Lars Binderup Larsen^1,2, Rikke Rysgaard¹, Henriette Thorlacius-Ussing¹
1. Danish Road Traffic Accident Investigation Board, Copenhagen, Denmark Havarikommissionen for Vejtrafik Ulykker, HVU 2. Accident Analysis Group, Odense, Denmark

Background: Head injuries are frequent in road traffic accidents involving cyclists and use of a bicycle helmet has been recommended to reduce the risk for these injuries. Several studies have shown good protective good overall effect.
Aim: • To assess in which accidents helmet use reduce head injury. • Can potentially use of helmets reduce head injuries for those cyclists not wearing a helmet? • To assess the role of helmet use for those who escaped head injury.
Materials and Methods: The AIB is a multi-disciplinary group that makes in-depth analyses of frequent and severe road traffic accidents. Analyses are based on a comprehensive collection of data and information. Information regarding the injuries is collected from medical recordings and data from autopsy. Injuries are classified according to AIS. For this study data regarding bicyclists involved in accidents in the period 2005 to 2021 were included.
Results: The study included 56 bicyclists with head injury and 35 bicyclists without head injury. The use of a helmet had not been effective against severe or fatal head injury in 8 out of 17. This was mainly due to the speed of the other part or the fact that the cyclists had been run over by a heavy vehicle. The use of a bicycle helmet would have been able to reduce head injuries in 20 out of 38 cyclists who did not use a helmet. 35 cyclists had no head injuries. In only 2 cases the helmet was the reason for that, while there was a large number where helmet use had not been important due to the lack of impact on the head.
Interpretation / Conclusion: In some accidents, there have been such great forces in the accidents that helmets have not had enough protective effect. It was most frequent due to high speed of vehicle, or the cyclist being run over by a heavy vehicle. To avoid accidents with severe and fatal head injuries with these factors, measures other than increased helmet use is required. However, in several accidents a positive effect of the helmets was recorded. There is still great potential in reducing head injuries through increased use of helmets.

Rikke Thorninger^1,2, Karen Romme¹, Daniel Wæver³, Bille Henriksen Martin¹, Michael Tjørnild¹, Lind Martin^2,3, Duedal Rölfing Jan^2,3
1: Department of Orthopaedics, Regional Hospital Randers, Skovlyvej 15, DK- 8930 Randers, Denmark 2: Department of Clinical Medicine, HEALTH, Aarhus University, Palle Juul- Jensens Boulevard 82, DK-8200 Aarhus, Denmark 3: Department of Orthopaedics, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, J801, DK-8200 Aarhus, Denmark

Background: Recent studies have shown that distal radius fractures (DRFs) in elderly patients can be treated non-operatively with good functional results after 1 year. However, scientific evidence regarding longer follow-up to assess post- traumatic arthritis (PA), complications, and functional outcomes is scarce.
Aim: This prospective case series aimed to evaluate these outcomes in a cohort of 50 patients (= 65 years old) with non-operatively treated DRFs, according to National Clinical Guidelines, after a minimum of 3 years.
Materials and Methods: The cohort of 50 patients also served as a control group in a prior published RCT study. The primary outcome was PA. Secondary outcomes were complications, Quick Disabilities of the Arm, Shoulder and Hand Outcome Measure (QuickDASH), Patient-Rated Wrist/Hand Evaluation (PRWHE), pain, range of motion and grip strength.
Results: Initially 50 patients were enrolled. Of these 50 patients 9 had died, 3 could not be reached, and 3 withdrew their consent to participate in the 3- year follow-up. Another 3 patients did not show up and further attempts to reach the patients by telephone were unsuccessful. Full data of 32 patients with a mean follow-up of 3.3 years were available: 10/32 patients had radiological signs of PA, but only 3 of these patients reported pain. A total of 11/32 fractures healed in mal-union (> 10° dorsal angulation). There was no significant difference in QuickDASH or PRWHE from 1 year to the latest follow-up.
Interpretation / Conclusion: This study thus adds to the literature stating that radiological signs, including PA and mal- union, do not necessarily result in symptoms. Moreover, it underpins that non-operative treatment of these patients results in good functional outcomes after 1 and 3 years.

Martin Aasbrenn^1,2, Luana Sandoval Castillo¹, Thomas Giver Jensen³, Morten Tange Kristensen^2,4, Troels Haxholdt Lunn^2,5, Eckart Pressel^1,2, Henrik Palm^2,3, Søren Overgaard^2,3, Anette Ekmann¹, Charlotte Suetta^1,2,
1. Department of Geriatric and Palliative Medicine, Copenhagen University Hospital Bispebjerg-Frederiksberg; 2. University of Copenhagen, Department of Clinical Medicine, Faculty of Health and Medical Science; 3. Department of Orthopaedic Surgery and Traumatology, Copenhagen University Hospital Bispebjerg-Frederiksberg; 4. Department of Physical and Occupational Therapy, Copenhagen University Hospital Bispebjerg-Frederiksberg; 5. Department of Anaesthesia and Intensive Care, Copenhagen University Hospital Bispebjerg-Frederiksberg; 6. Copenhagen University Hospital Herlev and Gentofte, Department of Internal Medicine

Background: Monoclonal gammopathy of undetermined significance (MGUS) is a premalignant plasma-cell disorder that can progress to multiple myeloma. MGUS is associated with increased risk of vertebral fractures but evidence regarding the association between monoclonal gammopathy and hip fractures is limited.
Aim: We aimed to examine the prevalence of MGUS among patients aged =65 years surgically treated for hip fractures.
Materials and Methods: Older patients (=65 years) surgically treated for a hip fracture at Copenhagen University Hospital Bispebjerg and Frederiksberg in 2021 and living in Denmark were included in the study. Blood tests during admission were analysed for a monoclonal immunoglobulin.
Results: In total, 375 patients were surgically treated for a hip fracture, out of these 218 (58%) were screened for MGUS. A monoclonal immunoglobulin was present in 26/218 (12%) of the screened patients. The isotype was IgG (17), IgM (7) and IgA (2), respectively. The concentration of the monoclonal immunoglobulin was above 2.0 g per deciliter in 5/26 (19%). In patients aged under 80 years, a monoclonal immunoglobulin was present in 8/93 (9%); whereas the prevalence was 11/85 (13%) in patients aged 80-89 years,and 7/40 (18%) in patients aged 90 years or older. The 1-year mortality in patients with a monoclonal immunoglobulin was 9/26 (35%) versus 38/192 (19%) in those without, P = 0.12.
Interpretation / Conclusion: The present data show that monoclonal gammopathy is relatively common among patients with hip fractures and that the 1-year mortality is high in these patients. However, further research is needed to better understand this relationship, and the clinical utility of screening remains unknown.

Andreas Saine Granlund¹, Arvind von Keudell^1,2
1. Department of Orthopaedics, Bispebjerg Hospital 2. Department of Orthopaedics, Harvard Medical School, Boston

Background: The optimal postoperative weight bearing regimen for uni- or bicondylar tibial plateau fractures remains a topic of debate. Traditionally, non- or touch down- weight bearing for at least 10-12 weeks with early range of motion is recommended, however more recent studies suggest that early weight bearing may not result in any loss of reduction or hardware failure.
Aim: This study aims to compare orthopedic trauma surgeons' preferences for postoperative regimens and the factors that influence their decision-making in relation to weight bearing status after tibial plateau fractures.
Materials and Methods: The survey was presented during the 2023 annual meeting for Danish Orthopedic trauma surgeons (DOT). Participants were asked questions related to surgical technique, the timing of weight bearing after osteosynthesis and factors that influenced the surgeon's decision-making process for 3 unicondylar and 3 bicondylar tibial plateau fractures.
Results: 79 out of 114 attending the annual DOT meeting answered our survey. 90% of respondents were Danish, 83% were men and around 50% of respondents treated > seven tibial plateau fractures per year. After surgery 25,5% of the respondents recommended non-weight bearing, 31,5% touch down weight bearing, 21,5 % partial weight bearing and 20,5% recommended full weight bearing respectively. 82% of the surgeons stated that the sense of stability in their own construction affects their postoperative weight bearing plan and in 51% the regimen was based on “gut feeling”. Responders believed they get absolute stability in only 59% of their own fixations and 50% responded do not believe patients are following the postoperative weight bearing plan.
Interpretation / Conclusion: Our survey study demonstrated wide variability among Danish surgeons regarding postoperative weight bearing in tibial plateau fractures. Interestingly only 59% of the surveyed felt they obtained absolute fixation treating tibial plateau fractures and over 80% believed that their presumed fixation construct affects weight- bearing status rather than following the AO recommendations. Further research is required to understand the stability of tibial plateau fractures and quantify whether we can allow patients to weight bear earlier.

Jonas Hammershøy¹, Charlotte Densing Petersen¹, Marlene Dyrløv Madsen², Doris Østergaard^2,4, Klaus Nymark Andersen², Torben Beck², Thomas Giver Jensen², Troels H. Lunn^1,3,4, Henrik Palm^1,4, Lene Viholt^1,3, Søren Overgaard^1,4
1. Copenhagen University Hospital – Department of Orthopedic Surgery and Traumatology Bispebjerg and Frederiksberg, Copenhagen 2.Copenhagen Academy for Medical Education and Simulation (CAMES Herlev), Capital Region Copenhagen 3. Department of Anesthesia and Intensive Care 4. Dept og Clinical Medicine, University of Copenhagen, Copenhagen, Denmark

Background: We introduced cemented HA as a new routine for treatment of patients with a femoral neck fracture (FNF). This is in accordance with the national Danish guideline. The implementation was preceded by an education strategy based on interviews and teaching sessions
Aim: To investigate and compare peri- and postoperative complications after the introduction of cemented HA to cementless in a general orthopedic department
Materials and Methods: We reviewed patient files of those who received a HA from July 2022 – February 2023. 3 HA brands were used. The change was from the uncemented Corail to the cemented Lubinus SPII stem with a unipolar modular head or some C- stems. During the period trauma surgeons have been supervised as needed. Perioperative complication (fissure, fracture, death), and postoperative complications (dislocation, infection, reoperation, death during admission) were identified
Results: A total of 93 HA’ies were performed on 33 males and 60 females from July 2022 to February 2023. During the period 50 cemented Lubinus SPII, 31 uncemented CORAIL, and 12 cemented C-stems were performed by 9 trauma and 6 reconstruction surgeons. Mean operation time was 88 min (95% CI 82-95) for Lubinus, 77 min (85-69) for CORAIL, 76 (86-66) min for C-stem. Perioperative complications: Lubinus: 1 fissure and 2 fractures (all wired), and 1 death. CORAIL: 3 fissures and 1 fracture (all wired), but 0 deaths. C-stem: no complications. Postoperative complications: Lubinus SPII were 1 dislocation which was reoperated, 0 infections, 2 deaths during hospital stay. CORAIL: 1 dislocation, 1 infection, 0 reoperations, 3 deaths during hospital stay. C-stem: 3 dislocations (2 reoperated), 0 infections, and 2 deaths during hospital stay
Interpretation / Conclusion: During this implementation period including the learning curve we observed some perioperative but a few postoperative complications with the newly introduced cemented HA stem (Lubinus). There seems to be even fewer complications as expected from earlier studies. We believe that by a well-planned introduction and implementation of a new surgical procedure we have so far achieved rather few complications

Anton Alexander Nolte Peterlin¹, Hans Gottlieb¹, Andreas Ibrahim Jørgensen¹
1. Department of Orthopedics, Herlev and Gentofte Hospital

Background: Morel-Lavallée lesion (MLL) is a posttraumatic soft tissue degloving injury, resulting from direct or tangential shearing forces hereby separating skin and subcutaneous tissues from the underlying fascia. A cavity characteristically containing hemolymphatic and serosanguinous fluid develops, and over time consolidates with an organized pseudocapsule. In contrast to the frequency of traumatic injuries, MLLs are uncommon, difficult to diagnose, and complicated to treat. Current literature around MLL management is based on lesions around the hip and trochanter region, with no previous studies reporting a uniform surgical management strategy for lesions over the knee and lower extremity.
Aim: To present an innovative treatment method for lower leg MLLs with subsequent negative pressure wound therapy (NPWT).
Materials and Methods: Case series, over one year two females and one male with lower leg MLL, all with similar trauma mechanisms with a direct and shearing force to the knee and or lower leg. Two involved motor vehicles and all had clinical presentations with painful and persistent lesions. Magnetic resonance imaging and ultrasound were the determining diagnostic modalities. Operative treatment included uniform surgical debridement while preserving dermal vascularity, capsulectomy, and partial wound closure using black foam (NPWT) to minimize fluid buildup and reformation of the lesion. Finally, the foam was retracted over 2 revisions in out-patient clinic.
Results: All had one effective operative debridement, hospitalized less than 5 days, had 2 NPWT changes, and treatment ending within 2-3 weeks. At their 12-month follow-up all were symptom free. Decreased cutaneous sensation around the lesion, which was present in 2 of the 3 patients prior to surgery was the only complication.
Interpretation / Conclusion: Morel-Lavallée lesions of the lower leg and knee are sparsely reported in literature, making the disease difficult to diagnose and treat. In our case series we reported an easy to manage diagnostic routine as well as a novel surgical treatment which included debridement, capsulectomy and secondary management with NPWT in an out-patient setting. The operative methods resulted in excellent healing results with pain free motion.

Alex Jørgen Romanowski, Hessel Andersen Jakob ¹, Peter Toquer², Rikke Malene H. Grønholm Jepsen¹
1. Department of Anaesthesiology, Zealand University Hospital 2. Department of Orthopaedic ?Surgery, Zealand University Hospital

Background: The use of peripheral nerve blocks (PNB) is associated with better outcomes for patients compared to general anesthesia. However, some surgeons are reluctant to use PNB due to the risk of adverse events, especially for patients in high risk of developing acute compartment syndrome (ACS) due to concerns that PNB will mask ischemia symptoms. This review is based on the latest literature and international guidelines available on PubMed.
Aim: The purpose was to investigate the risks of applying PNB.
Materials and Methods: The review is based on systematic searches in PubMed using PRISMA 2020 guidelines. Included articles investigated the use of PNB without concomitant use of spinal or epidural anesthesia. Articles in Danish or English, from 2012 onwards were included. Thirty articles were selected, due to a limit on references when publishing a review in The Journal of the Danish Medical Association.
Results: Nerve damage from PNB can be divided into chemical, vascular, inflammatory, and systemic damage. The incidence of nerve damage is low and often transient. Anesthetic literature generally concludes that low dose PNB blocks postoperative pain, but not ischemic pain related to ACS. Anesthetic literature regards low dose PNB, even in high- risk procedures, to be safe with sufficient post- operative observation of ACS symptoms. The use of low dose PNB is supported in the rather scarce number of case reports published on patients with PNB developing ACS and experiencing break-through pain. Some of these reports seems to be interpreted differently, depending on the publishing journal/guideline being orthopedic or anesthesiologic. The most recent American orthopedic guideline does not - as opposed to previous versions being against - conclude anything on the use of PNB.
Interpretation / Conclusion: The risk of adverse events associated with the use of PNB is low. Low dose PNB is considered safe by anesthesiologists and is no longer discouraged in orthopedic guidelines. However, as the evidence level is low, there is a need for more research to inform the interdisciplinary discussion between orthopedic surgeons and anesthesiologists on the risk of using PNB in patients at risk of developing ACS.

