3.2 days. Previous studies have shown that out-patient TAR is safe and cost- effective but others have found increased complication rates associated with out-clinic surgery but the literature is sparse on this topic.
Aim: To evaluate the admission length together with complication, re-admission and non-scheduled contact to the out-patient clinic rates in patients operated with TAR at Hvidove University Hospital. The study also aims at identifying risk factors associated with admission length >1 day.
Materials and Methods: Since 11th of December 2015 all patients treated at Hvidovre University Hospital with TAR have been subjected to the fast track setting where discharge is planned the first post-operative weekday after cast application. For this study data was collected on all patients treated during the period 11th of December 2015 to 1th of October 2019 with a minimum of three months follow-up. Data was collected regarding age, sex, ASA-score, BMI, co-morbidity, complications-, re- admission rates and non-scheduled contact to the out-patient clinic.
Results: 151 patients were included. No difference was found between patients discharged after one day when compared with those admitted >1 day. 54.3% was discharged one day after surgery while 32.4 % was discharged after 2 days and 13.3 % after >2 days. The overall readmission rate was 1.95 % while 5.95 % had a complication and 16.65 % had a non-scheduled contact to the out-patient clinic. None of the included variables was found associated with admission length >1 day in both uni- and multivariate logistic regression analysis.
Interpretation / Conclusion: Fast track TAR seems safe even though only 50 % of the patients could cohere to this. The main reasons for prolonged admission was soft-tissue swelling not allowing cast application or surgery at the end of the week delaying cast application. Also, special attention has to be made regarding analgesic treatment and cast application, in order to reduce the number of non-scheduled contacts to the out-patient clinic.

Kristian Brink Behrndtz, Kristian Kibak Nielsen, Frank Skydsgaard Linde
Dept. Orthopaedic surgery, Foot and Ankle section, Aarhus University Hospital

Background: STAR is a treatment option for advanced arthritic conditions in the ankle joint. Formation of cysts under the talar component is a known complication. Increasing cyst volume may increase risk for implant failure.
Aim: To evaluate a uniform cohort with talar cyst formation under STAR talar component treated with allogenic bone graft and simultaneous subtalar arthrodesis.
Materials and Methods: During the period from June 1998 to June 2018, 465 patients, 254 (55%) males and 211 (45%) females, were treated with a total of 518 implants. 83% of cases had primary implant due to Osteoarthritis (OA), 17% due to Rheumatoid Arthritis(RA). Data was collected prospectively. 15(3,2%) patients treated with allogenic bone graft and subtalar arthrodesis were identified. A clinical examination, AOFAS-score, VAS pain score and x-rays were obtained pre-operatively, post operative and at follow-up.
Results: 15 patients, 11 (73%) males and 4 (27%) females, treated with allogenic bone graft and subtalar arthrodesis were identified. All 15 patients had the primary implant due to OA. Median time from primary surgery to graft and athrodesis was 5,5 years (IQR 4,6 - 9,0). Median time from bone graft and arthrodesis to follow-up was 5,0 years (IQR 3,6 - 6,4). At follow-up 11(73%) patients had healed, of which 2(13%) had re-formation af talar cysts but no migration on x-ray. 3(20%)patients had migration of the talar component with a still functional implant. 1(7%) had revision surgery after 1,2 years.
Interpretation / Conclusion: Allogenic bone graft with simultaneous subtalar arthrodesis is a good treatment option for implant threatening cyst formation under STAR talar component. After median 5,0 years follow-up 11 patients had healed successfully, and a further3 implants remained satisfactory functional in spite of migration and only 1 implant had failed demanding revision.

Jorgen Baas, Nina Dyrberg Lorenten, Frank Dyrberg Lorenten, Sundstrup Claus, Kristian Kibak Nielsen
Orthopedics - Section for Foot and Ankle Surgery, Aarhus University Hospital

Background: The classic Rheumatoid Arthritis (hereafter RA) deformities include Hallux Valgus, hammertoes and a collapse of the transverse arch. The typical patient presents with metatarsalgia as the main complaint, but also pressure points from shoewear on bunion and hammertoes. The goal of rheumatoid forefoot surgery is to reduce pain and normalize the foot to fit common shoewear by correcting deformities. In our department, this surgical correction has consisted of first ray metatarsophalangeal arthrodesis, small metatarsal head resection and hammertoe correction by proximal interphalangeal arthrodesis.
Aim: To establish a basic understanding of patient satisfaction and surgical outcome of this surgical procedure in our institution.
Materials and Methods: We report from a consecutive retrospective self- controlled cohort study of 33 patients (50 feet) operated with the same technique.
Results: 30 of the 33 patients confirmed willingness to repeat surgery. 16 of 33 patients wore hand- sewn shoes before surgery, postoperatively this was reduced to 7 of 33. Solid metatarsophalangeal fusion of the great toe was found in 47 of 50 feet and the metatarsal parabola was acceptable by radiological assessment.
Interpretation / Conclusion: This cohort showed a high level of patient satisfaction and outcome. This cohort is non- comparative and allows no conclusions on the effects of surgery, but patient willingness to repeat is good and we will continue to offer this procedure to our patients with severe rheumatoid forefoot deformities.

Marianne Christensen, Karin Grävare Silbernagel, Jennifer A Zellers, Michael Skovdal Rathleff, Inge Lunding Kjær
Department of Physical and Occupational Therapy, Aalborg University Hospital, Aalborg, Denmark; Interdisciplinary Orthopaedics, Aalborg University Hospital, Aalborg, Denmark; Department of Clinical Medicine, Aalborg University, Aalborg, Denmark; Department of Physical Therapy, University of Delaware, Newark, USA; Program in Physical Therapy, Washington University School of Medicine in St. Louis, USA

Background: Long-term muscular deficits are common after Achilles tendon ruptures. Early use of exercises is recommended in the literature, but the actual content of the exercises is sparsely investigated.
Aim: To examine the feasibility of an early progressive resistance exercise program for patients with Achilles tendon rupture regarding patient acceptability of the exercises and compliance of the intervention.
Materials and Methods: Participants with an acute Achilles tendon rupture treated non-surgically were recruited at Aalborg University Hospital. During the 9 weeks of immobilizing with a walker boot, the patients attended weekly supervised exercises sessions and performed home exercises. Exercises were ankle plantarflexion isometric exercises, seated heel-raises and resistance exercise with elastic band. Patient acceptability was evaluated using a 7-point Likert scale, and we hypothesized 80% of the patients would rate the top four scores. Adherence to the exercise program was defined as 80% of the patients performing at least 50% of the home exercise sessions. During the intervention, tendon healing was monitored, and adverse events were recorded.
Results: 16 patients [mean age 46 (range 28-61), male/female = 13/3] completed the intervention. Cause of rupture were sport in 12 cases and four had recently returned to sport after a longer break. Pre-intervention Achilles tendon total rupture score was 98 (SD 7.6). All patients rated the acceptability of the exercise program in the top three on the 7-point Likert scale at 9- and 13- weeks follow-up and 9/16 rated the highest score (very acceptable). The mean performance of home exercises was 74% (range 4-117) of the total sessions possible. One patient had difficulties coping with the intervention and activity of daily living during the intervention period. There were no re-ruptures, but one case of deep venous thrombosis (pain and edema at the second session).
Interpretation / Conclusion: The early progressive resistance exercise program was feasible based on patients rating the exercise program highly acceptable and compliance with the exercises was high.

Marianne Christensen, Inge Lunding Kjær, Henrik Riel, JL Olesen, Karl Landorf, Matthew Cotchett, Michael Skovdal Rathleff
Department of Physical and Occupational Therapy, Aalborg University Hospital, Aalborg, Denmark; Interdisciplinary Orthopaedics, Aalborg University Hospital , Aalborg, Denmark; Center for General Practice at Aalborg University, Aalborg, Denmark; Discipline of Podiatry, School of Allied Health, Human Services and Sport, La Trobe University, Melbourne, 3086, Australia; La Trobe Sports and Exercise Medicine Research Centre, School of Allied Health, Human Services and Sport, La Trobe University, Melbourne, 3086, Australia; Department of Health Science and Technology, Aalborg University, Denmark

Background: Plantar heel pain (PHP) used to be considered a self-limiting condition, where pain was thought to resolve within a year after onset. Recent investigations have indicated that a large proportion of patients may experience pain for several years despite having received specialized care.
Aim: To explore the long-term prognosis of individuals treated for PHP.
Materials and Methods: Patients treated for PHP at the orthopaedic foot and ankle ward, Aalborg University Hospital, between 2011-2018 were contacted via e-mail and asked to participate in the study by completing online questionnaire. Questionnaires concerned demographic and participant characteristics, presence of heel pain during the past four weeks, mean heel pain intensity during the past week measured on a 0 to 10 numerical rating scale, work situation, comorbidities, and overall health status as measured by the EQ5D. These results are preliminary and data collection is continuing, so a higher response rate is expected.
Results: A total of 254 (68% women) completed the questionnaire (38% of all diagnosed with PHP during the 8 year period), median BMI of 28.0 kg/m2 (IQR 25.0-32.2). Mean age was 54 years (SD 12) and the median period of heel pain was 20.5 months (IQR 9- 60). 55% (95%CI 49-61%) reported they had experienced heel pain during the past four weeks at follow-up, with a median pain intensity of 5 (IQR 3- 7). 76-86% of these reported concomittant pain in either shoulders, legs/hips or backs. Among those still experiencing heel pain, 17.5% had to change their work assignments due to heel pain, 25% had days with sick leave due to heel pain (median days off work 21 (IQR 7-90)) and 27% reported depressive symptoms on the EQ5D.
Interpretation / Conclusion: Despite specialized care, more than half the sample still reported PHP up to 10 years after initial treatment. Not only were they still experiencing pain, but the condition was also found to be associated with sick leave and a change in work assignments in a substantial number of participants, and one in four reported depressive symptoms. These results emphasise the large impact PHP may have on people with PHP and highlights the need for more effective treatments.

Julie Sandell Jacobsen, Thorborg Kristian , Dorthe Sørensen, Stig Storgaard Jakobsen, Rasmus Oestergaard Nielsen , Lisa Gregersen Oestergaard, Kjeld Søballe, Inger Mechlenburg
Research Centre for Health and Welfare Technology, Programme for Rehabilitation, VIA University College; Research Unit for General Practice in Aarhus; Sports Orthopaedic Research Center-Copenhagen (SORC-C), Department of Orthopaedic Surgery, Copenhagen University Hospital, Amager-Hvidovre; Physical Medicine and Rehabilitation Research-Copenhagen (PMR-C), Department of Physical and Occupational Therapy, Copenhagen University Hospital, Amager-Hvidovre; Department of Orthopaedic Surgery, Aarhus University Hospital; Department of Clinical Medicine, Aarhus University; Department of Public Health, Aarhus University; DEFACTUM, Central Denmark Region, Aarhus; Department of Occupational Therapy and Physiotherapy, Aarhus University Hospital.

Background: Hip dysplasia can be surgically treated with periacetabular osteotomy (PAO). However, PAO is not offered to or accepted by all patients. Hence, no evidence- based interventions exist for patients ineligible for PAO.
Aim: The aim was to evaluate the feasibility and acceptability of a six-month progressive exercise therapy and patient education intervention for patients with hip dysplasia ineligible for PAO prior to conducting a full-scale randomised controlled trial (RCT).
Materials and Methods: Feasibility was evaluated as recruitment, retention and mechanisms of impact. Recruitment and retention were monitored through intervention records. Mechanisms of impact were evaluated as change in Copenhagen Hip and Groin Outcome Score (HAGOS) pain, hip muscle strength and single-leg hop test (SLHD) over a 6-month follow-up period. Acceptability was evaluated as expectations, perceptions, adherence, benefits and harms. Adherence was evaluated by self-reports, whereas the other components were evaluated through semi- structured interviews.
Results: The feasibility evaluation showed that 30 (median age: 30, IQR 24-41) of 32 eligible patients accepted inclusion in the study, and that 24 patients completed the 6-month follow-up. Furthermore, HAGOS pain improved by 11 (CI 5-17) points and hip strength improved by 0.2 (CI 0.04-0.4) Nm/kg (abduction), 0.2 (CI 0.01-0.4) Nm/kg (flexion) and 0.3 (CI 0.02-0.5) Nm/kg (extension). Finally, SLHD improved from a median of 0.4 (IQR 0.3-0.4) metres to 0.5 (IQR 0.5-0.6) metres, p<0.001. Patient acceptability was characterised by high perceived value of the intervention, and that expectations to the intervention were met. A total of 20 of 24 patients completed at least 2/3 of planned training sessions.
Interpretation / Conclusion: A six-month progressive exercise therapy and patient education intervention is considered feasible and acceptable. Thus, it seems relevant to conduct an RCT to investigate the effectiveness on pain, muscle strength and performance. If such trial can confirm the results of the present study, it has potential clinical impact in patients with hip dysplasia ineligible for PAO.

Anders Falk Brekke, Anders Holsgaard-Larsen, Trine Torfing, Stig Sonne-Holm, Søren Overgaard
A.F. Brekke: Department of Orthopaedic Surgery and Traumatology, Odense University Hospital, Denmark. Department of Clinical Research, University of Southern Denmark, Denmark. University College Absalon, Center of Nutrition and Rehabilitation, Department of Physiotherapy, Region Zealand, Denmark; AH. Larsen: Department of Orthopaedic Surgery and Traumatology, Odense University Hospital, Denmark. Department of Clinical Research, University of Southern Denmark, Denmark; T. Torfing: Department of Clinical Research, University of Southern Denmark, Denmark. Department of Radiology, Odense University Hospital, Denmark; S. Sonne-Holm: Copenhagen Osteoarthritis Study, Copenhagen City Heart Study, Frederiksberg Hospital, Denmark; S. Overgaard: Department of Orthopaedic Surgery and Traumatology, Odense University Hospital, Denmark. Department of Clinical Research, University of Southern Denmark, Denmark. Department of Orthopaedic Surgery and Traumatology, Copenhagen University Hospital, Bispebjerg. Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen;

Background: The prevalence of acetabular retroversion is sparsely investigated and it may be associated with increased anterior pelvic tilt.
Aim: To investigate whether patients with symptomatic and radiographically verified acetabular retroversion demonstrated increased anterior pelvic tilt compared to a control group, and furthermore to evaluate the prevalence of acetabular retroversion in the general population.
Materials and Methods: We assessed anteroposterior pelvic radiographs in standing position of 111 patients with acetabular retroversion and 132 matched controls from the general population. Pelvic tilt was assessed by the sacrococcygeal joint–symphysis distance and pelvic-tilt-ratio. Acetabular retroversion was defined as positive cross-over sign and posterior wall sign. A nonparametric regression model was used to test between-group differences in median pelvic tilt. The prevalence was calculated as the ratio of subjects and hips with acetabular retroversion, respectively.
Results: The patient group had significantly larger median anterior pelvic tilt of 14.3 mm in sacrococcygeal joint–symphysis distance and -0.08 in pelvic-tilt-ratio, compared to controls. The prevalence of subjects in the general population was 24% and 18% for unilateral or bilateral acetabular retroversion, respectively.
Interpretation / Conclusion: We found that patients with symptomatic acetabular retroversion have increased anterior pelvic tilt compared to the general population. Radiographic sign of acetabular retroversion was highly prevalent in the general population. This should be considered when diagnosing and treating patients with hip pain, as they may not necessarily originate from the radiographic verified acetabular retroversion.

Anders Falk Brekke, Søren Overgaard, Bo Mussmann, Erik Poulsen, Anders Holsgaard-Larsen
A.F. Brekke Department of Orthopaedic Surgery and Traumatology, Odense University Hospital, Denmark. Department of Clinical Research, University of Southern Denmark, Denmark. University College Absalon, Center of Nutrition and Rehabilitation, Department of Physiotherapy, Region Zealand, Denmark; S. Overgaard Department of Orthopaedic Surgery and Traumatology, Odense University Hospital, Denmark. Department of Clinical Research, University of Southern Denmark, Denmark. Department of Orthopaedic Surgery and Traumatology, Copenhagen University Hospital, Bispebjerg. Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen; B. Mussmann Department of Clinical Research, University of Southern Denmark, Denmark. Department of Radiology, Odense University Hospital, Denmark Faculty of Health Sciences, Oslo Metropolitan University, Norway; E. Poulsen Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Denmark; AH. Larsen Department of Orthopaedic Surgery and Traumatology, Odense University Hospital, Denmark. Department of Clinical Research, University of Southern Denmark, Denmark;

Background: Patients with symptomatic acetabular retroversion is reported having reduced functional ability and quality of life but little is known about the effect of non-surgical interventions.
Aim: To investigate feasibility and change in patient-reported symptoms of a home-based exercise intervention in patients with acetabular retroversion and excessive anterior pelvic tilt, in comparison with a prior control period.
Materials and Methods: Patients with symptomatic acetabular retroversion and excessive anterior pelvic tilt were included. Following an 8-week control period, patients were instructed to follow an 8-week targeted (3 times/week) progressive home-based exercise intervention. Feasibility assessment included; dropout, acceptable adherence (=75% of sessions), exercise-related pain, and adverse events. Primary outcome was change in the Copenhagen Hip and Groin Outcome Score (HAGOS) pain subscale. Secondary outcomes included change in the remaining HAGOS subscales, EQ-5D- 3L questionnaire, and pelvic tilt measured by EOS® scanning.
Results: Forty-two patients (39 women) (median [interquartile range (IQR)], 20.5 [19 - 25 years]) were included. Three patients were lost to follow-up (one regretting participating during the control period, one during the intervention period and one patient was lost at follow-up). Adherence to exercise sessions was 85%. Exercise- related pain and adverse events were acceptable. Between-period mean change score for the HAGOS-PAIN subscale was 5.2 points (95% confidence interval [CI]: [-0.3 – 10.6] and -1.6 degree [-3.9 – 0.7]) of anterior pelvic tilt. Additionally, patients who responded positively (= minimal clinically important difference) to the exercise intervention (n = 10, 26%), all had a pre- exercise HAGOS-PAIN score between 47.5 to 70 points.
Interpretation / Conclusion: Current exercise intervention was feasible. However, no clinical relevant changes in self- reported hip-related pain, function, quality of life, nor anterior pelvic tilt were found. Post- hoc responder analysis revealed that patients with moderate pain at baseline might benefit from current exercise.

Martin Bækgaard Stisen, Andre Nis Klenø, Julie Sandell Jacobsen, Matthew DL O’Connell, Salma Ayis, Catherine Sackley, Alma Becic Pedersen, Inger Mechlenburg
Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus N Department of Orthopaedic Surgery, Aarhus University Hospital, Denmark Research Centre for Health and Welfare Technology, Programme for Rehabilitation, VIA University College, Aarhus Research Unit for General Practice in Aarhus, Aarhus Department of Population Health Sciences, School of Population Health and Environmental Sciences, Kings College London, London, UK Department of Clinical Medicine, Aarhus University, Denmark.

Background: Total hip replacement (THR) is commonly performed on patients with severe hip osteoarthritis (OA). Clinically meaningful improvements on pain and function have been reported for primary THR, while there is little evidence on improvement after revision THR. Moreover, outcomes such as pain and function after THR may be associated with socioeconomic status (SES).
Aim: We investigated if changes in Harris Hip Score (HHS) differ among patients undergoing primary and revision THR, and their association with SES.
Materials and Methods: A population-based cohort study was conducted on 16,932 patients undergoing primary and/or revision THR from 1995-2018 due to hip OA. The patients were identified in the Danish Hip Arthroplasty Registry. Outcome was defined as mean change in HHS (0-100) from baseline to 1-year follow-up, and its association with SES markers (education, cohabiting and wealth) was analyzed using multiple linear regression adjusting for sex, age, comorbidities and baseline HHS.
Results: Over 1-year follow-up, mean change in HHS increased for both patients undergoing primary THR: 42.9 (95% CI 42.6;43.1) and revision THR: 30.8 (95% CI 28.7;32.8), (P < 0.001). For primary THR, SES markers higher education, cohabiting and higher wealth were associated with significantly greater improvement in HHS compared to lower education, living alone and lower wealth.
Interpretation / Conclusion: Patients undergoing primary and/or revision THR can expect clinically important improvement on HHS 1 year after surgery. However, higher improvement can be expected after primary THR, and the improvements are negatively related to low SES, which may help directing rehabilitation resources to the patients with the highest need.

Nina M. Edwards, Claus Varnum, Søren Overgaard, Alma B. Pedersen
Department of Clinical Epidemiology, Aarhus University Hospital, Denmark; Department of Orthopaedic Surgery, Lillebaelt Hospital - Vejle, Denmark, and Department of Regional Health Research, University of Southern Denmark, Denmark; Danish Hip Arthroplasty Register; Department of Orthopaedic Surgery and Traumatology, Copenhagen University Hospital, Bispebjerg, University of Copenhagen, Denmark, and Department of Clinical Medicine, Faculty of Health and Medical Sciences, Denmark

Background: Socioeconomic inequality in health is increasingly recognized as an important public health issue. Low socioeconomic status (SES) correlates with negative outcome after total hip arthroplasty (THA). However, only few studies have investigated the impact of SES on revision risk and mortality.
Aim: To examine whether SES is associated with revision and mortality rates after THA within 90 and 365 days.
Materials and Methods: We obtained individual-based information on SES markers (cohabitation, education, income, and liquid assets) on 103,901 THA patients from Danish health registers (year 1995-2017). The outcome was revision (any revision or due to infection, fracture, or dislocation) and mortality. We calculated the cumulative incidence with 95% confidence intervals (CI) treating death as competing risk. Cox regression analysis was used to estimate adjusted hazard ratio (aHR) of each outcome with 95% confidence interval for each SES marker.
Results: The cumulative incidence of any revision at 1 year was highest among patients who lived alone (2.2% (CI 2.1-2.4)), had the highest education (2.1% (CI 1.9-2.9)), had the highest income (2.1% (CI 2.0-2.3)), and had the lowest liquid assets (2.3% (CI 2.1-2.4)). Within 90 days, the aHR for any revision was 1.3 (CI 1.1-1.4) for patients living alone vs cohabiting; 2.0 (CI 1.4-2.6) for low income vs high income among patients <65 years, and 1.2 (CI 0.9-1.7) for low liquid assets among patients >65 years. Education was not associated with 90-days revision rate. The same trends were seen within 365 days. Living alone and the low SES markers were all associated with increased mortality rate within both 90 and 365 days.
Interpretation / Conclusion: We showed that living alone, low income, and low liquid assets were associated with increased revision and mortality up to 365 days after THA surgery indicating substantial socioeconomic inequality. By knowing these risk factors, we may focus on how we can prevent complications in patients with low SES. This may be by offering better rehabilitation to patients living alone, thereby securing a better minimal level of function, improving their outcome and minimizing inequality in this respect.

Casper Bindzus Foldager, Kjeld Søballe, Jakobsen Stig Storgaard
Department of Orthopaedics, Aarhus University Hospital

Background: Periacetabular osteotomy (PAO) is a well- established surgical treatment of symptomatic developmental dysplasia of the hip (DDH) in young patients by normalizing the lateral center edge angle (LCEA) and acetabular index (AI). Hence, the correction of the acetabular fragment is a hallmark of the PAO procedure.
Aim: To evaluate the efficacy of common practice using fluoroscopy-guided visual estimation of the correction of the fragment during PAO.
Materials and Methods: Forty-nine consecutive patients undergoing PAO due to symptomatic DDH was enrolled. Following the surgical correction of the acetabular fragment the surgeon was asked to visually assess the postoperative lateral center-edge angle (LCEA) and acetabular index (AI). At the follow-up 6-8 weeks postoperative standing x-rays were obtained. Perioperative assessments of LCEA and AI were compared with perioperative and postoperative measurements obtained by three PAO surgeons. Interobserver variation was assessed by regression analysis and Bland- Altman analysis was determine correlation between visual assessment and measurements. A clinical relevant difference (CRD) of 5 degrees was selected a priori.
Results: Mean correction of the LCEA was 11.1 degrees (-4 to 23.5) and the average AI correction was -10.7 degrees (-20 to -4). The interobserver agreement was high for LCEA (r2=0.83) and acceptable for AI (r2=0.60). Visual estimation significantly overestimated the correction of the LCEA angle by 1.5 degrees (95%CI 1.0:1.9) and significantly overestimated AI by 0.31degrees (95%CI 0.22;0.39) compared with postoperative result. Retrospective measurements on the perioperative x-rays showed that this would have led to a significant underestimation of the correction of LCEA of 1.4 degrees (95%CI 1.0:1.9) and overestimation of AI by 2.7 degrees (95%CI 1.9;3.5). This bias was below the CRD threshold. LCEA each using perioperative measurement rather than visual estimation would lower the number of patients outside the CDR from 22 patients (45%) and 16 patients (33%). For AI a shift from under- to overestimation was observed.
Interpretation / Conclusion: Perioperative visual estimation is not sufficiently effective for assessing the postoperative outcome of LCEA and AI in PAO.

Mathias Høgsholt, Stian Langgård Jørgensen, Nanna Rolving, Inger Mechlenburg, Lisa Cecilie Urup Reimer, Marie Bagger Bohn
Stud. Scient. San, Aarhus University, Aarhus, Denmark; Department of Occupational and Physical Therapy, Horsens Regional Hospital, Horsens, Denmark; H-HIP, Horsens Regional Hospital, Horsens, Denmark; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; Center of Rehabilitation Research, DEFACTUM, Central Denmark Region, Aarhus, Denmark; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; Department of Orthopedics, Aarhus University Hospital, Aarhus, Denmark; Department of Orthopedics, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; Department of Orthopedic Surgery, H-Hip, Horsens Regional Hospital, Horsens, Denmark

Background: To date, there exists no gold standard conservative treatment for lateral hip pain due to tendinopathy of the gluteus medius and/or minimus tendon (GMT), a condition often complicated by pain and disability. Higher loads during everyday activities and exercise seems to be contraindicated with GMT.
Aim: To evaluate the feasibility of resistance training with low-loads concurrent partial blood flow restriction (BFR) and patient education.
Materials and Methods: Patients were recruited from three hospitals in the Central Denmark Region. The intervention consisted of four sessions/week for 8 weeks with one weekly supervised session. From week three patients exercised with applied partial BFR by means of a pneumatic cuff around the proximal thigh of the affected leg. Baseline and 8 weeks follow-up (8FU) testing included maximal voluntary isometric contraction of hip abduction (MVC), 30-second chair stand test (30-s CST), and patient reported outcome measures (The Victorian Institute of Sport Assessment-Gluteal Questionnaire (VISA-G), EuroQol -Visual Analogue Scale (EQ-VAS) and pain Numerical Rating Scale (NRS 0-10)). At 8FU Global Rating of Change (GROC) was collected.
Results: 16 women with a median (IQR) age of 49 (44-60) years were included. Mean Body Mass Index 27.3±3.8 kg/m2. Adherence to the total number of trainingsessions and the BFR-exercise was 96.4% and 94.4%. Two patients dropped out due to i) illness before initiation of BFR-exercise and ii) pain in the affected leg related to the BFR-exercise. From baseline to FU8 mean pain decreased from 5.5 to 2.7 NRS (p>0.001). 30-s CST improved from 14.9 to 20 repetitions (p>0.001). EQ-VAS and VISA-G improved from 70.1 to 80.4 (p=0.02) and 55.2 to 65.9 (p=0.11). MVC of the affected leg increased by 0.21(95% CI 0.10;0.32) Nm/kg. MVC of the unaffected leg increased by 0.11 (95%CI -0.01;0.24) Nm/kg. At FU8 the success rate of GROC (”moderately better” to ”very much better”) was 66.67%.
Interpretation / Conclusion: BFR-exercise seems to be a feasible treatment for GMT. At FU8, patients reported clinically relevant reduction in pain, increased quality of life and high global improvement rating. Improvements of both MVC and 30-s CST implies improved strength and function.

Marie Bagger Bohn, Bent Lund, Kasper Spoorendonk, Jeppe Lange
Department of Orthopedic Surgery, Horsens Regional Hospital; Department of Orthopedic Surgery , Horsens Regional Hospital; Department of Physio and Occupational Therapy, Horsens Regional Hospital; Department of Orthopedic Surgery, Horsens Regional Hospital

Background: Lateral hip pain (LHP) due to tendon pathologies of M. gluteus medius and minimus’ insertion at the greater trochanter are often misdiagnosed and may lead to unrecognized disability. To what degree this disability subjectively affects the patient has not yet been clearly elucidated.
Aim: The aim of this study was to evaluate pain and patient reported outcomes in patients presenting with LHP in the context of a public financed health care system.
Materials and Methods: Data were collected from September 2017- November 2020 at a regional teaching hospital. Inclusion criteria were clinical and MRI verified hip abductor tendon pathology. Baseline testing included pain scoring (NRS) and patient reported outcome scores: Copenhagen Hip and groin outcome score (HAGOS), Oxford hip score (OHS)) and EuroQol-Visual Analogue Scale (EQ-VAS).
Results: In the study period, 151 patients (94% women) with a median age of 55 years were included. LHP (NRS, 0-10) at rest, during activity and worst pain at any given time was 4, 7 and 9, respectively. Mean patient reported outcome scores were HAGOS: Pain 42.9, Symptoms 49.8, ADL 42.2, Sport/Rec 28.1, PA 25, QOL 27.8; OHS: 24; EQ-VAS: 59.6.
Interpretation / Conclusion: We found that patients with hip abductor tendon pathology displays poor patient reported outcomes, which are comparable to patients suffering from severe hip Osteoarthritis. There is a need for further research into this patient group. The results are based on a heterogeneous study population in terms of variety of hip abductor tendon pathology and co- morbidities and needs to be interpreted as such.