Markus Gadeberg¹, Adam Witten¹, Lisbet Hölmich², Jan Rölfing³, Per Hölmich¹, Kristoffer Barfod¹,
1. Sports Orthopedic Research Center – Copenhagen (SORC-C), Department of Orthopaedic Surgery, Copenhagen University Hospital Amager-Hvidovre, Denmark; 2. Department of Plastic Surgery, Copenhagen University Hospital, Herlev-Gentofte, Denmark; 3. Department of Orthopaedics, Aarhus University Hospital, Denmark

Background: Morel-Lavallée lesion (MLL) is a closed degloving injury caused by traumatic sheering of subcutaneous tissue from the underlying fascia. The lesion typically occurs in high-energy traumas but may also occur in low-energy traumas in sports (most often cycling, football, and American football). It is estimated that the diagnosis is missed in upwards of one-third of patients in the acute stage.
Aim: To present an overview of MLL and propose a treatment algorithm.
Materials and Methods: In this narrative review, Pubmed was searched for original studies from inception to 13-09- 2022 using the term “Morel-Lavallée”. 264 studies were identified.
Results: MLL can be divided into acute (<3 weeks) and chronic (>3 months or verified capsule formation). Treatment revolves around minimizing fluid and necrotic tissue and creating persistent contact between cavity walls. Treatment includes compression, percutaneous aspiration, sclerodesis and surgery. Surgical treatment is recommended for acute MLL with infection, avascular skin, or underlying fractures, and for chronic MLL with inadequate response to non-surgical treatment or chronic MLL with capsule formation. There are many surgical options, that can be applied stepwise depending on the treatment response. Suction curettage is the first-choice surgical approach for both acute and chronic MLL. Surgical drainage and open debridement are other surgical options. Vacuum Assisted Closure (VAC) can be used as adjunct to surgical treatment. Postoperative treatment should consist of compression and low-suction drainage. MRI and ultrasound can be used to verify the diagnosis and to monitor treatment progress if multiple interventions are needed.
Interpretation / Conclusion: Morel-Lavallée lesion (MLL) is a rare painful condition, but is probably significantly underdiagnosed, especially in the acute phase. Surgery should be reserved for complicated cases and chronic cases with insufficient response to non-surgical treatment. The literature primarily consists of heterogenous case-series and cohort studies, why further research is warranted.

Fatma Kandela¹, Adalet Corap¹, Yasemin Corap¹, Michael Brix¹, Bjarke Viberg¹, Martin Lindberg-Larsen¹
Orthopaedic Research Unit, Department of Orthopaedic Surgery and Traumatology, Odense University Hospital, Department of Clinical Research, University of Southern Denmark

Background: Studies investigating patient safety in terms of postoperative complications and readmissions after treatment of distal femoral fractures are very limited. The one-year mortality after operative treated native distal femoral fractures has been reported between 2 to 37%.
Aim: To evaluate the risk of in-hospital complications, readmissions and mortality after surgical treatment of distal femoral fractures using locking plates.
Materials and Methods: We retrospectively identified 263 patients by procedure codes (KNFJ64, KNFJ65, KNFJ84, KNFJ85) and diagnosis codes (DS723, DS724, DS728, DS729) in a single institution from 2011 to 2022. Out of 263 patients, 162 patients were treated for a distal femoral fracture with a locking compression plate (LCP). Indications for surgery were native distal femoral fracture (n=117) and periprosthetic femoral fractures (n=45).
Results: Out of the 162 eligible patients, 77% were females and the population had a median age of 76 years. Most (73.5%) of the patients were living in their own homes and 19.1% of the patients were living in nursing homes. The median length of stay (LOS) was 7 days (range 1-46 days) and in 28.4% (n=46) of cases an in-hospital complication was observed. The most frequent in-hospital complications were urinary tract infections (n=17), and anemia or electrolyte imbalances (n=7). The median time from diagnosis to operation was 42 hours (range 5-411 hours). The 90-day readmission risk was 24.2% and the most frequent causes were infections in the treated area (n=9) and pneumonia (n=5). 5 patients were readmitted more than one time. The most serious complications observed within 90 days were cardiovascular complications (n=3) and pneumonia (n=5). The 1-year mortality was 18.8%.
Interpretation / Conclusion: We found high rates of in-hospital complications, readmissions and mortality after surgical treatment of distal femoral fractures using locking plates. These results indicate room for improvement in the perioperative set-up when treating these at-risk patients.

Sara Woldu¹, Alexander Farid², Tynan H. Friend³, Henrik Palm¹, Arvind Von Keudell^1,2
1. Copenhagen University Hospital, Bispebjerg and Frederiskberg Department of Orthopaedic Surgery and Traumatology Section for Sports Traumatology Institute of Sports Medicine Copenhagen Nielsine Nielsens Vej 2400 Copenhagen NV, Denmark 2. Department of Orthopaedic Surgery, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA. 3. Center for Surgery and Public Health, Department of Surgery, Brigham and Women’s Hospital, Boston, MA, USA.

Background: Humeral shaft fractures can be managed operatively with open reduction–internal fixation (ORIF) or intramedullary nailing (IMN) or nonoperatively with functional bracing. A consensus on optimal management has not been reached. Surgical advances have made operative treatment increasingly attractive, particularly given the shorter time to union, decreased nonunion rate, and earlier mobility.
Aim: Cost-effectiveness has increasingly become a consideration in the management of orthopedic injuries. The aim of this study is to compare the cost- effectiveness of operative versus nonoperative management of humeral shaft fracture in a Danish context.
Materials and Methods: A decision tree model for treatment options were developed. We used DRG fees from the Danish Health Data Authority and expert opinion based on total surgical costs acquired from our institution to determine all relevant hospitalization costs. We obtained the costs of antibiotics from promedicin.dk. The average wages and weeks missed were obtained from Statistics Denmark and the existing literature. The Disabilities of the Arm, Shoulder, and Hand (DASH) scores were also extracted from existing literature. An economic evaluation was conducted to investigate the cost-effectiveness of each treatment option by use of rollback analysis and Monte Carlo simulation. The results are presented in DKK per meaningful change in DASH score. The Willingness- to-Pay (WTP) threshold was set at DKK300.000 per meaningful change in DASH score (10 points).
Results: Operative treatment is the preferred treatment strategy; it is both more effective and less costly to the patient at 6 months and 1-year follow-up when including lost wages compared to non-operative treatment. The sensitivity analyses show that even when non-operative success is changed to 100%, 6 months and 1-year follow-up with wages still favor operative intervention. Nonoperative treatment is only more cost-effective than operative treatment at or above 96.4% union rate at 1 year follow up not including wage loss.
Interpretation / Conclusion: Operative management is cost-effective at both 6 months and 1 year, compared to non-operative treatment when including wage loss. Level of Evidence: Economic and Decision Analysis Level II

Marcus Landgren^1,3, Rasmus Jørgensen Wejnold², Robert Gvozdenovic^1,3, Stig Jørring¹, Lars Soelberg Vadstrup^1,4
1Department of Orthopedic Surgery, Hand Surgery Unit, Copenhagen University Hospital Herlev and Gentofte, Gentofte, Denmark 2Department of Orthopedic Surgery, Trauma Unit, Copenhagen University Hospital Herlev and Gentofte, Herlev, Denmark 3University of Copenhagen, Faculty of Health and Medical Sciences, Institute of Clinical Medicine, Copenhagen, Denmark 4President, Danish Society for Surgery of the Hand

Background: Treatment of distal radius fractures (DRF) in Denmark has been in accordance with the Danish National Clinical Guidelines (DNCG) on treatment of DRF since published in 2014 (2017). Increasing diversity in interpretation of the emerging evidence on treatment of elderly with DRF amongst orthopedic and hand surgeons has arisen. Most publications on non- surgical vs. surgical treatment have been on patients older than 65 years. Using age as a proxy for function and recommending patients non-surgical treatment merely based on age, is age discrimination, a potential risk of undertreatment, and could result in increased costs if domestic care or corrective surgery is needed.
Aim: We aimed to review the local guidelines in Denmark to investigate if they differed from the DNCG.
Materials and Methods: A review of the hospital guidelines using search words “distal radius fraktur” was performed by searching the intra- and internet from the five different regions in Denmark. Local guidelines were searched in VIP-instruks in the Capital Region of Denmark, the Region Sjællands Dokumentportal in Region Zealand, the Infonet in Region of South Denmark, the e-dok in Central Denmark Region, and the pri in North Denmark Region. The guidelines were reviewed for treatment recommendations for elderly patients.
Results: In total, we found 15 different local hospital guidelines from all 5 Danish regions regarding treatment for DRF. Most guidelines were in accordance with the DNCG for treatment of DRF, in which age is not considered a contraindication for surgical treatment. Amongst the local guidelines, only Zealand University Hospital used age as a strict cut-off for surgical treatment (age >60 years), non- surgical treatment was recommended regardless of the severity of the displacement. Four other hospitals considered age, function, and comorbidity when recommending treatment.
Interpretation / Conclusion: As of 2023, the DNCG are no longer applicable, an increasing diversity in treatment based on geographical differences is troubling. Treatment guidelines for this common injury should be similar nationwide. Hand and orthopedic surgeons should seek not to divide, but to unify. A Short Clinical Guideline in the treatment of elderly with a DRF is warranted.

Robin Bawer¹, Jakob Bak¹, Hans Gottlieb¹
1. Department of Orthopaedic Surgery, Herlev University Hospital

Background: In the treatment of bone and joint infections (BJIs), The Oral Versus Intravenous Antibiotics (OVIVA) trail demonstrated that a switch to oral antibiotic therapy after 1 week of initial intravenous antibiotics therapy was noninferior to a switch after 2 or more weeks of intravenous antibiotic therapy.
Aim: Following the OVIVA trail it was decided to implement the trail findings into clinical practice combined with a one-stage surgery setup. This postimplementation study presents our clinical experience with implementing the OVIVA setup allowing for comparison.
Materials and Methods: All patients surgically treated for BJIs between Sep. 2019 and Sep. 2020 were included. Patients were followed with physician consultations 1 and 8 weeks after discharge, a telephone consultation after 6 months and electronic patients journals were reviewed after 1 year. Data was collected on demographic information, type and length of antibiotic regime, switches from intravenous to oral antibiotic therapy, length of stay, microbiological findings, adverse drug reactions, complications and clinical outcome including treatment failure. We compared our results with the OVIVA trail and a study that has demonstrated the reproducibility of the trail findings in a real-world setting.
Results: A total 129 patients were included in the study. 98.4% of the patients (127 out of 129) were switched to a suitable oral antibiotic regimen. The median value for the duration of intravenous antibiotic therapy before switching to an oral antibiotic regimen was 7 days. The most frequent type of oral antibiotic used was penicillins (67.7%). Only 1 patient was treated with oral rifampicin. Definite treatment failure for all patients following the one-stage surgery setup and antibiotic regimen according to the OVIVA trail at 1 year was 12.1% (15 out of 129). The group of patients who remained on intravenous antibiotic treatment after surgery (2 patients) had no failures.
Interpretation / Conclusion: Our experience with implementing the OVIVA trail findings are in concordance with the study that show their reproducibility. By applying one-stage surgery and the OVIVA setup we were able to safely implement the trail findings into clinical practice with sufficient results.

Kristian Kjærgaard^1,2, Marjan Mansourvar³, Ming Ding^1,2
1. Orthopaedic Research Laboratory, Department of Clinical Research, University of Southern Denmark 2. Department of Orthopaedic Surgery and Traumatology, Odense University Hospital. 3. The Maersk Mc-Kinney Moller Institute, University of Southern Denmark.

Background: Experimental bone research frequently generates large amounts of histology and histomorphometry data, and the analysis of these data is often lengthy and trivial. Machine learning provides a suitable alternative to manual analysis, provided that the researcher has access to the know-how and equipment needed.
Aim: To develop a neural network for image segmentation to measure total area of a given type of tissue (e.g. bone tissue), and to determine the accuracy of this network on ectopic bone formation samples.
Materials and Methods: Thirteen tissue slides (summing up to 114 megapixels) of ectopic bone formation were selected for model building. The dataset was splint into training/validation/test samples by proportions 62%/15%/23%. We developed a neural network resembling U-Net with 22,017,012 parameters that takes 512x512 pixel tiles. To improve model robustness, images were augmented with flip, transpose, scale, rotate, or elastic transformations; blur or noise filters; and adjustment of brightness, contrast, or gamma, or shift of RGB or HSV channel values. The network was trained for 3 days (200 epochs) on a NVidia Tesla K80 provided by a free online learning platform against a ground truth annotated by an experienced researcher.
Results: Training and validation loss stabilized (apart from a few drops in validation loss) and were above 95% from epoch 49 and onwards. The accuracy on the test dataset (external, independent dataset) was 96.12%.
Interpretation / Conclusion: Most experiments using ectopic bone formation will yield a between-group difference of significantly more than 4%, so the current approach may be a valid and feasible technique for automated image segmentation for large datasets as an alternative to manual analysis. More meticulously annotated ground truth (such as a consensus-based ground truth) may improve training stability and validation accuracy.

Maria Louise Gamborg^1,2, Lisa Beicker Salling^1,2,3, Jan Duedal Rölfing^1,2,3, Rune Dall Jensen^1,2
1. Corporate HR, MidtSim, Central Denmark Region; 2. Department of Clinical Medicine, HEALTH, Aarhus University; 3. Department of Orthopaedics, Aarhus University Hospital.

Background: Medical education often aims to improve technical skills (TS) and thus patient safety and reduce adverse events. However, human factors have a huge impact on patient safety and has given rise to research into ‘non-technical skills’ (NTS). The two skill sets are often investigated independently, and little is known about how TS and NTS influence each other.
Aim: In this scoping review, we therefore aim to investigate the association between TS and NTS.
Materials and Methods: Scoping review of four databases in order to summarize, analyse, and collate findings from the included studies.
Results: In total, 192 of 2267 identified papers were included in the final analysis. The first article was published in 1991, but the majority of studies were published in the last decade. The majority were intervention studies including 39 randomized controlled trials. The most common validated assessment of TS was a the objective structured assessment of technical skills (OSATS), but many non-validated variations were used. Conversely, non-technical skills for sugeons (NOTSS) was the most used validated tool for assessing NTS. However, the majority of studies used non-validated self-assessment tools for NTS assessment. The correlation between TS and NTS was assessed in 43/192 studies with 86% of them finding a positive correlation.
Interpretation / Conclusion: Our results echoes previous literature suggesting that empirical literature investigating the interaction between TS and NTS are methodologically weak. In this review we only identified a small group (n =43) of studies investigating this correlation. However, the results strongly indicate a correlation between TS and NTS skills, meaning that improving NTS also improves TS, and thus the distinction between them in learning designs may be arbitrary. While this result is promising, the limited methodological rigour may indicate a lack of proper understanding of NTS and how to properly assess them.

Line Houkjær¹, Dennis Winge Hallager¹, Stig Brorson¹
1. Centre for Evidence-Based Orthopaedics, Zealand University Hospital, Køge

Background: Effective implementation of evidence-based practice presupposes behavioural changes at both an individual and a collective level. Updating clinical knowledge is a major challenge for performing evidence-based practice. We propose a method to facilitate implementation of updated evidence in clinical decision-making at a department level.
Aim: We aimed to develop a structured and adaptable model for implementation of evidence-based practice in an orthopaedic department.
Materials and Methods: The CEBO model can be divided into four phases. In phase 1 the clinical question is defined and best evidence is compared with current practice. Leadership support is ensured and identification of barriers to change are identified. Phase 2 contains a symposium involving all stakeholders. The relevant high-quality literature identified in phase 1 is presented and discussed. Before closing the symposium, a decision on future practice is made. In phase 3 a local guideline is written and subsequently disseminated repeatedly to end-users. Behavioural designs to facilitate adherence to the guideline are considered. In phase 4 behavioural changes are evaluated by comparing clinical practice in a predefined period before and after the implementation of the local guideline.
Results: The CEBO model has been validated on two occasions. In both cases several barriers were identified and procedural changes to accommodate these were made. Both applications led to substantial changes in behaviour among orthopaedic surgeons in a Danish university hospital.
Interpretation / Conclusion: The CEBO model provides a structured way to align clinical practice with the best available evidence at a department level. We present the model in generic terms and invite fellow physicians to apply the model in cases where alignment of clinical practice to best evidence are warranted.

Marie Sønderup¹, Amandus Gustafsson^{1, 2, 3}, Kristoffer Borbjerg Hare^{4, 5}, Mads Emil Jacobsen^{1, 2, 3}
1: Faculty of Health and Medical Sciences, University of Copenhagen 2: Center for Orthopaedic Research and Innovation (CORI), Department of Orthopaedics, Næstved, Slagelse, and Ringsted Hospitals 3: Copenhagen Academy for Medical Education and Simulation (CAMES), Rigshospitalet 4: Department of Orthopaedics, Odense University Hospital 5: Department of Regional Health Research, University of Southern Denmark

Background: Intraoperative fluoroscopy is an essential tool in distal radius volar locking plate surgery, and it requires expertise to obtain acceptable images. Fluoroscopy imaging is used to ensure accurate fracture reduction and appropriate implant positioning. Due to the complex bony anatomy of the distal radius, several fluoroscopy views are required. Virtual reality (VR) simulation offers a safe, radiation-free training and testing environment for this critical skill. However, it is fundamental to assess validity and reliability using a respected validity framework before implementing simulator training on a larger scale.
Aim: The aim of this study is to create a test of proficiency in intraoperative fluoroscopy control of a distal radius fracture fixated by a volar locking plate in a VR simulator. Further, we aim to explore validity evidence of this test using Messick’s contemporary validity framework.
Materials and Methods: Two groups of physicians; novice interns/residents and experienced traumatologists/hand surgeons are invited to participate in the study. In two individual sessions, participants are asked to perform three repetitions of a VR simulator test in intraoperative fluoroscopic control of a distal radius fracture fixated with a volar locking plate. Automatically measured simulator metrics consist of the exact angles of the surgically treated upper limb for all images, as well as number of images taken and time to complete the procedure. Performance of the two groups will be compared by independent samples t-tests for all metrics . Test reliability will be explored by calculating an intra-class correlation coefficient. A pass/fail standard will be set using the mastery learning principle.
Results: Data collection is ongoing and will be completed by August 2022. Results will be presented at the congress.
Interpretation / Conclusion: This study will explore evidence of validity for a test on a VR simulator for training competence in intraoperative fluoroscopy control of a surgically treated distal radius fracture. The lack of formal, standardized training in this essential skill inherent to fracture surgery is a critical issue that VR simulation has the potential to address.

Jasmin Bagge¹, Per Hölmich¹, Jan Nehlin², Kristoffer Weisskirchner Barfod¹
1. Sports Orthopedic Research Center - Copenhagen (SORC-C), Department of Orthopedic Surgery, Copenhagen University Hospital - Hvidovre, Denmark; 2. Department of Clinical Research, Copenhagen University Hospital - Hvidovre, Denmark.

Background: Treatment of knee osteoarthritis (OA) with autologous stem cells from microfragmented adipose tissue (AT) has shown promising but varying results. Multiple stem cells have been identified in microfragmented AT, such as adventitial stem cells (CD31-/CD34+/CD45-/CD146-), pericytes (CD31-/CD34-/CD45-/CD146+), and CD271+ stem cells (CD31-/CD45-/CD271+). These subtypes have shown varying differentiation potential when derived from bone marrow. The patient-dependent heterogeneity of the stem cell population and content of highly potent cells may be determining factors for a successful outcome.
Aim: To identify the most promising stem cell type from microfragmented AT for the treatment of OA.
Materials and Methods: CD34+, CD146+, and CD271+ stem cells from microfragmented abdominal AT from 8 knee OA patients were separated by magnetic activated cell sorting (MACS) and analyzed as subtypes. Efficiency of sorting was measured by flow cytometry. Unsorted cells were used as a control. The immunomodulatory and beneficial secretomes of the cell subtypes, involved in the OA-healing processes, were investigated with and without an OA-simulated inflammatory environment (TNF-a and IL-1ß) using Luminex. IL-10 secreting cells (anti- inflammatory) were identified using flow cytometry. The chondrogenic and osteogenic in vitro differentiation performance of the cells were assessed using quantitative Safranin-O staining, pellet size, and qPCR for chondrogenesis, and Alizarin Red S staining and qPCR for osteogenesis.
Results: CD34+, CD146+, and CD271+ stem cells can be successfully separated using MACS. A subset of the patient population has currently been analyzed. Most stem cells secreted anti- inflammatory IL-10, although there might be some differences between subtypes, particularly in response to OA-like spiking with TNF-a and IL-1ß. Chondrogenic induced 3D pellets can be made. All the subtypes can undergo osteogenic differentiation.
Interpretation / Conclusion: The results open for selection of suitable OA patients with a high quantity of highly potent stem cells based on a small AT biopsy. Injection of the best stem cell type using recent cell sorting methods might improve stem cell therapy of OA in a personalized manner.

Maria Tirta¹, Markus Winther Frost¹, Ole Rahbek¹, Laura Amalie Rytoft¹, Ming Ding², Ming Shen³, Kirsten Duch⁴, Søren Kold¹
1. Department of Orthopaedics, Aalborg University Hospital, Aalborg, Denmark 2. Department of Orthopaedic Surgery & Traumatology, Odense University Hospital, and Department of Clinical Research, University of Southern Denmark, Odense, Denmark 3. Department of Electronic Systems, Aalborg University, Denmark, Aalborg, Denmark 4. Unit of Clinical Biostatistics, Aalborg University Hospital, Aalborg, 9000, Denmark

Background: Healing after bone fracture is assessed by frequent radiographs, which expose patients to radiation and lacks behind biological healing.
Aim: This study aimed to investigate whether the electrical impedance using electrical impedance spectroscopy correlated to quantitative scores of bone healing obtained from micro-CT and mechanical bending test.
Materials and Methods: Eighteen rabbits were subjected to tibial fracture that was stabilized with external fixator. Two electrodes were positioned, one electrode placed within the medullary cavity and the other on the lateral cortex, both three millimeters from the fracture site. Impedance was measured daily across the fracture site at a frequency range of 5 Hz to 1 MHz. The animals were divided into three groups with different followup time: 1, 3 and 6 weeks for micro-CT (Bone volume/tissue volume (BV/TV, %)) and mechanical testing (maximum stress (MPa), failure energy (kJ/cm3), young modulus (Mpa)).
Results: There was a statistically significant correlation between last measured impedance at 5 Hz frequency immediately prior to euthanasia and BV/TV of callus (-0.68, 95%CI: (-0.87; -0.31)). Considering the mechanical testing with three-point bending, no significant correlation was found between last measured impedance at 5 Hz frequency immediately prior to euthanasia and maximum stress (-0.35, 95%CI: (-0.70; 0.14)), failure energy (-0.23, 95%CI: (-0.63; 0.26)), or young modulus (-0.28, 95%CI: (-0.66; 0.22))
Interpretation / Conclusion: The significant negative correlation between impedance and BV/TV might indicate that impedances correlate with the relative bone volume in the callus site. The lack of correlation between impedance and mechanical parameters when at the same time observing a correlation between impedance and days since operation (0-42 days), might indicate that the impedance can measure biological changes at an earlier time point than rough mechanical testing.

Christian Kveller¹, Anders M. Jakobsen², Nicoline Hjort Larsen³, Joakim L. Lindhardt², Thomas Baad-Hansen¹
1. Department of Orthopedics, Aarhus University Hospital 2. Department of Plastic and Breast Surgery, 3D Innovation, Aarhus University 3. Department of Dentistry, Section for Oral and Maxillofacial Surgery, Aarhus University

Background: 3D printing has gained increasing attention as the technology behind has improved. In 2018, a 3D printing center was established at Aarhus University Hospital, widening accessibility.
Aim: To identify the clinical impact and potential benefits of in-house 3D-printed objects through a questionnaire, focusing on three principal areas: (1) patient education; (2) interdisciplinary cooperation; (3) preoperative planning and perioperative execution.
Materials and Methods: Questionnaires were sent to every clinician who ordered a 3D-printed object from January 2021 to August 2022. On questions assessing the clinicians’ experiences, participants were directed to rate on a scale from 1-10 – with 1 being ‘none’ and 10 being ‘highly’ influenced . One question asked the surveyed to rate from 1-10 – 1 being ‘less invasive’ and 10 being ‘more invasive’.
Results: The response rate was 43%. A majority were affiliated with the Orthopedic or Maxillofacial Surgery Departments. 80% were senior specialists. The results of the rated questions are given as averages. 84% reported using 3D-printed objects in informing the patient about their condition/procedure. Clinician- reported improvement in patient understanding of their procedure/disease was 8.1. The importance of in-house placement was rated 9.2. 96% reported using the 3D model to confer with colleagues. Interdisciplinary cooperation was reported at 8.5. Delay in treatment due to 3D printing lead-time was 1.8. The degree with which preoperative planning was altered was 6.9. The improvement in clinician perceived preoperative confidence was 8.3. The alteration in intraoperative predictability was reported 7.2. The degree with which the scope of the procedure was affected, in regard to invasiveness, was 5.6, wherein a score of 5 is taken to mean unchanged. Reduction in surgical duration was rated 5.7.
Interpretation / Conclusion: Clinicians report the utilization of 3D printing in surgical specialties improves procedures pre- and intraoperatively, has a potential for increasing patient engagement and insight, and in-house location of a 3D printing center results in improved interdisciplinary cooperation and allows broader access with only minimal delay in treatment due to 3D printing lead-time.

Charlotte Abrahamsen^1,2, Ane Simony^1,2, Dorte Dall-Hansen¹, Sarah Køberl¹, Katja Schrøder³, Chelina Evers¹, Hanne Vase¹
1. Department of Orthopaedic Surgery, Lillebaelt Hospital Kolding, Denmark 2. Department of Regional Health Research, University of Southern, Denmark 3. IST, University of Southern, Denmark

Background: Major limb amputations is often associated with loss- a loss of a limb but also independence. Patients undergoing lower limb amputations are often patients with multiple comorbidities, requiring care from numerous healthcare professionals (HCP). It is a patient population with complex needs and limited surplus that might benefit from an integrated care model.
Aim: This study aims to explore Health Care Professionals views and experiences during the transition process from Hospital to Home after a lower limb amputation, using the Safe Journey integrated care program.
Materials and Methods: Two focus group interviews were conducted with 13 HCP’s from a Danish Hospital and three surrounding Municipalities. Included in both groups were nurses, occupational therapists and one physiotherapists. The interview was based on the following 5 questions, and the data was analyzed based on Braun and Clarke´s reflexive thematic analysis. - Which advantages of the systematic cross-sectoral collaboration did you find? - Which disadvantages of the systematic cross-sectoral collaboration did you find? - What do you consider to be most important issues regarding patients transfer? - What do you consider to be most important issues regarding collaboration? - How can we ensure safety and continuity when working with patient transfer?
Results: Three themes were identified when analyzing the group interviews. - Becoming a team across sectors - Continuity of care as a driver of patients safety - Challenges in achieving safe transitions The Safe Journey integrated care program facilitated the construction of an interdisciplinary team and cross-sectoral communication and professional relations, increasing care continuity and patient’s safety. However, HCP’s experienced an increased workload, and The Safe Journey integrated care program was time consuming and required coordination and at- home patient’s visits.
Interpretation / Conclusion: HCP’s found the The Safe Journey integrated care model to be valuable for patients undergoing major lower limb amputation and promotive of cross-sectoral professional relations, communication, continuity and patient safety. However, the model was time- and resource consuming compared to conventional models.