Lisa Reimer, Signe Kierkegaard, Inger Mechlenburg, Julie Jacobsen
Department of Orthopaedic Surgery, Aarhus University Hospital Department of Clinical Medicine, Aarhus University

Background: Femoroacetabular impingement syndrome (FAIS) and acetabular hip dysplasia (HD) are common hip diseases. The literature describes patients with FAIS as athletic males, while patients with HD have been described as primarily non-athletic females.
Aim: The aim was to compare accelerometer-based physical activity (PA) behaviours between patients with Femoroacetabular impingement syndrome (FAIS) and patients with acetabular hip dysplasia (HD), and to compare PA of patients with healthy volunteers. Furthermore, to compare self-reported sporting function between patients with FAIS and patients with HD.
Materials and Methods: In this cross-sectional study, combining data from previously studies involving patients with FAIS or HD, PA was measured with accelerometer-based sensors and sporting function was measured with the Copenhagen Hip and Groin Outcome Score. Data on patients with FAIS or HD and healthy volunteers was collected in other studies and merged for comparison in this study.
Results: Fifty-five patients with FAIS (36% males), 97 patients with HD (15% males) and 60 healthy volunteers (40% males) were included. Patients with FAIS spent 4% point more time on very low intensity activities and 1% point less time on moderate intensity activities compared with patients with HD, while self-reported sporting function did not differ between the two groups. Both groups spent 2% point less time on high intensity activities per day than healthy volunteers.
Interpretation / Conclusion: Patients with FAIS had lower level of PA than patients with HD. Since both groups spent less time on high intensity activities than healthy volunteers, the majority of these patients may be described as non-athletic.

Kathrine Rasch, Claus Østergaard, Lasse Enkebølle Rasmussen, Per Kjærsgaard-Andersen, Jens Kjølseth Møller, Claus Varnum
Department of Orthopaedics, Sygehus Lillebælt Kolding; Department of Microbiology, Syghus Lillebælt Vejle; Department of Orthopaedics, Syghus Lillebælt Vejle; Department of Orthopaedics, Syghus Lillebælt Vejle; Department of Microbiology, Syghus Lillebælt Vejle; Department of Orthopaedics, Syghus Lillebælt Vejle

Background: Prosthetic joint infection (PJI) is a severe complication in total hip and knee arthroplasty with great consequences. S. aureus is the most common pathogen within PJI. The most important independent risk factor for PJI is nasal colonization with S. aureus. Nasal colonization represents both a risk for the colonized individuals and their immediate contacts.
Aim: To identify the sub-types of S. aureus colonizing the individual surgeons and examine if the carrier state and sub-type changes over a period of one year and secondly to examine if the isolates of S. aureus from PJI is the same as carried by the surgeon performing the surgery.
Materials and Methods: This prospective study included all 11 surgeons employed at Section for Hip and Knee Replacement, Lillebaelt Hospital Vejle. All have been tested from the nares every 2nd week from December 1, 2017 to November 30, 2018. Patients operated in the same period were followed one year to register if they have undergone revision surgery due to PJI. At the end of the study period all isolates of S. aureus have undergone typing by matrix- assisted laser desorption ionization time-of- flight mass spectrometry (MALDI-TOF MS). Isolates identified from PJI were compared to the most recent isolates obtained from the surgeon around the time of the surgery.
Results: During the study period, the mean number of tests obtained from each was 20 (range 17- 25). 4 surgeons were chronic carriers, 5 intermediate and 2 were non-carriers of S. aureus. All 9 either chronic- or intermediate- carriers had different sub-types. Out of 1,670 primary hip or knee arthroplasties, 10 patients had revision due to PJI. 9 was infected with S. aureus and only 1 with S. epidermidis. The 10 PJIs were distributed between 6 surgeons. One surgeon had 3 infected patients, 2 had 2, the remaining 3 only 1. None of the S. aureus sub-types found in the surgeons were the same as in the samples from the PJI.
Interpretation / Conclusion: The proportion of chronic- and intermediate- S. aureus carriers seems to be high among surgeons compared to the general population, but they all had different sub-types indicating that there was no endemic departmental strain. None of the sub-type found among the surgeons were isolated from the PJI.

Nikolaj Winther, Martin Kirkegaard, Erik Kragegaard, Anders Odgaard, Mørk Petersen Michael
Department of Orthopaedic Surgery, Rigshospitalet, Copenhagen, Denmark; Department of Orthopaedic Surgery , Rigshospitalet, Copenhagen, Denmark

Background: Increasing numbers of THA and TKA are performed with expanding applications in a younger and elderly population. Recurrent complicated aseptic and septic revisions and periprosthetic femoral fractures are growing in numbers resulting in extensive loss of femoral bone stock making it unable to support revision implants. For these complicated cases Total Femur Replacement (TFR) is an alternative to amputation.
Aim: To assess the functional outcomes and the complication associated with TFR used in revision arthroplasty.
Materials and Methods: We retrospectively reviewed 24 non-tumour cases that received a TFR for revision surgery: mean age 71 (40-85) years, F/M=13/11, mean follow-up 51 (12-180) months, mean number of previous revisions 3.8 (1-12), history of periprosthetic infection (n=11). The indications for TFR were severe femoral bone loss because of aseptic loosening (n=10), septic loosening (n=7), periprosthetic fracture (n=7) and osteomyelitis (n=1).
Results: Mean operating time was 271 (133-600) minutes and mean blood loss was 3417 (560-7300) ml. 9 patients had a well-fixed acetabulum component and 15 cases had acetabular cup revision. 11 hips received a constraint liner, 4 patients a dual mobility cup and 9 cases had non-constraint liners. The knee components were all rotating- hinged knee. None of the 11 cases with a constraint liner dislocated, 8 of 13 patients (62%%) without constraint liners dislocated. 12 patients had no additional procedures and 12 patients had additional surgical procedures with 6 patients revised for infection: 1 total exchange of the TFR and 5 treated with DAIR. No amputations were performed. 16 patients were on lifelong antibiotics, and at end of follow-up 4 patients had died of causes unrelated to surgery. We found good patient satisfaction and low pain scores with low activity level.
Interpretation / Conclusion: TFR for revision surgery in non-tumour cases resulted in limb salvage in all patients and with only 1 patient having total exchange of the TFR implant. However, minor revision for infection and hip dislocation was common occurrences and and high rates of infection should be expected.

Katrine Wade, Katrine Hvidt, Marianne Vestermark, Niels Krarup
Department of Orthopeadics, Viborg

Background: Total hip arthroplasty (THA) is used to treat osteoarthrosis in the hip as well as fractures of the femoral neck. Instability followed by dislocation is a common indication for THA revision surgery. A dual- mobility acetabular component (DMC) has been designed to address this issue and lower dislocation rates in THA. A major concern with the DMC is increased stress on the implant components and therefore, accelerated polyethylene (PE) wear. It has been proposed that the increased PE wear will lead to a shorter survival of the prosthetic components, but long-term follow-up studies on DMC THA have yet to be performed. Viborg Regional Hospital has since 2001 primarily used the dual mobility cup in THA for patients over the age of 70, presenting a unique possibility to study the long-term revision rate for the DMC.
Aim: The aim of the study is to investigate the revision rate of the dual mobility cup in total hip arthroplasty. Furthermore we wish to investigate if the indication for THA had any effect on survival of the prosthetic components.
Materials and Methods: A retrospective cohort study of all patients who received a primary THA with a DMC at Viborg Regional Hospital between 2001 and 2018 was conducted. Information regarding revision arthroplasty were obtained from the National Registry of Patients and the Danish Hip Register.
Results: We found the 10-year survival rate for the DMC in THA to be 91% (95% CI=7.43% to 10.90%). We found no significant difference in the 10-year revision rate between THA performed due to arthrosis and THA performed due to fractures. We did however, find a significant difference in 5 and 10 year survival for those two subgroups.
Interpretation / Conclusion: Our findings suggest that, when performing a primary THA, the DMC is level with the conventionally used liner regarding long-term component survival.

Marie Bagger Bohn, Claus Tvedsøe, Bent Lund, Jeppe Lange
H-HiP, Department of Orthopedic Surgery, Horsens Regional Hospital, 8700 Horsens, Denmark, Department of Clinical Medicine, Aarhus University, 8200 Aarhus N, Denmark; Diagnostic Center, Silkeborg Regional Hospital, 8600 Silkeborg, Denmark; H-HiP, Department of Orthopedic Surgery, Horsens Regional Hospital, 8700 Horsens, Denmark; H-HiP, Department of Orthopedic Surgery, Horsens Regional Hospital, 8700 Horsens, Denmark, Department of Clinical Medicine, Aarhus University, 8200 Aarhus N, Denmark

Background: Bursitis at the greater trochanter has historically been identified as a major pain generator in patients presenting with lateral hip pain (LHP), and the majority of established treatments have focused on treatment of this anatomic structure. Steroid injections has been the mainstay in conservative treatment, sometimes combined with various types of rehabilitation. In cases of refractory LHP, surgery on the Iliotibial band often combined with a bursectomy has been the gold standard. However, a recent retrospective study in 1.000, non-selected, hip magnetic resonance imaging (MRI) scans has highlighted the potentially low prevalence of trochanteric bursa, which questions the role of an inflamed trochanteric bursa as the origin of LHP.
Aim: To evaluate prospectively performed MRI in LHP patients with special attention to the presence of isolated trochanteric bursitis.
Materials and Methods: MRI scans of 120 patients (94% women, median age of 54 years (IQR: 48-64)) with LHP seen at a public outpatient orthopedic clinic between 2016- 2020 were independently evaluated by two raters. The presence of high-intensity signals in the trochanteric area, and the subjective interpretation of these high intensity signals were independently noted by each rater. Subsequently, a consensus agreement was made between the raters in cases of disagreement.
Results: Two patients (2%) had isolated greater trochanteric (GT) bursitis, 30 patients (25%) had to some degree elements of inflammation in the GT bursa but with concomitant pathological changes to the hip abductor tendons, and 5 patients (4%) had relevant pathological changes to the hip abductor tendons with bursitis in the sub-gluteus minimus bursa with no bursitis in the GT bursa. 24 patients (20%) had pathological changes to the hip abductor tendons without concomitant bursitis. The remaining patients did not have high-intensity signals in neither the bursa nor the hip abductor tendons.
Interpretation / Conclusion: Isolated bursitis in the trochanteric area in patients referred with LHP in an outpatient orthopedic clinic is infrequent, whereas pathologies in the hip abductor tendons are frequent, and this finding should guide future diagnostic and treatment choices.

Nikolaj winther, Jens Styrup, Sebastian Winther, Michael Mørk Petersen
Department of Orthopaedic Surgery, Rigshospitalet, Copenhagen, Denmark; Department of Orthopaedic Surgery , Rigshospitalet, Copenhagen, Denmark

Background: Revision of a failed total hip arthroplasty with massive acetabular bone loss and pelvic discontinuity is a reconstructive challenge. Treatment options includes morselized bone graft and structural allograft used with uncemented hemispherical acetabular components, cages, porous metal augments, and cup- cage reconstruction. A custom-made triflanged implant has recently been introduced as a new option of treatment.
Aim: The purpose of this study was to evaluate the use of a Custom made Triflanged Implant in cases with pelvic discontinuity. We monitored healing rate, migration and overall survivorship defined as revision of the implant for any reason.
Materials and Methods: We reviewed 40 consecutive patients, mean age 68.7 years (48-85) with a failed THA and pelvic discontinuity. Mean follow-up was 54 months (24-132). The implant for acetabular reconstruction was custom- manufactured on the basis of a three- dimensional model of the hemi-pelvis created from computed tomography (CT). The Harris Hip score was performed and the acetabular bone defects were all classified as type V according to the Gross classification. Center of rotation (COR) was calculated. Postoperative radiograph was analyzed in relation to: Healed or unhealed discontinuity and stable/unstable fixation.
Results: Mean Harris Hip score was 80 (47-96). Mean intraoperative blood loss was 1500 ml (235-6500) and mean surgery time was 147 min. (72-331). COR was established in 36 of the patients and no major intraoperative complications occurred. The discontinuity healed in 40 (95%) of the cases. Thirty-five patients (83%) had no additional procedures. Seven patients experienced dislocation (16%) five of these were treated with a constrained liner. We observed two septic loosening (5 %) revised in 2 stage procedures, and one re-infection (2%) treated with DAIR and life-long antibiotic. 40 (95%) of the implants was defined as stable with 100% survivorship for aseptic loosening.
Interpretation / Conclusion: The 3D costum made Triflanged Implant makes it possible to optimized screw and implant positioning with high accuracy and with rigid fit on bone fixation thus permitting healing of the discontinuity and biological fixation of the acetabular component.

Adam Omari, Christian Skovgaard Nielsen, Henrik Husted, Kristian Stahl Otte, Anders Troelsen, Kirill Gromov
University of Copenhagen, Faculty of Health and Medical Sciences, Blegdamsvej 3B, 2200 Copenhagen N, Denmark; Department of Orthopedic Surgery, Copenhagen University Hvidovre Hospital, Kettegård Alle 30, 2650 Hvidovre, Copenhagen, Denmark

Background: Increasing global usage of cementless prostheses in total hip arthroplasty (THA) surgery presents a challenge, especially for elderly patients. To reduce the risk of early periprosthetic femoral fractures (PFF), a new treatment algorithm for females >60 years undergoing primary THA was introduced.
Aim: The aim of this study was to determine the impact of the new treatment algorithm on the early risk of peri- and post-operative PFFs and guideline compliance.
Materials and Methods: A total of 2,405 consecutive THAs that underwent primary unilateral THA at out institution were retrospectively identified in the period January 1st 2013 to December 31st 2018. A new treatment algorithm was introduced on April 1st 2017 with female patients aged >60 years intended to receive cemented femoral components. Prior to this, all patients were scheduled to receive cementless femoral components. Demographic data, number of peri- and post-operative PFFs and surgical compliance were recorded, analyzed and intergroup differences compared.
Results: The utilization of cemented components in female patients >60 years increased from 12.3% (n=102) to 82.5% (n=264). In females >60 years a significant reduction in the risk in early post-operative and intra-operative PFF following introduction of the new treatment algorithm was seen; (4.57% vs 1.25%, p=0.007) and (2.29% vs. 0.31%, p=0.02), respectively. Overall risk for post-operative and intra-operative fractures combined was also reduced in the entire cohort (4.1% vs 2.0%, p=0.01).
Interpretation / Conclusion: Use of cemented fixation of the femoral component in female patients >60 years significantly reduces the number of PFF. Our findings support use of cemented femoral fixation in elderly female patients.

Sebastian winther, Naima Elsayed , Karen Dyreborg , Elinborg Mortensen, Michael Mørk Petersen, Nikolaj winther
Department of Orthopaedic Surgery, Rigshospitalet, Copenhagen, Denmark; Department of Orthopaedic Surgery , Rigshospitalet, Copenhagen, Denmark

Background: Revision total hip arthroplasty (rTHA) is a challenging procedure especially in the presence of severe bone loss where implant fixation is compromised. Tapered fluted stem and long cylindric stems provide the possibility to bypass the regions of proximally deficient bone and to obtain stability and fixation in the distal femoral bone.
Aim: the purpose of this study was to assess the performance and evaluate the midterm results after femoral revision with an uncemented modular implant design in a cohort with severe bone loss; 44% being classified as Saleh’s type lll-V bone defect.
Materials and Methods: We performed a retrospective review of 100 patients (101 hips) who underwent a (rTHA) using a fluted, tapered, or long cylindric modular femoral stem design. (Arcos Modular Revision Femoral System (ZimmerBiomet®, Warsaw, IN, USA). Mean follow-up was 5,8 (range 2,5 to 9,4.) years. Mean age 69,5 (range 24-91) years. Harris Hip Score (HHS), Oxford Hip Score (OHS) and EQ-5D were obtained. Radiographs were reviewed evaluating bone loss, osseointegration of the distal femoral stem, migration, and restoration of the proximal femur.
Results: The Indication for revision were infection (41%), aseptic loosening (37%) and periprosthetic fracture (11%). 5 hips required revision with removal of the femoral stem (5%). 3 patients had their stem removed because of infection, 1 was removed because of aseptic loosening, and 1 had early dislocation twisting the stem in retroversion. (was revised with a new long cylindric stem with distal screw fixation). During follow-up 10 patients experienced dislocation, 1 sustained periprosthetic fracture, and 1 had soft tissue revision. Of the 76 hips available for radiographic evaluation, 61 hips (80%) showed radiographic evidence of restoration of proximal femoral bone. Mean HHS was 78 points (range 41-100). The mean OHS results was 35 points (range 8-48). Mean EQ-5D VAS score was 70 (range 25-100).
Interpretation / Conclusion: Distal fixated modular femoral components have the potential to achieve long-term biological fixation, even in the presence of extensive bone loss with 95% survivorship at midterm follow-up.

Sally Oppendieck Andersen (1,2), Lasse Ishøi (1), Anke Ninija Karabanov (3), Jesper Bencke (2), Per Hölmich (1)
1) Sports Orthopedic Research Center – Copenhagen (SORC-C), Department of Orthopedic Surgery, Copenhagen University Hospital, Amager-Hvidovre, Denmark. 2) Human Movement Analysis Laboratory, Department of Orthopedic Surgery, Copenhagen University Hospital, Amager-Hvidovre, Denmark. 3) Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark.

Background: Hip dysplasia is characterized by a shallow and oblique acetabulum, potentially resulting in damage to intra-articular structures and early development of secondary osteoarthritis. Periacetabular osteotomy (PAO) is the standard joint articular structures and early development of secondary osteoarthritis. Periacetabular osteotomy (PAO) is the standard joint-preserving surgical treatment for young and middle preserving surgical treatment for young and middle-aged patients with symptomatic hip dysplasia. Despite improvements in patient-reported outcome measures (PROMs), the physical activity profile remains unchanged, and lack of functional capacity and abnormal biomechanics still persist following PAO. This may compromise the efficacy of PAO, and leave patients at risk of early conversion to total hip arthroplasty and development of life style related problems as cardiovascular disease.
Aim: The aim of this study was to investigate parameters of impaired physical capacity following PAO.
Materials and Methods: Eight patients (women, aged 27+/-2 years), with a body mass index of 23+/-1, treated with PAO for hip dysplasia within the last 2+/-1 years, were included. Physical capacity was investigated using PROMs, laboratory-based, and clinical measures, and the associations between these measures. Hip and groin function and pain was measured with The Copenhagen Hip and Groin Outcome Score (HAGOS). Laboratory based, and clinical measures, and the associations between these measures. Hip and groin function and pain was measured with The Copenhagen Hip and Groin Outcome Score (HAGOS). Laboratory-based and clinical measures were assessed by standardized 3D gait analysis and examination of hip and muscle-tendon-related pain using a standardized clinical entity approach. related pain using a standardized clinical entity approach.
Results: HAGOS scores were (mean (SD): pain=61 (5), symptoms=58 (3), ADL=68 (7), sport/rec=54 (7), PA=25 (10), QoL=42 (8)). The prevalence of positive flexion-adduction-internal rotation test and iliopsoas-related pain was 75% and 50%, respectively. The association between HAGOS pain and peak hip extension angle and peak hip flexor moment was r=0.71 (p=0.07) and r=0.02 (p=0.96), respectively.
Interpretation / Conclusion: Patients with hip dysplasia experience impaired physical capacity two years following PAO. Our preliminary results indicate a possible correlation between hip pain and biomechanical parameters, however this needs to be investigated further in a larger cohort.

Thomas Frydendal, Kristine Sloth Thomsen, Inger Mechlenburg, Lone Ramer Mikkelsen, Søren Overgaard, Kim Gordon Ingwersen, Corrie Myburgh
Department of Physiotherapy, Lillebaelt Hospital, Vejle Hospital, Vejle, Denmark, Department of Clinical Research, University of Southern Denmark, Odense, Denmark; Department of Physiotherapy, Lillebaelt Hospital, Vejle Hospital, Vejle, Denmark; Department of Orthopaedic Surgery, Aarhus University Hospital, Aarhus, Denmark, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark, Elective Surgery Centre, Silkeborg Regional Hospital, Silkeborg, Denmark; Department of Orthopaedic Surgery and Traumatology, Copenhagen University Hospital, Bispebjerg Hospital, Copenhagen, Denmark, Department of Clinical Medicine, Faculty of Health and Medical Sciences University of Copenhagen, Copenhagen, Denmark; Department of Physiotherapy, Lillebaelt Hospital, Vejle Hospital, Vejle, Denmark, Department of Regional Health Research, University of Southern Denmark, Odense, Denmark; Department of Sport Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark

Background: Total hip arthroplasty (THA) and exercise provide improved function and reduced pain for hip osteoarthritis. Current treatment selection is based on low evidence as no randomised controlled trials (RCTs) are available. Furthermore, low recruitment rates and intervention crossover are common in RCTs comparing surgery to exercise. Patient and public involvement (PPI) may improve trial design and implementation of research findings. Thus, a PPI protocol was embedded into the Progressive Resistance Training versus Total Hip Arthroplasty in Patients with End-stage Hip Osteoarthritis (PROHIP) trial.
Aim: To explore context-relevant key stakeholder input in order to optimise the design and execution of a planned comparative RCT.
Materials and Methods: Fourteen patients undergoing THA, two orthopaedic surgeons and two physiotherapists, and four political stakeholders were recruited. Six focus group interviews were conducted according to group status using semi-structured interview guides. Interviews were recorded, transcribed verbatim and thematic analysed.
Results: Three key themes emerged: (1) ‘Patient recovery expectations‘, (2) ‘The influence of professional authority’, and (3) ‘Inconsistent health care provider communication‘. Theme 1 suggested that patients experienced their hip problem as disabling and considered recovery without THA unlikely. However, after THA, expectations for a quick return to activities of daily living were high. Theme 2 highlighted that both surgeons and physiotherapists claimed expert knowledge and clashed regarding explanatory and management frameworks. Therefore, patients may feel pressured into choosing between THA or exercise. Finally, theme 3 indicated that health care providers tended to use a management narrative best suited to their preferred intervention. Therefore, patients risk being medicalised differently.
Interpretation / Conclusion: Patients, orthopaedic surgeons and physiotherapists may introduce systematic bias into the PROHIP trial. Methodological considerations to improve trial design may include development of a neutral patient information narrative delivered by an independent health care provider group during enrolment and a prospective cohort study investigating the external validity.

Troels Kjeldsen, Inger Mechlenburg, Lisa Cecilie Urup Reimer, Thomas Frydendal, Ulrik Dalgas
Department of Orthopaedic Surgery, Aarhus University Hospital; Department of Clinical Medicine, Aarhus University; Department of Clinical Research, University of Southern Denmark; Department of Physiotherapy, Lillebaelt Hospital–University Hospital of Southern Denmark, Vejle Hospital; Exercise Biology, Department of Public Health, Aarhus University; The Research Unit PROgrez, Department of Physiotherapy and Occupational Therapy, Næstved-Slagelse-Ringsted Hospitals.

Background: Exercise may be a preventive, disease-modifying, or alleviating treatment at different stages of hip osteoarthritis (OA); pre-clinical, mild-moderate hip OA, severe hip OA and after hip arthroplasty (THA).
Aim: To summarize the effects of exercise as primary, secondary and tertiary prevention at different stages of hip OA and in patients undergoing THA.
Materials and Methods: In a narrative review, we summarized the evidence investigating exercise as a risk factor in the development of hip OA (primary prevention). Then, we summarized secondary and tertiary preventive effects of exercise in patients having mild-moderate or severe hip OA. Finally, we evaluated the effects of exercise after THA (tertiary prevention).
Results: High exposure to exercise and sports injuries may increase the risk of developing hip OA, while moderate levels of exercise oppositely may decrease the risk of developing hip OA. In mild to moderate hip OA, exercise can reduce pain and improve function, while sparse evidence suggest no effect on quality of life. In patients with severe hip OA, exercise may improve function and muscle strength, and reduce pain when assessed before and/or shortly after THA, whereas the effects seem to cease at long-term follow-up postoperatively. We found no results indicating that exercise has a secondary preventive effect on hip OA. Postoperative exercise initiated within one year after THA show improved functional capacity and muscle strength, while having little effect on patient-reported function and quality of life.
Interpretation / Conclusion: Being moderately physically active and maintaining muscle strength is primary prevention of hip OA. Furthermore, exercise may offer tertiary prevention in mild-moderate and severe OA, as well as in patients undergoing THA. There is no data on exercise as secondary prevention of hip OA.

Mikkel Rathsach Andersen, Mathias Willadsen Brejnebøl, Michael Skettrup
Department of Orthopeadics, Gentofte Hospital; Department of Radiology, Herlev Hospital; Department of Orthopeadics, Gentofte Hospital

Background: Preoerative assesment of the degree and location of bone defects of the actabulum and proksimal femur is essential to planing succesfull revision surgery. When based on traditional x- rays and CT-scans exact classification of acetabular bone loss is diffucult. When planning acetabular revision using a customized component a 3D-boneprint is often provided by the manufactorer, however, this isan expensive solution and often not provided when planing operation using standard revision cups and augmentation. In our institution 3D prints are now provided by the radiologic department.
Aim: To improve preoerative assesment of the degree and location of bone defects of the actabulum and proksimal femur and reduce the cost in doing so.
Materials and Methods: We present examples of clinical cases and the cost reducing method of in house bone printitng. As a result of a collaboration between department of radiology, the ortopaedic surgeon can now request a 3d-print bone model based on the CT generated 3D images. The bone models are printed at the department of radiology and sent to the surgeon as an in the fascillity service.
Results: The bone prints are used as 1:1 sized sketch works for implanting revision cups and augments to ensure these will achieve sufficient fixation prior to surgery. If the surgeon estimates that a customized component is required the patient is referred to a highly specialized center for revision surgery.
Interpretation / Conclusion: 3D-print bonemodels for preoperative planning in patients with acetabular and femur bone defects, holds the perspective of improving the outcome for a challenging group of patients. When provided by Ortopedic companies 3D-prints come at a high price, however in our institution 3D-prints are now available provided by the radiologic department, at a lower cost. The socio-economic perspectspive could be advantages as some pateints who might otherwise be planned for surgery with an expensive customized component, might be assessed suitable for surgery with a less expensive revision component. Also a thorough preoperative planning using bonemodels, could potentially reduce the need for later revisions having made the right choise in components the first time.

Müjgan Yilmaz, Christina Holm, Thomas Lind, Gunnar Flivik, Michael Mørk Petersen
Department of Orthopedic surgery, University Hospital of Copenhagen Rigshospitalet 2100 Copenhagen, Denmark Department of Orthopedic surgery University Hospital of Copenhagen Herlev Gentofte Hospital 2900 Hellerup, Denmark Department of Orthopedics Skane University Hospital Clinical Sciences, Lund University 222 42 Lund, Sweden Department of Clinical Medicine Faculty of Health and Medical Sciences University of Copenhagen, Denmark

Background: Aseptic loosening is one of the major reasons for late revisions in Total Knee Arthroplasty (TKA), this risk can be detected with Radiostereometric Analysis (RSA) where micromovements (migration) can be measured and therefore recommended in the phased introduction of orthopedic implants. A decrease in Bone Mineral Density (BMD), measured with Dual-energy X-ray Absorptiometry (DXA), is related to the breaking strength of the bone and measured concurrently with RSA.
Aim: Aim: Evaluate implant migration and bone remodeling of cemented asymmetrical tibial and uncemented femoral TKA components with a follow-up period of 2-years.
Materials and Methods: A prospective longitudinal cohort of 29 patients (F/M=17/12, mean age 65.2 years), received a hybrid Persona? TKA (Zimmer Biomet, Warszawa, Indiana) consisting of a cemented tibial, an all-polyethylene patella and uncemented trabecular metal femoral components. Follow-up: preoperative, one week, 3, 6, 12 and 24 months after surgery, and double examinations for RSA and DXA were performed at 12 months. RSA results were presented as Maximal Total Point of Motion (MTPM) and segmental motion (translation and rotation), whereas DXA results were presented as changes in BMD in different Regions of Interest (ROI).
Results: MTPM at 3, 6, 12 and 24 months were 0.65 mm, 0.84 mm, 0.92 mm and 0.96 mm for the femoral component and 0.54 mm, 0.60 mm, 0.64 mm and 0.68 mm, respectively for the tibial component. The highest MTPM occurred within the first 3 months. Afterwards, most of the curves flatten and stabilize. The proportion of femoral components with migration greater than 0.10 mm between 12-24 months were 16% and the proportion of tibial components with migration greater than 0.2 mm between 12- 24 months were 15%. BMD distal femur: ROI I 26.7%, ROI II 9.2% and ROI III 3.3%. BMD proximal tibia: ROI I 8.2%, ROI II 8.6% and ROI III 7.0% after 2- years.
Interpretation / Conclusion: Migration patterns and changes in BMD for femoral component correspond well with previous studies and marginally higher migrations results are observed with the tibial component.

Anders Bagge, Christian Bredgaard Jensen, Mette Mikkelsen, Kirill Gromov, Christian Skovgaard Nielsen, Anders Troelsen
Dept. of Orthopedic Surgery, Clinical Orthopedic Research Hvidovre (CORH), Copenhagen University Hospital Hvidovre

Background: The global prevalence of obesity is increasing, and unicompartmental knee arthroplasty (UKA) accounts for an increasing proportion of primary knee arthroplasties. Contemporary indications suggest that obesity is not a contraindication to UKA, but some surgeons may still be reluctant to perform surgery on obese patients.
Aim: This study examines the effect of obesity on Patient Reported Outcome Measures (PROMs), complication and readmission rates after UKA surgery.
Materials and Methods: UKAs performed at Hvidovre Hospital, Denmark from April 2016 to December 2020 were divided into three groups based on body mass index (BMI): BMI <30 (ref.), BMI 30-34.9, BMI >34.9. Oxford Knee Score (OKS), Forgotten Joint Score (FJS) and Activity and Participation Questionnaire (APQ) were assessed pre- operatively and at 3, 12 and 24 months after surgery. Student’s t-test and linear regression models adjusted for sex and age were used to compare mean PROM scores and score improvements respectively. Readmissions and complications within 90 days of surgery were compared using chi-square test.
Results: 492 UKAs with a mean BMI of 30.1 (SD 5.8) were included. From pre-op to 3, 12 and 24 months, no significant differences in adjusted OKS and FJS improvements were present between BMI groups, however, mean pre-operative OKS was lower for both BMI 30-34.9 (22.7, p<0.01) and BMI >34.9 (19.5, p<0.01) compared with BMI <30 (25.2). BMI >34.9 also had lower pre-op FJS and APQ. After 12 months, obese patients’ adjusted APQ improvement remained lower compared with non- obese; -9.5 (CI -18; -1) for BMI 30-34.9 (p=0.036) and -10.8 (CI -21; -0.2) for BMI >34.9 (p=0.047). After 24 months, the differences in mean APQ scores and score improvements were non-significant. There was no difference in 90-day readmission and complication rates between BMI groups.
Interpretation / Conclusion: Although their pre-operative scores are lower, obese patients can expect PROM improvements within 2 years of UKA surgery that do not differ from those seen in non-obese patients. This supports contemporary evidence-based indications for UKA and should be used in the shared-decision making process when addressing expectations after surgery in obese patients.