Saber Muthanna Saber ^1,2, Ida Tryggedsson¹, Maj Britt Køhler Astow¹, Anne Marie Halmø Elholm¹, Kenneth Chukwuemeka Obionu¹, Michael Rindom Krogsgaard^1,2
1. Department of Orthopaedic Surgery and Traumatology, Copenhagen University Hospital, Bispebjerg and Frederiksberg 2. University of Copenhagen, Department of Clinical Medicine, Faculty of Health and Medical Sciences

Background: Ankle plantarflexion (PF) and dorsiflexion (DF) are important for daily activities and sports, but both are reduced after injuries or with pathological conditions. Ankle range of motion (ROM) can be measured with a goniometer, but it would be advantageous if patients could self- report ROM without physical attendance
Aim: To develop a pictorial questionnaire that can be completed by patients to self-assess ankle ROM
Materials and Methods: Photos of ankles in various degrees of movement were presented to patients and the questionnaire was developed after their inputs. The reliability of patient reported ROM was compared to goniometer measurements performed by a registered nurse and a doctor and analyzed using weighted kappa, Bland- Altman plots and Interclass correlation coefficient (ICC) in agreement analysis. For correlation, we used Pearson correlation coefficient and density curves
Results: After the final version had been developed, 102 patients completed the pictorial questionnaire and had goniometer measurements of ankle ROM. The ICC for measurements by nurse and doctor was 0.77 (95% CI 0.67 to 0.84, P < 0.001) for PF, 0.67 (95% CI 0.54 to 0.76, P < 0.001) for DF with straight knee (DFSK) and 0.76 (95% CI 0.67 to 0.84, P < 0.001) for DF with flexed knee (DFFK). The agreement between patients’ reported results and those calculated from mean of the values measured by observers showed a weighted kappa of 0.35 (P < 0.001) in PF, and 0.5 (P < 0.0001)) for DFSK, and 0.42 (P < 0.001) for DFFK. The Pearson correlation coefficient between patients’ reported results and the mean goniometer measurements was 0.65 (95% CI 0.52 to 0.75, P < 0.001) for PF, 0.53 (95% CI 0.37 to 0.66, P < 0.001) for DFSK and 0.54 (95% CI 0.38 to 0.66, P < 0.001) for DFFK. The density curves showed obscured thresholds between the categories
Interpretation / Conclusion: The agreement of goniometer measurements between observers was moderate, and it was fair to moderate between patients’ choice and the mean observed value. The correlation between patients’ choice and goniometer measure was strong, but there were weak thresholds. Therefore, individual measurements by the CARS should be interpreted as rough indicates and the scale is best used for groups

Thomas Aagaard^1,2,3, Søren Thorgaard Skou^4,5, Stig Brorson^3,6, Ulla Riis Madsen^2,7
1. Department of Physiotherapy and Occupational Therapy, Holbaek Hospital 2. Department of Orthopaedic Surgery, Holbaek Hospital. 3. Department of Orthopaedic Surgery, Zealand University Hospital 4. The Research Unit PROgrez, Department of Physiotherapy and Occupational Therapy, Naestved-Slagelse-Ringsted Hospitals 5. Research Unit for Musculoskeletal Function and Physiotherapy, Department of Sports Science and Clinical Biomechanics, University of Southern Denmark 6. Department of Clinical Medicine, University of Copenhagen 7. REHPA, Danish Knowledge Centre for Rehabilitation and Palliative Care, University of Southern Denmark, Odense, Denmark

Background: A diabetic foot ulcer (DFU) constitutes a substantial burden for patients and is one of the most serious complications of diabetes mellitus. Having a DFU often requires patients to refrain from bearing weight on the affected limb, leaving some patients immobile for weeks, months or even years. These requirements can lead to patients being unable to follow guidelines for diabetes, as physical activity is a core element in the rehabilitation and treatment of the disease. Previous research has indicated a gap in our understanding of life with a DFU and short- or long-term repercussions on everyday activities when living with the disorder. Closing this gap could help health professionals have a better understanding of patients’ behaviour when starting DFU treatment and potentially more successful treatment.
Aim: The aim of this study was to construct a grounded theory regarding patients’ activity behaviour over time after referral to an outpatient clinic for diabetic foot ulcer care.
Materials and Methods: A constructivist grounded theory approach was used. Data from observations of and interviews with 5 participants were collected and analysed using the constant comparative method. The grounded theory ‘Just a bump in the road’ was constructed based on this.
Results: Participants considered their ulcers as ‘Just a bump in the road’ in their lives. Four categories are embedded in this core category: Restricting my freedom; Trusting or doubting the system; Feeling no pain or illness and Receiving insufficient information. Together, these categories describe the participants’ behaviour and underlying concerns related to daily activities after referral to an outpatient clinic for the care of their diabetic ulcer.
Interpretation / Conclusion: The grounded theory ‘Just a bump in the road’ describes how participants with a diabetic foot ulcer viewed their condition as merely a passing phase that would end in them regaining what they considered a normal life. Integrating these results in clinical practice could lead to improved care and a focus shift among healthcare professionals from seeing patients as defined by their wounds to seeing them as people who live with a wound.

Andreas Bentzen¹, Stian Langgård Jørgensen^{2, 3}, Per Hviid Gundtoft¹, Sara Birch⁴, Louise Mortensen⁵, Michael Godsvig Lindvig⁶, Marianne Toft⁷, Inger Mechlenburg¹
1. Department of Orthopaedic Surgery, Aarhus University Hospital, Aarhus N, Denmark 2. Department of Occupational and Physical Therapy, Horsens Regional Hospital, Horsens, Denmark 3. H-HIP, Department of Occupational and Physical Therapy and Department of Orthopedic Surgery, Hor-sens Regional Hospital, Denmark 4. Department of Orthopaedic surgery, Gødstrup Regional Hospital, Herning 5. Department of Occupational and physical therapy, Aarhus University Hospital, Denmark 6. Emergency Department, Gødstrup Regional Hospital, Herning 7. Department of Orthopaedic Surgery, Viborg Regional Hospital, Viborg

Background: Achilles tendon rupture is a common injury followed by a prolonged period of immobilization, resulting in skeletal muscle atrophy, loss of maximal muscle strength and function in the affected lower limb. Blood flow restricted exercise (BFRE), utilizing low load intensities, appears to pro-vide a unique opportunity to preserve i) lower limb muscle mass and strength and ii) function, without violating the load restrictions suggested for optimal tendon healing, in the early phase of rehabilitation.
Aim: To investigate the feasibility of applying BFRE in patients with an Achilles tendon rupture. Addi- tionally, to evaluate thigh and calf circumference, patient-reported ankle function, symptoms, complications, and physical activity following 12-weeks BRFE.
Materials and Methods: Feasibility was measured by adherence to training sessions, completion rate, intervention acceptability, ankle pain exacerbation on a numerical rating scale (NRS) and adverse events. Patients completed the Achilles Tendon Total Rupture Score questionnaire at baseline and 12 weeks follow-up. At the follow-up visit patients’ thigh and calf circumference was measured and patients’ ability to perform a single-leg heel-rise was tested.
Results: 16 out of 18 patients completed the 12-weeks BFRE program and for those who completed the intervention, adherence to training sessions was 88% (95%CI: 79; 98%). Intervention acceptability was excellent with 94% responding they were likely or much likely to recommend BFRE to others and to choose BFRE if they experienced a new Achilles tendon rupture tomorrow. Mean NRS pain following BFRE sessions was 1 (95%CI: 0.9; 1.2). Three adverse events were registered; two re-ruptures unrelated to the BFRE protocol and one deep venous thrombosis, which occurred in the period following cast-immobilization.
Interpretation / Conclusion: BFRE is feasible in terms of adherence to training sessions, completion rate, intervention accepta-bility, and ankle pain exacerbation. Despite three adverse events, BFRE appears as safe as usual care for this patient group. However, the efficacy and safety of BFRE compared to usual care war-rants further investigation.

Mette Sørensen Studstrup¹, Peter Larsen^{1, 2}, Søren Kold¹, Pernille Bønneland¹, Rasmus Elsøe¹
1. Department of Orthopaedic Surgery, Aalborg University Hospital, Aalborg Denmark; 2. Department of Occupational Therapy and Physiotherapy, Aalborg University Hospital, Aalborg Denmark.

Background: Articular and periarticular pain in patients with rheumatoid arthritis may be related to juxta-articular insufficiency fractures. They are often only visualized by MRI. Pain and intraosseous edema and fracture healing assessed by MRI resolves exceedingly slow. To avoid a prolonged period of pain and immobilization a bone void filler may be injected at the fracture site. This may alleviate pain and increase function. Patients are allowed full weight bearing without restrictions immediately postoperative.
Aim: The aim was to report feasibility and the first clinical results of five consecutive patients treated with bone void filler following a lower extremity insufficiency fracture non-responding to conservative treatment.
Materials and Methods: This pilot and feasibility study used a cross sectional design with retrospective follow-up. A predefined feasibility outcome was based on two questions regarding patients experience with the treatment and the absence of any serious adverse events. Clinical results were reported before treatment, 2 weeks after treatment and at follow-up. Patient-reported results were reported by the body-region specific questionnaires, KOOS or FOAS. Overall health related quality of life was reported by the Eq5D-5L questionnaire. Furthermore, pain reactions and adverse events were reported.
Results: Five patients were included. Median age was 70, range 56 to 80. Four patients were female. Fracture sites were proximal tibia (2), distal tibia (2) and distal femur (1). All patients reported high satisfaction regarding patient’s perception, indicating that bone filler may be feasible in the treatment of insufficiency fractures. No serious adverse events were observed. High pain intensity and low scores in the KOOS/FAOS and Eq5d-5L questionnaires were observed before treatment. Two weeks after treatment and at the final follow-up all patients reported low pain intensity and better KOOS/FAOS and Eq5D-5L scores.
Interpretation / Conclusion: Treatment with bone void filler to insufficiency fractures in RA patients seems feasible. Patient-reported outcome was satisfactory and considerable decrease in pain reactions after treatment was observed. More research is needed to investigate efficacy of this new treatment.

Charlotte Myhre Jensen^1,2, Rikke Serritslev ³, Charlotte Skov Abrahamsen^{3, 4}
1. Department of Orthopaedic Surgery and Traumatology, Odense University Hospital, Denmark. 2. Department of Clinical Research, University of Southern Denmark, Odense, Denmark 3. Department of Orthopaedic Surgery and Traumatology, Hospital Lillebaelt – University Hospital of Southern Denmark, Kolding Hospital, Denmark. 4. Department of Public Health, University of Southern Denmark, Odense, Denmark

Background: Following a surgically or non-surgically treated ankle fracture,patients express feelings of uncertainty regarding their ankle symptoms (e.g., swelling and pain), mobility, medication, weight- bearing limitations, and rehabilitation regimes. They additionally face challenges concerning what to expect during rehabilitation which can be linked to a lack of ability to understand and remember oral information. The involvement of users in designing solutions to address information needs has been acknowledged as essential to creating successful solutions.
Aim: The aim of this study was to employ a user-driven participatory design (PD) approach to develop an mHealth solution that addresses patients’ information needs after surgical or non-surgical treatment for an ankle fracture.
Materials and Methods: Patients with an ankle fracture and healthcare professionals (nurses, therapists and surgeons) along the treatment pathway in both the hospital and municipality participated in four workshops (WS). In WS 1 and 2, needs and wishes were identified, and in WS 3 and 4, a solution to address the identified needs was developed. Data were analysed using qualitative content analysis and the continuous iterations in PD. User acceptance testing was conducted using alpha and beta testing of the mHealth solution by the development- and research team and a new group of patients and clinicians.
Results: We found that patients with an ankle fracture need information on topics such as “a typical course,” “bandages and assistive devices,” “what can I feel,” “what may I do,” “what to usually worry about,” “medicine,” “tips and tricks,” and “contact information.” Moreover, patients above all requested diverse modes of dissemination of information, preferably a combination of text, timelines, pictures, animations, and videos.
Interpretation / Conclusion: Involving representatives of future users in creating this mHealth solution using PD demonstrates the benefits of creating a solution that aligns with users’ needs.

Bente Schumacher
Middelfart Kommune

Background: Surgery often results in a long-term absence from work, dependent on the extent of the operation and the recommendations from the surgeon, often without regard to the nature of the work/work functions. Carpal tunnel operation is, for the surgeon, a small operation but can, for the patient, result in a longer- term work absence. This is highly depending on the recommendations the surgeon gives the patient.
Aim: The purpose of the study is to investigate recommended work absence after carpal tunnel operation.
Materials and Methods: Patient information, available on the internet, from 15 clinics and hospitals i Denmark. Their recommendations for return to work after carpal tunnel operation were evaluated.
Results: The recommended absence from work after carpal tunnel operation ranges from 1-10 weeks. Median value is 4-6 weeks. In several clinics, the absence from work is recommended in relation to the job, with e.g. lighter work such an office job and heavier work as a gardner.
Interpretation / Conclusion: A major reason for the variation in recommendation for work absence is due to the surgeon recommends in relation to different jobs. The work as a gardener or nurse consists of several work functions, and it is possible to adjust the work place or avoid certain work functions by a partial absence from work. A partial absence from work can lead to a quicker return to the job and reduce the likelihood of the patient losing income or losing his job. Based on this it is recommended that the surgeon before operation, instead of recommend the period of work absence, provides information on precautions after operation, functions to avoid and for how long, e.g. no wet or dirty work functions for the first 14 days until the wound is healed, avoid lifting things heavier than 0.5 kilogram, avoid twisting, static or vibration work functions with the operated wrist for a certain amount of weeks etc. If the patients know the precautions after operation, what must be avoided and for how long, the patient can better, with the work place, plan absences or partial start-up, so their return is safe and effective for optimal surgical outcomes.

Emil Østergaard Nielsen¹, Dennis Winge Hallager¹, Stig Brorson¹
Department of Orthopaedics, Zealand University Hospital

Background: Evidence is fundamental in the treatment of patients. It is unclear to what extent evidence translates into clinical practice or implies behavioral changes. Several factors have been identified as barriers or facilitators of change. Taking these into account increase the chance of successful implementation of evidence. The CEBO model has been developed to facilitate adaption of evidence into local practice. Based on recent systematic reviews and meta-analysis of randomized controlled trials, we found, that elderly patients with dorsally displaced distal radius fractures (DRF), on average do not benefit from surgery beyond minimal clinical importance difference in patient reported outcome scores. Since the vast majority of elderly received surgical treatment in our department, we identified an evidence-practice gap.
Aim: This study evaluates behavioral change in orthopedic surgeons at our department following the application of the CEBO model in the treatment of elderly patients with dorsally displaced DRF.
Materials and Methods: After obtaining leadership support, the relevant evidence was disseminated to all colleagues across the department. All stakeholders were invited to a symposium containing a discussion on best evidence and future practice. Conclusions from the symposium were summarized in a local clinical guideline by a team of junior and senior colleagues. The guideline was published in the local guideline repository and repeatedly presented at morning conferences. Smart phrases were prepared to facilitate practice change. To monitor the changes, patient charts regarding patients over 60 years of age with dorsally displaced DRF were retrospectivelyreviewed from February 1st 2019 to January 31st 2020 and compared to a period from February 1st 2022 to January 31st 2023.
Results: In the first period 120 of 95 (79%) were surgically treated compared to 146 of 16 (11 %) in the second period, thus a decrease in operation rate of 68% was observed.
Interpretation / Conclusion: We report a substantial behavioral change following the application of the CEBO model in the treatment of elderly with dorsally displaced DRF.

Ane Simony^1,2, Katrine Rasch¹, Tord Salomonsen¹, Rasmus Buch Bendtson¹
1. Department of Orthopedic Surgery, Kolding, Hospital Lillebelt. 2. IRS, University of Southern Denmark

Background: Colles fractures, fractures of the distal radial bone and distal ulna are common fractures that often affects woman > 65 years of age due to low energy trauma. Treatment regime’s has consisted of reduction and treatment with a cast for 5 weeks, or surgery with anatomic reduction of the fracture and fixation by a volar plate and screws. After one year, patients report similar outcome, regardless the treatment received.
Aim: The aim of this study was to implement shared decision-making for patients > 65 years, with a Colles fracture and report the patients and doctor satisfaction, while using the tool for choosing the treatment preferred by the patient.
Materials and Methods: A shared-decision making tool for patients > 65 years, diagnosed and treated by reduction and casting at orthopedic department in Kolding was implemented after this process, 1. Literature search (diagnosis, complications, revision rates, outcome) 2. Patient interview, with patients treated with surgery and conservative regime 3. Creating the Shared Decision-making tool with balanced information 4. Pilot test, with interview to ensure patients satisfaction with illustrations, information etc. 5. Education and implementation of Shared Decision-making 6. Survey regarding satisfaction, including both patients and doctors performed 3 months after implementing the tool, in clinical practice. The survey consist of 5 questions (aim of the tool, level of information, patients preference, complications and benefits, guiding the patients to a choice), each item scoring 1-5.
Results: A shared decision making tool is created, and handed out to the patients after reduction of the fracture. The tool is used after 5 days in the outpatient clinic, and patients are encouraged to choose the treatment by their preference. A survey conducted after 3 months including 10 visits in the outpatient clinic, shows high rates of satisfaction patients 22,6 (20-25), doctors 20.7 (10-25).
Interpretation / Conclusion: Patients and doctors, to decide the preferred treatment after a Colles fracture, can use a shared decision-making tool. Patients and Doctors reports that they are satisfied, after using the Materiale.

wisam kino¹, Per Hölmich¹, Kristoffer Weisskirchner Barfod¹
Wisam Nafie Youssef Kino1, Per Hölmich1, Kristoffer Weisskirchner Barfod1. 1. Sports Orthopedic Research Center – Copenhagen (SORC-C), Department of Orthopedic Surgery, Copenhagen University Hospital, Amager-Hvidovre, Denmark

Background: Irreparable rotator cuff tears are difficult to treat. Arthroscopic Supra Capsular Reconstruction (SCR) stops the humeral head from migrating proximally, theoretically allowing the muscles related to the shoulder to develop a relevant recruitment and activation pattern in order to optimize the function of the glenohumeral joint. The procedure is increasing popular though only sparsely investigated. SCR was introduced at Copenhagen University Hospital Hvidovre in 2019.
Aim: To monitor range of motion, pain, and patient reported outcomes 3, 6, 12 and 24 months after SCR with an acellular human dermal graft.
Materials and Methods: Patients were offered SCR if they had unacceptable shoulder pain due to an irreparable tear of the supra spinatus tendon, an intact or reparable subscapularis tendon and no osteoartrosis in the gelenohumeral joint. Patients were prospectively followed prior to and 3, 6, 12 and 24 months after surgery. Outcomes were range of active motion in abduction (AROM), pain at abduction (NRS), the Western Ontario Rotator Cuff (WORC) Index, and the shoulder pain and disability index (SPADI). Development over time was investigated using Univariate Analysis of Variance.
Results: 28 patients (mean (SD) age 62 (8), BMI 29 (5), m/k 19/9) were operated from July 2019 to October 2022. 26 patients contributed data at 3 months, 23 at 6 months, 18 at 12 months and 6 at 24 months. AROM improved (p<0.01) from mean (SD) 80 (37) prior to surgery, to 92 (39), 105 (46), 127 (44), and 151 (33). NRS pain improved (p<0.01) from 7.8 (1.6) to 3.7 (2.6), 2.8 (2.8), 3.3 (3.5), and 1.1 (1.4). WORC index improved (p<0.01) from 28 (14) to 38 (18), 46 (26), 58 (32), and 73 (19). SPADI improved (p<0.01) from 74 (18) to 60 (24), 52 (28), 41 (34), and 24 (21).
Interpretation / Conclusion: Arthroscopic Supra Capsular Reconstruction with an acellular human dermal graft is a promising treatment for patients with irreparable cuff tears as statistical significant and clinically relevant improvements were seen in ROM, NRS pain, WORC and SPADI. A randomized controlled trial, investigating if the observed improvements can be ascribed the surgical procedure or merely change over time, is needed.

Josefine B. Larsen^1,2, Theis M. Thillemann^1,2, Antti P. Launonen³, Helle K. Østergaard^2,4, Thomas Falstie-Jensen¹, Aleksi Reito^3,5, Steen L. Jensen^6,7, Inger Mechlenburg^1,2
1Department of Orthopaedic Surgery, Aarhus University Hospital, Aarhus N, Denmark 2Department of Clinical Medicine, Aarhus University, Aarhus N, Denmark 3Department of Orthopaedic Surgery, Tampere University Hospital, Tampere, Finland 4Department of Orthopaedic Surgery, Viborg Regional Hospital, Viborg, Denmark 5Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland 6Department of Orthopaedics, Aalborg University Hospital, Aalborg, Denmark 7Department of Clinical Medicine, Aalborg University, Aalborg, Denmark

Background: Reverse total shoulder arthroplasty is an established treatment for patients with rotator cuff tear arthropathy, recently it has gained popularity and the use has expanded. The outcome after reverse total shoulder arthroplasty has been investigated in several studies and national registries; however, the treatment has not been compared to non-surgical treatments.
Aim: The primary aim of this trial is to investigate whether reverse total shoulder arthroplasty is superior compared to exercise in patients with rotator cuff tear arthropathy eligible for reverse total shoulder arthroplasty.
Materials and Methods: In this Nordic multicenter randomized controlled clinical trial, 102 patients with rotator cuff tear arthropathy (Hamada grade 3-5) eligible for surgery will be randomly allocated to either reverse total shoulder arthroplasty followed by usual care or a shoulder exercise intervention. The exercise intervention comprises 12 weeks of exercise with one weekly physiotherapist- supervised session and home-based exercises. The primary outcome is the total Western Ontario Osteoarthritis of the Shoulder index (WOOS) score at 12 months follow-up. Secondary outcomes include Disabilities of the Arm, Shoulder, and Hand score (DASH); changes in pain intensity measures using a Visual Analogue Scale at rest, during activity and nightly pain; the use of analgesics during the previous week; and adverse events.
Results: The end of patient inclusion is expected ultimo 2025, and results are expected in ultimo 2026 . The primary analysis will be blinded and presented to the project group followed by two written interpretations.
Interpretation / Conclusion: To our knowledge, the REACT trial is the first to compare the effectiveness of surgical to non-surgical treatment in patients with rotator cuff tear arthropathy. Treatment decisions, including surgery, for patients with rotator cuff tear arthropathy, will depend on different factors. It remains important to know where there is reliable evidence and where there is uncertainty in making health decisions.

Simon Kornvig^1,2, Henrik Kehlet^3,4, Christoffer Calov Jørgensen^3,4, Anders Fink-Jensen⁵, Poul Videbech⁶, Martin Lindberg-Larsen⁷, Kirill Gromov⁸, Mathias Bæk Rasmussen⁹, Kim Sperling¹⁰, Claus Varnum^1,2
1. Department of Orthopeadic Surgery, Lillebaelt Hospital - Vejle; 2. Department of Regional Health Research, University of Southern Denmark; 3. Section for Surgical Pathophysiology, Copenhagen University Hospital; 4. Centre for Fast-track Hip and Knee Replacement, Rigshospitalet; 5. Mental Health Center, Frederiksberg and University of Copenhagen; 6. Mental Health Center, Glostrup and University of Copenhagen; 7. Department of Orthopeadic Surgery and Traumatology, Odense University Hospital - Svendborg; 8. Department of Orthopeadic Surgery, Hvidovre Hospital; 9. Department of Orthopeadic Surgery, Aalborg University Hospital - Farsø; 10. Department of Orthopeadic Surgery, Næstved Hospital.

Background: Psychiatric disorders and psychopharmacological treatment (PT) have been identified as important risk factors for increased LOS and readmissions after hip and knee arthroplasty. PT has a prevalence of 11% in these patients and a recent study has shown that PT may be an independent risk factor. Thus, temporary discontinuation of PT in the perioperative period may be beneficial, but carries a risk of discontinuation syndrome and relapse. However, to address this in future studies a description of PTs regarding type, dose, duration, indication and initiating doctor is needed.
Aim: The aim was to describe PT in patients planned for hip or knee arthroplasty.
Materials and Methods: This study was a prospective cohort study of 483 patients planned for hip or knee arthroplasty from 2021 to 2023 in Hvidovre, Næstved, Svendborg, Vejle and Farsø. All patients were in PT for psychiatric disorders at inclusion. Type, dose, duration, indication and initiating doctor (general practitioner, psychiatrist in primary healthcare or department of psychiatry) were registered for each treatment.
Results: 430 (89%) patients were treated with an antidepressant (AD); most frequently either selective serotonin (SSRI; 47%) or serotonin-norepinephrine reuptake inhibitors (SNRI; 21%). The frequency of patients treated with antipsychotics or anxiolytics was 20% and 15%, respectively. The majority received monotherapy (70%); most frequently with either an SSRI (36%) or an SNRI (12%). Most AD treatments and especially SSRI treatments were initiated by general practitioners (71%; 80%) and had lasted more than one year (87%; 89%). The median doses of SSRIs/SNRIs were generally low and the most frequent indication for ADs was depression (77%).
Interpretation / Conclusion: ADs and especially SSRIs/SNRIs were the most frequent PTs in patients planned for hip or knee arthroplasty. Most ADs were initiated by general practitioners and were primarily SSRIs/SNRIs in low doses lasting more than one year. Thus, a study of postoperative outcomes after temporary discontinuation of SSRIs/SNRIs in the perioperative period may be feasible from a psychiatric perspective.

André S Klenø¹, Maaike GJ Gademan², Inger Mechlenburg³, Henrik Sørensen¹, Nina M Edwards⁴, Alma Pedersen¹
1. Department of Clinical Epidemiology, Department of Clinical Medicine, Aarhus University and Aarhus University Hospital, Aarhus, Denmark; 2. Department of Orthopaedics, Department of Clinical Epidemiology, Leiden University Medical Center, the Netherlands; 3. Department of Orthopaedic Surgery, Department of Clinical Medicine, Aarhus University Hospital and Aarhus University, Aarhus N, Denmark; 4. Department of Orthopaedic Surgery, Regionshospitalet Horsens, Denmark.

Background: Opioids are commonly used for post-surgical pain management after total hip arthroplasty (THA). Most patients use opioids for a brief period, but some continue to use opioids for up to one year after THA. Continued opioid use has been linked to health inequality, a concept that remains elusive in health research. Patients’ perception of their health is reported to be associated with a broad range of health outcomes in general, however, its impact on outcomes after THA is sparsely investigated.
Aim: To examine the association between preoperative self-reported health (SRH) and the risk of continued opioid use after THA in patients with osteoarthritis.
Materials and Methods: We extracted data from several Danish medical registries. Information on SRH (either good or poor) among 4,155 THA patients (2010-2018) was available from the Danish National Health Survey (SRH was collected at a median number of 1082 days before THA). Opioid use was defined as the redemption of =2 prescriptions 1-12 months after THA. We calculated prevalences of opioid use with absolute differences and prevalence ratios (aPR) (with 95% confidence interval) using log-binomial regression adjusting for sex, age, comorbidities, and education. We calculated the morphine milligram equivalent (MME) dose as a total dose for the entire year. Analyses were performed overall and by preoperative opioid use (defined as =1 opioid dispensing 0-6 months before THA).
Results: 3,283 patients reported good SRH and 872 reported poor SRH. Prevalence of opioid use was overall 13% for good SRH vs. 36% for poor SRH (aPR: 2.37, 2.04-2.76). Among preoperative non-users, 6% for good SRH vs. 14% for poor SRH (aPR: 2.22, 1.63-3.04). Among preoperative users, 31% for good SRH vs. 54% for poor SRH (PR: 1.66, 1.40-1.98). Overall, the median MME dose was 600 (interquartile range: 225-1,200) for good SRH vs. 1200 (450-5807) for poor SRH. For preoperative non-users, the MME dose was 420 for good SRH vs. 651 for poor SRH; for preoperative users, 1000 for good SRH vs. 2454 for poor SRH.
Interpretation / Conclusion: Patients with poor SRH were not only at higher risk of continued opioid use but also tended to consume a noticeably higher MME dose in the year after THA than patients with good SRH.

Jacob Lund-Andersen¹, Mathilde LH Petersen², Krassimir Kostadinov¹, Lennart Friis-Hansen^2,3,4, Henrik Calum⁵, Søren Overgaard^1,3
1. Copenhagen University Hospital, Bispebjerg and Frederiksberg, Department of Orthopedic Surgery and Traumatology, Copenhagen, Denmark; 2. Copenhagen University Hospital, Bispebjerg and Frederiksberg, Department of Clinical Biochemistry, Copenhagen, Denmark; 3. University of Copenhagen, Department of Clinical Medicine, Faculty of Health and Medical Sciences, Copenhagen, Denmark; 4. Center for Translational Research, Bispebjerg and Frederiksberg Hospital, Copenhagen, Denmark; 5. Copenhagen University Hospital, Amager and Hvidovre, Department of Clinical Microbiology, Copenhagen, Denmark.

Background: Diagnosing periprosthetic joint infection (PJI) can be a challenge. Microbiological culture growth of synovial fluid and/or tissue biopsies is considered the standard for detection of the pathogen causing the PJI. Molecular diagnosis methods such as PCR technology have not yet been included in the proposed PJI definitions, but have the theoretical advantage of a short turnaround time and high sensitivity.
Aim: The aim of this study was to evaluate the diagnostic accuracy (sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV)) of the multiplex PCR based BioFire® Joint Infection Panel (BioFire JI Panel) test against microbiological culture growth in a clinical setting on patients with a total joint arthroplasty.
Materials and Methods: Synovial fluid and/or tissue biopsies were prospectively collected pre- or perioperatively at Copenhagen University Hospital, Bispebjerg and Frederiksberg, Department of Orthopedic Surgery and Traumatology from June 2022 to January 2023 from patients with a total knee or hip arthroplasty and suspected of a PJI. Synovial fluid samples were tested with the BioFire JI Panel and compared with standard culture of the synovial fluid samples and tissue biopsies as reference.
Results: 15 samples were included in our study, seven collected preoperatively and eight perioperatively. Testing for all pathogens the sensitivity of the BioFire JI Panel was 66.7% (0.95 CI; 30.0% to 90.3%) and the specificity was 77.8 % (0.95 CI; 45.3% to 93.7%). With a prevalence of PJI of 40% in our sample, we found a PPV of 66.7% (0.95 CI; 30.0% to 90.3%) and a NPV of 77.8 % (0.95 CI; 45.3% to 93.7%). Testing only for the 31 pathogens in the BioFire JI Panel we found a sensitivity of 100% (0.95 CI; 51.0% to 100%) and a specificity of 81.8% (0.95 CI; 52.3% to 94.7%), giving us a PPV of 66.7% (0.95 CI; 30.0% to 90.3%) and a NPV of 100% (0.95 CI; 70.1% to 100%).
Interpretation / Conclusion: Our results suggest that the BioFire JI Panel has a high accuracy for detecting the pathogens included in its panel. However, the limitation is the pathogens not included in the panel, including common pathogens such as staphylococcus epidermidis, which lowers the sensitivity and the NPV of the test.