Nissa Khan, Kim Lyngby Mikkelsen, Michael Mørk Petersen, Henrik Morville Schrøder
Department of Orthopaedic Surgery, Holbæk Hospital; The Danish Patient Compensation Association, Copenhagen; Department of Orthopaedic Surgery, Rigshospitalet; Department of Orthopaedic Surgery, Næstved Hospital

Background: In Denmark, 99,507 primary total knee arthroplasties (TKA) were performed between 2005-2017. Although TKA surgeries have a high success rate for providing substantial health gains in quality of life, complications, failed surgeries, and patient dissatisfaction are unavoidable. As we’ve shown in a previous study, 2.6% of all primary total hip arthroplasties in Denmark resulted in a compensation claim reported to Danish Patient Compensation Association (DPCA), and half of these were approved.
Aim: We examined the Danish Patient Compensation Association (DPCA) database to outline the frequency and financial burden of compensation claims after primary TKA in Denmark.
Materials and Methods: This was a retrospective study of closed compensation claims following TKA reported to DPCA between 1st of January 2005 and 31st of December 2017. The primary cause for claim was included.
Results: There were 1,611 primary TKA claims out of 29,370 orthopaedic cases reported (5.5%). This accounts for 2% of all TKAs performed in this period. The approval rate was 42%. The number of claims filed was gradually increasing with a peak in 2012, followed by a decrease. The total payout was DKK 145,269,621. The highest payouts were for infection (DKK 59,011,085), insufficient or incorrect treatment (DKK 32,371,468), nerve damage (DKK 19,831,988), and incorrect indication (DKK 9,069,492). Collectively, these four complications accounted for 83% of the total amount of payouts. Claims most likely to be filed were due to insufficient or incorrect treatment (29%), infection (23%), dissatisfaction with correct treatment (17%), and nerve damage (7%). However, those likely to result in payout were incorrect prosthesis or equipment, and infection, both with a payout acceptance-rate of 14%, respectively.
Interpretation / Conclusion: 2% of all primary TKAs resulted in a compensation claim reported to DPCA with a 42% approval-rate. The majority of payouts were due to infection, insufficient or incorrect treatment, nerve damage, and incorrect indication. Although DPCA manages claims for patients, the data can also provide beneficial feedback to arthroplasty surgeons with the aim of improving patient care.

Lasse Harris, Lina Ingelsrud, Kirill Gromov, Christian Nielsen, Thue Ørsnes, Anders Troelsen
Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre, Copenhagen Denmark

Background: Worldwide, the coronavirus outbreak causes postponement of elective surgery. For patients with end-stage osteoarthritis awaiting knee or hip arthroplasty, uncertainty remain whether the treatment effect will be the same, or if the postponed surgery has led to deterioration in pain, function and general health.
Aim: To evaluate the impact of postponing elective knee and hip arthroplasty, due to the pandemic, on pre- operative pain, function and general health in patients with end-stage osteoarthritis.
Materials and Methods: A prospective cohort study of 194 patients from one Danish public hospital with postponed elective primary knee or hip arthroplasty due to the nationwide lockdown from March 2020. Patients responded to questionnaires when surgery was cancelled and again before surgery, if re-scheduled within December 1, 2020. Changes in pain and function were evaluated with the Oxford Knee and Hip Scores (OKS, OHS) and general health with the EuroQol 5- dimension scale (EQ5D). Additionally, we asked about patients’ concerns and whether they felt improved, unchanged or deteriorated during the wait-period.
Results: Complete data were obtained for 110 (57%) patients, 59 awaiting knee arthroplasty (median age 70, 58% female) and 51 awaiting hip arthroplasty (median age 72, 67% female). Knee and hip arthroplasty were postponed for median (range) 111 (29-244) and 83 (35-216) days, respectively. 34% were concerned the postponement would lead to poorer outcome. Mean differences in OKS and OHS were 0 (95% Confidence interval (95% CI) -1 – 1) and -1 (95% CI -2 – 0) from surgery cancellation to re-scheduled surgery. Mean difference in EQ5D index was 0.0 (95% CI 0.0 - 0.1) for both groups. 75 (68%) patients felt importantly deteriorated.
Interpretation / Conclusion: Pre-operatively, patients worry about altered treatment outcome due to postponed surgery and feel deteriorated during the wait-period although not reflected in patient-reported outcome measures.

Liselotte Hansen, Rasmus Elsoe, Peter Larsen
Liselotte Hansen and Rasmus Elsoe Department of Orthopedic Surgery, Aalborg University Hospital, Denmark   Peter Larsen Department of Occupational Therapy and Physiotherapy, Aalborg University Hospital, Aalborg, Denmark.

Background: Surgical treatment with open reduction and internal fixation (ORIF) is the primary choice of treatment for displaced tibial plateau fracture (TPF). Most of the patients report a satisfying outcome at long term follow-up. Some patients develop knee pain, valgus misalignment and post-traumatic osteoarthritis. Early treatment with a total knee replacement (TKR) is a widely accepted treatment option for severe knee complications after ORIF. However, only limited information regarding specific characteristics of patients at high-risk of developing posttraumatic osteoarthritis and early conversion to TKR is available.
Aim: The aim of this study was to compare basic characteristics of patients requiring early treatment with TKR and patients not requiring TKR within 3 years following a lateral tibial plateau fracture.
Materials and Methods: The study design was a comparative cohort study with a 3-year follow-up from the primary fracture. From December 2013 to November 2016, 56 patients were diagnosed and surgically treated for a lateral TPF at Aalborg University Hospital. Characteristics regarding the patients’ age, gender, BMI, trauma mechanism, co-morbidity, Charlson index, smoking status, alcohol consumption, medicine and number of days from primary surgery to TKR were obtained from the patient's medical chart and from an interview. Fracture classification was performed according to the AO- classification on preoperatively obtained CT- scans and soft tissue injuries were identified by MR-scans. Prior to TKR, all patients were evaluated by x-ray of the knee and valgus malalignment and osteoarthritis were measured.
Results: Five of the 56 patients were operatively treated with a TKR no longer than 3 years from the primary surgery. Median age 61 years, 80% females, median BMI 29.9 kg/m2, 4 patient had osteoporosis or osteopenia. Four of the patients presented with an AO-type 41-B1, 1 patient a 41-B3 and all the patients had soft tissue injuries in the knee.
Interpretation / Conclusion: Being female in gender, severe co- morbidity, obesity, osteopenia, fracture type AO 41-B1 and soft tissue injuries were associated to early total knee replacement following surgically-treated lateral tibial plateau fractures.

Yasemin Corap, Michael Brix, Claus Emmeluth, Martin Lindberg-Larsen
Orthopaedic research unit, Department of Orthopaedic Surgery and Traumatology, Odense University Hospital, Department of Clinical Research, University of Southern Denmark

Background: Distal femoral resection knee arthroplasty may be a viable option for several indications other than bone tumors. Resection knee arthroplasty appears to be becoming more common, but patients requiring this type of surgery are often elderly and with high comorbidity.
Aim: The aim of this study was to report in-hospital complications, readmissions, reoperations, and mortality after distal femoral resection knee arthroplasty for non-tumor indications.
Materials and Methods: We retrospectively identified a consecutive cohort of 41 knees (41 patients) treated with distal femoral resection knee arthroplasty in a single institution between 2012 and 2020. Indications for surgery were failure of osteosynthesis (8), primary fracture treatment (2), periprosthetic fracture (20), and revision arthroplasty with severe bone loss (11). A major reoperation was defined as a major component exchange procedure or amputation. Mean follow-up was 3.7 years.
Results: The mean age was 71.3 years (SD 12.6), and 68.3% were female; 9.8% were ASA I, 43.9% ASA II, and 46.3% ASA III. Median length of stay was 6 days (range 3-15) with no major in- hospital complications, but 24.2% required blood transfusion. The 90-day readmission rate was 19.5% (n=8), of which 50% was prosthesis- related. Four patients (9.8%) underwent major reoperation due to infection (n=2), mechanical failure (n=1), or periprosthetic fracture (n=1). The mortality rate was 0% = 90 days and 2.4% =1 year.
Interpretation / Conclusion: Distal femoral resection knee arthroplasty in this fragile patient population appears to be a viable and safe option considering that the alternative in most cases is femoral amputation.

Christian Bredgaard Jensen, Anders Troelsen, Henrik Kehlet, Nicolai Bang Foss, Kirill Gromov
Clinical Orthopaedic Research Hvidovre (CORH), Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre; Section for Surgical Pathophysiology, Rigshospitalet; Department of Anesthesiology and Intensive Care Medicine, Copenhagen University Hospital Hvidovre.

Background: Cardiac complications after arthroplasty surgery are a leading cause of postoperative morbidity and mortality. Monitoring arthroplasty patients regarding myocardial injury after non-cardiac injury (MINS) using high-sensitive troponin T (hsTnT) measurements has been suggested. However, limited knowledge regarding perioperative hsTnT levels in fast-track hip and knee arthroplasty (THA/TKA/UKA) is available.
Aim: This study aims to describe perioperative hsTnT levels fast-track THA/TKA/UKA. Secondarily we aimed at describing the occurrence of MINS, cardiac complications and mortality within 90 days.
Materials and Methods: Patients undergoing either primary total hip (THA), total knee (TKA) or unicompartmental knee arthroplasty (UKA) in a fast-track setting between January 2019 and February 2020 had hsTnT levels measured preoperatively and on postoperative day 1. HsTnT levels =14 ng/L were considered elevated. MINS was defined as a post-hsTnT level =20 and <65 ng/L with an absolute change =5 ng/L from the pre-hsTnT level or a post-hsTnT level =65 ng/L.
Results: 546 patients were included. Pre- and postoperative hsTnT (pre- and post-hsTnT) levels were elevated in 139 patients (25.5%) and 165 patients (30.2%), respectively. 31 patients (5.7%) had MINS. Of 407 patients with non-elevated pre-hsTnT levels, 48 patients (11.8%) had elevated post-hsTnT levels. Of the 139 patients with elevated pre-hsTnT levels; 117 patients (84.2%) had elevated post-hsTnT levels and 22 patients (15.8%) had decreased to non- elevated post-hsTnT levels. Of the 139 patients with elevated pre-hsTnT levels, 86 patients (61.9%) had a post-hsTnT level below the pre-hsTnT level. In total 2 (0.4%) cases of mortality due to cardiac complications occurred within the first postoperative days both in MINS patients.
Interpretation / Conclusion: In summary 25.5% and 30.2% of hip and knee arthroplasty patients had preoperative and postoperative hsTnT elevation, respectively. 84.2% of patients with elevated preoperative hsTnT levels remained elevated postoperatively. Further knowledge on perioperative hsTnT levels in surgery specific subpopulations is needed.

Ulrik Kragegaard Knudsen, Martin Kirkegaard, Kurt Skovgaard, Christina Holm, Anders Odgaard, Michael M. Petersen, Nikolaj S. Winther Winther
Department of Orthopaedic Surgery Rigshospitalet, Copenhagen, Denmark

Background: Mega-prosthetic joint replacement of the distal femur is also an option for management of massive bone loss in revision total knee arthroplasty (TKA) or because of fractures. Even though this surgery is challenging with high rate of infection, patellar complications, and implant failure it is often the only option to avoid knee arthrodesis or amputation.
Aim: The purpose of this study was to evaluate the complications and outcome after implantation of mega-prostheses of the distal femur in non-tumor cases.
Materials and Methods: We retrospectively reviewed 65 patients mean age 66 (38-84) years, F/M=47/18, mean follow- up 45 (12-220) months that received a distal femoral resection and reconstruction with a mega-prosthesis because of a failed TKA due to loosening (aseptic or septic) or periprosthetic fracture or complications after a complex fracture with failed osteosynthesis. 41 patients (64 %) had previous TKA revision surgery and 19 patients (29%) previous periprosthetic infection. In this cohort 19 patients were revised for aseptic loosening and 12 patients for septic loosening. 18 patients were diagnosed with periprosthetic fracture and 6 patients with pseudoarthrosis. 6 cases with instability, 1 case with a comminute distal femur fractur and in in 3 cases pain were the reason for revision.
Results: We found good patient satisfaction and low pain scores with moderate to low activity level. 39 patients (60%) had no additional procedures. 18 patients (27%) had major revision defined as removal or exchange of the femoral component because of aseptic loosening (n=11), periprosthetic fracture (n=4), septic loosening (n=2) and amputation (n=2), and 13 patients had minor revision due to instability, pain or patellar complications. Survival analysis shows that 70 % was free of major revision after 5 years.
Interpretation / Conclusion: Mega-prosthetic joint replacement of the distal femur is a good option for management of non-tumor cases (revision TKA and fractures) with massive bone loss, and thus amputation and knee arthrodesis can be avoided in most patients. However, there is a high risk that the patients have to undergo future additional surgery including major revision.

Christoffer Jørgensen, Pelle Petersen, Louise Daugbjerg, Thomas Jakobsen, Kirill Gromov, Claus Varnum, Andersen Mikkel, Henrik Palm, Henrik Kehlet,
Section for Surgical Pathophysiologi, Rigshospitalet; Department of Orthopaedics, Aalborg Universitetssygehus, Department of Orthopaedics, Holstebro Sygehus; Department of Orthopaedics, Aalborg Universitetssygehus; Department of Orthopaedics, Hvidovre and Amager Hospital; Department of Orthopaedics, Vejle Hospital; Department of Orthopaedics, Gentofte and Herlev Hospital; Department of Orthopaedics, Bispebjerg and Frederiksberg Hospital

Background: Postoperative pain remains a challenge after total hip and knee arthroplasty (THA/TKA). Regardless, major reductions in length of stay without increased readmissions have been reported with the use of enhanced recovery protocols. Peripheral nerve blocks (PNB) are recommended for postoperative analgesia and potentially reducing length of stay (LOS) and readmissions. However, whether routine PNB are needed to achieve a LOS of =1 day within an enhanced recovery protocol with multimodal opioid-sparing analgesia, including high-dose preoperative steroid and local anaesthetic infiltration(LIA) is uncertain.
Aim: To investigate the use of PNB in fast-track THA and TKA patients with LOS = 1 day and relation to department of surgery, 90-days readmissions, preoperative patient characteristics and discharge destination.
Materials and Methods: Observational multicentre study of consecutive elective enhanced recovery THA and TKA with a LOS of =1 day from January 2016-August 2017. Prospective recording of preoperative characteristics, information on PNB, anaesthesia, LIA, discharge destination, LOS and readmissions through the Danish National Patient Registry and medical records. A previously published risk-score for having a LOS >2 days was used for comparing preoperative patient characteristics.
Results: Of 3471 procedures, 1763 (50.8%) had a LOS of =1 day with 99.7% discharged to own home. PNB was used in 2.5% of THA and 35.1% of TKA, but with considerable variations between departments (0.0- 33.1%). There were no differences in 90-days readmissions with or without PNB (4.7% (CI:2.6-8.5) vs. 5.9% (CI:3.9-8.7) in TKA (p=0.553) and 5.3% (CI: 1.0-25.8) vs. 5.7% (CI:4.5-7.3) after THA (p=0.999)). Patients with PNB did not have a higher risk of scoring =6 points in risk of having a LOS >2 than patients without use of PNB, (5.9% (CI:1.1-2.7) vs. 3.1% (CI:2.2-4.3) in THA (p=0.421) and 13.6% (CI:9.6-18.9) vs. 17.0% (CI:13.5-21.1) in TKA, p=0.284)
Interpretation / Conclusion: Routine use of peripheral nerve blocks may not be necessary to achieve LOS =1 day or reduce 90-days readmissions after fast-track THA and TKA. Further studies are needed to identify potential benefits of PNB in patients with LOS >1 day or “high-risk” patients.

Nizar Hamrouni, Jens H. Højvig, Ulrik K. Knudsen, Kurt K. Skovgaard, Anders Odgaard, Lisa T Jensen, Christian T Bonde
Department of Plastic Surgery and Burns Treatment, Center of Head, Neck and Orthopedics, University Hospital of Copenhagen, Rigshospitalet; Department of Orthopedic Surgery, Center of Head, Neck and Orthopedics, University Hospital of Copenhagen, Rigshospitalet

Background: Soft tissue defects after total knee arthroplasties (TKA) represent a major orthopedic challenge with amputation as a feared outcome. Microvascular free flap coverage can increase limb salvage rates, but complications related to the procedure are yet to be explored further.
Aim: The purpose of this study is to review our experience with free flap coverage for soft tissue defects after revision total knee arthroplasty.
Materials and Methods: Through a retrospective chart review of the past 15 years, we identified all patients who had free flap transfer to a knee with an existing TKA and in need of revision. Typically, the patients underwent standard two-stage revision arthroplasty. To identify areas of intervention, we divided the entire regimen into two phases divided by the free flap transfer.
Results: We identified 18 patients with a median age at primary TKA of 66 years (range 37 to 81), who were followed for a median of 5.1 years (range 0.2 to 10.6). The median duration from insertion of primary TKA to their final operation was 523.5 days (range 19 to 2591). During the entire period, patients underwent a mean of 7.6 surgical procedures one their knee with 3.6 orthopedic revisions prior to the free flap surgery and 0.6 after. Soft tissue coverage was achieved in all patients and no patients underwent amputation. One third of patients experienced early complications at recipient site after free flap surgery.
Interpretation / Conclusion: Microvascular free flap coverage of complex soft tissue defects after revision total knee arthroplasty proved achievable in all patients with successful limb salvage.

Jakob Bie Granild-Jensen, Alma Becic Pedersen, Eskild Bendix Kristiansen, Esben Thyssen Vestergaard, Bente Langdahl, Charlotte Søndergaard, Stense Farholt, Gija Rackauskaite, Bjarne Møller-Madsen
Department of Paediatrics and Adolescent Medicine, Randers Regional Hospital; Department of Clinical Epidemiology, Aarhus University Hospital; Department of Clinical Epidemiology, Aarhus University Hospital; Department of Paediatrics and Adolescent Medicine, Randers Regional Hospital; Department of Endocrinology and Internal Medicine, Aarhus University Hospital; Department of Paediatrics and Adolescent Medicin, Regional Hospital of Gødstrup; Department of Paediatrics and Adolescent Medicin, Aarhus University Hospital; Department of Paediatrics and Adolescent Medicin, Aarhus University Hospital; Department of Children’s Orthopaedics, Aarhus University Hospital

Background: Cerebral palsy (CP) is the most common cause of motor impairment in children and occurs in about two per 1,000 live births. In CP low bone strength is highly prevalent and is associated with a risk of fractures. In fact, yearly fracture rates have been reported to be twice as high in children with non-ambulant CP compared to the general population. Epilepsy affects one third of children with CP and seizures as well as anti-epileptic drugs may negatively affect fracture rates.
Aim: We aimed to establish the age-specific fracture rates in Denmark including the entire Danish population of children with and without CP. Further, to specify the fracture rates in children with CP and epilepsy with and without anti-epileptic treatment.
Materials and Methods: Children with CP born 1997 to 2007 were compared to all persons born in the same period. Data from The National CP Register, The Danish National Health Register, The Civil Registration Register and The Danish Prescription Database were combined to establish fracture rates in groups of children based on the diagnosis and severity of CP as well as the diagnosis and treatment of epilepsy. Outcomes were registered 1997- 2017.
Results: We identified 1,451 children with CP and 787,159 children without CP. Average follow-up time was 14 years. Fracture rates per 1,000 person years were 23/27 for females/males with CP and 23/29 for females/males without CP. Overall, 27% of children with CP sustained one or more fractures, while this proportion was 29% for children without CP. We stratified by sex and age group and found peak fracture rates of 35 to 50 in the age groups 5-9 years and 10-14 years. None of the fracture rates were significantly increased in children with CP when comparing peak rates or age group rates to children without CP. In children with and without CP an epilepsy diagnosis was associated with a 35%-56% increased fracture rate while anti-epileptic drug treatment was associated with a 53%-95% increased fracture rate.
Interpretation / Conclusion: We found no evidence that children with CP have more fractures than their peers. Fracture rates are increased in children diagnosed with epilepsy and particularly in children treated with anti-epileptic drugs.

Arash Ghaffari, Marlene Jørgensen, Helle Rømer, Maibrit Sørensen, Søren Kold, Ole Rahbek, Jannie Bisgaard
Interdisciplinary Orthopaedics, Aalborg University Hospital; Orthopedic Anaestesia Department, Aalborg University Hospital

Background: Continuous peripheral nerve blocks (cPNBs) have shown good results in pain management after orthopedic surgeries. However, the variation of performance between different subspecialties is unknown.
Aim: Describe our experience with cPNBs after lower limb orthopedic surgeries in different subspecialties.
Materials and Methods: This prospective cohort study was performed on collected data from cPNBs after orthopedic surgeries in lower limbs. Catheters were placed by experienced anesthesiologists using sterile technique. After catheterization, the patients were examined daily, by specially educated acute pain service nurses. The characteristics of the patients, duration of catheterization, severity of the post-operative pain, need for additional opioids, and possible complications were registered.
Results: We included 246 patients (=547 catheters). 115 (21%) femoral, 162 (30%) saphenous, 66 (12%) sciatic, and 204 (37%) popliteal sciatic nerve catheter were used. The median duration of a catheter was 3 days [IQR = 2 – 5]. The proportion of femoral, sciatic, saphenous, and popliteal nerve catheters with duration of more than two days was 81%, 79%, 73%, and 71% for, respectively. This proportion varied also between different subspecialties. 91% of the catheters remained in place for more than two days in amputations (n=56), 89% in pediatric surgery (n=79), 76% in trauma (n=217), 64% in foot and ankle surgery (n=129), and 59% in limb reconstructive surgery (n=66). The proportion of pain-free patients were 77 – 95% at rest, 63 – 88% at mobilization. 79 – 92% did not need increased opioid doses, and 50 – 67% did not require PRN opioid. 443 catheters (81%) were removed as planned. The cause of unplanned catheter removal was loss of efficacy in 69 (13%), dislodgement in 23 (4.2%), leakage in 8 (1.5%), and erythema in 4 catheters (0.73%). No major complication occurred.
Interpretation / Conclusion: 81 % of catheters remained in place until planned removal and opioid usage after surgery was lower than expected. Catheters were efficient in both adult and pediatric surgery; however a variation was seen between orthopaedic subspecialties regarding duration of nerve catheter usage.

Soeren Bodetker *, Louise * Klingenberg, Billy Kristensen **, Lens Svendsen #, Ellen Koefoed ##, Mai Pedersen ##
Dep. of Orthopedics, Copenhagen University Hospital, Hvidovre* Dep. of Ambulatory Surgery, Copenhagen University Hospital, Hvidovre** Dep. of Pediatrics, Copenhagen University Hospital, Hvidovre# Dep. of Physiotherapy, Copenhagen University Hospital, Hvidovre ##

Background: Complex regional pain syndrome (CRPS) is a neuropathic condition characterized by circular allodynia and functional loss of an extremity. Treatment with continuous peripheral nerve blockade in children has so far only been reported in case studies.
Aim: This study reports our results and complications combining continuous peripheral nerve blockade for pain relieve and physio-occupational therapy in children with CRPS.
Materials and Methods: Inclusion criteria were children meeting Budapest criteria for CRPS, having sensory disturbances and allodynia, thereby losing the ability to self- support on their limb. Under general anesthesia and with ultrasound and electric stimulation guidance, a catheter was placed close to either the sciatic nerve, the saphenous nerve or the Brachial plexus. All children received continuous infusion of ropivacaine 0.2%, 5-7 mL/h combined with immediate physiotherapy and/or occupational therapy with a supplement of self- training every two hours throughout the day. The therapy focused on improving coordination, strength and sensory motor skills.
Results: 28 children were consecutively included (25 girls and 3 boys). 23 children had foot pain, 4 had pain in the hand and 1 had combined foot and hand pain. On admission the average age was 12 years (8-16); the average duration of pain was 12 months (2-64) with a median VAS score of 9 (7-10). Initiation of pain was either no trauma (9), minor trauma/distortions (17) or fracture (2). After an average observation period of 68 months (5.6 year) the median VAS score was 0 (0-7). In 2 children the treatment plan had no effect. In one child a relapse occurred 3 weeks after removal of the catheter, but renewed nerve catheter treatment was successful. One catheter had to be replaced due to accidental discontinuation. Finally, one child had a superficial infection. No neurological complications were observed during the period.
Interpretation / Conclusion: Treatment with continuous peripheral nerve block and training seems safe, effective and feasible for children with CRPS, resulting in pain-free or almost pain-free patients.

Kasper Krommes, Kristian Thorborg, Per Hölmich,
Orthopedic Department, Sports Orthopedic Research Center - Copenhagen, Hvidovre Hospital

Background: A common knee complaint during adolescence, a crucial time for staying physically active, is Osgood Schlatter (OS). Activity ladders has been used for knee pathologies in adolescents to guide progression of loading during rehabilitation. They are based on order of expected symptom provocation from common activities. It is, however, unknown how adolescents with OS rate the level of aggravation from common activities.
Aim: To obtain self-reported ratings of common activities by adolescents with OS in order to rank them and comprise a activity ladder.
Materials and Methods: Adolescent patients with OS attending a specialized orthopedic clinic filled out a survey containing twenty-three activities, all of which were nominated as important by previous patients. Activities were rated by participants on a 5-point Likert scale ranging from 0 “does not provoke knee pain” to “provokes extreme knee pain” and subsequently ranked in groups (most, second most/least, and least aggravating activities) using median scores (x~) and individually using mean (x¯) scores.
Results: Thirty-three patients (age 13.5±1.7 years, symptom-duration 23.6±16.1 months) participated. Activities were ranked in 3 groups (median scores 4, 3 and 2). The most aggravating activities (x~ 4) were kneeling (x¯ 3.9), sprinting (x¯ 3.8), acceleration (x¯ 3.7), landing (x¯ 3.6), high-speed running (x¯ 3.6), and deceleration (x¯ 3.5). The second-most/least aggravating activities (x~ 3) were squatting (x¯ 3.3), climbing stairs (x¯ 3.3), fast/hilly cycling (x¯ 3.2), one-legged jumping (x¯ 3.2), side-ways change of direction (x¯ 3.1), walking fast or for a long distance (x¯ 3.0), two-legged jumping (x¯ 2.9), jogging (x¯ 2.8), kicking a ball (x¯ 2.7), and backwards change of direction (x¯ 2.6). The least aggravating activities (x~ 2) were getting up from chair/toilet (x¯ 2.7), side-ways running (x¯ 2.5), light cycling (x¯ 2.5), skipping (x¯ 2.4), prolonged standing (x¯ 2.4), kicking in the air (x¯ 2.4), and walking shortly (x¯ 2.2).
Interpretation / Conclusion: For adolescents with OS, knee pain is provoked especially by kneeling and high-velocity sports- specific actions. These findings can form the basis for an OS-specific activity ladder to guide rehabilitation.

Hvidberg Emma J., Rölfing Jan D. , Møller-Madsen Bjarne , Abood Ahmed A.
Department of Orthopaedics, Aarhus University Hospital; Danish Pediatric Orthopaedic Research (www.dpor.dk)

Background: The use of tension-band plating, i.e. eight- plates is commonly used to correct coronal limb deformities in children. Changes in joint morphology have been observed after epiphysiodesis using eight-pates. It thus seems relevant to investigate if joint morphology also changes after temporary epiphysiodesis with this implant.
Aim: To evaluate potential changes in knee joint morphology after treatment of genu valgum with eight-plates.
Materials and Methods: A retrospective study was performed on radiographs of 39 children. All patients undergoing temporary medial hemi epiphysiodesis using eight-plates between 2015 and 2020 were included. Anteroposterior knee radiographs of all patients were reviewed. The patients were assigned to two groups, tibial and femoral group according to anatomic insertion of the eight-plates. Medial and lateral slope angles of the tibial plateau, tibial roof angle and femoral notch angle were measured. Mean differences between pre-operative and post- operative values were estimated with corresponding confidence intervals and p- values.
Results: 81 eight-plates were identified (femur 74, tibia 7) in 39 children. Mean insertion time was 17 months (95% CI: 14;20). Mean change of medial tibial and lateral slope angles was -1° (-3;0) and -5° (-8; -3, p<0.05). Mean difference in roof angle was -0.3° (-2; 1) in the tibial group. Mean change in femoral notch angle was -1° (-3; 1).
Interpretation / Conclusion: A minor change in the lateral tibial plateau angle was observed in the tibial group, however it may be within the measurement error of the evaluation. Otherwise, the insertion of eight-plates for hemi epiphysiodesis did not alter the knee joint morphology.