Martin Bækgaard Stisen^1,2, Inger Mechlenburg^1,2, Lindsay Mary Bearne^3,4, Emma Godfrey^4,5, Alma Becic Pedersen^1,6 , Dorthe Sørensen⁷
1. Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; 2. Department of Orthopaedic Surgery, Aarhus University Hospital, Aarhus N, Denmark; 3. Population Health Research Institute, St George's, University of London, London, United Kingdom; 4. Department of Population Health Sciences, School of Life Course & Population Sciences, King's College London, London, United Kingdom; 5. Health Psychology Section, Department of Psychology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom; 6. Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus N, Denmark; 7. Programme for Rehabilitation, Research Centre for Health and Welfare Technology, VIA University College, Aarhus, Denmark

Background: Patients obtain poorer outcomes after revision total hip replacement (THR) than after primary THR. Current evidence on rehabilitation after revision THR is inadequate and the development of rehabilitation interventions is warranted. To inform the design of new interventions understanding patients’ experiences of revision THR rehabilitation is crucial.
Aim: This study aimed to explore patients' rehabilitation experiences after revision THR.
Materials and Methods: Using constructivist grounded theory, we conducted semi-structured qualitative interviews with 12 participants (mean age 65.9 years, 58% females) with completed or ongoing rehabilitation after revision THR. Patients were recruited from Aarhus University Hospital and municipal rehabilitation centers in Central Denmark Region. Data collection and analysis were a constant comparative process conducted in three phases; an initial, a focused, and a theoretical phase.
Results: Important perspectives influencing the participants’ ability to integrate revision THR into their lives were; need for support, the experience of therapeutic relationship, health authority belief, physical function, and previous experiences with rehabilitation. We generated a substantial theory of the participant’s circumstances and ability to integrate rehabilitation into their everyday life after revision THR from the data. Based on patients’ experiences in different contexts, four categories were constructed; resignation, low personal drive, high health literacy, and faithfulness.
Interpretation / Conclusion: This study highlighted that patients’ expectations, past experiences, attitudes, beliefs, motivation, and circumstances interact to influence engagement and adherence to rehabilitation and described four categories relating to the integration of THR rehabilitation into their everyday life. Clinicians should be aware of and account for these categories during rehabilitation. Tailored individual rehabilitation interventions and clinician approaches to optimize commitment and adherence are needed among patients with revision THR.

Martin Bækgaard Stisen^1,2, Alma Becic Pedersen^1,3, Troels Kjeldsen^1,2, Inger Mechlenburg^1,2
1. Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; 2. Department of Orthopaedic Surgery, Aarhus University Hospital, Aarhus N, Denmark; 3. Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus N, Denmark

Background: Evidence on the effectiveness of pain relief and functional improvement in patients undergoing revision total hip replacement (THR) is sparse, and patients undergoing revision THR achieve markedly smaller improvements in hip pain and function than patients following primary THR. Further, there are no clinical guidelines or consensus on optimal rehabilitation after revision THR.
Aim: To compare the clinical effectiveness of an exercise intervention targeting hip strengthening with standard community-based rehabilitation in patients undergoing revision THR.
Materials and Methods: This multicenter randomized controlled assessor- blinded trial will be conducted at seven hospitals and multiple municipality rehabilitation centers in Denmark. A total of 84 patients undergoing revision THR will be allocated to either an exercise intervention targeting hip strengthening (strength group) or to standard community-based rehabilitation (control group). The primary outcome is change in functional performance measured by the 30s Chair Stand Test, from baseline to 4 months after the start of the intervention. Secondary outcomes include Hip disability and Osteoarthritis Outcome Score; 40m Fast-paced Walk Test; 9-step Timed Stair Climb Test; leg extensor muscle power; Global Perceived Effect; and adverse events. Other outcomes include The International Physical Activity Questionnaires; patient-reported pain intensity at rest; and European Quality of Life - 5 Dimensions. Between-group comparisons of change in the 30s Chair Stand Test from baseline to 4-month follow-up will be analyzed using a repeated measures mixed model.
Results: Expected in ultimo 2025.
Interpretation / Conclusion: This study is the first randomized controlled trial examining different rehabilitation programs, that hopefully will contribute with clinically important evidence about what type of rehabilitation patients undergoing revision THR should be offered to improve their functional performance, physical function, and quality of life, which will be of great importance to patients, relatives, physiotherapists, and decision-makers.

Arne Michael Storås¹, Karen Toftdahl Bjørnholdt¹
Department of Orthopaedics, Horsens Regional Hospital

Background: Pain after total knee replacement (TKR) is initially often pronounced, and multi-modal treatment including opioid is used to cover the pain sufficiently. Although opioids are effective against pain, the side effects and addiction potential encourage prescribing a correct amount post operative. Attention to patients using opioids beyond the expected period of treatment, could be helpful in limiting long term use.
Aim: 1. To investigate the duration of need for opioids after TKA so that we can provide relevant patient information and prescribing and reduce over/undertreatment based on an educated estimate of the expected treatment period. 2. To find prevalence and characteristics of the subgroup that continues to use opioids 1 year after the operation.
Materials and Methods: Register-based cohort study, using national, regional and municipal data available in Tværspor. Information on collected prescriptions for opioids can illustrate the number of patients using opioid over time from the day of surgery so that it can be assessed statistically. Comorbidities, BMI, smoking status, alcohol consumption, nutritional status, prosthesis complications, preoperative opioid consumption, dose at discharge and other information can contribute to characterizing the subgroup that continues to use opioids after 1 year.
Results: In a preliminary analysis of 1356 patients in the Horsens Hospital population base undergoing TKR in 2012-2019 in Central Denmark Region, 92 % of patients collected one or more opioid prescriptions within the first month of surgery, 27 % in the second month, 17 % in the third month, 11 % in the 6th month and 9 % in the 12th month. Further analysis is pending.
Interpretation / Conclusion: Based on this study, we hope to improve prescription and phasing out of opioid use following TKR, based on expected duration of necessity. Patients with predictors of long-term opioid use may require further counseling and support both before and after the operation.

Caroline Halken¹, Christian Bredgaard Jensen¹, Cecilie Henkel¹, Kirill Gromov¹, Anders Troelsen¹
1. Department of Orthopaedic Surgery, Clinical Orthopaedic Research Hvidovre (CORH), Copenhagen University Hospital Hvidovre, Denmark

Background: There has been an increasing interest in outpatient hip and knee arthroplasty, and previous studies have found it to be safe and feasible in selected populations. However, little is known about patients’ attitudes towards day-of-surgery (DOS) discharge.
Aim: Therefore, we explored patients’ attitudes towards DOS discharge and identified patient characteristics associated with different attitudes.
Materials and Methods: We included 5273 patients scheduled for hip or knee arthroplasty from 2016 to 2022. Preoperatively, patients were asked if they were interested in DOS discharge (“Yes”, “Do not know”, “No”). We investigated age, body mass index, and sex, and explored patient reported outcome measures (PROMs) such as EuroQol 5-dimensions 3-level (EQ5D-3L) for each attitude group. We also investigated change in attitude in patients who had answered the questionnaire in association with previous hip or knee arthroplasty.
Results: We found that 41.9% of the patients were interested in DOS discharge, 20.7% answered “Do not know”, and 37.4% were not interested. Patients who were not interested had a higher mean age (“No” = 70.2 years vs. “Yes” = 65.2 years), with most of them being female (“No” = 72.2% vs. “Yes” = 48.8%). Around 20% of the patients responded “Do not know” regardless of age, sex, and PROM scores. Patients experiencing anxiety/depression based on EQ5D-3L more often answered “No” (55.6%) compared to patients not experiencing anxiety/depression (33.6%). Over 70% of the patients responding “Do not know” before their first surgery, changed their answer to either “Yes” (29.7%) or “No” (40.6%) at their following surgery.
Interpretation / Conclusion: 41.9% of the patients were interested in DOS discharge and 37.4% were not interested. Elderly, female patients and patients with lower– or worse–PROM scores were more likely to respond “No”. Even though DOS discharge is used increasingly and is considered safe in selected patients, there seems to be a mismatch as 58.1% of the patients are uncertain or not interested in DOS discharge. Further studies are needed to examine what preoperative information patients find essential for them to decide on being discharged on day-of-surgery.

Christian Fugl Hansen¹, Michael Krogsgaard¹, Anders Odgaard², Søren Overgaard^1,3, John Brandt Brodersen^{4, 5}
1. Department of Orthopaedic Surgery and Traumatology, Copenhagen University Hospital, Bispebjerg; 2. Department of Orthopaedic Surgery, Copenhagen University Hospital, Rigshospitalet; 3. Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen; 4. The Research Unit for General Practice and Section of General Practice, Department of Public Health, University of Copenhagen; 5. Primary Health Care Research Unit, Region Zealand.

Background: Since its development in 1998, the Oxford Knee Score (OKS) has been frequently used as an outcome for evaluating patients with knee osteoarthritis (OA), in particular patients treated with a knee arthroplasty. However, the methods used to develop OKS do not ensure adequate content validity - the most important property of a patient reported outcome. The Oxford Hip Score, which was developed like OKS, has been shown not to possess content validity. We hypothesized that this would also be the case for OKS
Aim: To determine the content validity of the Danish OKS in a cohort of patients with severe OA
Materials and Methods: Patients with severe OA scheduled for surgical treatment with total knee arthroplasty (TKA) and patients already surgically treated (3-24 months postoperative) were eligible for the study. The cohort was by intention non-randomly sampled with respect to gender, age, time since treatment and socioeconomical status. By semi- structured group interviews relevance, coverage, comprehensibility, recall period and response options of all items of OKS were qualitatively assessed. Whether any other aspects were missing were further explored within the ICF-model domains of activity, symptoms and participation
Results: Overall, the cohort deemed all items relevant, and most items comprehensible with the exception of two ‘double-barreled’ items. The response options were also endorsed. Patients treated with TKA questioned the recall period of four weeks as being too long in the early postoperative phase. However, large gaps in coverage were revealed with several key concepts missing. Among these concepts were the impact of lacking participation, feeling like a burden to friends and family, fatigue, and a wider spectrum of physical symptoms
Interpretation / Conclusion: The OKS possessed inadequate content validity for its intended use as a general one- dimensional measure of the disease burden of the target population. This may hamper its responsiveness and thus its ability to detect true changes over time. As a consequence, drawing conclusions from trials using OKS as an outcome carries a high risk of misinterpretation, especially due to false-negative results (type II errors)

Simon Limbrecht Mogensen ¹, Carsten Femhøj Holm ¹, Lars Peter Jorn¹, Jacob Beck¹, Morten Vase¹, Jens Rolighed Larsen ¹
1. Elective Surgery Centre, Silkeborg Regional Hospital

Background: Treatment options for effusion and pain in knee joints with an arthroplasty are few. Intraarticular corticosteroid injections (ICI) are commonly used in the osteoarthritic knee but because the supposed risk of infection only rarely used in patients with arthroplasty.
Aim: We report on the use of ICI in knees with an arthroplasty at our institution and screened for occurrences of periprosthetic joint infection and possible effect of ICI on knee symptoms.
Materials and Methods: We retrospectively evaluated electronic health records (EHR) of patients with a knee arthroplasty receiving ICI inside the operating theater under strict aseptic conditions during a 5-year period from 2017-2021. We reviewed patients EHR for periprosthetic joint infections and patient reported effects of the ICI at follow- up.
Results: 180 intraarticular corticosteroid injections in knees were given in 146 patients with either a TKA, UKA or a revision arthroplasty. No infections occurred at a mean follow up period of 23,9 months. 50% reported some to good effect of injections, 22% had no effect of injections and in 27% of the EHR it was not recorded if the injection had an effect.
Interpretation / Conclusion: We found no infections at a mean follow up of 23,9 months when ICI was administrated under strict aseptic conditions. Patients reported effects could indicate a possible favorable effect on effusion and pain in knees with an arthroplasty.

Niels Christian Kaldau¹, Frederik Flensted Andersen¹, Kristoffer Weisskirchner Barfod¹, Peter Nyby Hersnæs¹, Per Hølmich¹
1. Sports Orthopedic Research Center Copenhagen (SORC-C), Department of Orthopedic Surgery, Copenhagen University Hospital Amager-Hvidovre, Copenhagen, Denmark

Background: The return to sport (RTS) rates in badminton after anterior cruciate ligament (ACL) injury are not know.
Aim: The purpose of this study was to report how many badminton players return to badminton after an anterior cruciate ligament (ACL) injury and to which level.
Materials and Methods: Patients in Denmark from 2000-2018 registered in the Danish National Patient Register with a diagnosis of ACL rupture and badminton as primary sport were asked about RTS and return to performance (RTP) after ACL injury. RTP was defined as return to full participation in the same sport, same level and same pre-injury performance. Statistics were performed using the unpaired Student t-test for continuous variables or the chi- square test for dichotomous or categorial outcomes.
Results: Badminton was the primary sport for 900. Only 435 players were injured during badminton, and 626 participants intended to return to performance. RTS was achieved by 63 % (396) and 19 % (117) returned to the same performance as their pre-injury level. However, 44 % (273) returned to full participation at the same level as pre-injury level but did not perform as well. Males had a significantly higher RTS than females (68 % (221) vs. 58 % (175), p=0.007 and RTP was also higher among males, however not significant (23 % (74) vs. 14 % (43), p=0.058).
Interpretation / Conclusion: Return to badminton after ACL injury was achieved by 63 % (396) and 19 % (117) returned to the same performance as their pre-injury level.

Torsten Grønbech Nielsen¹, Ole Gade Sørensen¹, Martin Lind
1. Department of Orthopaedic Surgery, Aarhus University Hospital, Aarhus N, Denmark

Background: The surgeons' choice of a single-stage or a two- stage procedure in revision anterior cruciate ligament reconstruction (ACLr) is based on the possibility of reuse of the tibia and femoral bone tunnels after primary ACLr. The advantage of a single-stage revision procedure is the need of only one surgery and rehabilitation period and a shorter period with ACL insufficiency. A two-stage revision due to tunnel malpositioning or tunnel widening requires two surgeries with a 4-6 months' interval to allow adequate bone graft healing.
Aim: The purpose of this present study was to compare failure rates and clinical outcome after either single- stage or two-stage ACL-revisions in a cohort of patients from The Danish Knee Ligament Reconstruction Registry.
Materials and Methods: Patients identified from 2005 to 2022 with ACL- revision and met the inclusions criteria; isolated ACL-revision and >2-years follow-up were included. Primary outcome was ACL-re-revision procedure. Secondary outcomes were knee laxity (side-to-side difference) and pivot shift (rotational stability difference - grade 0-1 or grade 2-3) evaluated at one-year follow up.
Results: 1,574 ACL-revisions were included in the study (1,331=single-stage and 243=two-stage). Baseline characteristics showed no difference in relation to age, gender, knee laxity, meniscus injury, cartilage damage or injury mechanism between the two groups. Significant differences were found in relation to pivot shift and type of graft. No statistical difference in two-years revision rates between single-stage group 2.79 (95%CI 2.03;3.84) and two- stage group 2.93 (95%CI 1.41;6.05) was found. No significant difference was seen in knee laxity and pivot shift between single-stage and two-stage ACL- revision at one-year follow up. Both groups demonstrated significant improvements from baseline to one-year follow up.
Interpretation / Conclusion: The primary finding of the study was that ACL- revision outcome was similar regarding re-revision rates and knee laxity for patients being managed with a single- or a two-stage surgical strategy.