Line Ellen Juul Sørensen, Emma Melhus Ericson, Søren Ege Qwist, Vilhelm Engell
Department of Fysiotherapy and Occupational therapy, Aarhus University Hospital ; The Ponseti clinic, Department of Orthopaedics, Aarhus University Hospital

Background: Every year, approximately one in 1000 children in Scandinavia are born with a clubfoot deformity. The Ponseti Method is used worldwide and the prognosis is good.
Aim: The aim of this study was to investigate the functional outcome using the Clubfoot Assessment Protocol (CAP) and the Oxford Ankle Foot Questionnaire for Children (OxAFQ-C) in children aged 6-7 years treated with the Ponseti Method.
Materials and Methods: This consecutive retrospective study included 17 children (21 feet) at 6-7 years of age, treated for clubfoot by the Ponseti Method at a Danish hospital. The CAP is a comprehensive standardized instrument to evaluate the clubfoot with respect to mobility, muscle function, morphology and motion quality. The level of function as experienced by the children was assessed with the OxAFQ-C. Data were calculated by descriptive statistics, or by estimate, confidence interval and p-value where appropriate. A correlation was calculated to examine the agreement between the results from the CAP and the domains in the OxAFQ-C.
Results: The Total Score in the CAP was 76%, which resulted in a significant deviation of -18.24 from maximum score (95% CI = -21.09; -15.45, p <.0001). In particular, three tests had significant deviations from maximum score. Dorsiflexion in the ankle deviated by -1.95 (95% CI = -2.17; -1.74, p <.0001), Heel walking deviated by -1.76 (95% CI = -2.11; -1.43, p <.0001) and One-leg hop deviated by -1.57 (95% CI = -2.15; -0.99, p <.0001). In the domain Physical in the OxAFQ-C the score was 73.77%, which was a significant deviation of -6.29 (95% CI = -8.43; -4.15, p <.0001) from maximum score. There was a correlation between the Total Score in the CAP and the two domains Physical and Emotional in the OxAFQ-C.
Interpretation / Conclusion: This study concludes that children treated for clubfoot have significant deviations from normal function based on the CAP, with poorer results in dorsiflexion in the ankle, heel walking one-leg hop, and the domain Physical Activity in the OxAFQ-C. These findings suggest a continued focus on the long term implications of congenital clubfoot and its treatment.

Kasper Krommes, Kristian Thorborg, Per Hölmich,
Orthopedic Department, Sports Orthopedic Research Center - Copenhagen, Hvidovre Hospital

Background: A common knee complaint during adolescence, a crucial time for staying physically active, is Osgood Schlatter (OS). As research into OS is only just emerging, a more detailed understanding of how OS patients presents are needed in order to design suitable treatments.
Aim: To explore Self-reported characteristics of adolescents with longstanding Osgood Schlatter.
Materials and Methods: Variables from self-reported instruments on symptoms, sports and physical activity participation, health, quality of life, mobility, pain beliefs and mental health amongst others, were collected from patients attending a specialized orthopedic inpatient setting, and the most novel findings are presented as summary data.
Results: Thirty-three patients (age 13.5±1.7 years, symptom-duration 23.6±16.1 months) participated. Acceptable symptom state was present in 36%, and 27% was satisfied with their sports performance. 81% had changed their level of physical activity and 51% currently participated in sports. Sports function was affected (mean KOOS child ‘sport/rec’ subscale 62 [95%CI 56-67]). Self-rated health was reduced (mean 0-100 EQ-D5-Y-VAS scale56.1 [95%CI 45-84], 69% reported either ‘some’- or ‘a lot problems doing usual activities’, and 31% ‘some’- or ‘a lot of problems walking about’. Quality of Life was reduced (mean KOOS child ‘QoL’ subscale score 49.6 [95%CI 45-55]). Patients scored mean 10 on the 0-12 pain-self efficacy scale (PSEQ-2), 62% reported a high level of kinesiophobia (TSK-17 38 point cutoff), and 31% being ‘a bit worried, sad or unhappy’. Previous insidious heel pain was reported by 39%.
Interpretation / Conclusion: Osgood Schlatter patients are affected on satisfaction with symptoms, sports and physical activity participation, health, quality of life, mobility, pain beliefs and mental health. The consequences of Osgood Schlatter, typically denoted as benign and self-limiting, seems to have significant consequences on adolescents suffering from this condition. Addressing these factors are likely important when designing future effective managements strategies.

Kasper Krommes, Kristian Thorborg, Per Hölmich,
Orthopedic Department, Sports Orthopedic Research Center - Copenhagen, Hvidovre Hospital

Background: A common knee complaint during adolescence, a crucial time for staying physically active, is Osgood Schlatter (OS). The recommended types of modalities for conservative management in the literature is abundant and conflicting, and no level 1 evidence is available. For this emerging area of research, knowing the contents of usual care, are key to develop uniform and effective management strategies.
Aim: To gain knowledge directly from OS patients and clinicians on what care is delivered in clinical practice.
Materials and Methods: Semi-structured interviews and surveys were conducted in a specialized orthopedic clinic with OS patients, and across sectors and professions with clinicians managing OS patients.
Results: Thirty-three patients (age 13.5±1.7 years, symptom-duration 23.6±16.1 months) participated in interviews and 63 clinicians (physiotherapists, GPs, pediatric orthopedic surgeons, median 13 years practicing [IQR:7.5- 19.5], seeing median 10 OS patients per year [IQR:5-17.5]), participated in interviews or filled out a survey. For patients, the most common modalities received were exercises (42%), advice to take a break from sports (24%), topical analgesics (24%), and cryotherapy (21%); followed by stretching, taping, acupuncture, laser therapy, shockwave therapy, and massage (12-18%); and 20 other types of modalities (>9%). Among clinicians, the most popular modality was ‘balance or alignment exercises’ used by 81%, followed by ‘straps or taping’ (79%). Other frequently used modalities were strength training (76%), cryotherapy (64%), stretching exercises (50%), orthoses (54%), manual therapy (41%), and painkillers (33%). All clinicians (100-98%) gave advice and information regarding load, pain and prognosis. The most agreed upon were “the prognosis is good” (90%) and “the condition is safe” (78%), and advise to “participate only with little pain” (54%) and “participate to your pain limit” (44%).
Interpretation / Conclusion: Numerous different modalities are received by Osgood Schlatter patients, but a set of modalities/advice seems to be the most prevalent in usual care: exercises, cryotherapy, stretching, topical/oral analgesic, advice on favorable prognosis, and advising a cautious approach to physical activity/sports.

Morten Jon Andersen
Department of Orthopedic Surgery, Herlev and Gentofte University Hospital

Background: A poorly treated pediatric lateral humeral condyle fracture (LHCF) can result in growth disturbance and loss of elbow function. LHCF are Salter- Harris type IV physeal fractures that in many cases also involve the articular surface of the humerus. Treatment success is dependent on reduction of the physis and joint surface and a stable fixation. The Song classification discerns fractures that are incomplete from complete and undisplaced from displaced thereby describing fracture stability and aiding the surgeon in choosing the treatment strategy.
Aim: This project aimed to 1) describe fracture stage according to Song, 2) investigate if adequate reduction and fixation of LHCF was obtained during surgery and 3) report number of loss of reduction (LOR) after fixation.
Materials and Methods: We retrospectively reviewed all cases of operatively managed LHCF in children at Herlev Hospital from 2017-2020. Age, gender, Song stage, reduction quality, K-wire configuration and LOR was investigated. Song stage 2 and 3 cannot be distinguished on plain radiographs and were in the present study compiled in one group. Satisfactory reduction was defined as <= 2 mm gap centrally in all radiographic planes.
Results: We reviewed 48 fractures in 35 boys and 13 girls, mean age was 5 years (range, 2 to 12 years). Two (4%) fractures were Song stage 1, 24 (50%) stage 2-3, 10 (21%) stage 4 and 12 (25%) stage 5. 32 (67%) fractures were stabilized with divergent and 15 (31%) with parallel K-wires, one fracture was only casted following reduction. Satisfactory reduction was obtained in 35 fractures (73%). 7/10 (70%) Song stage 4 and 8/12 (67%) stage 5 had satisfactory reduction. Four (8%) fractures suffered LOR of which two were primarily fixed with divergent and two with parallel wires.
Interpretation / Conclusion: This study shows that 73% of fractures were reduced satisfactory and fixed with at stable K-wire configuration in 67% of cases. However, more than 1 in 4 fractures were either not properly reduced or were poorly stabilized and 8% suffered loss of reduction. The successful operative treatment of LHCF in children relies on the surgeons understanding of this fracture type and ability to properly reduce and fix the fracture.

Arash Ghaffari, Søren Kold, Ole Rahbek
Interdisciplinary Orthopaedics, Aalborg University Hospital, Aalborg, Denmark

Background: Double and triple femoral neck lengthening osteotomies have been described to correct coxa brevis deformity. Only small studies reported the results.
Aim: Our aim was to provide an overview of the outcomes of double and triple femoral neck lengthening.
Materials and Methods: After an extensive search of different online databases, we included studies reporting the results of double and triple femoral neck osteotomies. Clinical and radiological outcomes, and reported complications were extracted. The review process was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.
Results: After evaluating 456 articles, we included 11 articles reporting 149 osteotomies in 143 patients (31% male, 64% female, 5% unspecified). Mean age of the patients was 20 years (range 7 years to 52 years). Indications were developmental hip dysplasia (51%), Perthes disease (27%), infection (6%), post-trauma (4%), congenital disorders (2%), slipped capital femoral epiphysis (1%), idiopathic (3%) and unknown (6%). The mean limb length discrepancy reduced by 12 mm (0 mm to 40 mm). In total, 65% of 101 positive Trendelenburg sign hips experienced improvement of abductor muscle strength. An 18% (9% to 36%) increase could be found in functional hip scores. Mean increase in articulo-trochanteric distance was 24 mm (10 mm to 34 mm). Five patients older than 30 years at the time of osteotomy and two younger patients with prior hip incongruency had disappointing results and required arthroplasty. In all, 12 complications occurred in 128 osteotomies, in which complications were reported.
Interpretation / Conclusion: Double and triple femoral neck lengthening osteotomies in coxa brevis show good results with few complications in the literature, especially in young patients with non-arthritic hips.

Hans-Christen Husum, Rikke Damkjær Maimburg, Søren Kold, Janus Laust Thomsen, Ole Rahbek
Interdisciplinary Orthopaedics, Aalborg University Hospital; Department of Gynaecology and Obstetrics, Aarhus University Hospital; Centre for General Practice, Aalborg University; Danish Paediatric Orthopaedic Research

Background: The positive predictive value of clinical hip examinations of newborns performed by midwives and general practitioners in the Danish screening programme for developmental dysplasia of the hip (DDH) is low.
Aim: To assess the self-reported recognition of nationally recommended clinical hip examination techniques used in the universal clinical screening programme for DDH in newborns in Denmark among midwives, general practitioners (GPs), and GPs in training.
Materials and Methods: Through invitations via personal email and closed social media groups, we invited midwives, GPs, and GPs in training to answer a web-based open survey, where respondents were asked to identify which of six written descriptions of clinical hip examinations were featured in the national recommendations on DDH screening by the Danish Health Authority. Three of the descriptions were the published descriptions of the Ortolani, Galeazzi, and hip abduction examinations from the national guidelines and three descriptions were false and constructed by the author group. There was no limit on the number of examinations the respondents could mark as featured in national guidelines.
Results: A total of 178 (58 GPs, 97 midwives and 23 GPs in training) responses were included. 89% of responders were able to correctly identify the Ortolani manoeuvre and 92% were able to correctly identify one of the constructed descriptions as being false. The remaining four descriptions had significantly lower correct answer percentages ranging from 41% to 58% with significantly lower correct answer percentages of midwives for three out of all six descriptions when compared to GPs.
Interpretation / Conclusion: The recognition of two out of three recommended clinical hip examinations featured in the Danish screening guidelines for DDH was overall low among current screeners. Results from this study demonstrate the need to heighten the knowledge level of screeners.

Morten Jon Andersen
Department of Orthopedic Surgery, Herlev and Gentofte University Hospital

Background: Management of medial humeral epicondyle fractures (MHEF) in children is one of the most controversial topics in pediatric fracture care. Historically fractures have been treated nonoperatively with good results. However, there has been a trend towards surgical fixation of this injury in the belief that it might improve grip strength and prevent elbow instability. There is consensus for fixation in cases of open fractures and entrapment of the epicondyle within the joint space. MHEF in conjunction with dislocation of the elbow favors fixation at many institutions. Fixation can be achieved with either K-wires or screws.
Aim: This project aimed to 1) describe fracture classification according to Wilkin, 2) describe fixation implant, and 3) investigate if adequate reduction was obtained during surgery.
Materials and Methods: We retrospectively reviewed all cases of operatively managed MHEF in children at Herlev Hospital from 2017-2020. Age, gender, Wilkin’s classification, fixation implant and reduction quality were investigated. Wilkin classified fractures in four types: 1) nondisplaced, 2) minimally displaced (<5 mm), 3) significantly displaced (>5 mm) and 4) incarcerated in the joint. Satisfactory reduction was defined as <= 5 mm displacement.
Results: We reviewed 44 fractures in 16 boys and 28 girls, mean age was 11 years (range, 6 to 17 years). Preoperatively four (9%) fractures were nondisplaced, 18 (41%) were displaced <5 mm, 13 (30%) were displaced >5 mm. 10 (23%) fractures occurred together with a dislocation of the elbow on primary radiographs. In 9/44 (21%) cases the medial epicondyle was entrapped in the joint. 18 (41%) fractures were fixed with K-wires and 25 (57%) with screws. One fracture was reduced along with a joint dislocation and not fixed with an implant. 37/44 (84%) fractures were reduced and fixed to <5 mm of displacement.
Interpretation / Conclusion: This study showed that 50% (22/44) of surgically managed fractures had less than 5 mm of displacement preoperatively. Screw fixation was slightly favored over K-wires and the epicondyle was appropriately reduced in 84% of cases. In 21% of fractures the epicondyle was incarcerated in the elbow joint.

Hans-Christen Husum, Janus Laust Thomsen, Søren Kold, Rikke Damkjær Maimburg, Ole Rahbek
Interdisciplinary Orthopaedics, Aalborg University Hospital; Department of Gynaecology and Obstetrics, Aarhus University Hospital; Centre for General Practice, Aalborg University; Danish Paediatric Orthopaedic Research

Background: Despite a national screening programme for developmental dysplasia of the hip (DDH), a high number of patients need surgery for hip dysplasia after childhood. The Danish selective screening programme for DDH is based on clinical hip examinations and screening of recognized risk factors for DDH of all newborns.
Aim: To review risk factors used in the current regional referral guidelines for DDH and the self-reported recognition of these among midwives, general practitioners (GP), and GPs in training.
Materials and Methods: Review of existing guidelines: A survey of regional referral guidelines for DDH was conducted through a search in online regional guideline databases. Further, risk factors used as referral criteria for DDH were compared across regions. Knowledge of guidelines: Through an online survey, we asked midwives, GPs and GPs in training to identify which of six risk factors for DDH were currently featured as referral criteria for specialized DDH examination in the referral guidelines of their employment region. Answers were compared to the DDH referral guidelines of the responders’ employment region.
Results: We collected 11 local and regional DDH referral guidelines. Six risk factors were identified from referral guidelines (breech presentation, oligohydramnios, family history of DDH, clubfeet, twins, and premature birth). No regions agreed in all risk factors used. We collected 178 survey responses. Overall correct answer percentages for currently used risk factors for DDH specified in alignment with regional guidelines was: 96% (breech presentation), 90% (family history of DDH), 66% (twins), 63% (premature birth), 34% (clubfeet), and 29% (oligohydramnios).
Interpretation / Conclusion: This is the first Danish study to find variation in referral criteria among Danish regional DDH referral guidelines within the national screening program. We found an overall high level of recognition for two out of six referral criteria but a low level of recognition for the other four. The lack of uniform usage of referral criteria for DDH, and the low knowledge of those used, is problematic in a selective screening program for DDH.

Line Kjeldgaard Pedersen, Lucas Yang Vincent Fisker, Jan D Rölfing, Karsten Gadegaard, Peter Ahlburg, Mette Veien, Lene Vase, Bjarne Møller-Madsen
Line Kjeldgaard Pedersen; Lucas Yang Vincent Fisker; Jan D Rölfing and Bjarne Møller- Madsen: Department of Childrens Orthopedics, Aarhus University Hospital Karsten Gadegaard; Peter Ahlburg; Mette Veien: Department of Childrens Anaestesiology, Aarhus University Hospital Lene Vase: Department of Psycology, Aarhus University

Background: Immersive Virtual Reality (VR) is a promising method to distract and lower pain and anxiety. It immerses the users in a 3D 360° alternate reality and its effect is thought to limit the processing of pain signals by stimulating the visual and auditory cortex. Studies indicates that the use of VR can reduce a child’s anxiety and pain level maybe through distraction. VR is progressively being used in a clinical pediatric setting and seems to be beneficial for the children; but the use in children is still not evidence-based or validated. It is not known how this effect is caused and if VR can modulate the perception of pain. Algometry can be used to assess the pressure pain threshold (PPT) and has been validated in children. It is indicated that PPT declines in children just before surgery potentially due to the child’s higher level of anxiety. A study has found that VR increases heat-pain tolerance and decreased anxiety in adults. This relationship has not yet been established in children.
Aim: The primary aim is to evaluate whether the use of immersive VR can modulate a child’s PPT and anxiety level. The secondary aim is to test the validity and feasibility of a VR video condition versus a VR game condition using both non-VR control condition as well as non-immersive 2D condition.
Materials and Methods: 48 children (6-14 yrs) seen in the orthopedic outpatient clinic at Aarhus University Hospital will be included. Each child will go through four conditions and at setup with 16 possible sequences is generated to control for time effects. Prior to each condition and 4 minutes in PPT, pulse and modified Yale Pediatric Anxiety Scale will be assessed. Before and after the study, both NRS and a verbally administered questionnaire regarding the child’s experiences with VR will be used.
Results: Pilot tests showed that PPT increases by 193 kPa (VR-Game), increases by 33 kPa (VR-Video) and declines by 5 kPa in the non-VR control condition.
Interpretation / Conclusion: The use of VR in healthy children increases the PPT and lowers anxiety. In addition, the use of VR in children is feasible. It is a promising tool for perioperative distraction, anxiety and pain management.

Marie Fridberg, Ole Rahbek, Tobias Nygaard
Pediatric Orthopaedic Department, Rigshospitalet, Copenhagen University Hospital, Denmark Interdisciplinary Orthopaedics, Orthopaedic department, Aalborg University Hospital, Denmark

Background: Cubitus varus deformity occur with an incidence of up to 30% of supracondylar fractures because of malunion. The most common treatment of cubitus varus is a lateral closed wedge correction osteotomy. To our knowledge there is only one case report concerning the correction of cubiti varus with guided growth
Aim: The purpose of this study was to describe our results with correction of cubitus varus deformity with guided growth.
Materials and Methods: The study is a retrospective case study of 7 cases. All 7 included patients had surgery from 2013-2019 at Rigshospitalet, Pediatric Orthopedic department. Data on demographics, primary fracture, clinical findings and radiological measurements were collected from electronical patient charts (EPIC). All patients and their parents were informed prior to surgery that the surgical method was novel and that osteotomy could still be necessary. They all had temporary small not angle stabile plates (eight plates) to arrest growth of the lateral condyle physis.
Results: Primary fracture pattern was either a supracondylar fracture Gartland III (4 cases) or a lateral condylar fracture (3 cases). Mean age at fracture was 5 (3-8) and mean age at hemi-epiphysiodesis was 9,1 (8-12). 4 did not yet have removal of the eight-plate when this study was conducted and mean treatment time was 39 (34-54) month. Varus deformity was improved clinically with a mean of 11,2°(0-20°). Radiological carrying angle was improved in 4 cases with a mean of 5°. During follow-up screw placement diverged at an average of 5°(0-13°). 2 cases of lateral condylar fractures with loss of reduction during conservative treatment had less or no effect. One patient needed a second surgery to exchange the distal screw. All patients report that the eight-plate was prominent at the lateral condyle but no complains of pain during treatment.
Interpretation / Conclusion: In 6 of 7 (2 moderate) cases we found clinical improvement of cubitus varus with guided growth. Guided growth might have a role in the future treatment of selected patients with cubitus varus.

Morten Jon Andersen
Department of Orthopedic Surgery, Herlev and Gentofte University Hospital

Background: Pediatric diaphyseal forearm fractures are common injuries and one of the most frequent reasons for orthopedic care. Fractures in need of surgery are often treated with metal Elastic Stable Intramedullary Nails (ESIN). Nail removal after 6-12 months is advocated in Denmark. Hardware removal has few complications; however, it is a substantial burden on the child, the family and healthcare economy. Bioabsorbable Intramedullary Nails (BIN) made from oriented poly L-lactide-co-glycolide (PLGA) copolymers are strong enough to support fractured bones. BIN have been developed for the same indications as metal ESIN.
Aim: We present the operative technique using the Activa IM-Nail™ (Bioretec Ltd., Finland) along with cases.
Materials and Methods: The fracture is reduced, and the cortical bone is opened using an awl. An appropriate size dilator is used to widen the medullary canal. The dilator is replaced with the appropriate size BIN which is inserted to the desired depth under image intensification. The implant is cut and inserted flush with the cortical surface. Wounds are closed using absorbable sutures and dressed. The injured arm is put in an above elbow splint. Post-operative radiographs of the forearm are taken. The patient is discharged when the child is well, either on the same day or day after surgery. The splint is worn until callus is established. Follow-up radiographs are taken after two and six weeks. Return to sports is not advocated before 3 months after surgery.
Results: We describe the surgical procedure and post- operative regime in detail using cases.
Interpretation / Conclusion: The use of BIN would deem hardware removal unnecessary and relieves the child of further surgery while reducing healthcare costs.

Andreas Falkenberg Nielsen, Ali Kuthayer Khalil Al-Hamdani, Jeppe Vejlgaard Rasmussen, Bo Sanderhoff Olsen
Department of Orthopaedic Surgery, Herlev and Gentofte Hospital, Gentofte Hospitalsvej 17, st, 2900 Hellerup, Denmark. Department of Clinical Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 København N, Denmark

Background: Open reduction and internal fixation (ORIF) is the standard treatment for multifragmentary intra-articular distal humeral fractures. Fractures not amenable by ORIF are treated with total elbow arthroplasty (TEA). In recent years, elbow hemiarthroplasty (EHA) has been used as an alternative to TEA, as weight bearing restrictions and risk of component loosening are lower.
Aim: To compare the results, we systematically reviewed the literature reporting functional outcomes and complication rates after either EHA or ORIF for AO/OTA type 13C fractures.
Materials and Methods: We searched Pubmed, Embase, The Cochrane Library, and Scopus. Inclusion criteria: At least five patients, aged 50 years or older, AO/OTA type 13C fracture treated with either ORIF or EHA, and evaluation with the mayo elbow performance score (MEPS). Two reviewers independently screened the literature, blinded to each other’s decisions. Initial data extraction was done by the first author, reviewed by the co- authors, and completed in plenum. Results were synthesized qualitatively with use of weighted means. No comparative statistical analyses were done.
Results: We included 24 papers, which included 88 patients treated with EHA and 507 patients treated with ORIF. We identified one RCT and 23 case- series. Weighted mean MEPS was 87,8 (n=83) in the EHA-group, and 84,5 (n=507) in the ORIF-group. Weighted mean flexion/extension arc was 106,6° (n=88) in the EHA-group and 98,8° (n=498) in the ORIF- group. Weighted mean pronation/supination arc was 165° (n=83) in the EHA-group and 146° (n=209) in the ORIF-group. There were 22 (31%) complications (n=70) in the EHA-group, and 95 (38%) complications (n=248) in the ORIF-group. Complication rates for ulnar nerve affection, infection with indication for revision, periprosthetic fracture, loosening, and non-union or fixation failure, were high in both groups.
Interpretation / Conclusion: We found comparable results of EHA and ORIF which indicate that EHA is a viable treatment option for AO/OTA type 13C fractures not amenable by ORIF. Due to high risk of bias, interpretation of the results should be done with caution, and randomized clinical trials comparing EHA with ORIF are needed before safe recommendation can be made.

Ali Al-Hamdani, Jeppe Rasmussen, Bo Olsen
Department of Orthopedic Surgery, Shoulder and Elbow Section, Herlev and Gentofte Hospital.

Background: Distal humeral fractures are relatively rare fractures, which comprise about 2% to 5% of all fractures and 30% of elbow fractures. Open reduction and internal fixation (ORIF) with use of Double-plating is often preferred. Previous studies reported satisfactory results following ORIF, despite considerable rate of complications.
Aim: The purpose of the study was to report the functional outcomes and complications after ORIF for acute distal humeral fractures AO/OTA type 13 C2 and C3 with minimum 2 years follow- up. Our hypothesis was that ORIF provides functional outcomes that are comparable to total elbow arthroplasty (TEA) and elbow hemiarthroplasty (EHA) reported in the literature. Thus, a case series that focuses on the functional outcome and complication rates of ORIF for AO/OTA type 13 C2-3, being the most complicated distal humeral fractures, is needed before ORIF can be indirectly compared with the results of TEA or EHA.
Materials and Methods: During a 6-year period, 23 patients older than 45 years were treated with double-plating for AO/OTA type 13 C2 or C3 fracture. The mean age was 62 years (range, 46-80 years). The Oxford Elbow Score (OES) was used as primary outcome; and Mayo Elbow Performance Score (MEPS), pain severity score (VAS), range of motion, reoperations and complications were used as secondary outcomes.
Results: Median OES was 42 (range 25-48), Twenty patients achieved "good" to "excellent" outcomes and 3 patients achieved "fair" outcomes. Median MEPS was 85 (range 60-100), Eighteen patients achieved "good" to "excellent outcomes" and 5 patients achieved "fair" outcomes. VAS was 2 (range 0-5). The median flexion/extension and supination/pronation arcs were 120 degree (range 70-155) and 160 degree (range 75-170) respectively. Eight complications were recorded in seven patients, four of them required reoperation. Our results are comparable to the results of previously published studies regarding the outcome of ORIF, EHA, or TEA.
Interpretation / Conclusion: ORIF is a reliable treatment option for acute distal humeral fractures AO/OTA type 13 C2 and C3 in middle-aged and elderly patients, despite the considerable rate of complications. Good to excellent results can be obtained in most of the patients.

Karen Mikkelsen, Adam Witten, Birgitte Hougs Kjær, Per Hölmich, Kristoffer Weisskirchner Barfod
Sports Orthopedic Research Center – Copenhagen (SORC-C), Department of Orthopedic Surgery, Copenhagen University Hospital Amager-Hvidovre, Denmark; Department of Physical and Occupational Therapy, Copenhagen University Hospital Bispebjerg- Frederiksberg, Copenhagen, Denmark; Institute of Sports Medicine Copenhagen (ISMC), Department of Orthopedic Surgery, Copenhagen University Hospital Bispebjerg-Frederiksberg, Copenhagen, Denmark

Background: Ultrasonographic measurements of the subacromial structures are reliable in the hands of experienced sonographers, but it is unknown if inexperienced clinicians can achieve a satisfactory level of reliability.
Aim: To investigate if standardized subacromial ultrasonographic measures are reliable in the hands of novice sonographers.
Materials and Methods: Two novice sonographers performed a standardized ultrasonographic protocol on symptomatic and asymptomatic shoulders of patients diagnosed with subacromial pain. The protocol consisted of measures of supraspinatus tendon thickness, subacromial bursa thickness, acromio-humeral distance and an assessment of dynamic impingement. Intraclass correlation coefficients (ICC(2,1)), standard error of measurement (SEM), minimal detectable change (MDC), 95% Limits of Agreement (LOA) and Cohen’s unweighted kappa were used to evaluate reliability and agreement.
Results: Twenty-eight patients were recruited resulting in the inclusion of 28 symptomatic and 20 asymptomatic shoulders. Intraclass correlation coefficients (ICC(2,1)) of supraspinatus tendon thickness ranged from 0.73 to 0.77 (SEM 0.4–0.5 mm; MDC 1.2-1.4 mm). Subacromial bursa thickness ICC ranged from 0.41 to 0.88 (SEM 0.2–0.4 mm, MDC 0.4-1.0 mm) and acromio-humeral distance ICC ranged from 0.68 to 0.72 (SEM 0.9 mm, MDC 2.5-2.6 mm). Cohen’s kappa of dynamic impingement in symptomatic shoulders was 0.29.
Interpretation / Conclusion: Novice sonographers achieved poor to good reliability depending on the subacromial measure. Assessment of dynamic impingement in symptomatic shoulders resulted in fair reliability and was associated with systematic bias. Results were inferior to results obtained by experienced sonographers in previous studies.

Anton Ulstrup, Michael Reinhold, Otto Falster, Nissa Khan
Department of Orthopaedic Surgery, Holbæk Hospital.

Background: A prerequisite for a satisfying functional result in the treatment of an irreparable rotator cuff rupture is significant reduction of shoulder pain and better range of motion with increased glenohumeral joint stability.
Aim: Prospective study to examine the outcome after superior capsular reconstruction using a porcine extracellular matrix dermal graft. A special emphasis was primarily on the functional outcome, secondarily on radiographical shoulder changes.
Materials and Methods: Results were evaluated using the Constant score and WORC index over a 2- year period. All patients had magnetic resonance imaging of the injured shoulder after approximately one year. Graft integration and durability were qualitatively estimated as well as any graft deterioration or resorption.
Results: 19 patients with 19 superior capsular reconstructions were included over a 4-year period. Mean age was 59 years (range 45 to 70) at the time of surgery. At final follow-up (mean 24 months, range 23 to 28) the mean Constant score had improved by a percentage average of 115 % (0-268, % increase). The mean WORC index had increased by a percentage average of 131 % (0-484, % increase). 2 out of 19 grafts were completely ruptured on follow-up magnetic resonance
Interpretation / Conclusion: We saw a group of patients with variable but significant increases in functional results with increased satisfaction and limited pain. We did not find a complete correlation between functional outcome scores and graft durability nor with single cuff defects versus larger rotator cuff defects. The group of patients were generally measurably satisfied with their result. This study suggests that a superior capsular reconstruction can yield results that are comparable or superior to other known salvage treatment options in patients with large to massive rotator cuff defects without significant cuff tear arthropathy. The hypothesis that superior capsular reconstruction can be a relevant treatment method for irreparable rotator cuff tears could not be refuted despite a fairly low patient inclusion number. With these results, selected patients can be considered for a different treatment than reverse shoulder arthroplasty, debridement or tendon transfer.