Peter Faunø^1,2, Thorsten Grønbech Nielsen¹, Bøge Larsen Larsen², Michael Bach Hellfritzsch², Mette Mølbye Nielsen², Martin Carøe Lind¹
1. dept Sports Trauma, dept orthop. Aarhus University Hospital 2. dept Radiology, Aarhus University Hospital

Background: Anterior Cruciate Ligament Reconstruction (ACLR) in skeletal immature patients can result in growth plate injury, wich may cause growth disurbances in the lower limp.
Aim: To compare radiological tibia and femoral length and axis growth disturbances as well as clinical outcome in age groups below 13 years in skeletal immature ACLR patients treated with a femoral physis sparing technique compared to a transphyseal technique.
Materials and Methods: Thirty patients with ACL injury operated with transphyseal ACLR in the period before 2010 were compared with 20 skeletal immature patients, who were operated with an femoral physis sparing ACLR technique in the period after 2013. All patients were below 13 years of age. Patients were evaluated at follow-up with full extremity radiographs measuring leg length discrepancy and malalignment as well as clinical evaluation with KT1000 measurements and KOOS and Tegner scores after an average 68 (29-148) months follow-up.
Results: In the group operated with transphyseally drilling technique 27% had a 10 mm or more leg length difference whereas only 15% in the physeal sparing technique was seen. In both groups 15% of patients had a 5? or more increased valgus difference in distal femur and in proximal tibia 3% in the transphyseally drilled and 6% in the physeal sparing group had increased varus angulation. None of the differences measured was statistically significant. There were no significant differences seen between the two groups regarding knee laxity or PROM´s
Interpretation / Conclusion: The femoral physis sparing technique resulted in less, but not statistically different growth abnormality compared to the transphyseally drilled femur tunnels. No statistically different outcome scores were seen.

Charlotte Anker-Petersen¹, Mikkel Bek Clausen², Birgit Juul-Kristensen³, Per Hölmich¹, Kristian Thorborg¹
1. Sports Orthopedic Research Center-Copenhagen, Department of Orthopedic Surgery, Amager-Hvidovre Hospital, Copenhagen University Hospital, Denmark; 2. Department of Midwifery, Physiotherapy, Occupational Therapy and Psychomotor Therapy, Faculty of Health, University College Copenhagen, Copenhagen, Denmark; 3. Department of Sports Science and Clinical Biomechanics, Research Unit for Musculoskeletal Function and Physiotherapy, University of Southern Denmark, Odense, Denmark

Background: Gymnastics is a sport demanding high training volume and early specialisation, however, many gymnasts drop out during adolescence due to pain and/or injuries associated with TeamGym. Only few and very small studies have investigated the prevalence and pattern of pain in TeamGym.
Aim: Therefore, the primary aim was to describe the pain prevalence and its regional body distribution in TeamGym gymnasts, and secondly, to describe differences between pain prevalence during a normal training period and a period with reduced training load.
Materials and Methods: Twice during the season 579 competitive TeamGym gymnasts, aged 10-30 years from nine clubs, completed a survey on self-reported history of pain/discomfort. The collected data from the two different training periods included: (1) a normal training period from Aug-Dec 2020; and (2) a period with reduced training load due to COVID-19 restrictions from Jan-June 2021.
Results: In total 65% of the invited gymnasts completed both surveys. Eighty percentage of the gymnasts experienced pain due to gymnastics and the most prevalent pain regions were knee (20% [95% CI 18.1;21.8]), wrist (17% [95% CI 15.5;19.0]), foot (16% [95% CI 14.4;17.8]) and heel (11% [95% CI 9.9;12.9]). Gradual pain onset was more commonly reported (42%) compared with acute or mixed onset (64%). Body regional pain distribution was similar in the two training periods, but with an absolute difference in number of painful musculoskeletal regions, with pain reported in 11.3% [95% CI 10.8;11.8] of all possible body regions in the normal training period compared with 8.4% [95% CI 7.9;8.8] in the reduced training period, corresponding to a 26% decrease.
Interpretation / Conclusion: Pain prevalence among TeamGym gymnasts was experienced by 4 of 5 gymnasts during a full season. Knee, wrist and foot pain were the most common painful regions and gradual pain onset was the most common. A reduced training period did not change the pattern in distribution of pain, but the number of painful regions were lower during this period.

Kaja Skare^{1, 2}, Bjarke Viberg^{1, 4}, Per Hölmich², Stewart Kerr³, Niels Christian Kaldau²
1. Department of Orthopaedic Surgery and Traumatology, Odense University Hospital 2. Sports Orthopedic Research Center - Copenhagen, Department of Orthopedic Surgery, Copenhagen University Hospital, Amager & Hvidovre Hospital, Denmark 3. Life Fit Wellness, Healthcare & Exercise Centre, Falkirk, Scotland, UK 4. Department of Clinical Research, University of Southern Denmark

Background: Sleep inadequacy has previously been associated with increased risk of injury and reduced performance. It is unclear if sleep disorders are associated with musculoskeletal symptoms, which may be a predictor of serious injury and affect performance.
Aim: The aim was therefore to assess sleep behavior in elite junior badminton players and its association to musculoskeletal symptoms.
Materials and Methods: In 2018, players at the World Junior Badminton Championship completed the Athlete Sleep Behavior Questionnaire and a modified version of the World Olympic Association Musculoskeletal Health Questionnaire. Participants were categorized with poor or moderate/good sleep behavior. Relevant musculoskeletal symptoms were defined as pain higher than 30 mm Visual Analog Scale pain score or more than 30 minutes of joint stiffness. Baseline group comparison was performed using chi- square analysis and logistic regression for primary outcome adjusted for age, sex, ethnicity, previous injury, training load, and resting days.
Results: Of the 153 participants, 28% reported poor sleep scores. There was no baseline difference between poor and moderate/good sleep score concerning sex, age, ethnicity, previous injury, training load, and resting days. There were 27% with current musculoskeletal symptoms but with no difference in groups between poor and moderate/good sleep score (p=0.376). This yielded an adjusted OR of 1.23 (95% CI 0.52;2.90).
Interpretation / Conclusion: Twenty-eight percent of the participants reported poor sleep behavior. Twenty- seven percent experienced current musculoskeletal symptoms. We found no statistical differences in reported musculoskeletal symptoms when comparing athletes with poor sleep behavior to athletes with moderate/good sleep behavior.

Lasse Wedege Penning¹, Jens Kristinsson¹, Jens Erik Jorgensen², Carsten Møller Mølgaard^1,3,4
1. Department of Orthopaedic Surgery, Aalborg University Hospital, Aalborg. Denmark 2. Sofiendal Aalborg Health Team. Sofiendalsvej 92A. 9200. Aalborg SV. Denmark 3. Department of Physiotherapy and Occupational Therapy, Aalborg University Hospital, Hobrovej 18-22, 9000, Aalborg. Denmark 4. Department of Clinical Medicine, Aalborg University. Denmark

Background: BACKGROUND: Greater trochanteric pain syndrome (GTPS) is a common syndrome resulting in long term pain and disability. Treatments include i.a. physiotherapy, corticosteroid injection(s), and arthroscopic surgery.
Aim: This study aimed to evaluate the outcome of iliotibial band release and trochanteric bursectomy and identify any patient characteristics that may predetermine the outcome.
Materials and Methods: This retrospective cohort study included 31 patients (26? / 5?) treated for GTPS with arthroscopic iliotibial band release and trochanteric bursectomy from 2016-2020. Comorbidities and basic patient data were extracted, and the Global rating of change score was used as the primary outcome and pooled the patients into two groups, Success or No success. The patients were asked to evaluate their daily function, pain, and overall health. Chi- square test and independent t-test were used for analysis.
Results: 41.9% of patients reported the surgery a Success. All of these were women. The mean duration of symptoms before surgery was 19.8 (±6.5) months for the Success group and 40.2 (±15.9) months for the No success group (p<0.05). The patients in the Success group reported less pain, a better level of function, and better overall health (p<0.001). No comorbidities were found to predetermine the outcome.
Interpretation / Conclusion: The outcome for the patients of this study is worse than what other studies have found. This may be due to an older cohort and the use of the global rating of change score as to define what constitutes a successful trochanteric bursectomy.

Christine K. Schrøder^1,2, Lisa U. Tønning^1,2, Marianne Tjur¹, Pia K. Kristensen^1,2, Inger Mechlenburg^1,2
1. Department of Orthopaedic Surgery, Aarhus University Hospital; 2. Department of Clinical Medicine, Aarhus University

Background: Physical activity provides essential information to assess general health and evaluate the outcome of interventions. However, evaluation of physical activity necessitates reference values for comparison.
Aim: The current study aimed to present reference values for accelerometer-based data on physical activity in a background population.
Materials and Methods: We conducted a population-based cross- sectional study using accelerometer-based data on physical activity and self-reported data on demographics and health from a cohort of randomly selected individuals of 18-80 years of age registered in the Danish Civil Registration System (CRS) (n = 242). We presented data according to the FITT model (frequency, intensity, time, and type), including number of steps, cadence, intensity, time spent sedentary, standing, walking, or cycling, as well as number of transfers from sitting to standing.
Results: Participants took an average of 6095 daily steps, had an average cadence of 98.5, spent 3.7 hours standing, 1.4 hours walking, 3.8 minutes cycling, 7.0 hours in sedentary activities, and had 43 sit-to-stand transfers. The results varied when examining sex and individual age groups.
Interpretation / Conclusion: This study provided reference values on physical activity from a Danish background population. Our findings are important to clinical practice and research as they provide sex- and age-specific reference values to enable comparison of daily physical activity levels.

Frederik Foldager¹, Signe Kierkegaard-Brøchner², Joanne Kemp³, Bent Lund⁴, Ulrik Dalgas⁵, Inger Mechlenburg¹
1. Department of Orthopaedic Surgery, Aarhus University Hospital, Aarhus N, Denmark; 2. Department of Occupational and Physical Therapy, Horsens Regional Hospital, Horsens, Denmark; 3. College of Science, Health and Engineering, LaTrobe University, Melbourne, Australia; 4. Department of Orthopaedic Surgery, Horsens Regional Hospital, Horsens, Denmark; 5. Department of Public Health, Section of Sports, Aarhus University, Denmark.

Background: Femoroacetabular impingement syndrome (FAIS) is considered a motion- or position related clinical condition of the hip often associated with pain, reduced physical function and poor hip-related quality of life. A proportion of patients respond positively to physiotherapy including strength exercise as first-line treatment, where better muscle strength in patients with FAIS has been found associated with less pain, better physical function and quality of life. Currently there is no evidence to support the type, intensity, volume and duration of the exercise offered as first-line treatment.
Aim: We aim to conduct a randomised controlled trial (RCT) investigating the clinical- and cost- effectiveness of a 6 month strength exercise intervention compared to usual care as first-line treatment in patients with FAIS.
Materials and Methods: This trial is a multicenter, randomized, controlled, assessor-blinded trial and will be conducted at hospitals and physiotherapy clinics across Denmark and in Melbourne, Australia. A total of 104 patients diagnosed with FAIS will be randomised to either 6 months of strength exercise or usual care. The primary outcome is change in hip- related quality of life measured with the International Hip and Outcome Tool (iHOT- 33) at the end of intervention. Secondary outcomes include maximal muscle strength, physical function and patient-reported outcomes measuring constructs of pain, pain catastrophizing, quality of life, sports participation and physical activity. Furthermore a health economic evaluation will be conducted. Outcomes will be measured at baseline, after the initial 3 months of intervention, and at 6-month and 12-month follow-up. An intention-to-treat approach will be used for analyzing changes in the primary and secondary outcome measures.
Results: Expected ultimo 2026.
Interpretation / Conclusion: This project will provide high-quality evidence- based knowledge that may contribute to recommendations for first-line treatment in patients with FAIS, relevant for patients, physiotherapists, orthopaedic surgeons and health funding policy decision-makers.

Inger Mechlenburg¹, Torsten Grønbech Nielsen¹, Nick Kristensen², Troels Kjeldsen¹, Stian Langgård Jørgensen³
1. Department of Orthopaedic Surgery, Aarhus University Hospital, Aarhus N, Denmark 2. Department of Public Health, Section of Sports, Aarhus University, Denmark 3. Department of Occupational and Physical Therapy, Horsens Regional Hospital, Horsens, Denmark

Background: Former American football player, 30 years of age, suffered several months of moderate left knee pain during daily life activities sustained after performing maximal flexion loaded goblet squats. Magnetic resonance imaging showed normal meniscus and cruciate ligaments and no extra joint fluid. The patient was seen by a physiotherapist and introduced to 12 weeks of low-load exercises with concurrent blood flow restriction (LL-BFR) as knee rehabilitation. Reliable evidence suggests LL-BFR to induce significant gains in maximal muscle strength, muscle mass with minimal exacerbation knee joint pain.
Aim: To describe the outcome of 12 weeks BFR-RT as a rehabilitation method for unspecific knee pain.
Materials and Methods: The patient performed 12 weeks of LL-BFR for the lower limbs (goblet squat, knee extensions) with a low amount of supervision after the first week of training. Assessment of muscle strength, single-legged hop test, low-thigh circumference 10 cm above apex patella, The Knee Injury and Osteoarthritis Outcome Score (KOOS) and The Forgotten Knee Joint Score (FJS) was performed at baseline and after 12 weeks of LL-BFR.
Results: The patient completed all planned exercise sessions. Maximal voluntary isometric contraction of knee extension improved from 3.1 to 3.5 nm/kg (31%) on the left leg, and from 3.5 to 3.7 nm/kg (6%) on right leg. Single-legged hop test improved with 26 cm (23%) on the left leg and 3 cm (2%) on the right leg. Low-thigh circumference increased 1.5 cm on the left leg and 2.4 on the right leg. KOOS pain, KOOS quality of life and FJS demonstrated improvements of 11, 6 and 40 points, respectively. After the BFR-RT rehabilitation, the patient was able to return to his usual training regime.
Interpretation / Conclusion: The present case study indicates that even with low amounts of supervision LL-BFR could increase muscle strength, functional performance and improve key patient-reported outcome. BFR-RT seems promising as a transition to help patients back to a healthy lifestyle of training and being physically active.

Ulrik Kähler Olesen¹, Klaus Hindsø¹, Michael Mørk Petersen¹, Upender Martin Singh¹, John Herzenberg²,
1. Rigshospitalet, Department of Orthopedics, Copenhagen, Denmark; 2. Rubin Institute of advanced orthopedics, Baltimore, USA.