Chris Zingel Amdisen, Michael Toft Væsel, Marianne Toft Vestermark
Department of Orthopedics, Regionshospitalet Viborg, Hospitalenheds MIDT

Background: Rotator cuff tears are common injuries. They are often missed upon the initial examination at the emergency room.
Aim: In this study, the incidence rate of rotator cuff tears in patients seen in the emergency room with relevant shoulder trauma is evaluated. Furthermore, it is investigated, whether a limited clinical examination is correlated to an ultrasonography confirmed rotator cuff tear.
Materials and Methods: Patients referred to the emergency room with isolated shoulder trauma and no x-ray verified fracture, were referred to a follow-up examination with a shoulder surgeon within 14 days after trauma. At follow-up a limited clinical examination with three diagnostic tests was performed. The patients were tested for: abduction, external rotation and impingement. The clinical examination was immediately followed by an ultrasonography examination to determine the status of the rotator cuff.
Results: We included 59 patients in the study with a median age of 47 years. 7 (12%) patients had a rotator cuff tear (RC tear) upon evaluation. If the patient was a candidate for surgery, the cuff tears would be verified by MRI or arthroscopy. 17 patients had all three tests positive at the follow- up examination. Of these, 7 (24%) patients, had a RC tear. All patients with a RC tear had a positive test for external rotation, and all three diagnostic tests had negative predictive values above 92%.
Interpretation / Conclusion: 12% of the patients seen in the emergency room after isolated shoulder trauma had a RC tear. This study shows that a limited clinical examination can assist the surgeon in determining which patients are likely to have a RC tear and for whom, a referral for a concluding ultrasonography examination is likely recommendable.

Josefine Beck Larsen, Helle Kvistgaard Østergaard, Theis Muncholm Thillemann, Thomas Falstie-Jensen, Lisa Urup Reimer, Sidsel Noe, Steen Lund Jensen, Inger Mechlenburg
Department of Orthopaedic Surgery, Aarhus University Hospital; Department of Clinical Medicine, Aarhus University; Department of Orthopedic Surgery, Viborg Regional Hospital; Interdisciplinary Orthopaedics, Aalborg University Hospital; Department of Clinical Medicine, Aalborg University;

Background: Only few studies have investigated the outcome of exercises in patients with glenohumeral osteoarthritis (OA) or rotator cuff tear arthropathy (CTA), and furthermore often excluded patients with a severe degree of OA. Several studies including a Cochrane review have suggested the need for trials comparing shoulder arthroplasty to non- surgical treatments. Before initiation of such a trial, the feasibility of progressive shoulder exercises (PSE) in patients, who are eligible for shoulder arthroplasty should be investigated.
Aim: To investigate whether 12 weeks of PSE is feasible in patients with OA or CTA eligible for shoulder arthroplasty. Moreover, to report changes in shoulder function and range of motion (ROM) following the exercise program.
Materials and Methods: Eighteen patients (11 women, 14 OA), mean age 70 years (range 57-80), performed 12 weeks of PSE with 1 weekly physiotherapist-supervised and 2 weekly home-based sessions. Feasibility was measured by drop-out rate, adverse events, pain and adherence to PSE. Patients completed Western Ontario Osteoarthritis of the Shoulder (WOOS) score and Disabilities of the Arm, Shoulder and Hand (DASH).
Results: Two patients dropped out and no adverse events were observed. Sixteen patients (89%) had high adherence to the physiotherapist-supervised sessions. Acceptable pain levels were reported. WOOS improved mean 23 points (95%CI:13;33), and DASH improved mean 13 points (95%CI:6;19).
Interpretation / Conclusion: PSE is feasible, safe and may improve shoulder pain, function and ROM in patients with OA or CTA eligible for shoulder arthroplasty. PSE is a feasible treatment that may be compared with arthroplasty in a RCT setting.

Adam Witten, Karen Mikkelsen, Per Hölmich, Kristoffer Weisskirchner Barfod
Sports Orthopedic Research Center – Copenhagen (SORC-C), Department of Orthopedic Surgery, Copenhagen University Hospital Hvidovre, Denmark.

Background: Scapular dyskinesis is defined as winging or dysrhythmia of the scapula. The Scapular Dyskinesis Test (SDT) is a visually based method for evaluation of scapular dyskinesis where the patient performs five bilateral repetitions of shoulder abduction and five bilateral repetitions of shoulder flexion. The Scapula Assistance Test (SAT) is a maneuver where the examiner manually assists the patient’s scapula in order to facilitate the normal scapulohumeral rhythm during active shoulder abduction in order to alleviate pain.
Aim: To investigate the interrater reliability of the SDT and the SAT performed by inexperienced raters in patients with subacromial pain.
Materials and Methods: Consecutive patients with subacromial pain from an orthopedic outpatient clinic were eligible for inclusion if they had at least three out of five positive tests from the following: Hawkin’s, Neer’s, Jobe’s, Painful Arc and External Rotation Resistance Test. A medical student and a junior orthopedic resident performed the SDT (rated normal, subtle or obvious) and the SAT (rated positive or negative). The two raters were blinded to each other’s results.
Results: 33 patients (mean age: 52 years, SD: 19) were included during a three-month period. 12 patients could not perform the SDT due to severe shoulder pain. The overall agreement for the SDT was 86% (linear weighted kappa = 0.81). The overall agreement for SAT was 82% (kappa = 0.61).
Interpretation / Conclusion: This study indicates that SDT and SAT are reliable in a clinical setting among inexperienced raters, with substantial and almost perfect reliability, respectively, and overall good agreement.

Catarina Malmberg, Kristine Rask Andreasen, Jesper Bencke, Per Hölmich, Kristoffer Weisskirchner Barfod
Department of Orthopedic Surgery, Copenhagen University Hospital Hvidovre; Sports Orthopedic Research Center – Copenhagen, Copenhagen University Hospital Hvidovre, Denmark

Background: Traumatic anterior shoulder dislocation, or subluxation, affects shoulder kinematics. Different measures of glenohumeral translation have been presented, but no summary of results and evaluation of measurement methods exists.
Aim: To investigate anterior-posterior (A-P) glenohumeral translation in shoulders after traumatic anterior dislocation or subluxation.
Materials and Methods: This is a systematic review following the PRISMA guidelines. Patients =15 years with traumatic anterior shoulder instability were included. No intervention or comparator were investigated. The outcome was the A-P glenohumeral translation. A systematic search of PubMed, Embase, and Cochrane library was performed on September 21st 2020. Two reviewers individually screened titles and abstracts, reviewed full text, extracted data, and performed quality assessment with the NewCastle Ottawa Scale.
Results: Ten studies (355 shoulders) using various investigation methods were included: 1 with unstable shoulders only, 9 comparing stable and unstable. The most frequently tested limb position was a degree of abduction and external rotation, where the anterior translation in unstable shoulders ranged from 0.0mm (SD0.8) to 12mm (range 10-16), and one study found posterior translation of 11.1mm (SD4.1). When an anterior or anterior-inferior force was applied to the unstable shoulders, translations were consistently anterior, ranging from 4.9mm (SD0.6) to 7.9mm (SD3.1). Out of 25 comparisons, 18 reported larger A-P translation in the unstable shoulders than in the stable (5 with and 10 without statistical significance, 3 without reported significance). The largest reported difference was 4mm anteriorly (during empty-can abduction in the scapular plane or flexion in the sagittal plane) and 4.2mm posteriorly (posterior drawer test).
Interpretation / Conclusion: In shoulders with traumatic anterior instability, the glenohumeral translation was anteriorly directed in a majority of investigated motion tasks. The A-P glenohumeral translation is often larger in unstable shoulders than in stable, but not always significant. The literature is inconsistent regarding investigation methods, and it seems that measurements depend on the applied technique and limb position.

Mainz, Hanne Frandsen, Lone , Lind, Martin Faunø, Peter
Sports traumatology, Orthopedic Department, Aarhus University Hospital, Aarhus N, Denmark

Background: Comprehensive preoperative information is important to ensure that ACL patients are able to observe and respond to symptoms after discharge. Based on interviews, many patients express that these information meetings can be problematic due to difficulty of absence from school and that it is too much information during the meeting. Further, many patients were concerned after surgery and felt they were left alone with the problems.
Aim: The aim of this study was to investigate if it was possible to replace a personal pre-operative information meeting with a Web-program preparing for ACL reconstruction and to develop and implement an Action Guide to help patients to assess and address their post-operative concerns and problems.
Materials and Methods: A Web-program with all the pre- operative information was designed. To investigate how patients would like to be informed pre- operatively, 93 patients were allowed to choose between participating in the pre- operative information meeting or only to be informed by the Web-program. To address the patients` concerns after ACL surgery, we created an "Action Guide" based on the patients´ experienced problems, The purpose of the Action Guide was to help the patients to decide what to do in the post- operative period according to different problems. To evaluate the Action Guide, 76 patients participated in a survey before and after implementation of the Action Guide. As an estimate of their concerns patients were asked about their telephone call to the clinic two weeks after surgery.
Results: After implementation of the Web- program patients participating in the information meeting were reduced by 89%. Patients have expressed satisfaction with the Web-program and it does not appear to have impaired the quality of the treatment. A survey showed that the number of telephone calls from post-operative patients decreased by 34% after implementation of the Action Guide.
Interpretation / Conclusion: Most patients with anterior cruciate ligament injuries prefer information from a Web-program instead of a pre- operative information meeting. An Action Guide can help the patients to assess and address their post- operative concerns and problems, which again can reduce telephone calls to the clinic.

Yasemin Corap, Michael Brix, Julie Ringstrøm Brandt, Claus Emmeluth, Martin Lindberg-Larsen
Orthopaedic research unit, Department of Orthopaedic Surgery and Traumatology, Odense University Hospital, Department of Clinical Research, University of Southern Denmark

Background: With the increasing number of knee arthroplasties performed, the need of reoperations due to periprosthetic fractures or due to bone loss will also increase. Hence, the need of distal femoral resection knee arthroplasty is expected to increase. The procedure may be safe, but the true impact of these procedures on patient functional and health status is unknown.
Aim: to present living conditions, pain, functional status and quality of life after distal femoral resection knee arthroplasty for non-tumor indications.
Materials and Methods: We identified 45 knees (45 patients) treated with distal femoral resection knee arthroplasty in a single institution between 2012 and December 2020. 16 patients refused or was unable to participate (6 deceased). A total of 30 patients were included after informed consent. Oxford Knee Score (0-48, 48 best), EQ5D (5 dimensions) and Copenhagen Knee ROM were completed and information on pain and living conditions was obtained.
Results: The mean age was 67.9 years (SD 13.6) and 21 (70%) were female. A total of 27 patients (90%) lived in own home and 3 (10%) were staying in nursing homes. 20 (66.7%) of patients living in their own homes did not need home care, 5 (16.6%) received home care 1-2 times every 2. weeks and 5 (16.6%) every day. 18 patients (60%) used mobility aids (9 (30%) canes, 8 (26.7%) walkers, 1 (3.3%) wheelchairs). 9 (30%) used paracetamol or NSAID and 2 (6.7%) used opioids for their knee pain. Mean VAS pain score when standing was 1.30 (SD 2.2) and 2.8 (SD 3.1) in motion. Mean total Oxford Knee Score was 30.1 (SD 10.3). Mean EQ- 5Dindex score was 0.70 (SD 0.22) and mean EQ-5D VAS score was 55.4 (SD 23.9). Mean Copenhagen Knee ROM flexion was 116° (SD 21.6) and mean extension was – 2° (SD10.1)
Interpretation / Conclusion: Distal femoral resection knee arthroplasty appears to be a viable treatment option. Acceptable outcomes in terms of daily living, pain, functional status and quality of life of the patients can be achieved, especially when comparing with status after treatment alternatives such as femoral amputations.

Naaja Petersson, Stian Langgård Jørgensen, Troels Kjeldsen, Inger Mechlenburg, Per Aagaard
Naaja Petersson: Department of Sports Science and Clinical Biomechanics, University of Southern Denmark. Stian Langgård Jørgensen: Department of Occupational and Physical Therapy, Horsens Regional Hospital; H-Hip, Horsens Regional Hospital; Department of Clinical Medicine, Aarhus University. Troels Kjeldsen: Department of Orthopedic Surgery, Aarhus University Hospital; Department of Clinical Medicine, Aarhus University. Inger Mechlenburg: Department of Orthopedic Surgery, Aarhus University Hospital; Department of Clinical Medicine, Aarhus University. Per Aagaard: Department of Sports Science and Clinical Biomechanics, University of Southern Denmark.

Background: Knee osteoarthritis (OA) negatively affects skeletal muscle size and strength, which impairs the capacity to perform activities of daily living and results in a reduced quality of life. Walking exercise with concurrent lower limb blood flow restriction (BFR- walking) has previously been shown to increase muscle strength and improve function in elderly Japanese individuals.
Aim: To examine changes in functional capacity and self-reported knee function in response to 8-10 weeks of blood flow restricted walking in elderly adults with knee osteoarthritis.
Materials and Methods: Fourteen elderly individuals diagnosed with knee osteoarthritis participated in 8-10 weeks of outdoor walking (4 km/h, 20 minutes/session, 4 times/week) with partial blood flow restriction (60% of arterial occlusion pressure) of the affected leg. Timed-Up & Go, 30-s sit-to-stand test, 40-m fast-paced walk test, 11-step stair-climb test, and Knee Osteoarthritis Outcome Score were assessed pre- and post-training.
Results: Nine participants completed 8-10 weeks of blood flow restricted walking. Considering completed case data, adherence rate was 93%, while mean knee pain and perceived exertion in the affected leg was 0.7 and 3.4 on a numerical rating scale from 0-10. Functional capacity was improved following the intervention period (30STS (+16%), TUG (-8%) and 40MWT (+5%)), while measures of self-reported knee function remained unchanged. Five participants withdrew from the study, of which four experienced intervention-related adverse events (knee pain, cuff discomfort).
Interpretation / Conclusion: The present group of elderly adults with knee osteoarthritis demonstrated improvements in functional capacity following 8-10 weeks BFR walk-training, without any changes in self-reported knee function.

Stian Langgård Jørgensen, Inger Mechlenburg
Department of occupational and physical therapy, Regional Hospital Horsens; Department of Clinical Medicine, Aarhus University; H-hip, Regional Hospitalet Horsens; Department of orthopedic surgery, Aarhus University Hospital

Background: Reactive arthritis (ReA) in the knee joint is characterized by joint swelling and pain. Exercise prohibiting muscular atrophy and loss of muscle strength is highly recommended. However, joint pain and swelling can affect the ability to reach sufficiently high exercise intensities to promote skeletal muscle hypertrophy and increase strength. Low-load blood flow restricted resistance exercise (BFRE) has previously been demonstrated to promote skeletal muscle hypertrophy and increase strength without exacerbating joint pain in other patient populations
Aim: To investigate if 12 weeks of BFRE every second day could increase lower limb function and decrease knee joint swelling in a young male patient suffering from long-lasting ReA
Materials and Methods: A 20-year-old male suffering from ReA in his right knee performed 12 weeks of home-based BFRE consisting of squat and lunges with body weight as the only resistance. Each exercise was performed every second day and consisted of 4 rounds of 30,15,15,15 repetitions interspaced by 30 seconds rest between sets and 5 min rest between exercises. Exercises were performed with a pneumatic cuff around the right limb and inflated to 130 mmHg (week 1-3), 140 mmHg (week 4-6), and then 150 mmHg (week 7-12). The pressure was maintained during each exercise and deflated in the 5-min rest pause between exercises At baseline and after 3, 6, 9, and 12 weeks, the patient performed unilateral 30-sec sit-to-stand test (30STST), thigh circumference, and completed Knee Injury and Osteoarthritis Outcome Score (KOOS) (0-100) and the Forgotten Knee Joint Score (FKJS) (0-48) questionnaires.
Results: All planned sessions were completed without pain exacerbation from the knee. 30STS improved from 10 repetitions (reps) to 17 reps on the right limb and from 13 reps to 18 reps on the left leg. Thigh circumference decreased from 41 cm to 40.4 cm on the right leg and from 38.4 cm to 37.4 cm on the left leg. KOOS symptoms, ADL, and quality of life demonstrated a clinically relevant improvement from 54 to 64, 82 to 96, and 56 to 69. The FKJS decreased from 38 points to 27 point.
Interpretation / Conclusion: Home-based BFRE may be an effective exercise method for patients suffering from long-lasting ReA.

Christian Kveller, Simon Toftgaard Skov, Kristian Høy, Cody Bünger
Department of Orthopedic Surgery, Horsens Regional Hospital; Spine Section, Center for Planned Surgery, Silkeborg Regional Hospital; Spine Section, Department of Orthopedic Surgery, Aarhus University Hospital; Spine Section, Department of Orthopedic Surgery, Aarhus University Hospital

Background: Chondrosarcomas are malignant tumors of connective tissue, characterized by the formation of a chondroid matrix by the tumor cells and are the second-most common primary spinal sarcoma in adults. These tumors are resistant to both chemotherapy and radiotherapy and are situated in close proximity to radiosensitive neural structures. In theory, particle therapy could remedy this based on the physical properties of the radiation.
Aim: The primary aim was to investigate the isolated clinical effects on overall survival following spinal chondrosarcoma (SCS) treatment with particle therapy versus photon radiotherapy in adults.
Materials and Methods: A systemic review of available literature was conducted in Cochrane, Medline and EMBASE and meta-analysis was performed on data from primary studies. The databases were searched from inception until December 2019. The search yielded 1239 articles of which 28 which were eligible for inclusion with a combined patient population of 2151.
Results: Our overall weighted estimate of the data suggests a slight advantage in treating SCS located in skull and spine with particle therapy compared to photon radiotherapy on 5-year overall survival (93.4% vs 88.2%) and an advantage on 5-year local control (91.8% vs 75.9%). A sub-analysis of particle therapy paradoxically suggests carbon ion therapy to be slightly superior compared to proton therapy on 5-year overall survival (97% vs 91.9%) but not 5-year local control (88.7% vs 93.1%).
Interpretation / Conclusion: Particle therapy allows for the safe and effective delivery of radiation doses exceeding 70 GyE (Gray equivalents), necessary to treat SCS. It can spare surrounding tissues of up to 25 GyE, resulting in acceptable levels of radiation toxicities, while 5-year overall survival is slightly improved and local control is substantially improved compared with photon-based therapies. The difference in the treatment of SCS with proton or carbon ion therapy does not appear substantial. Further analysis of the outcomes and evidence of treatment effect is needed to eliminate center bias in the body of evidence.

Gustav Østerheden Andersen, Stefan Milosevic, Mads Moss Jensen, Mikkel Østerheden Andersen, Ane Simony, Mikkel Mylius Rasmussen, Leah Carreon
Cense-Spine, Department of Neurosurgery, Aarhus University Hospital; Cense-Spine, Department of Neurosurgery, Aarhus University Hospital; Cense-Spine, Department of Neurosurgery, Aarhus University Hospital; Center for Spine Surgery & Research, Middelfart Hospital; Center for Spine Surgery & Research, Middelfart Hospital; Cense- Spine, Department of Neurosurgery, Aarhus University Hospital; Center for Spine Surgery & Research, Middelfart Hospital

Background: Coccydynia is pain originating from the os coccygis, a condition for which several treatments are being practised today.
Aim: To evaluate the efficacy of available treatment options for patients with persistent coccydynia through a systematic review.
Materials and Methods: Original peer-reviewed publications on treatment for coccydynia were identified using PRISMA guidelines by performing a literature search of relevant databases, from their inception to January 17, 2020, combined with other sources. Data on extracted treatment outcome was pooled based on treatment categories to allow for meta-analysis. All outcomes relevant to the treatment efficacy of coccydynia were extracted. No single measure of outcome was consistently present among the included studies. Numeric Rating Scale, (NRS, 0 to 10) for pain was used as the primary outcome measure. Studies with treatment outcome on adult patients with chronic primary coccydynia were considered eligible.
Results: A total of 1980 patients across 64 studies were identified: 5 randomized controlled trials, 1 experimental study, 1 quasi-experimental study, 11 prospective observational studies, 45 retrospective studies and unpublished data from the DaneSpine registry. The greatest improvement in pain was achieved by patients who underwent radiofrequency therapy (RFT, mean VAS decreased by 5.11cm). A similar mean improvement was achieved from Extracorporeal Shockwave Therapy (ESWT, 5.06), Coccygectomy (4.86) and Injection (4.22). Although improved, the mean change was less for those who received Ganglion block (2.98), Stretching/Manipulation (2.19) and Conservative/Usual Care (1.69).
Interpretation / Conclusion: Ganglion block, conservative therapy and Stretching/Manipulation showed limited improvement. Although sparsely investigated, injections and ESWT showed promising results and should be considered before coccygectomy. Coccygectomy remains the most studied treatment, and despite having varying complication rates consistently demonstrates high efficacy when treating otherwise refractory patients. RFT demonstrated overall good relief of pain and may prove an alternative to surgery in the future.

Mads Moss Jensen, Stefan Milosevic, Gustav Østerheden Andersen, Leah Carreon, Ane Simony, Mikkel Mylius Rasmussen, Mikkel Østerheden Andersen
Cense-Spine, Department of Neurosurgery, Aarhus University Hospital; Center for Spine Surgery & Research, Middelfart Hospital

Background: Coccydynia is pain originating in the coccyx and surrounding tissue. Coccygectomy, which is surgical amputation of the coccyx, is a way to relieve patients from their debilitating symptoms if nonoperative therapy fails to do so. The authors investigate prognostication in a prospective cohort of 134 coccygectomized patients who all suffered from persistent coccydynia and were diagnosed with instability of the coccyx. At present, no tool to improve patient selection is available.
Aim: The purpose of this study is to identify prognostic factors predictive of poor outcome following coccygectomy on patients with persistent coccydynia due to instability of the coccyx.
Materials and Methods: Through DaneSpine, the Danish National Spine Registry, 134 consecutive patients were identified from a single center experience on coccygectomy performed from 2011 to 2019. Patient demographics, including age, gender, body-mass- index (BMI), smoking status, work status, welfare payments as well as patient-reported outcomes (PROs), including pain VAS-score (0-100), Oswestry Disability Index (ODI), Euro-QoL-5D (EQ-5D), Short Form-36 (SF-36) Physical Component Score (PCS) and Mental Component Score (MCS) were obtained at baseline and at 1-year follow-up. In addition, patient satisfaction with the procedure was obtained at follow-up.
Results: A minimum of 1-year follow-up was available in 112 patients (84%). Mean age was 41.9 years (range 15-78) and 97 of the patients were female (87%). Patients were divided into three groups based on satisfaction. Regression showed no statistically significant association between the investigated prognostic factors and a poor outcome following coccygectomy. The satisfied group showed a statistically significant improvement in PROs at 1- year follow-up from baseline, whereas the not satisfied group did not show a significant improvement.
Interpretation / Conclusion: We did not identify factors prognostic for a poor outcome following coccygectomy. This suggests that neither of the included parameters should contradict treatment with coccygectomy for patients who suffer from persistent coccydynia with instability of the coccyx.

Lene Lindberg Miller, Torsten Grønbech Nielsen, Inger Mechlenburg, Martin Lind
Sports Trauma Clinic, Department of Orthopaedics, Aarhus University Hospital; Sports Trauma Clinic, Department of Orthopaedics, Aarhus University Hospital; Department of Orthopaedics, Aarhus University Hospital, Department of Clinical Medicine, Aarhus University; Sports Trauma Clinic, Department of Orthopaedics, Aarhus University Hospital

Background: Knee function and ability to return to pivoting sports activities after anterior ligament (ACL) reconstruction is assumed to be influenced by postoperative rotational knee stability, which can be evaluated by the degree of pivot shift. The Knee injury and Osteoarthritis Outcome Score (KOOS) is an instrument to assess the patients’ opinion about their knee problems. The relationship between postoperative pivot shift and the KOOS subscores Sports and Quality of life (QoL) have not previously been investigated.
Aim: The aim was to investigate whether KOOS Sports and KOOS QoL are related with the postoperative rotational stability evaluated one year after primary ACL reconstruction. The hypothesis is that patients with a pivot shift test degree =1 have lower outcome scores than patients with a pivot shift test degree =0.
Materials and Methods: This cross-sectional study was based on data from the Danish Ligament Reconstruction Register (DLRR) from 2005-2019. Inclusion criteria: Primary isolated ACL reconstruction; age >16 years; Patients had completed KOOS; Patients were evaluated and registered at the DLRR by orthopaedic surgeon or physiotherapist 1 year postoperatively including pivot shift test. The relationship between Sports, QoL and knee stability were analyzed using students t-test and presented as mean values with confidence intervals (95% CI).
Results: 1615 patients (48% females), mean age 25 (SD 8) years were found eligible for this study. 1334 (83%) patients had no pivot shift while 281 (17%) had degree 1-3. Mean KOOS Sports for patients with no pivot shift: 63.6 (95% CI 62.3;64.9) and with positive pivot shift: 59.4 (95% CI 56.6;62.3), (P < 0.004). Mean KOOS QoL for patients with no pivot shift: 59.0 (95% CI 57.9;60.1) and with positive pivot shift: 54.2 (95% CI 51.9;56.5), (P < 0.0003). The minimal important changes (MIC) for the KOOS Sports and QoL (12.1 and 18.3) were not met.
Interpretation / Conclusion: Knee related Sports and Quality of life is statistically related to rotational knee stability 1 year after ACL reconstruction. However, the differences in KOOS Sports and KOOS QoL between the groups were not clinically relevant.

Anders Rottwitt, Nichlas Bek, Carsten Jensen, Bjarke Viberg
Department of Orthopaedic Surgery and Traumatology, Lillebaelt Hospital, University Hospital of Southern Denmark

Background: Strengthening of the quatriceps musculature through high load resistance (HL-RT) training is a cornerstone in knee rehabilitation. Despite decreasing symptoms and improving strength, HL- RT can be unfeasible for some patients. Low-load blood flow restricted training (LL-BFRT) is an alternative, incorporating partial vascular occlusion. LL-BFRT has been found equal to HL-RT in terms of strength improvements, while being less stressful on the knee.
Aim: To assess the effect of an eight-week training protocol using LL-BFRT in patients with persisting knee pain.
Materials and Methods: Prospective cohort study consisting of participants with at least six months of persisting knee pain or at least 3 months of unsuccessful rehabilitation. The participants were instructed, by a physiotherapist, to do daily sessions of single-legged squat on the leg of the affected knee with blood flow restriction (BFR). Baseline and eight-week measurements were performed for the Knee injury and Osteoarthritis Outcome Score (KOOS), isometric maximal voluntary contraction (iMVC) for quadriceps extensions, thigh girth and physical performance tests. Results are given with 95% confidence interval.
Results: Thirty-five participants completed the study, two participants dropped out (one due to exercise related pain) and seven declined follow-up. The mean age was 38 years and 47% were female. LL-BFRT had a statistically significant effect with a mean change of 5.6 [0.1 ; 11.2] points in the KOOS-subscale for Quality of Life (QoL) (p<0.04), 14.6 [5.1 ; 24.0] Nm in iMVC (p<0.01), 11.6 [0.8 ; 22.4] cm in one-leg jump for distance (p<0.04), 25.9 [1.9 ; 49.9] cm in one-leg crossover jump (p<0.04), and 7.2 [3.0 ; 11.3] reps in one-leg 30 seconds side hop (p<0.01). Of the participants completing the study, the general session completion rate was 5.4 out of 7 weekly sessions, with a mean VAS score of 56.9 out of 100. No statistically significant im¬provements were observed in any other KOOS-subscales.
Interpretation / Conclusion: LL-BFRT is a feasible training form for patients otherwise unable to perform physiotherapy with improvements in the QoL subscale, iMVC and physical performance, but not in the subscale for pain.

Lasse Ishøi, Per Hölmich, Kristian Thorborg, Jesper Bencke
Sports Orthopedic Research Center - Copenhagen (SORC-C), Ortopædkirurgisk Afdeling, Hvidovre Hospital

Background: Athletes with femoroacetabular impingement syndrome often report problems in sprinting compared to walking and jogging. This discrepancy may be related to the difference in peak moments distributed across the hip joint
Aim: In this cross-sectional study, we examined external hip joint moments during walking, jogging, and sprint acceleration.
Materials and Methods: We included 20 healthy sports active adults (mean age 24.7 years). The primary outcome was external hip joint peak moments for adduction, abduction, flexion, and extension during: walking with a self- paced speed; jogging with 8-11 km/h; and maximal sprint acceleration. Data was collected in a 3D Motion Analysis Laboratory with two floor-embedded AMTI force platforms. The mean of three trials for each activity was captured on the dominant leg for analyses.
Results: Maximal sprint acceleration resulted in higher external peak moments than jogging and walking for all external moments (p=0.006). The increase from walking and jogging to sprinting was 16-128 % for adduction, 168-195 % for abduction, 105-148 % for flexion, and 61-121 % for extension. Furthermore, a 36 % higher extension moment was observed for walking compared to jogging (p<0.001), whereas a 96 % higher adduction moment was observed for jogging compared to walking (p>0.001).
Interpretation / Conclusion: Substantially higher hip joint moments were observed in sprint acceleration compared to walking and jogging, whereas jogging only showed a higher adduction moment compared to walking. This information may explain why patients with femoroacetabular impingement syndrome often tolerate walking and jogging activities and to a lesser extent sprinting.

Thomas Linding Jakobsen, Kristian Thorborg, Jakob Fisker, Thomas Kallemose, Thomas Bandholm
Department of Orthopedic Surgery, Amager and Hvidovre Hospital

Background: In musculoskeletal rehabilitation, blood flow restriction (BFR) resistance exercise is potentially indicated in patients who may not load tissues as required for “classic” heavy resistance exercise.
Aim: The purpose of this study was to explore the feasibility of rehabilitation with BFR resistance exercise in patients with early weight bearing restrictions after meniscus or cartilage repair in the knee joint.
Materials and Methods: In total, 42 patients with meniscus (n=21) or cartilage repair (n=21) in the knee joint attended 9 weeks of supervised rehabilitation with BFR resistance exercise at an outpatient rehabilitation center (5 sessions/week). Clinical outcomes were assessed at different time points from 2 to 26 weeks postoperatively and included: Thigh circumference (muscle size proxy), isometric knee-extension strength, knee joint and thigh pain, knee joint range of motion and effusion, perceived exertion, self- reported disability and quality of life, and adverse events.
Results: On average, patients performed 48 BFR sessions (35 home, 13 supervised). 38 patients reported 64 harms (dizziness, n=52) - none considered serious. Thigh circumference increased 0.6 cm (SD=1.5) from baseline to end of the rehabilitation program for the operated leg from 52.8 to 53.3 cm (p=0.01), and 0.1 cm (SD=1.1) for the healthy leg from 54.9 to 55.0 cm (p=0.41). At 26 weeks postoperatively, isometric knee-extension strength (limb symmetry index) was 83% (SD=25).
Interpretation / Conclusion: Rehabilitation with BFR resistance exercise initiated early after meniscus or cartilage repair in the knee joint seems feasible and may increase thigh muscle mass during a period of weight bearing restrictions. Harms were reported, but no serious adverse events were found. Trial registration: NCT03371901

Christian Fugl Hansen, Maria Østergaard Madsen, Martin Rathcke, Susan Warming, Michael Rindom Krogsgaard, Karl Bang Christensen
Section for Sports Traumatology M51, Bispebjerg and Frederiksberg Copenhagen University Hospital; Department for Physio- and Ergotherapy, Bispebjerg and Frederiksberg Copenhagen University Hospital; Section of Biostatistics, Department of Public Health, University of Copenhagen

Background: The Knee injury and Osteoarthritis Outcome Score for Children (KOOS-Child) is a modified version of the adult KOOS. It consists of five domains (‘Symptoms’, ‘Pain’, ‘ADL’, ‘Sports/Play’, and ‘QoL’), and aims to evaluate “knee injury that can result in post-traumatic osteoarthritis”, including ACL deficiency. However, the measurement properties of KOOS-Child have yet to be assessed in a cohort of children with ACL deficiency.
Aim: To study the structural validity of the questionnaire KOOS-Child using modern test theory models (Rasch analysis and confirmatory factor analysis (CFA)).
Materials and Methods: Data were collected prospectively before surgery and at 1-year follow-up in a cohort of 226 children with ACL deficiency, treated with epiphyseal sparing reconstruction at Bispebjerg University Hospital. Patients with age >16, incomplete data, previous surgery, or concomitant fractures were excluded. For each subscale, we evaluated the fit of a CFA model, looked at modification indices to find a model with better fit if necessary, and confirmed the models using Rasch analysis. Rasch analysis assessed item fit. Floor and ceiling effects were reported.
Results: Four out of five subscales showed inadequate fit to the CFA model, while the ‘QoL’ subscale data fitted the model well. Rasch analysis confirmed these results. When adjusting the four subscales using a bi-factor CFA model, modelling local dependence, and removing redundant items, subscales exhibited better model fit. Most items in the three subscales ‘Symptoms’, ‘Pain’, and ‘ADL’ demonstrated substantial ceiling effects, with few exceptions.
Interpretation / Conclusion: The QoL subscale of KOOS-Child has adequate measurement properties in its original form for children with ACL deficiency. The four other subscales can be adjusted, either by removing non- functioning and redundant items, or by changing the scoring principles, to make them fit the models better. Suggestions for this are presented and can be used in a version 3.0 if they are confirmed in other studies. However, large ceiling effects in three subscales may reduce the sensitivity of these and induce type two errors. Future research should aim at determining the responsiveness and MCID of the scale.

Astrid K. Petersen, Mette K. Zebis, Hanne B. Lauridsen, Per Hölmich, Per Aagaard, Jesper Bencke
Department of Physiotherapy, University College Copenhagen, Copenhagen, Denmark; Department of Physiotherapy, University College Copenhagen, Copenhagen, Denmark; Team Danmark, Brøndby, Denmark; Department of Orthopaedic Surgery, Amager- Hvidovre Hospital, Hvidovre, Denmark; Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark; Human Movement Analysis Laboratory, Department of Orthopaedic Surgery, Amager-Hvidovre Hospital, Hvidovre, Denmark.

Background: Ankle sprain is the most common type of sports injury, especially in team sports. Previous ankle ligament sprain predisposes for recurrent ankle sprain. Standing and dynamic balance, as an indicator of ankle ligament re-injury risk, have been investigated using varying experimental approaches.
Aim: The aim of the present study was to examine a new test of functional recovery after ankle injury by focusing on the very early landing stability.
Materials and Methods: In the present cross-sectional study, 81 adolescent female elite team handball and football players were divided into two groups based on previous ankle sprain injury (PI) or not (C). The PI group were all back in full participation in their sports. All players were tested during a one-legged landing (OLL) and in a one-legged static stand balance test (OLBT). In the OLL test, CoP trajectory displacement was calculated in 200 ms time epochs for evaluation of the initial stages of dynamic landing balance. OLBT was evaluated by calculating total (10 seconds) displacement of the CoP trajectory.
Results: CoP displacement was greater in PI than C during the first 200 milliseconds epoch after landing (p = 0.001, PI (SD) = 44, C (SD) = 28) and in the subsequent 200 ms epoch (p = 0.02, PI (SD) = 20, C (SD) = 16). No significant differences between CI and C were observed in time epochs from 400 to 1000 milliseconds or in OLBT.
Interpretation / Conclusion: Adolescent elite athletes with a history of previous ankle sprain demonstrate impaired one- legged landing balance in the first 400 milliseconds following one-legged jump-stop landing compared to non-injured controls. Consequently, although athletes with previous ankle sprain may return to sport, dynamic postural control may not be fully restored. The one-legged landing test may be considered a relevant criterion tool for safe return-to-sport, and this test seems more sensitive to functional stability than a standing balance test.

Christian Fugl Hansen, Jonas Jensen, Anders Odgaard, Volkert Siersma, Jonathan Comins, John Brodersen, Michael Rindom Krogsgaard
Section for Sports Traumatology M51, Bispebjerg and Frederiksberg University Hospitals; Department of Orthopaedic Surgery, Rigshospitalet University Hospital; The Research Unit for General Practice and Section of General Practice, Department of Public Health, University of Copenhagen; Primary Health Care Research Unit, Region Zealand

Background: Content validity is the most important measurement property of PROMs. The latest COSMIN guidelines for evaluating the content validity of PROMs are often referred to as a gold standard and have only sparsely been applied to PROMs for musculoskeletal conditions
Aim: To use the COSMIN Risk of Bias checklist to evaluate the content validity of five PROMs, that are highly relevant in musculoskeletal research and used by the arthroscopic community: the modified Harris’ Hip Score (mHHS), the Copenhagen Hip and Groin Outcome Score (HAGOS), the International Knee Documentation Committee Subjective Knee evaluation Form (IKDC-SKF), the Knee injury and Osteoarthritis Outcome Score (KOOS) and the Knee Numeric-Entity Evaluation Score - ACL (KNEES- ACL).
Materials and Methods: The development articles for the five PROMs were identified through searches in PubMed and SCOPUS. An additional literature search was performed to identify studies assessing content validity of the PROMs. Any missing information were obtained from the five original developers after direct request if possible. To evaluate the quality of the development studies and rate the content validity, the COSMIN Risk of Bias checklist was applied to all relevant studies.
Results: Five development studies and three subsequent content validity studies were identified. One content validity study was of inadequate quality and excluded from further analysis. The development of mHHS, IKDC-SKF, and KOOS were rated inadequate and these PROMs possess insufficient content validity for their target populations. Due to the irrelevance of multiple items, KOOS was in particular inappropriate to evaluate patients with an ACL injury. The development of HAGOS was also rated inadequate, although the insufficiency aspects can be regarded as minor. KNEES-ACL possessed sufficient content validity.
Interpretation / Conclusion: Out of five highly relevant orthopaedic PROMs, only KNEES-ACL possessed sufficient content validity according to COSMIN guidelines. There is an urgent need in musculoskeletal research for condition- specific PROMs developed with adequate methods.

Jesper Glerup, Henrik Aagaard, Jakob Klit
Department of Orthopedics, Zealand University Hospital, Køge; Department of Clinical Medicine, University of Copenhagen; Aleris-Hamlet Hospital, Copenhagen

Background: The typical patient considered for anterior cruciate ligament reconstruction (ACLR) is an athlete in the second and third decade of their lives. As more people tend to be more physically active in their 30s and later on, the demands to the anterior cruciate ligament (ACL) may increase in this part of the population. This leaves the surgeon with an increasing need of scientific evidence when counselling patients =30 years prior to ACLR.
Aim: To determine the relationship between age at ACLR and patient reported outcomes (PRO) at one-year follow-up.
Materials and Methods: Nationwide registry study with prospectively collected data. Patients undergoing ACLR from 2005 to 2018 completed the Knee Injury and Osteoarthritis Outcome Score (KOOS) and Tegner activity scale prior to and one year after ACLR. Patients with multiligament injuries or revision ACLR were excluded, as were nonresponders. Patients were divided into three age groups of 0-14 years (n = 174), 15-29 years (n = 2,873) and =30 years (n = 1,862). Change in PRO from preoperatively to one-year follow-up and absolute PRO at baseline and one-year follow-up were assessed independently by univariable analyses. A multivariate regressions model for change in KOOS was performed to assess whether gender was a confounder.
Results: A total of 4,909 subjects were included (2,348 female, mean age 27.9 ± 10.6 years). Change in KOOS varied between the three age groups (p < 0.001). The =30 years age group had better outcomes than the 15-29 years age group in change in KOOS (1.44, CI: 0.19;2.69, p < 0.01), KOOS Pain (p < 0.01), KOOS ADL (p < 0.0001) and KOOS QoL (p < 0.001), but worse in Tegner (p < 0.001). No statistically significant differences were found in KOOS4, KOOS Symptoms or KOOS Sports/Recreation. The =30 years age group had statistically significant poorer absolute results before ACLR and at one-year follow-up compared to the 15-29 years age group in KOOS, all KOOS subscales and Tegner. Gender was not a confounder for change in KOOS between age groups 15-29 years and =30 years.
Interpretation / Conclusion: Patients =30 years show similar or greater benefits from ACLR as patients 15-29 years of age in KOOS and KOOS subscales, but not in Tegner, during one-year follow-up.

Bjørn Borsøe Christensen, Morten Lykke Olesen, Casper Bindzus Foldager, Kris Chadwick Hede, Jonas Jensen, Martin Lind
Department of Orthopedics, Horsens Regional Hospital; Department of Orthopedics, Aarhus University Hospital; Orthopedic Research Laboratory, Aarhus University; Department of Radiology, Aarhus University Hospital; Division of Sports trauma, Aarhus University Hospital, Denmark

Background: Osteochondral injuries are difficult to treat, and no gold standard treatment exists. Autologous Dual- Tissue Transplantation (ADTT) is a one-step, combined autologous bone and articular cartilage chips transplantation for osteochondral injuries.
Aim: The aim of this study was to investigate the long- term results of Autologous Dual-Tissue Transplantation
Materials and Methods: Eight patients with osteochondral injuries were included. The bottom of the debrided defect was filled with autologous bone and superficially cartilage chips were embedded in fibrin glue. Evaluation was performed using MRI, CT and patient reported outcome scores.
Results: The IKDC score increased from 35.9 to 68.1, 73.0, 75.3 and 72.9 after one, two, five and 7.5 years (p<0.01). The Tegner score improved from 2.5 to 4.7, 4.8, 4.8 and 4.6 at one, two, five and 7.5 years (p<0.001). KOOS improved at one year and the improvements persisted at two, five and 7.5 years (p<0.01). Cartilage repair evaluated using MOCART score improved from 22.5 to 53.1 at one year (p <0.01), with a slight deterioration to 44.3 after 7.5 years (not statistically significant). CT showed an average bone defect filling of 80% at one year. At 7.5 years CT showed an average bone filling of 90% and a more even surface than at one year.
Interpretation / Conclusion: ADTT resulted in good subchondral bone restoration and cartilage repair. Significant improvements in patient reported outcome was found at one year postoperative and the improvements persisted at two, five and 7.5 years. This study suggests ADTT as a promising, low-cost, treatment for osteochondral injuries.

Lasse Ishøi, Kristian Thorborg, Joanne Kemp, Michael Reiman, Per Hölmich
Sports Orthopedic Research Center – Copenhagen (SORC-C), Department of Orthopedic Surgery, Copenhagen University Hospital, Amager-Hvidovre, Denmark ; La Trobe Sport and Exercise Medicine Research Centre, School of Allied Health, Human Services and Sport, La Trobe University, Melbourne, Australia. ; Duke University Medical Center, Department of Orthopedic Surgery, Duke University, Durham, North Carolina, United States.

Background: Reduced sports function is often observed after hip arthroscopy for femoroacetabular impingement syndrome (FAIS). Impaired muscle strength could be reasons for this.
Aim: We aimed to investigate hip muscle strength after hip arthroscopy for FAIS and its association with levels of sports function and participation.
Materials and Methods: We included 45 patients (34 males; mean age: 30.6 ± 5.9 years) after unilateral hip arthroscopy for FAIS (mean follow-up [range]: 19.3 [9.8-28.4] months). Maximal isometric hip muscle strength (Nm/kg) including early- (0-100 ms) and late-phase (0-200) rate of torque development (Nm/kg/s) for adduction, abduction, flexion, and extension was measured with an externally fixated handheld dynamometer and compared between operated and non-operated hip. Associations between muscle strength and self- reported sports function and return to sport were investigated.
Results: For maximal hip muscle strength, no between-hip differences were observed for adduction, abduction, flexion, and extension (p=0.102). For rate of torque development, significantly lower values were observed for the operated hip in flexion at both 0- 100 ms (mean difference: 1.58 Nm/kg/s, 95% CI [0.39; 2.77], p=0.01) and 0-200 ms (mean difference: 0.72 Nm/s/kg, 95% CI [0.09; 1.35], p=0.027). Higher maximal hip extension strength was significantly associated with greater ability to participate fully in preinjury sport at preinjury level (Odds ratio: 17.71 95% CI [1.77; 177.60]).
Interpretation / Conclusion: After hip arthroscopy for FAIS subjects show limited impairments in maximal and explosive hip muscle strength between operated and non-operated hip. Higher muscle strength was positively associated with higher sports function and ability to participate in sport.

Simone Elmholt, Kris Hede, Bjørn Christensen, Martin Lind
: Department of Sports Traumatology, Aarhus University Hospital

Background: Bone marrow stimulation (BMS) is the most frequently used surgical treatment method for symptomatic cartilage injuries in the knee. During this treatment the subchondral bone is perforated in order to initiate a bone marrow healing response. How these perforations affect the subchondral bone morphology and remodeling postoperatively has not been extensively investigated.
Aim: The purpose of this study was to investigate how (BMS) affects the subchondral bone plate morphology and remodeling compared to adjacent untreated subchondral bone in a validated minipig model.
Materials and Methods: Three adult Göttingen minipigs received BMS with drilling as treatment for two chondral defects in each knee. The animals were euthanized after six months. Follow-up consisted of semiquantitative evaluation of histology with a novel subchondral bone scoring system and ?CT of the BMS subchondral bone. Data from BMS-treated subchondral bone was compared to adjacent healthy subchondral bone.
Results: Data from ?CT showed that subchondral bone treated with BMS had significantly higher connectivity density (CD) (25.7 1/mm3 vs. 21.4 1/mm3, p = 0,048) compared to adjacent untreated subchondral bone. For the histological semiquantitative score subchondral bone had good resemblance with adjacent untreated subchondral bone (7.9 vs. 10 p = 0.00002) with sparse formation of bone cysts (1%) but some surface irregularities and bone overgrowth were seen in 27% of the histological sections.
Interpretation / Conclusion: BMS with drilling does not cause extensive changes to the subchondral bone microarchitecture. Furthermore, the morphology of BMS subchondral bone had good resemblance with untreated subchondral bone with almost no formation of bone cyst but some surface irregularities and bone overgrowth.

Mathias Fabricius Nielsen, Kristian Thorborg, Kasper Krommes, Kasper B. Thornton, Per Hölmich, Juan J. J. Penalver, Lasse Ishøi
Sports Orthopedic Research Center – Copenhagen (SORC-C), Department of Orthopedic Surgery, Copenhagen University Hospital, Amager-Hvidovre, Denmark.

Background: The long lever squeeze test can be used to screen and detect groin problems, based on hip adduction squeeze strength, and provoked groin pain, when maximal squeeze contraction is sustained for 5 seconds; referred to as the Copenhagen 5-second-squeeze test (5SST). A novel strength assessment system, the ForceFrame, also provides a method to measure squeeze strength and provoked pain in the long-lever position, albeit with a slightly different hip abduction angle. Since the hip angle can influence hip adduction strength values, this may affect the agreement between the 5SST and the ForceFrame.
Aim: To evaluate the agreement between the Copenhagen 5-Second-Squeeze test and the ForceFrame for measures of hip adduction squeeze strength and provoked groin pain in elite male soccer players.
Materials and Methods: From a Danish professional 1st tier soccer club, 83 elite youth to senior soccer players cleared for full training and match participation were included (mean age 16 ±2.7 years). Maximum isometric squeeze strength (Nm/kg) and provoked groin pain intensity (numerical pain rating scale [0-10]) were obtained from both methods in a random order during the pre-season. Peak strength (best of two trials) and peak provoked groin pain intensity (highest of two ratings given immediately after each squeeze test) were extracted for analyses.
Results: A Bland-Altman plot of squeeze strength showed a systematic bias (-0.47 Nm/kg, 95% CI [-0.57;-0.38]) and very wide 95% limits of agreement [-1.31;0.39 Nm/kg], with strength being lower in the ForceFrame. The ForceFrame also resulted in lower provoked pain intensity (median NPRS 0 [IQR: 0-1] vs. 5SST: 1 [0-3], p <0.001). Less players reported provoked groin pain (NPRS > 0) in the ForceFrame (27% [n=22] vs. 5SST: 61.4% [n=51], p <0.001).
Interpretation / Conclusion: Agreement between the Copenhagen 5-second- squeeze test and the ForceFrame is poor. In the ForceFrame strength values was 15% lower, provoked pain was less intense and fewer players reported provoked groin pain. Consequently, the two methods are not interchangeable for assessing squeeze strength or provoked groin pain which may have implications for screening and early detection of groin problems.

Kasper Krommes, Jesper Dyhr, Vibberstoft Thomas, Niels Nedergaard, Jesper Bencke, Kristian Thorborg, Per Hölmich, Lasse Ishøi
Orthopedic Department, Sports Orthopedic Research Center - Copenhagen, Hvidovre Hospital; Bachelor's Degree Programme in Physiotherapy, Faculty of Health and Technology, University College Copenhagen; Bachelor's Degree Programme in Physiotherapy, Faculty of Health and Technology, University College Copenhagen; Orthopedic Department, Human Movement Analysis Laboratory, Hvidovre Hospital; Orthopedic Department, Human Movement Analysis Laboratory, Hvidovre Hospital; Orthopedic Department, Sports Orthopedic Research Center - Copenhagen, Hvidovre Hospital; Orthopedic Department, Sports Orthopedic Research Center - Copenhagen, Hvidovre Hospital; Orthopedic Department, Sports Orthopedic Research Center - Copenhagen, Hvidovre Hospital

Background: The unilateral drop jump has been proposed as a test for measuring single-limb reactive strength index (RSI), a metric for the ability to rapidly absorb and produce force. RSI is considered important for performance and for guiding rehabilitation in athletes and physically active patients. RSI can be obtained clinically using a simple smartphone app based in video analysis. However, no data exists on the reliability or validity of deriving single- limb RSI from the MyJump2 application.
Aim: This study aims to investigate the reliability and validity of MyJump2 compared to a force platform, when measuring.
Materials and Methods: Thirty-seven participants (Tegner >5) aged 18-35 years attended two sessions and performed UDJs from three different box heights (15, 20, 25 cm) down onto a force plate in a random order whilst being recorded on a smartphone camera. Minimal detectable change (MDC) was established, and Bland-Almand plots and ICC (intraclass correlation coefficient) scores between instruments were examined for systematic bias.
Results: Excellent validity was found across all three heights; 15, 20 and 25 cm, respectively (ICC = 0.986, 95%CI:0.976-0.989, p<0.001). However, MyJump2 underestimated the RSI by approximately 0.05 RSI. Inter-rater reliability within MyJump2 showed excellen to near to perfect correlation (ICC = 0.989, 95%CI:0.952- 0.996, p<0.001). Intra-day reliability showed moderate-excellent correlation across all three heights (ICC = 0.810-0.887, p<0.001). Inter- day reliability showed moderate-excellent correlation across all three heights (ICC = 0.805-0.865, p<0.001). Low SB was found between the two instruments. The MDC of the RSI extracted from MyJump2 ranged 0.08-0.18 (10.4-24.25%), with the 25 cm box height having the lowest MDC.
Interpretation / Conclusion: MyJump2 app is valid and reliable compared to a force platform when measuring the RSI of UDJs from different jump heights. The 25 cm box height had the best results indicating that this height would be the best option when testing UDJs. Systematic bias is present between the app and force platform; therefore, practitioners should not compare results across these two instruments.

Christian Fugl Hansen, John Brodersen, Karl Bang Christensen, Michael Rindom Krogsgaard
Section for Sports Traumatology M51, Bispebjerg and Frederiksberg Copenhagen University Hospital; The Research Unit for General Practice and Section of General Practice, Department of Public Health, University of Copenhagen; Primary Health Care Research Unit, Region Zealand

Background: Patient-reported outcome measures (PROMs) are important to evaluate treatment effects of orthopaedic procedures. In Denmark, approximately 50 children are treated with ACL reconstruction each year. However, for those PROMs that are currently available to assess self-reported health- status in this patient group, content validity was not adequately ensured.
Aim: To use state-of-the art qualitative methods to develop a condition-specific PROM for children with ACL deficiency.
Materials and Methods: The development process followed modern principles for PROM development, and the ICF model was chosen as framework. Children with ACL deficiency were strategically recruited for interviews based on age, gender and treatment method to ensure maximum variation for all subgroups. Using a re-worded version of the adult ‘KNEES-ACL’ as a draft PROM, cognitive in-depth semi-structured interviews were conducted until data saturation was achieved. Relevance, coverage, and understandability also, were investigated. All interviews were recorded and transcribed. The NVivo 12 software was used in coding of items. All items were tested in their final form.
Results: There were substantial differences in the psycho- social challenges between adults and children/adolescent, with the latter group suffering a far wider negative psycho-social impact following their injury, mostly related to loss of participation in sports, lower self-confidence, lack of socializing with friends, and lower learning outcomes in school. The physical challenges were quite similar with few exceptions. Instead of one psycho-social domain, four new domains were created to ensure coverage. Most items from KNEES-ACL were retained; however, requiring rewording into simpler language.
Interpretation / Conclusion: A preliminary version of ‘KIDS-KNEES’ was created. Assessment of its psychometric measurement properties will be undertaken and likely result in a modified version, before it is valid for use.

Thomas Linding Jakobsen, Mads Thorup Langelund, Thomas Bandholm, Kristian Thorborg
Centre of Rehabilitation, City of Copenhagen; Area of Health, UCL University College, Odense; Department of Orthopedic Surgery, Amager and Hvidovre Hospital; Department of Orthopedic Surgery, Amager and Hvidovre Hospital

Background: Blood flow restriction (BFR) resistance exercise is considered to be a safe and effective rehabilitation modality in increasing muscle mass and strength.
Aim: The aims of this study were to report changes in thigh muscle mass and knee pain, as well as adverse events during rehabilitation with BFR in a large cohort of patients seen in clinical practice after knee surgery or injury.
Materials and Methods: In this descriptive, retrospective, practice-based study, we included 324 patients who performed rehabilitation with BFR resistance exercise after knee surgery or injury at an outpatient rehabilitation center. From medical records, we extracted: Thigh circumference (muscle mass proxy) and knee pain during self-reported activity ((11-point numerical rating scale (NRS)) before and after rehabilitation, and any adverse events recorded.
Results: Thigh circumference difference between non- affected and affected leg was significantly smaller post- than pre-rehabilitation (1.1 vs 2.4; mean difference, -1.3 cm, [95% CI = -1.7 to -0.9], p < 0.0001, n=76). Knee pain during activity was lower post- compared to pre- rehabilitation (2.0 vs 3.7; mean difference, -1.9 NRS-points, [95% CI = -2.3 to -1.5], p < 0.0001, n=159). One patient fainted in relation to BFR resistance exercise during the rehabilitation period (n=324).
Interpretation / Conclusion: In this retrospective study, rehabilitation with BFR resistance exercise applied in clinical practice after knee surgery or injury appeared to increase thigh muscle mass while reducing knee pain during activity. Very few harms were reported suggesting underreporting.

Mathias Fabricius Nielsen, Lasse Ishøi, Carsten Juhl, Per Hölmich, Kristian Thorborg
Sports Orthopedic Research Center – Copenhagen (SORC-C), Department of Orthopedic Surgery, Copenhagen University Hospital, Amager-Hvidovre, Denmark; Research Unit Musculoskeletal function and physiotherapy, Department of Sport Science and Clinical Biomechanics (IOB), University of Southern Denmark; Department of Physiotherapy and Occupational Therapy, Copenhagen University Hospital, Herlev and Gentofte, Denmark

Background: Patients with longstanding groin pain are clinically examined with pain provocation tests and groin pain can be classified into clinical entities from these tests. It is, however, unknown how the number of positive pain provocation tests and clinical entities relates to groin pain intensity and disability in patients with groin pain.
Aim: Firstly, to investigate how the number of positive pain provocation tests relates to groin pain intensity and disability. Secondly, to investigate how the number of clinical entities relates to groin pain intensity and disability.
Materials and Methods: Male patients with longstanding groin pain, recruited from tier 2-5 soccer clubs, underwent a standardized clinical examination and 33 specific pain provocation tests were conducted. Groin pain was classified from pain provocation tests into clinical entities as adductor-, iliopsoas-, inguinal- or pubic-related groin pain. Groin pain intensity (0-10) was measured by the Copenhagen 5-second-squeeze test (5SST). Disability was measured with the Copenhagen Hip And Groin Outcome Score (HAGOS).
Results: We included 40 patients (mean 24 [SD: 3.2] years; 182 [5.7] cm; 78 [6,6] kg) with a median pain duration of 8.5 months (IQR: 4-36). The number of positive pain provocation tests (range: 2-23) showed a strong positive correlation to groin pain intensity (r = 0.70 [95% CI: 0.50;0.83]). Number of positive tests also showed weak to moderate negative correlations with disability measured by HAGOS subscales Pain (r = -0.38 [95% CI: -0.69;-0.06]), Symptoms (-0.52 [-0.73;-0.24]), ADL (-0.48 [-0.71;-0.18] and Sport (-0.62 [-0.81;-0.36]). Similarly, the number of groin pain entities (range: 1-7) correlated positively with pain intensity and negatively with disability.
Interpretation / Conclusion: When examining patients with longstanding groin pain, the number of positive pain provocation tests correlate strongly with groin pain intensity and correlate weak to moderately with disability. Thus, in patients where pain is intense, and disability is severe - more pain provocation will often be positive - and consequently, relying on pain provocation tests in the diagnostic work-up of these patients is challenging.

Kasper Spoorendonk , Jens Ole Storm, Marie Bagger Bohn, Signe Kierkegaard
H-HiP, Department of Physio and Occupational Therapy, Horsens Regional Hospital; H-HiP, Department of Orthopedic Surgery, Horsens Regional Hospital

Background: Proximal Hamstring avulsion (PHA) is a rare injury. PHA´s injury mechanism typically involves hyperextended knee and hyperflexed hip as seen in waterskiing, football and slipping injuries. Symptoms are a large hematoma on the back of the thigh, stiffness and pain during walking and sitting. Surgical repair is a treatment option. The effect of the surgery with regard to pain, function and quality of life is not well described.
Aim: The aim of the study was to investigate the effect of surgical treatment of PHA in regards to pain, function and quality of life at 6 and 12 months after surgery.
Materials and Methods: Patients with an (Magnetic Resonance Imaging) MRI verified PHA were included. MRI findings were avulsions from the Ischial Tuberosity involving 2-3 hamstrings tendons with a 1-2 cm retraction. In 2019 and 2020, patients had surgery and supervised rehabilitation. Subjective outcome measures were: Perth Hamstring Assessment Tool (PHAT), overall health visual analog scale (VAS), and Hip Sports Activity Scale (HSAS). Knee flexion strength was measured with a hand held dynamometer pre-surgery, and 6 and 12 months after surgery.
Results: 11 patients (7 males), mean age 49±16, were treated surgically mean 22 days after injury. At abstract submission 11 patients had 6 months scores and 8 patients had 1 year scores. The PHAT score increased from before surgery 41±15 to 6 months 69±20 (p<0.001) and 12 months 70±20 (p<0.001). Furthermore, the VAS improved (p=0.02): Before surgery 48±22 to 6 months: 74±18. HSAS was rated 0 in all patients before surgery corresponding to “no participation in physical activities”. At 6 months, the mean score was 2.2±1.1 (p=0.005) and at 12 months: 2.1±1.7 (p=0.014). Knee flexion strength at 30 degrees improved more than twofold after surgery: Before surgery: 0.29±0.2 Nm/kg, 6 months: 0.69±0.3 Nm/kg (p<0.001), 12 months: 0.76±0.5 Nm/kg (p<0.001). Furthermore, the median strength difference between patient legs went from 70% to 32% at 6 months (p<0.001) and 29% at 12 months (p<0.001).
Interpretation / Conclusion: After surgical repair of a proximal hamstring avulsion, all patients improved in knee flexion strength, PHAT and VAS after surgery. Furthermore, patients were able to participate in sports.

Ole Gade Sørensen, Torsten Nielsen, Martin Lind
Department of Orthopaedics, Aarhus University Hospital

Background: Anterior cruciate ligament (ACL) revision results in worse outcome compared to primary ACL reconstruction (ACL-R).
Aim: To identify risk factors in primary ACL reconstruction leading to ipsilateral ACL revision surgery.
Materials and Methods: Data extracted from the Danish Knee Ligament Reconstruction Registry was used to identify risk factors for ACL revision surgery. Patients undergoing ACL reconstruction between 2005-2018, no contra-lateral knee injury and age > 14 years were included. Patient age, gender, trauma mechanism at primary ACL tear, graft selection, lateral and medial meniscus injury at primary ACL-R, meniscus repair or resection and Tegner activity score before primary ACL injury were evaluated using regression analysis to determine individual factors impact on risk for ACL revision surgery.
Results: A total of 29018 patients (60 % males) met the inclusion/exclusion criteria. Ipsilateral revision surgery was seen in 1436 cases (5 %). Hamstringgraft, bone-patella-tendon bone graft (BPTB), and quardricepstendon graft (QT) was used in 84, 9 and 6 % of the cases, respectively. Antero-medial portal for femoral tunnel drilling was used in 17480 patients (60 %). Increasing age at ACL-R resulted in significant reduction in the hazard ratio (HR) for later ACL revision. Antero-medial portal use for femoral tunnel drilling resulted in significant increase in HR compared to trans-tibial drilling. No significant difference in HR was observed regarding gender, trauma mechanism, meniscal injury, meniscal injury treatment, graft selection, or Tegner activity score.
Interpretation / Conclusion: Younger age and antero-medial drilling of the femoral tunnel in ACL-R were found to be predictors for increased HR for later ipsilateral ACL revision.

Marie Fridberg, Ole Rahbek, Hans-Christen Husum, Arash Ghaffari, Søren Kold
Interdisciplinary Orthopaedics, Department of Orthopaedics, Aalborg University Hospital, Aalborg, Denmark

Background: Digital infra-red thermography may have the capability of identifying local inflammations. Nevertheless, the role of thermography in diagnosing pin site infection has not been explored yet and the reliability and validity of this method for pin site surveillance is in question.
Aim: The purpose of this study was to explore the capability and intra-rater reliability of thermography in detecting pin site infection.
Materials and Methods: This explorative proof of concept study follows GRRAS -guidelines for reporting reliability and agreement studies. After clinical assessment of pin sites by one examiner using Modified Gordon Pin Infection Classification (Grade 0 – 6), thermographic images of the pin sites were captured with a FLIR C3 camera and analyzed by the FLIR tools software package. The maximum skin temperature around the pin site and the maximum temperature for the whole thermographic picture was measured. Intra-rater agreement was established and test-retests were performed with different camera angles.
Results: Thirteen (4 females) patients (age 9-72 years) were included. Indications for frames: 4 fracture, 2 deformity correction, 1 lengthening, 6 bone transport. Days from surgery to thermography ranged from 27 to 385 days. Overall, 231 pin sites were included. Eleven pin sites were diagnosed with early signs of infection: five grade 1, five grade 2, one grade 3. Mean pin site temperature was 33.9 °C (29.0-35.4). With 34 °C as cut-off value for infection, sensitivity was 73%, specificity 67%, positive predictive value 10% and negative predictive value 98%. Intra-rater reliability for thermography was ICC 0.85 (0.77-0.92). The temperature measured was influenced by the camera postioning in relation to pin site with a variance of 0.2.
Interpretation / Conclusion: Measurements of pin sites using the handheld FLIR C3 infrared camera was a reliable method and the temperature was related to infection grading. This study demonstrates that digital thermography with a handheld camera might be used for monitoring the pin sites after operations to detect early infection, however, future larger prospective studies are necessary.

Mie Pilegaard Bjarnesen, Johanne Overgaard Wessels, Julie Ladeby Erichsen, Henrik Palm, Per Hviid Grundtoft, Bjarke Viberg
Department of Orthopaedic Surgery and Traumatology, Lillebaelt Hospital; Department of Orthopaedic Surgery and Traumatology, Lillebaelt Hospital; Department of Orthopaedic Surgery and Traumatology, Lillebaelt Hospital; Department of Orthopaedic Surgery and Traumatology, Bispebjerg Hospital; Department of Orthopaedic Surgery and Traumatology, Lillebaelt Hospital; Department of Orthopaedic Surgery and Traumatology, Lillebaelt Hospital

Background: Studies have demonstrated no difference in outcome when comparing the sliding hip screw (SHS) with the intramedullary nail (IMN) in the treatment of trochanteric fractures. However, systematic analyses on the separated AO/OTA fracture subtypes 31A1-A2-A3 are not available.
Aim: To assess whether a sliding hip screw (SHS) or an intramedullary nail (IMN) is the best treatment for AO/OTA 31A1-A2-A3 trochanteric fractures.
Materials and Methods: A systematic review and consequent meta- analysis was conducted using search strings for the databases: Cochrane Library, CINAHL, Medline, and Embase. Two authors (JOW and MPB) independently screened the studies and performed data extraction. The primary outcome was major complications in total. The secondary outcomes were the specific major complications non-union, infection, mortality, and function measurements by any scoring system or Patient Reported Outcome Measurement (PROM). Quality assessment was performed using the Cochrane Risk Of Bias tool for randomized trials for RCT studies, and Cochrane Risk Of Bias In Non-Randomized Studies – of Interventions for non-RCTs. The meta-analyses were performed using Log Risk Ratio as the primary effect estimate.
Results: two thousand and fifty one studies were screened, but only six RCTs and six non-RCTs could be included in the meta-analysis, yielding a total of 10.402 patients. There were no significant difference concerning the outcomes: major complications in total, non-union, infection, and mortality when comparing SHS to IMN in AO/OTA 31A1, 31A2 or 31A3 trochanteric fractures. Due to a lack of compatible data, we were unable to perform a meta-analysis on function scores and PROM, but there were trends favoring IMN in 31A1 and 31A2 fractures.
Interpretation / Conclusion: No significant difference between SHS and IMN was found in the meta-analysis forin any of the examined AO/OTA fracture subtypes concerning the primary and secondary outcomes. When assessing function scores and PROM, we found trends favoring IMN for 31A1 and 31A2 fractures, which should be explored further. Finally, all future studies should include the use of AO/OTA-subtype classification to improve data collection.

Joakim Jensen, Pernille Engell Bovbjerg, Jens Lauritsen
Department of Orthopaedics Odense University Hospital; Department of Clinical Medicine, University of Southern Denmark (SDU).

Background: Managing self-harm patients in the emergency department (ED) is a complex task. Multiple visits, patient denial of having a psychological issue as the cause for self-harm, patient denial of follow-up in psychiatric services, short time slots etc. all play a major role. The short treatment time slots in the ED are not well suited to manage complex psychosocial patients. This is further complicated by systematic reluctance to accept patient referral to psychiatric services. The code ALCC05 for “intended self-harm without expressed suicide” introduced in 2019 allows for identification of a cohort, before ALCC004 or ALCC02 were used for the “self- harm group”
Aim: To ascertain total contact pattern due to self-harm for a well-defined cohort and analyze whether covid- 19 pandemic lockdown has led to changes in contacts due to self-harm in the ED
Materials and Methods: All patients with at least one visit due to “intended self-harm” to the ED at Odense University hospital during: Pre-covid (11/03/2019-10/03/2020) or Covid (12/03/2020-11/03/2021) are included. All contacts due to “self-harm” (ALCC05), “suicide attempt” (ALCC04) or “potential self-harm injury” defined as: cuts, bites, suffocation, inappropriate medication (ALCC02+EUBE/EUBF/EUBM/EUBP) were extracted in anonymized form for the two periods. Age by 11/03/2019
Results: The cohort consists of 264 patients with 933 contacts. Age range (11-95), median age (m=34/f=19). Males were older (p<10-3). Contacts in pre-covid (m=105/f=336), Covid period (m=72/f=420). Sex Ratio (m/f) by age < 18: (6/58), 18-21:(22/47), 22-33:(30/35), 33+:(35/34).). Females had more contacts per patient (Avg 4.4, 95% CI 4.1- 4.7) than males (1.9, 95% CI 1.7-2.3). Type of injury was 59% cuts, 34% inappropriate medication and 7% other. About 10% of males and 15% of females have more than 5 contacts per year, but most have 1-2 per year (males: 89%, 95% CI 82%-95%) (females 69%, 95% CI 62-75%). No change in type of injury or average number of contacts per patient between pre-covid and covid period was observed
Interpretation / Conclusion: There was no difference in the number of patients treated for self-harm in the ED after Covid-19 lockdown. No difference was found in injury type or number of contacts per patient

Sebastian Strøm Rönnquist, Bjarke Viberg, Carsten Fladmose Madsen, Morten Tange Kristensen, Jens-Erik Bech Jensen, Henrik Palm, Søren Overgaard, Kristina Åkesson, Cecilia Rogmark
Lund University, Skåne University Hospital, Department of Orthopaedics, Malmö, Sweden; Department of Orthopedic Surgery and Traumatology, Kolding Hospital – Part of Hospital Lillebaelt, Kolding, Denmark; Department of Orthopedic Surgery and Traumatology, Odense University Hospital, Denmark; PMR-C, Departments of Physiotherapy and Orthopaedic Surgery, Copenhagen University Hospital – Amager and Hvidovre, Denmark AND Department of Clinical Medicine, University of Copenhagen, Denmark; Hvidovre University Hospital, Endocrine Department, Denmark; Copenhagen University Hospital, Bispebjerg, Department of Orthopaedic Surgery and Traumatology, Denmark AND University of Copenhagen, Department of Clinical Medicine, Faculty of Health and Medical Sciences, Denmark; Department of Orthopaedic Surgery and Traumatology, Odense University Hospital, Denmark AND Department of Clinical Research, University of Southern Denmark, Denmark AND Copenhagen University Hospital, Bispebjerg, Department of Orthopaedic Surgery and Traumatology, Denmark AND University of Copenhagen, Department of Clinical Medicine, Faculty of Health and Medical Sciences, Denmark; Lund University, Skåne University Hospital, Department of Orthopaedics, Malmö, Sweden; Lund University, Skåne University Hospital, Department of Orthopaedics, Malmö, Sweden

Background: Research on younger hip fracture patients is limited, and common preconceptions are that they suffer fractures due to high-energy trauma, alcohol- or substance use disorder but not due to osteoporosis.
Aim: We aimed to descriptively analyze the characteristics of young and middle-aged hip fracture patients and analyze bone mineral density (BMD) by dual energy x-ray absorptiometry (DXA) at the time of the hip fracture.
Materials and Methods: In a prospective multicenter cohort study on adult hip fracture patients under the age of 60 years, we collected detailed information on patient characteristics regarding demographics, the trauma mechanism, previous fractures, comorbidity and medication as well as lifestyle and health factors. BMD was investigated at the time of the fracture and DXA results were compared to population-based reference data.
Results: The cohort consists of 91 women and 127 men aged 23-59 years, median (IQR) 53 (47-57), accounting for 6% of all hip fractures during the study inclusion period. Most fractures, 83%, occurred in patients aged 45-59 years. Two-thirds of all fractures were the result of low-energy trauma. Half of the patients had a history of any previous fracture, and 5% had suffered a previous hip fracture. 32% of the patients were healthy, 33% had one previous disease, and 35% presented with multiple comorbidities, the health status distribution being different between women and men. The use of medication associated with increased fracture risk, e.g., cortisone, was 32%. Smoking was prevalent in 42%, harmful alcohol use reported by 29%, and signs of drug-related problems by 8%. Physical activity level was below WHO recommendations in 59% of the patients. Osteoporosis (t-score <-2.5) was found in 31%, osteopenia (t-score -2.5 to <-1) in 57% and normal BMD in 12%.
Interpretation / Conclusion: In hip fracture patients under the age of 60, risk factors for osteoporosis and fractures were abundant. Moreover, one-third of the patients had osteoporosis, a prevalence markedly higher than in the general population of the same age (7%). We suggest that young and middle-aged patients with hip fractures undergo a thorough health investigation, including DXA to rule out decreased bone mineral density.

Signe Hulsbæk, Carsten Juhl, Alice Røpke, Thomas Bandholm, Morten Tange Kristensen
Department of Physiotherapy and Occupational Therapy, Copenhagen University Hospital, Amager-Hvidovre; Department of Physiotherapy and Occupational Therapy, Copenhagen University Hospital, Herlev-Gentofte; Research Unit for Musculoskeletal Function and Physiotherapy, Department of Sports Science and Clinical Biomechanics, University of Southern Denmark; Department of Orthopedic Surgery, Copenhagen University Hospital, Amager-Hvidovre; Department of Clinical Research, Copenhagen University Hospital, Amager-Hvidovre; Department of Clinical Medicine, University of Copenhagen.

Background: Exercise therapy are often provided following hip fracture, but with large variations in time of initiation, content, duration, and intensity of the interventions provided. Previous reviews on the topic have been inconclusive, although positive trends were shown. A large number of new trials have been published within the last years, which calls for an update on the effects of exercise therapy in older patients following hip fracture.
Aim: To evaluate the short- and long-term effect of exercise therapy on physical function, independence and wellbeing in older patients following hip fracture from time of surgery up-to 1 year, and secondly, whether the effect was modified by trial level characteristics such as intervention modality, duration and initiation timepoint.
Materials and Methods: Medline, CENTRAL, Embase, CINAHL and PEDro was searched up-to November 2020. Eligibility criteria was randomized controlled trials investigating the effect of exercise therapy on physical function, independence and wellbeing in older patients (60+) following hip fracture and initiated within one year post-surgery.
Results: Forty-nine studies were included involving 3904 participants. Exercise therapy showed a small to moderate effect at short term on mobility (Standardized mean difference, SMD 0.49, 95%CI 0.22-0.76); Activities of Daily Living (ADL) (SMD 0.31, 95%CI 0.16-0.46); lower limb muscle strength (SMD 0.36, 95%CI 0.13-0.60); balance (SMD 0.34, 95%CI 0.14-0.54). At long term, a small to moderate effects were found for mobility (SMD 0.74, 95%CI 0.15-1.34); ADL (SMD 0.42, 95%CI 0.23-0.61); balance (SMD 0.50, 95%CI 0.07-0.94) and Health related Quality of Life (HRQoL) (SMD 0.31, 95%CI 0.03-0.59). Level of evidence was evaluated using GRADE ranging from moderate to very low, due to study limitation and inconsistency.
Interpretation / Conclusion: We found low level of evidence for a moderate effect of exercise therapy on mobility in older patients following hip fracture at end-of-treatment and follow- up. Further, low evidence was found for small to moderate short-term effect on ADL, lower limb muscle strength and balance. Trial registration:CRD42020161131

Mindaugas Mikuzis, Ole Rahbek, Knud Stenild Christensen, Søren Kold
Department of Orthopaedics, Aalborg University Hospital; Interdisciplinary Orthopaedics, Aalborg University Hospital

Background: Intramedullary bone transport nails have been introduced to treat segmental bone defects. Only 5 cases have been reported in the literature, and no studies have reported outcomes after nail removal.
Aim: We investigated the healing and the complication rates in patients treated for segmental bone defects with a combined bone transport and lengthening FITBONE® nail.
Materials and Methods: A retrospective case series with fifteen patients (ten males, five females) were treated between 2012 and 2016. Informed consent from patients and approval by institutional board. The segmental bone loss was due to resection of non-union site in eight femurs and four tibias, or traumatic bone loss in two femurs and one tibia. The bone gap was ranged from 1 to 10 cm (median 3). The total nail distraction (transport and lengthening) was a median of 4 (2-8) cm. Preoperative limb length discrepancy was median of 2 (0-7) cm. Preoperative mechanical axis deviation was from 88 mm varus to 7 mm valgus. Median follow-up after nail removal was 46 (6-89) months. Complications were severity graded (Black et al). and rated as device or non- device related (Song et al.)
Results: 9 out of 10 femoral cases, and 4 out of 5 tibial cases healed with the bone transport nail. The unhealed femoral case was treated with shortening, bone graft and trauma nail. The unhealed tibial case was treated with external fixator and bone graft. At latest follow-up all fifteen patients have healed docking site and regenerate. 24 complications (15 device-related and 9 non-device) occurred in 11 out of 15 patients. 19 unplanned surgeries were performed in 10 out of 15 patients. The number of complications was: 0 in 4 patients, 1 in 4 patients, 2 in 3 patients, 3 in 2 patients, 4 in 2 patients. Final limb length discrepancy was median of 1 (0-3) cm.
Interpretation / Conclusion: In selective cases, segmental bone defects might heal with bone transport nail. Future research should focus on reducing device and non-device related complications by optimizing nail design and patient selection.

Morten Tange Kristensen, Tobias Kvanner Aasvang, Pia Bjørnsdall Iheme, Nicolai Bang Foss
PMR-C, Departments of Physiotherapy & Orthopaedic Surgery, Copenhagen University Hospital – Amager and Hvidovre & Department of Clinical Medicine, University of Copenhagen; Department of Orthopaedic Surgery, Copenhagen University Hospital – Amager and Hvidovre; Department of Anaestesiology, Copenhagen University Hospital – Amager and Hvidovre.

Background: 30-day readmission rates in the Capital Region of Denmark reported by The Multidisciplinary Hip Fracture Registry ranges from 21-29% (2018 report) and 15-19% (2019). Differences might be related to whether emergency ward visits are included.
Aim: We examined total readmission rates including emergency ward referrals within 30 days of discharge among elderly patients with a hip fracture.
Materials and Methods: Total of 687 consecutive patients aged =65 years discharged after treatment of an acute hip fracture at a university hospital between Jan 2018 and June 2019, were included. A readmission was defined as any hospital contact with physical attendance, and patients were followed until death or 30-days post-discharge. Date of readmission, place of “residence” at this time, cause and length of readmission were obtained from patient charts at the study hospital.
Results: Total of 220 (32% in 2018 and 31% in 2019) patients were readmitted within 30 days. Their median (IQR) age was 82 (76-89) years, 135 were women, 166 came from own home, 100 had a trochanteric fracture and 142 had an ASA grade=3. Their acute care stay was a median of 8 (6-11) days post-surgery, and time to readmission was median 8.5 (4-18) days. Fifty-six (25%) and 89 (40%) of these patients, respectively, came from a nursing home and other 24-hour settings (“rehab”). Length of readmission stays were median 1 (0-6) day, and distributed as; 0 (emergency ward), 1, 2 and 3 days for respectively 89 (40%), 27, 18 and 14 of patients. Sixty-five (73%) of patients with an emergency ward visit came from a nursing home or other 24-hour setting. Readmissions were related to many potential or confirmed reasons; the most prominent being a new fall, hip fracture related pain, pulmonary, gastrointestinal, infection and luxation of arthroplasty.
Interpretation / Conclusion: One third of patients with hip fracture aged =65 years were readmitted within 30 days post-discharge and almost half was seen only in the emergency ward. Two thirds came from a nursing home or other 24-hour settings, and with the majority seen and handled in the emergency ward. Findings suggest that enhanced post-discharge medical attention and cross-sectorial collaboration is needed for these frail patients.

Bjarke Viberg, Nickolaj Risbo, Per Hviid Gundtoft, Søren Overgaard, Alma Becic Pedersen
Department of Orthopaedic Surgery and Traumatology, Lillebaelt Hospital Kolding; Department of Orthopaedic Surgery and Traumatology, Odense University Hospital; Department of Department of Clinical Epidemiology, Aarhus University Hospital

Background: Surgery for hip fracture in patients treated with new oral anticoagulant (NOAC) is often delayed due to the presumed increased risk of bleeding and mortality. In contrast, surgical delay is associated with an increased mortality in non-NOAC patients.
Aim: To assess the association of surgical delay with readmission and mortality in hip fracture patients above 65 years with NOAC treatment
Materials and Methods: This is a register study from 3 regions during 01.01.2011-31.12.2017. All hip fracture patients with a dispensing for NOAC within 230 days before surgery were included. Primary exposure was surgical delay +/- 36 hours, secondary exposures were delays of <12 hours, 12 to <24 hours, 24 to <36 hours, 36 to <48, and 48 to <72 hours. Transfusion was defined as red blood cell transfusion within 7 days of surgery and readmission as any within 30 days of discharge. We performed Cox regression to estimate adjusted Hazard Ratios (aHR) with 95% confidence intervals adjusting for age, sex, BMI, comorbidity, marital status, type of fracture, type of surgery, year of surgery, region of residence, cohabiting status, and prior medication.
Results: A total of 911 hip fracture patients in NOAC treatment were identified. There were 63% females and 71% were older than 80 years old. There were 61% patients with a surgical delay less than 36 hours yielding an aHR for transfusion of 0.98 (0.79-1.22), for 30-day mortality 1.39 (0.88-2.17), for 1-year mortality of 1.06 (0.78-1.43), and for any readmission of 1.35 (0.99-1.83) compared to patients operated later than 36 hours. We observed no difference concerning transfusion, 30-day mortality, and 1-year mortality when comparing patients operated with delay of <12 hours, 12 to <24 hours, 24 to <36 hours, and 36 to <48 hours to patients operated between 48 to <72 hours. There is some indication that early surgery <24 hours is associated with increased risk of any readmission.
Interpretation / Conclusion: Surgical delay in NOAC treated patients was not associated with transfusion, 30-day or 1-year mortality. There was an indication of an associated higher risk of readmission with early surgery which could be due a proportion of +90 years patients.

Bjarke Viberg, Frank Damborg, Lars Rotwitt, Anders Jordy, Michael Boelstoft Holte, Per Hviid Gundtoft
Department of Orthopaedic Surgery and Traumatology, Hospital Lillebaelt Kolding; Department of Orthodontics, Hospital of South West Jutland

Background: 3D-printing of bones is novel way in preoperative planning giving the surgeon a real-size fracture to evaluate by hand. There are studies from China showing shorter operation time, intraoperative blood loss, and better functional outcome but there are no studies assessing the impact on the preoperative plan.
Aim: To assess the effect of 3D-printed proximal tibia fractures in the preoperative plan. Secondarily, to perform subanalysis of the effect divided on operative experience.
Materials and Methods: Data on bicondylar proximal tibia fractures treated with open reduction and internal fixation including dual plating was retrieved for 2019. We included 10 consultants in traumatology to perform a preoperative plan on the basis of CT- scan two times, thereafter the 3D-print, and divided them in to senior consultants and consultants, all specialized in traumatology. Data was entered in an electronic database. We defined a critical change in the preoperative plan as a change in the operative starting point, arthroscopic use, posterior plate, solitary screws, elevation of joint surface through fenestra, and in auto-/allograft use. Minor change was defined as change in length of plates. The surgeons evaluated their confidence after each preoperative plan. Chi-square test was used for categorical group comparison.
Results: There were 10 3D-printed proximal tibia fractures, median age 59 (range 45-79), 5 were female, and 92% were min. Schatzker type 4. The 3D-print lead to a critical change in 27% of the preoperative plans with no difference between junior or senior surgeons (p=0.11). The amount of changes was median 1 (1-5). There were 34% minor changes with no differences among the surgeon groups (p<0.55). There was a significant improvement in the level of confidence with the preoperative plan among junior surgeons (p<0.001) but not among senior surgeons (p<0.24).
Interpretation / Conclusion: 3D-print of proximal tibia fractures has a significant effect leading to a critical change in 27% of the preoperative plans with no difference due to the surgeons’ experience.

Anders Kjærsgaard Valen, Rikke Thorninger, Bjarke Viberg, Per Hviid Gundtoft
Department of Orthopaedic Surgery and Traumatology, Regional Hospital Randers, Denmark; Department of Orthopaedic Surgery and Traumatology, Lillebaelt Hospital, University Hospital of Southern Denmark, Denmark

Background: Should trochanteric hip fractures (AO/OTA 31-A) be treated with a sliding hip screw (SHS) or an intramedullary nail (IMN)? This debate is still ongoing and while most studies find no differences in post-operative complication rates, recent studies suggest an association between IMN and excess mortality rates when compared to SHS.
Aim: To compare mortality rates for IMN and SHS in elderly patients with trochanteric hip fractures (AO type 31-A).
Materials and Methods: This is a national registry study based on data from DFDB. Data on patients aged >65 years treated for a non-pathological AO- type 31-A trochanteric hip fracture with either IMN or SHS from January 2012 to December 2018 were retrieved. Data from DFDB was merged with data from the Danish Civil Registration System for time of death. Outcome measures were mortality presented as 30-day, 90-day, and 1-year mortality and the relative mortality risk in crude numbers and adjusted for age, sex, ASA-class, AO-type, and department.
Results: A total of 9,547 patients were included. The mean age was 83 years, 69.2% were female, and 55.1% were ASA-class 3-5. Most patients suffered a 31-A2 fracture (56.1%), followed by 31-A1 fractures (32.3%), and 31-A3 fractures (11.6%). Stable 31-A1 fracture subtypes were primarily treated with SHS (60.9%). Fracture subtypes 31-A2 and 31-A3 were treated with IMN in 90.2% and 96.6% of cases. The implant of choice was IMN in 74.4% of cases. The 30-day mortality for IMN- patients was 12.2% (867/7105) and 10.2% (248/2442) for SHS-patients. This trend persists at 90 days (19.7% vs 17.4%) and 1 year (31.0% vs 29.3%). The relative mortality risk for IMN compared to SHS was 1.20 [95% CI 1.06; 1.35] at 30- days, 1.11 [1.01; 1.22] at 90-days, and 1.05 [0.98; 1.13] at 1 year. The adjusted relative mortality risk for IMN compared to SHS was 1.12 [0.96; 1.31] at 30-days, 1.03 [0.91; 1.17] at 90-days, and 1.01 [0.92; 1.11] at 1 year.
Interpretation / Conclusion: We find an association between excess mortality and the use of IMN versus SHS in elderly patients with AO-type 31A fractures at 30 days and 90 days post-operatively, consistent with recent studies. However, this association diminishes when adjusting for sex, age, ASA-class, AO-type, and department.

Veronique Vestergaard, Henrik Morville Schrøder, Kristoffer Borbjerg Hare, Peter Toquer, Anders Troelsen, Alma Becic Pedersen
VV: Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre; HMS: Department of Orthopaedic Surgery, Næstved Hospital; KBH: Department of Orthopaedic Surgery, Slagelse Hospital; PT: Department of Orthopaedic Surgery, Køge Hospital; AT: Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre; ABP: Department of Clinical Epidemiology, Aarhus University Hospital

Background: Few studies have described patient-reported outcomes (PROMs), prognoses and the current state of care of the knee fracture population. Studying risk factors of poor PROM scores is important in understanding the key drivers of poor outcome and in directing future quality-improvement initiatives.
Aim: 1) Report knee-specific and generic median PROM scores after knee fracture. 2) Identify risk factors for poor outcome defined by low median PROM scores.
Materials and Methods: In a Danish cross-sectional study of 7,133 distal femoral, patellar, and proximal tibial fracture patients during 2011-2017, OKS, FJS-12, EQ5D-5L Index and EQ5D-5L Visual Analogue Scale (VAS) were collected electronically via a national, CPR- linked digital mail system (response rate 53%; median age 60 years; 63% female). Poor outcome was defined as score lower than median PROM score. Poor outcome risk factors were estimated as odds ratios with 95% confidence intervals from binary logistic regression models.
Results: At 0-1 years after knee fracture, median PROM scores were 31 (OKS), 27 (FJS-12), 0.50 (EQ5D-5L Index) and 74 (EQ5D-5L VAS). All four PROM scores plateaued at 3-5 years after knee fracture. At >5 years after knee fracture, median PROM scores were 40 (OKS), 54 (FJS-12), 0.76 (EQ5D-5L Index) and 80 (EQ5D-5L VAS). Age >40 years was associated with poor OKS and FJS-12 scores at both short- and long-term follow-up after knee fracture. Comorbidity burden, distal femoral fracture and treatment with external fixation and knee arthroplasty were risk factors for poor outcome at long-term follow-up, for all four PROMs.
Interpretation / Conclusion: Knee fracture patients have relatively high knee function and quality of life (OKS, EQ5D-5L Index and EQ5D-5L VAS), while their ability to forget about the knee joint after knee fracture is compromised (FJS- 12). Risk factors for poor outcome vary depending on the PROM and follow-up period studied. This study will further research in ensuring high quality of care for all patient groups regardless of their associated patient-, fracture- and treatment-related factors and in informing patients on varying aspects of expected outcome after knee fracture, including the presented risk factors which modulate their outcome.

Markus Frost1, Søren Kold1, Ole Rahbek1, Anirejuoritse Bafor2, Molly Duncan2, Christopher Iobst2
1 . Department of Orthopedic Surgery, Aalborg University Hospital; Interdisciplinary Orthopaedics, Aalborg University Hospital 2. Department of Orthopaedics Center for Limb Lengthening and Reconstruction Nationwide Children’s Hospital Columbus, USA

Background: Due to high complication rates and patient discomfort with external fixators, externally controlled motorized intramedullary lengthening nails have been introduced. These lengthening nails have shown excellent short-term results for lower limb lengthening. For the most frequently used intramedullary lengthening nails (FITBONE, PRECICE, STRYDE), the producers acclaim removal of the implants after accomplished treatment. Despite the requirement for nail removal, there is a lack of reports of complications on intramedullary lengthening nail removal.
Aim: The aim was to examine the intraoperative and postoperative complications of elective intramedullary lengthening nail removals.
Materials and Methods: A retrospective chart review of patients operated with intramedullary lengthening nails at Nationwide Children’s Hospital, Ohio, USA and Aalborg University Hospital, Denmark were performed. Patient demographics, nail-information, and any complications occurring at or after nail removal were retrieved from the patient charts. Only elective nail removal of FITBONE and PRECICE or STRYDE nails in lower limb were included. Bone transport, stump lengthening and humeral lengthening were excluded.
Results: A total of 225 patients with 271 elective nail removals were included in the study. The mean (min-max range) follow-up time after nail removal was 282 days (0 – 2882 days). In 3 % complications occurred during nail removal and in 13 % after nail removal. Postoperative knee pain was reported in 18 cases, who all had nail removal through the knee joint, representing 8% of the retrograde femur nail removals and 7% of the tibia nail removals. 2 of the 4 postoperative fractures that occurred needed surgery. For femur and tibial nail, complications were 11% and 26 % respectively.
Interpretation / Conclusion: This is the first study examining complications in removal of bone lengthening nails. In 16 % of 271 nail removals a complication occurred at or after nail removal. This emphasizes that studies reporting on the overall risks of complications of bone lengthening nails must include nail removal and an adequate follow-up after this.

Imran Jamal Iversen, That Minh Pham, Hagen Schmal,
Department of Orthopaedic Surgery and Traumatology, Odense University Hospital, Odense, Denmark; Department of Clinical Research, University of Southern Denmark, Odense, Denmark; Clinic of Orthopedic Surgery, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, Germany; OPEN, Odense Patient data Explorative Network, Odense University Hospital/Institute of Clinical Research, University of Southern Denmark, Odense, Denmark

Background: Patients with intra-articular fractures tend to develop post-traumatic osteoarthritis (PTOA). The initial inflammatory response with elevation of inflammatory cytokines following joint trauma might be responsible for triggering cartilage catabolism and degradation.
Aim: We aimed to identify and quantify cytokine levels in fractured and healthy knee joints and the correlation of these cytokines with clinical outcomes.
Materials and Methods: In this prospective cohort study, synovial fluid and plasma were collected from 12 patients with proximal intra-articular tibia fractures before surgery. The concentration of sixteen inflammatory cytokines, two cartilage degradation products and four metabolic mediators where measured, comparing the acute injured knee with the healthy contralateral knee. Patients were evaluated 3- and 12-months after surgery with clinical parameters and radiographical scanning. Non-parametrical Wilcoxon rank-sum and Spearman tests were used for statistical analysis, and a P-value below 0.05 was considered significant.
Results: We found an elevation of the pro-inflammatory cytokines IL-1ß, IL-2, IL-6, IL-8, IL-12p70, TNF-a, IFN-y, MMP-1, MMP-3, and MMP-9 and a simultaneous elevation of the anti-inflammatory cytokines IL-1RA, IL-4, IL-10, and IL-13 in the injured knee. Several pro- and anti-inflammatory cytokines and metabolic mediators were correlated with clinical outcomes 12 months after surgery, especially with pain perception.
Interpretation / Conclusion: Our results support that an inflammatory process occurs after intra-articular knee fractures, which is characterized by the elevation of both pro- and anti- inflammatory cytokines. There was no sign of cartilage damage within the timeframe from injury to operation. We found a correlation between the initial inflammatory reaction with clinical outcomes 12 months after surgery.

Morten Jon Andersen
Department of Orthopedic Surgery, Herlev and Gentofte University Hospital

Background: Faulty reduction or fixation of pediatric supracondylar humerus fractures (SCHF) can lead to loss of reduction (LOR), malunion and poor functional outcome. Configuration of K- wires have been extensively investigated and there is support for two divergent lateral-entry K-wires for stable fracture patterns and either three divergent lateral-entry or two crossed K- wires for unstable fracture patterns.
Aim: This study aimed to investigate if adequate surgical reduction and fixation of SCHF were obtained.
Materials and Methods: We reviewed all surgical cases of SCHF in children at Herlev Hospital from 2017-2020. Age, gender, Gartland classification, reduction, K-wire configuration, and LOR was recorded. Type 2A fractures were defined as minimally displaced and stable and other types as displaced and unstable. Satisfactory reduction was defined as the anterior humeral line (AHL) passing through the capitellum, the absence of rotation, varus and valgus, and less than 5 mm of displacement of the distal fragment in any plane.
Results: We reviewed 171 fractures in 85 girls and 86 boys, mean age was 6 years (range, 1 to 15 years). 53 (31%) fractures were stable/minimally displaced. 124 (73%) fractures were reduced to satisfaction. 8/53 (15%) minimally displaced and 39/118 (33%) displaced fractures were inadequately reduced. 26/53 (49%) stable fractures were treated with two lateral-entry K-wires and 16 (30%) with crossed wires. 23/118 (20%) unstable fractures were fixed with two lateral-entry wires, 13 (8%) with three lateral-entry wires and 56 (33%) with crossed wires. In 50/171 (29%) cases K- wire placement suffered from improper technic. We found 4 (2,3%) reoperations, one due to inadequate reduction and three due to LOR.
Interpretation / Conclusion: Satisfactory reduction was not achieved in 27% of cases. 20% of unstable fractures were only treated with two lateral-entry K-wires. 31% of fractures were fixed with other patterns than those recommended. K-wire configuration was technically faulty in 29% of cases. Focus should be on satisfactory reduction and adequate configuration of wires but equally so on the technical aspect of placing the wires to avoid instability and LOR.

Hilda K. Svensson, Sebastian Strøm Rönnquist, Charlotte Myhre Jensen, Søren Overgaard, Cecilia Rogmark
Academy of Health and Welfare AND Centre of research on Welfare, Health and Sports, Halmstad University, Sweden; Lund University, Skåne University Hospital, Department of Orthopaedics, Malmö, Sweden; Department of Orthopaedic Surgery and Traumatology, Odense University Hospital, Denmark AND Department of Clinical Research, University of Southern Denmark, Denmark; Department of Orthopaedic Surgery and Traumatology, Odense University Hospital, Denmark AND Department of Clinical Research, University of Southern Denmark, Denmark AND Copenhagen University Hospital, Bispebjerg, Department of Orthopaedic Surgery and Traumatology, Denmark AND University of Copenhagen, Department of Clinical Medicine, Faculty of Health and Medical Sciences; Lund University, Skåne University Hospital, Department of Orthopaedics, Malmö, Sweden

Background: The lived experience refers to how something is directly experienced by someone, not ascertained or registered by others. The experiences of sustaining a hip fracture (HF) in elderly are well known, but in younger age, this has not been described.
Aim: The aim was to illuminate the lived experience of recovery after HF in adults under the age of 60 years, to guide future healthcare services.
Materials and Methods: Participants were purposely sampled from a prospective multicenter cohort study and narrative interviews were conducted with 19 patients 0.7-3.5 years after the fracture by two experienced researchers. We used a phenomenological hermeneutic method to describe the patients’ expressed essential meaning.
Results: The experience of sustaining a HF was expressed as a painful and protracted process of regaining self-confidence, function, and independence. The fracture threw the person into a situation of total stand-still in everyday life with feelings of weakness, disability, and inability. Participants described that the HF implied a sense of becoming old from one day to another, the body being feebler, and being looked upon as a burden by employees and colleges. Patients were afraid of new falls and fractures, resulting in an increased wariness. Stiffness, pain, and reduced physical abilities created a need for margins, never before required. At times of expressing fears and persisting symptoms related to the HF, patients describe being neglected and marginalized by the health care system, which was perceived as non-receptive and routinely driven by a notion that HFs affect only elderly. Rehabilitation targeted towards needs different from geriatric patients’ was lacking but was requested by younger patients. Hope was a crucial part of the recovery process. Other encouraging factors to uphold motivation were family, understanding employers, and feedback from physiotherapists with a program based on individual abilities.
Interpretation / Conclusion: The lived experience of HF in patients aged under 60 includes substantial challenges in their everyday lives, still up to 3.5 years after the injury. Other rehabilitation pathways tailored to the needs of these patients, not only towards geriatric HF patients, are requested.

Christina Frandsen, Eva Glassou, Maiken Stilling, Torben Bæk Hansen
University Clinic of Hand, Hip and Knee Surgery, Department of Orthopaedics, Gødstrup Hospital, Denmark; Department of Quality, Gødstrup Hospital, Denmark; Department of Clinical Medicine, Aarhus University, Denmark; University Clinic of Hand, Hip and Knee Surgery, Department of Orthopaedics, Gødstrup Hospital, Denmark

Background: Despite extensive research, a complete understanding of what influences mortality risk among patients with hip fractures is lacking. Previous research has primarily focused on non- modifiable risk factors, however, to improve outcome optimization of modifiable risk factors should be of great interest.
Aim: to examine 19 variables as risk factors for mortality among patients with hip fractures in a large, prospective cohort treated within a well-defined guideline.
Materials and Methods: All consecutive patients surgically treated for a hip fracture from January 2011 to December 2017 were included in the study (n=2,810). Variables were obtained from patient records and the Holstebro Hip fracture database, which prospectively registered data regarding demographics, comorbidity, malnutrition (low BMI or albumin), fracture type and treatment, hospital stay (including biochemistry, mobilization and discharge). Outcome was 30-day and 1-year mortality. The association between variables and mortality was examined by logistic regression.
Results: The patients were predominantly female with a median age of 81.6 years. The overall mortality was 9.5% and 24.1% for 30 days and 1 year, respectively. Unsurprisingly, some non- modifiable risk were associated with increased mortality at 30 days and 1 year; age =75 years (OR 2.25; CI 1.60-3.18), male gender (OR 1.85; CI 1.46-2.33) and nursing home residence (OR 1.87; CI 1.46-2.41). For modifiable risk factors ASA=3 (OR 1.70; CI 1.37-2.12), BMI<20 kg/cm2 (OR 1.86; CI 1.44-2.41), albumin<35g/L (OR 2.25; CI 1.79-2.84), low NMS (OR 2.26; CI 1.78- 2.88), not regaining CAS (OR 1.53; CI 1.09-2.14) and no mobilization (OR 1.48; CI 1.11-1.97) were all associated with increased mortality at 30 days and 1 year (1-year OR are reported).
Interpretation / Conclusion: Multiple comorbidities, malnutrition, low pre-fracture mobility and inadequate recovery were found to be important risk factors for increased mortality among patients with hip fractures. Especially interesting as they, to a certain extent, are modifiable. Further research into optimizing is needed.

Camilla Hattig Bonefeld, Marianne Lind, Michael Mørk Petersen, Müjgan Yilmaz, Anders Paulsen
Orthopedic Department, Rigshospitalet; Orthopedic Department, Rigshospitalet; Orthopedic Department, Rigshospitalet; Orthopedic Department, Rigshospitalet; Orthopedic Department, Rigshospitalet

Background: More than 60-65% of the surface area of the talus bone is covered with articular cartilage, which limits the intra-osseous blood supply. Talus account for 0.5 % of all fractures, and only 3% of all foot fractures. The primary mechanism of injury is often severe, and includes high energy, often making the patient group multi-traumatic. Associated skeletal lower leg injuries has been reported in 54% of all talus fractures, and 8% were multi-traumatic with injuries at other locations of the body. Sequelae such as avascular osteonecrosis (54%) and post-traumatic arthritis (25%) are common complications seen after treatment of all types of talus fractures.
Aim: Describe the demography and early complication rate after surgical treatment of both talar neck and corpus fractures.
Materials and Methods: In 2010-2013 we operated 29 consecutive patients (34 (14-54) years, F/M= 11/18) with 33 talus fractures, 19 corpus fractures and 14 neck fractures. All fractures were evaluated pre- and post- operatively with plain X-rays and CT. The operative technique was selected by the surgeon and was either ORIF (n=29), external fixation (n=3) or primary arthrodesis (n=1).
Results: Corpus fractures were classified by the Sneppen classification (type 1 (n=3), type 2 (n=3), type 3 (n=3) type 5 (n=10)) and neck fractures by the Hawkins classification (type 1 (n=7), type 2 (n=3), type 3 (n=3) type 4 (n=1). 19 patients sustained their injury in a high-energy trauma, 7 patients had an open fracture, and 4 patients had bilateral fractures. The number of associated injuries found were: 1-2 (n=15), 3-4 (n=5), 5 or more (n=2). 11 patients required more than one surgery in order to gain soft tissue coverage, infection control and ultimate heling. 2 patients had secondary arthrodesis of the ankle joint caused by AVN.
Interpretation / Conclusion: We found a higher number of associated injuries in patients with talus fractures than seen in other studies. The number of AVN was lower than otherwise reported, however, we experienced a high number of surgical interventions in order to archive healing.

Jonas Adjal, Ilija Ban
Department of Orthopaedic Surgery and Traumatology, CORH, Hvidovre Hospital, Capital Region, Denmark.

Background: Patella fractures requiring surgery are traditionally treated using metallic implants which are associated with high re-operations rates mainly due to implant prominence. Non-metallic fixation methods could be a solution to this problem.
Aim: To report results on adults with a patella fracture treated with a non-metallic all suture-based fixation technique.
Materials and Methods: From 01.11.2018 all adult patients with a patella fracture requiring surgery were treated using a suture tension band fixation method - a non- metallic all suture-based fixation technique. Prior to surgery all were informed of this technique and the possibility to be treated with the standard metallic tension band technique. 24 patients were enrolled consecutively by the end of august 2019 with no patients declining the non-metallic technique. We had no exclusion criteria regarding high age, fracture type, or functional level. Two surgeons performed the surgery. The standardized postoperative regimen comprised partial knee immobilization for 4 weeks. Follow- up was done at 2 and 4 weeks and 3- and 6- months post-surgery.
Results: No patients were lost to follow-up. 15 of 24 were females, median age of 59 years (19-81 years), and 8 open fractures. Fractures were simple 2- part in 5 cases and comminuted in 19 cases. In one case additional k-wires were needed for stability due to severe comminution. At 6 months the median knee ROM was 125 degrees (90- 150), median pain VAS at rest was 0,3 (0-2), median pain VAS at activity was 1,2 (0-5). Data on VAS were missing on two patients. All but 1 united radiologically. 7 patients had unexpected events (1 with asymptomatic non-union needing no further intervention, 2 with superficial wound infections treated successfully with oral antibiotics, 1 with prominent knots requiring implant removal, 2 with inflammation of the quadriceps tendon requiring corticoid injections and prolonged rehabilitation, 1 with deep venous thrombosis requiring oral antithrombotic medication).
Interpretation / Conclusion: This non-metallic all suture-based technique seems safe and could be an alternative to traditional metallic fixation for all types of patella fractures with a potential to significantly reduce the problem of prominent implants.

Mads Terndrup, Nicholas Bonde, Job Doornberg, Tue Smith Jørgensen, Christoffer Seem, Morten Grove Thomsen, Søren Kring, Peter Hersnæs, Dennis Karimi
Department of Orthopedics, Copenhagen University Hospital Hvidovre, Denmark University Medical Centre Groningen, The Netherlands

Background: Isolated lateral malleolar fractures (ILMFs) should be examined with a diagnostic stress- test to differentiate stable from unstable injuries, in order to guide optimal treatment. Weightbearing radiographs (WBRs) one to two weeks after injury could be a feasible stress-test and be increasingly utilized, but the reliability of the radiographic measurements used to evaluate stability needs consideration.
Aim: What is the most reliable measure of tibiotalar joint clear space in diagnostic WBRs of ILMFs -one to two weeks after injury?
Materials and Methods: The primary outcome of this inter-observer reliability study was the Intraclass Correlation Coefficient (ICC) between eight observers obtaining four clear space measures described in the literature: Superior Clear Space (SCS); Medial Oblique Clear Space (MoCS); Medial Perpendicular Clear Space four mm below the talar dome (Mp4CS); and Medial Perpendicular Clear Space five mm below the talar dome (Mp5CS). Measurements were performed on diagnostic WBRs of 116 consecutive patients with ILMFs sampled from a single-center prospective cohort study conducted in our setting during 01.06.2016–31.05.2018, where all patients with ILMFs were treated non-operatively and examined with WBRs one to two weeks after injury.
Results: The SCS showed the highest inter-observer reliability (ICC = 0.92 CI 0.883–0.935) and could be obtained by all observers in all 116 cases (100%). The MoCS showed the highest inter-observer reliability of the medial clear space measurements (ICC = 0.883 CI 0.844–0.914), obtained by all observers in 115 cases (99.1%). The Mp4CS showed good inter-observer reliability (ICC = 0.864 [95%CI 0.821–0.899)], obtained by all observers in 106 cases (91.4%). The Mp5CS measure showed good inter-observer reliability (ICC = 0.870 [95%CI (0.827–0.907)] and could be obtained by all observers in 84 cases (72.4%).
Interpretation / Conclusion: When assessing tibiotalar alignment in diagnostic WBRs of ILMFs, we recommend using the superior clear space measure and the perpendicular medial clear space measured four mm below the talar dome in clinical practice.

Sofie Ryaa, Jens-Christian Beuke, Per Hviid Gundtoft, Michael Brix, Bjarke Viberg
Department of Orthopaedic Surgery and Traumatology, Hospital of Southern Jutland; Department of Orthopaedic Surgery and Traumatology, Odense University Hospital; Department of Orthopaedic Surgery and Traumatology, Kolding Hospital – part of Hospital Lillebaelt; Department of Regional Health Research, University of Southern Denmark

Background: There is an impression of a relatively high complication rate in osteosynthesis of patella fractures. It is not clear whether surgeons’ experience is a factor in reoperation rates.
Aim: To estimate any association between the surgeon’s level of experience and major reoperation rates in patients with primary patella fractures treated with Open Reduction Internal Fixation (ORIF).
Materials and Methods: All adult patients with patella fractures treated with tension band wiring technique registered in Danish Fracture Database (DFDB) from 2012 to 2016 were included. Major reoperation was defined as re- osteosynthesis, deep infection or arthroplasty within one year but also included removal of hardware within three months. Minor reoperation was defined as hardware removal more than three months after primary surgery. Surgeons’ level of experience was defined as the highest ranking member of the surgical team and grouped into 1) postgraduate doctor, internship, or residency 2) consultant doctor. Multivariate regression analysis for major reoperation was performed with surgeons’ experience as the primary variable including adjustment for age, sex and American Society of Anaesthesiologists (ASA)-score. Results are given with 95% confidence interval.
Results: There were 610 patients included (440 treated by consultants) with a mean age of 63 (62;64), 52% male, 50% ASA group 2, 8% open fractures, and 33% AO type C3 fractures with no clinical relevant difference between the surgical experience groups. There were 9.4% major reoperations in the most inexperienced surgeon group compared to 10.7% in the experienced group. This yielded an adjusted relative risk of 1.14 (0.65;2.01). There were 34% with minor reoperation within one year after primary surgery yielding a relative risk of 1.01 (0.75; 1.36) with no statistical difference between the groups.
Interpretation / Conclusion: There was no statistical significant difference in rate of major or minor reoperation between consultants and non-consultants. Patients should preoperatively be informed of a high risk of reoperation due to major or minor complications within a year of primary surgery.

Mads Emil Jacobsen, Leizl Joy Nayahangan, Monica Ghidinelli, Chitra Subramaniam, Kristoffer Borbjerg Hare, Lars Konge, Amandus Gustafsson
Dep. of Orthopaedics, Slagelse Hospital, Region Zealand; Copenhagen Academy for Medical Education and Simulation (CAMES), Capital Region of Denmark; AO Education Institute, AO Foundation, Switzerland; AO North America, AO Foundation, PA, USA; Faculty of Health and Medical Sciences, University of Copenhagen, Denmark

Background: Simulation-based training is emerging to meet the challenges of orthopaedic surgical education and assessment is essential to drive learning and ensuring competency. A prerequisite for meaningful assessment is an agreement on what constitutes competency and specific assessment tools.
Aim: The aim of the study is to identify technical assessment parameters to be included in 7 procedure specific assessment tools to evaluate the competencies of novice orthopaedic residents in applying basic principles of osteosynthesis (tension band, compression plate, locking plate, intramedullary nail, buttress plate, lag screw + neutralization plate and bridge plate) on a virtual reality simulator.
Materials and Methods: A 4-round international Delphi study is used to achieve consensus, among key international experts, on the content of the assessment tools, by use of online questionnaires. All panelists are AO faculty members. In round 1 open-ended questions are used to identify all potential assessment parameters to include in the assessment tools. In rounds 2 and 3 the panelists will rate the importance of each assessment parameter, eliminating those that do not meet the predefined thresholds for consensus. Additionally, in round 3, the panelists will define optimal intervals for each assessment parameter that will yield a maximum score, and the slope of a curve, on each side of the optimal interval, by which a less-than-maximum score will be determined. Finally, in round 4, the panelists will define weights of each the assessment parameters in the final assessment tools.
Results: Data collection is ongoing and is projected to be completed by July 2021. At present, the first Delphi round has been concluded with participation of a total of 100 AO faculty members from 45 different countries. Round 1 yielded a total of 1.051 parameters, that were reduced to 279 potential assessment parameters after qualitative analysis. The final assessment parameters will be presented at the congress.
Interpretation / Conclusion: The study will yield procedure-specific assessment tools for seven basic osteosyntheses allowing for automated assessment on a virtual reality simulator. Validity of the assessment tools will be explored in future studies.

Kiran Anderson, Rasmus Wejnold Jørgensen


Background: We have implementated the use of processed nerve allografts and conduits for nervereconstruction where direct end-to-end suture was not possible after nerveinjury.
Aim: To evaluate our ongoing results of nervereconstruction from 2017 and onwards.
Materials and Methods: We have thus far had 51 individual nerve injuries with this type of nerve reconstruction. Sufficient data was available for 42 injuries (32 sensory, 9 mixed, and 1 motor nerves). The mean age was 44 (SD 16, range 12-72). Data collected at follow up included visual analog scale (VAS) pain scores, static two point discrimination (S2-PD) - defined as meaningful with values <15 mm, Semmes Weinstein Monofilament Examination (SMWE), grading of cold intolerance and hyperestesia from 0-3 of perceived problems from pain or discomfort of normal touch when using the hand (0=hinders function, 1=disturbing, 2=moderate, 3=none/minor problems), grip strength, pinch strength and the disabilities of the arm, shoulder and hand score (Quick-DASH).
Results: The mean time of the last follow up was 250 days (SD 147, range 84-550). The mean VAS scores were 1.29 (SD 2.6, range 0-8) at rest and 2.75 (SD 3.4, range 0-10) at function. S2-PD with 14/22 (66.7%) patients having meaningful S2- PD. SWME with 65.2% with protective sensation. Grip strength of the injured hand with a mean of 22.6 KgF (SD 11, range 2-48) and pinch strength with a mean of 5 KgF (SD 2.2, range 0-8). Cold intolerance of 0% with grade 0 and 69.6 % with grade 3, and hyperestesia with 4.5 % with grade 0 and 63.6% with grade 3 function. Q-DASH with a median of 18 (SD 22.2, range 0-73). No difference in functional outcome was found between allografts and conduits. Two patients developed neuromas in connection with the allograft. One had revision surgery with a new allograft and one had the allograft removed, burying the proximal nerve end in adjacent muscle. Two other patients with allografts have not had satisfying functional outcomes and have had tendon transfers to restore function.
Interpretation / Conclusion: Thus far the results are good but not as good as other studies alike. At this point we found no obvious differences in subjective or objective results between nerve allografts and nerve conduits.

Thomas Giver Jensen, Almadareb Mostafa Aqeel Khudhair, Nielsen Maria Booth, Hansen Emil Jesper, Lindberg-Larsen Martin
Department of Orthopaedic Surgery, Bispebjerg and Frederiksberg Hospital; Department of Orthopaedic Surgery, Odense University Hospital.

Background: Surgical treatment of lateral distal fibula fractures is associated with high risk of reoperation and complications. Within the last decade anatomical plates have been introduced.
Aim: The aim of this study was to report risks of reoperation and wound healing problems within one year after treatment with one-third tubular plate, locking compression plate or distal anatomical locking compression plate.
Materials and Methods: From 1 January 2010 until 31 December 2015 all patients having osteosynthesis of distal fibula with a one-third tubular plate, LCP or distal anatomical LCP plate at Copenhagen University Hospital, Bispebjerg, Denmark, were identified and retrospectively evaluated with a follow up of at least one year. Data on patient characteristics, fracture classification, surgical time, surgical delay and weight bearing were registered.
Results: 588 patients were included. 417 were treated using a one-third tubular plate with a reoperation risk of 11% (95% CI 8-14) (n=46) and wound healing problems risk of 21% (95% CI 18-25) (n=89). 114 received a LCP plate with a reoperation risk of 20% (95% CI 13-28) (n=23) and wound healing problems of 31% (95% CI 23- 40) (n=35). 57 had a distal anatomical LCP plate with a reoperation risk of 23% (95% CI 14-35) (n=13) and wound healing problem risk of 40% (95% CI 29-53) (n=23). No difference was seen in fracture classification (Weber) between one- third tubular plate and distal anatomical LCP plate. Patient age = 70 years (p<0.001), smoking (p=0.001), surgical time = 90 min (p=0.006) were associated with increased risk of wound healing problems in a multivariate regression model. We found no significant association between patient or fracture related risk factors and risk of reoperation within one year.
Interpretation / Conclusion: Distal anatomical LCP plates seems to be associated with higher risk of reoperation and wound healing problems compared to the one-third tubular plate and risk factors for wound healing problems were high patient age, smoking and increased surgical time.

Charlotte Abrahamsen, Bjarke Viberg, Birigtte Nørgaard
Department of Orthopaedic Surgery and Traumatology, Hospital Lillebaelt – University Hospital of Southern Denmark; Department of Regional Health Research, University of Southern Denmark; Department of Public Health, University of Southern Denmark

Background: Time to recovery in everyday life functioning after a hip fracture ranges from four to twelve months. As duration of the recovery process varies considerably, patients’ perspectives on everyday life may change over time.
Aim: To explore the impact of hip fracture on elderly patients’ perspectives on everyday life at different time points
Materials and Methods: This is a longitudinal interview study. Twelve hip fracture patients were interviewed once during admission, and further three times within a year after the fracture. Hip fracture patients undergoing surgery, and of different gender, marital status and pre-fracture mobility were of interest.
Results: The fracture occurred at home while performing activities of everyday life. During admission, patients felt restricted by pain when performing activities of everyday life and expressed concern for their future ability to manage in everyday life. Briefly after discharge they were able to manage personal care, yet their everyday life activities were restricted for up to six months after the fracture. Most had regained their physical functioning 12 months following the fracture. Pain and the fear of falling were pervasive topics in all interviews.
Interpretation / Conclusion: Their hip and the fracture itself had little prominence in the fracture patients’ responses. They referred to activities of everyday life and the level of support they needed as measures of the rehabilitation and recovery progress towards their usual lives before the hip fracture.

Jonas Adjal, Ilija Ban
Department of Orthopaedic Surgery and Traumatology, CORH, Hvidovre Hospital, Capital Region, Denmark.

Background: Patella fractures requiring surgery are traditionally treated using metallic implants, which are associated with high re-operations rates mainly due to implant prominence.
Aim: To overcome the problem of prominent metallic implants we present a non-metallic all suture-based technique based on braided sutures – the suture tension band fixation.
Materials and Methods: The suture is passed through soft tissue solely, that is: the quadriceps tendon, the patellar ligament, and the medial and lateral retinacula. Upon reduction the first and second sutures are passed through soft tissue in two distinct ways: “the modified circular suture” and “the modified figure-of-eight” suture, respectively. Both sutures start in the upper lateral corner of the quadriceps tendon where knots are likewise tied. If comminution is present the fracture is converted into a simple two-part fracture with one or two “box sutures” around the upper and lower pole, respectively.
Results: This technique is here described on our first six patients treated with this technique at our institution along with their clinical and radiological follow up. It is furthermore described in a step-wise, standardized way that can be adapted to all types of patella fractures. The described suture configuration allows maintenance of inter-fragmentary reduction until bony union without symptoms from the suture material.
Interpretation / Conclusion: The suture tension band fixation is a safe technique and non-metallic techniques may be a promising alternative to traditional metallic fixation methods.

Lili Worre Høpfner Jensen, Nina Aagaard Madsen, Birthe Dinesen, Ole Rahbek, Søren Kold
1) Interdisciplinary Orthopaedics, Aalborg University Hospital; 2) Department of Physiotherapy, Horsens Regional Hospital; 3) Department of Health Science and Technology, Aalborg University; 4) Interdisciplinary Orthopaedics, Aalborg University Hospital; 5) Interdisciplinary Orthopaedics, Aalborg University Hospital

Background: Treatment with external circular frame after complex tibia fractures burdens both patients, relatives and the healthcare system. The treatment is long-lasting, with an average of 5.6 months, and thus patient courses must be well coordinated across sectors and knowledge sufficiently shared. Telerehabilitation, defined as rehabilitation using information and communication technologies to support health from a distance, may be a possible solution for this patient group.
Aim: The aim of this study was to develop a digital platform prototype for telerehabilitation of patients treated with external circular frame based upon participatory design and to test and evaluate the prototype.
Materials and Methods: The study was inspired by participatory design, in which users are involved in the development and design of technological solutions in order to ensure usability and inclusion of relevant functionalities. An iterative process took place in collaboration with patients (n=8), relatives (n= 4) and health professionals across sectors (n=6), where qualitative data collection techniques were used: cultural probes, observation in patients’ homes, interviews (n= 18) and workshops (n=3). Patients were included until data saturation was reached.
Results: The first iteration of the prototype was qualitatively evaluated with a focus on design, content and relevance; patients and relatives found that the prototype was easily manageable, and the content supported their needs in the rehabilitation context, but health professionals expressed concerns about extra workflows and risk of double documentation. The prototype has to be further developed and tested in several clinical tests and on a larger scale before implementation.
Interpretation / Conclusion: Patients expressed a potential of telerehabilitation when treated with external circular frame. The study has initiated further investigation within Telehealth for orthopaedic surgery patients at Aalborg University Hospital.