Background: We describe a novel and time saving technique for large bone defects (8-10 cm and greater) using two internal lengthening nails (ILN), one antegrade and one retrograde, working together and aligned inside a custom-made titanium sleeve, augmented by an internal locking plate. An illustrative case that successfully produced 17 cm of regenerate in 3.5 months, is presented.
Aim: Reconstructive orthopedic surgery can be very burdensome for the patient due to long term treatment and rehabilitation, causing absenteeism from the workforce and social life and depression. We aimed at designing a time saving device to cut treatment time in half after large bone defect.
Materials and Methods: A 28-year-old otherwise healthy male presented with a slowly growing mid-diaphyseal mass in the left femur. No generalized symptoms, weight loss, or previous illness were reported. Based on X-rays, PET/CT, and MRI, a malignant bone tumor was suspected. An open biopsy through an anterior incision diagnosed an unspecified low-grade osteosarcoma. There was no evidence of metastases. Wide surgical resection of the 17 cm diaphyseal tumor was performed followed by a 3-stage trifocal bone transport. A 3D model of the bone was used to plan and trial the surgery.
Results: Trifocal bone transport using two counter opposed internal lengthening nails (ILN) in a custom-made slotted tube device and augmented with an internal locking plate for additional stability, filled the 17 cm bone defect in 3.5 months. This was a planned three stage procedure and can be considered a further advanced modification of the previously described Plate Assisted Bone Segment Transport (PABST). No signs of local recurrence or metastases were seen during the 1.5-year follow-up period. The distraction index was 1.6 mm/day. The overall consolidation index was 20 days/cm.
Interpretation / Conclusion: The presented double nail technique successfully solved a challenging clinical problem and is a potential steppingstone for further developments of devices for complex and large bone transport and lengthening.

Christina Holm^1,2,3, Jonathan A. Forsberg², Thomas Baad-Hansen³, Andrea Thorn ¹, Michala Skovlund Sørensen¹, Michael Mørk Petersen¹
1 The Musculoskeletal Tumor Section, Department of Orthopedic Surgery, Rigshospitalet, University of Copenhagen, Denmark, 2 Orthopaedics, USU-Walter Reed Department of Surgery, Bethesda, MD, USA, 3 Department of Orthopaedic Surgery, Tumor Section, Aarhus University Hospital, Aarhus, Denmark

Background: Osteosarcoma is the predominant subtype of bone sarcoma. Estimated life expectancy is important in the clinical decision making. There is currently no prognostic algorithms using machine learning technique to predict short- term survival in patients with osteosarcoma.
Aim: The purpose of present study is 1) To develop a Gradient Boosting machine (GBM) model estimating 1-year survival in patients with newly diagnosed osteosarcoma, 2) To describe the relationship between outcome variables and their relative influence on 1-year survival
Materials and Methods: The training cohort comprised 178 patients with newly diagnosed osteosarcoma included from The Danish Sarcoma Registry between January 1 st , 2000 and June 30, 2016. Data extracted for analyses were: age, sex, tumor size, tumor location, tumor site, metastasis, pathologic fracture, grade, survival. A GBM model was trained on a training set (n=157). We performed internal validation on the corresponding holdout test set (n=39). The ability of accuracy and discrimination was evaluated by receiver operator characteristic (ROC) analysis and area under the curve (AUC). Validation was considered suitable for clinical usage if the AUC under the ROC curve was greater than 0.7. Overall predictive model performance was evaluated with the Brier score.
Results: We successfully generated a Gradient Boosting Machine learning model. Features with the highest relative importance to 1 year survival were: age, tumor size, metastasis at diagnosis. On internal validation the model demonstrated good accuracy and discrimination by receiver operating characteristic (ROC). Area under the curve (AUC) demonstrated 81% (95%CI: 52%-96%). Overall model performance by Brier score was 0,11 (95%CI: 0.03-0.19).
Interpretation / Conclusion: The developed Gradient Boosting Machine can accurately predict 1-year survival in patients with newly diagnosed osteosarcoma. Age and metastasis at time of diagnosis had the largest prognostic effect on survival. When properly external validated we believe present model can provide the clinician with a useful tool in the clinical decision making

Shoresh Moradi ¹
Principal supervisor: Prof. Michael Mørk Petersen Co-supervisor: Dr. Afrim Iljazi The tumor section, Department of Orthopedic Surgery, Rigshospitalet, Copenhagen University Hospital,

Background: Patients suffering from a pathological fracture or painful bony lesion in hip joint because of metastatic bone disease often benefit from a total joint replacement(THA) with partiel pelvic reconstruction(PPR). However, it is a major operation in patients who are already weak.
Aim: The purpose of the study is to calculate the cumulative incidence of: ? - Postoperative complications - General revision rate - Revision with removal of a bone-anchored prosthetic component ? - Patient survival
Materials and Methods: It was an observational cohort study. We identified 42 patients (mean age 67 years, 28 females and 14 males) who received THA with partiel PPR as the treatment for bone metastasis in the hip joint during the period 2008–2019. Clinical and survival data were extracted from patient files, electronic medical records/the Health Platform (SP). Prosthesis-related complications calculated according to the Henderson classification. Kaplan– Meier’s analysis was applied to estimate the probability of patient survival.
Results: 18 patients out of 42 patients experienced at least one prosthesis-related complication with a CI of 31% and 44% after 1 and 5 years. 7 (18%) of 18 patients resulted in revision surgery.. But 3 patients (9%) ended up having revision surgery with removal of bone anchored parts. The median survival time was 10,5 (0,5-144) months.
Interpretation / Conclusion: The results show that the incidence of postoperative complications (44% after 5 years) in our patient group is higher compared to the literature. Furthermore, the incidence of revision surgery (22% after 5 years) and prosthesis failure (7% after 5 years) is also higher in our patient group compared to the literature. However, our results are not higher when we compare with other studies that have also examined patients undergoing pelvic reconstruction and THA. The median survival in our patient group is 10,5 months, which corresponds to what can be found in the literature. Therefore, we can highlight that the surgical treatment with THA and PPR for metastatic bone disease does not result in worse patient survival than other forms of surgical intervention.

Albert Lauge Gellert¹, Mikkel Østerheden Andersen^2,4, Leah Yaccat Carreon^2,4, Ane Simony^2,3,4
1. Department of Orthopedics, Esbjerg and Grindsted Hospital, University hospital of Southern Denmark 2. Department of Spine Surgery & Research, Spine Center Middelfart 3. Department of Orthopaedic Surgery, Lillebaelt Hospital Kolding, Denmark 4. Department of Regional Health Research, University of Southern, Denmark

Background: Coccydynia may greatly impact patients’ quality of life and functional level, including sexual health which is important for physiological well-being and relationships. Despite its fundamental role in human life, there are limited data available on sexual function and health in patients undergoing surgery for Coccydynia. Coccygectomy is a definitive treatment option for chronic cases where other therapies have been without pain relief. Several studies has described this procedure to be an effective treatment where the tailbone is removed surgically either total or partially. Earlier studies have not identified factors associated with lesser or better outcome.
Aim: The aim of this study was to investigate the effect of coccygectomy on sexual and social function in patients with persistent coccygodynia
Materials and Methods: The study is a retrospective collected, prospective cohort study performed in a single center Rygcenter Syddanmark, in Southern Denmark. 106 identified participants from the Dane Spine Database with persistent coccydynia who had undergone coccygectomy between 2011- 2022 and where included in the study. Inclusion criteria consisted of, only females, age > 18 years, data availability pre- operative as well as one and two years postoperative of the Oswestry Disability item 8 (ODI8) regarding sexual function, and item 9 (ODI9) regarding Social Function. Patients were excluded if no problems regarding sexual function was present, or patients had previous surgery in the area.
Results: All included patients were female 91 patients (85.8%) with a mean age of 40,4 years. Ethnicity primarily Caucasian. A significant improvement was found (<0.001) in their ODI8 one-year after surgery, from pre-op of 2.01±1.3 to 0.85±1.3 after one year. The ODI9 score for social function also showed a significant improvement from 2.12±1.0 preoperative to 0.99±1.2 postoperative (<0.001). No significant change in ODI8 or ODI9 was observed between one and two years after surgery.
Interpretation / Conclusion: In female patients with persistent coccydynia and impaired sexual function, coccygectomy improves their sexual function. An improvement of social function is also observed.

Girts Murans^1,2, Stig Mindedahl Jespersen¹, Laurynas Meska¹, Gaurilcikas Marius¹, Lindberg-Larsen Martin^1,2
1) Department of Orthopedic Surgery and Traumatology, Odense University Hospital and Svendborg. 2) Orthopedic Research Unit, Department of Clinical Research, University of Southern Denmark

Background: The treatment guidelines for thoracolumbar spinal fractures are controversial although minimally invasive surgery (MIS) is a popular alternative to the traditional open approach (TOA). Limited data exists about outcomes after MIS fracture treatment. The main aim of our study was to evaluate self-reported disability, health-related quality of life, pain, and satisfaction after MIS compared with TOA.
Aim: The main aim of our study was to evaluate self- reported disability, health-related quality of life, pain, and satisfaction after MIS compared with TOA.
Materials and Methods: Of 173 patients operated from March 2014 to July 2018, 112 patients (64.7%) completed the Oswestry Disability Index (ODI), the EQ-5D-5L, and a tailored clinical follow-up questionnaire on employment status, pain, activity level, and satisfaction with treatment.
Results: Of the 112 patients, 34 had MIS and 78 had TOA. Mean follow-up was 56 months (range 32-82). The two groups were comparable on demographic variables apart from mean age where MIS group was in average 10 years older. The MIS group had better ODI scores than the TOA group (p=0.046), but the groups were similar regarding return to work and disability retirement. The mean and median EQ-5D- 5L index score for the MIS group was marginally (mean -0.033, median +0.04901) lower than the mean Danish population score, while the TOA group showed a greater deviation (mean - 0.12508, median -0.040). The MIS group used less pain medication than the TOA group . Both groups were similarly satisfied with treatment results.
Interpretation / Conclusion: Our data indicates that MIS surgery for thoracolumbar spinal fractures can achieve acceptable self-reported outcomes in terms of disability, health-related quality of life, pain, and satisfaction with treatment. However, a randomized controlled trial is needed to determine whether the MIS approach is superior to TOA.

Josefine Slater^1,2,3, Maiken Stilling^1,2,3, Pelle Hanberg^1,3, Sofus Vittrup^1,2,3, Martin Bruun Knudsen^1,2,3, Sara Kousgaard Tøstesen^1,2,3, Josephine Olsen Kipp^1,2,3, Mats Bue^1,2,3
1. Department of Orthopaedic Surgery, Aarhus University Hospital; 2. Department of Clinical Medicine, Aarhus University; 3. Aarhus Denmark Microdialysis Research (ADMIRE), Orthopaedic Research Laboratory, Aarhus University Hospital

Background: Pyogenic spondylodiscitis remains a diagnostic and therapeutic challange for the clinician. The incidence is rising, particularly in high-risk patient populations, and culture-negative cases are increasing. The optimal choice for empirical treatment remains unknown. As in other complex orthopaedic infections, co-administration of meropenem and vancomycin has been suggested for systemic empirical antibiotic treatment of pyogenic spondylodiscitis.
Aim: The aim of this study was, in an experimental model, to evaluate a theoretical treatment target, the percentage of an 8-h dosing interval of co- administered meropenem and vancomycin concentrations above relevant minimal inhibitory concentrations (MICs) (%T>MIC), in spinal tissues using microdialysis.
Materials and Methods: Eight female pigs received a single-dose bolus infusion of 1000 mg of meropenem and 1000 mg vancomycin simultaneously before microdialysis sampling. Microdialysis catheters were applied in the C3 vertebral cancellous bone, the C2-C3 intervertebral disc, paravertebral muscle, and adjacent subcutaneous tissue. Plasma samples were obtained from a central venous catheter for reference. Given the diversity of possible causative bacteria in pyogenic spondylodiscitis, we chose to investigate a range of MIC targets for both meropenem and vancomycin. We considered vancomycin as the relevant drug of choice for coverage against Gram- positive organisms, while meropenem would provide Gram-negative and anaerobic coverage.
Results: The main finding was that for both drugs the %TMIC was demonstrated in plasma, and the lowest %TInterpretation / Conclusion: When indicated, our findings suggest a more aggressive dosing approach of both meropenem and vancomycin to increase spinal tissue concentrations to treat the full spectrum of poten- tially encountered bacteria in a spondylodiscitis treatment setting.

Morten Jon Andersen^1,2
1. Dept of Orthopedic Surgery, Copenhagen University Hospital - Herlev and Gentofte 2. Dept of Clinical Medicine, University of Copenhagen

Background: Plain radiographs cannot show the chondral epiphysis of the distal humerus and therefore cannot evaluate the stability of pediatric lateral humeral condyle fractures (LHCF).
Aim: The aim of this study was to evaluate an MRI protocol for the pediatric elbow to distinguish the stability of LHCF in children.
Materials and Methods: Children suspected of minimally displaced LHCF were referred for expedited MRI. Exams were performed during daytime hours and with an above elbow splint on. No sedation or anesthesia was administered. Flexible coils and 3 tesla scanners were used. The MRI protocol consisted of three sequences: 3D WATS, T1 coronal and STIR coronal with breaks in between. Total scan time was less than 10 minutes; however, 45 minutes was set aside for each child.
Results: 12 children, 3 girls and 9 boys, with suspicion of minimally displaced LHCF on plain radiographs were referred for MRI. Mean age was 5.5 years (range 3-9). One scan could not be performed due to anxiety in a 3-year-old boy. All scans were evaluated by a musculoskeletal radiologist. 3 scans showed only bone edema and no fracture. 8 scans showed LHCF of which 4 were stable and 4 unstable.
Interpretation / Conclusion: MRI gave a clear overview of the extent of the injury in both the bone and chondral areas of the distal humerus. Evaluating the stability of LHCF is key to choosing the right treatment strategy. In some institutions minimally displaced LHCF are treated with open surgery to prevent secondary dislocation. We believe that MRI can better guide non-surgical treatment.

Lili Worre Høpfner Jensen¹, Rikke Emilie Kildahl Lauritsen¹, Søren Kold¹, Ole Rahbek¹
Interdisciplinary Orthopaedics, Aalborg University Hospital, 9000 Aalborg, Denmark

Background: Transition from hospital to home after orthopaedic surgery pose a risk to patient safety. Poor communication and coordination between patients and healthcare professionals from hospital and municipality leads to fragmented care. Digital communication is increasingly used to facilitate easy and accessible asynchronous communication between patients and healthcare professionals across settings. It may provide optimized quality of care in the postoperative period following hospital discharge. No studies have explored the use of team-based digital communication between patients and healthcare professionals after orthopaedic surgery and discharge, even though these patients often have long periods of rehabilitation that involves various healthcare professionals across settings.
Aim: The aim of this study was two-fold; 1) to explore orthopaedic surgery patients’ perspectives on current communication pathways at a tertiary hospital in Denmark, and 2) to explore patients’ experiences and use of a GDPR-safe team- based digital communication solution following hospital discharge (eDialogue).
Materials and Methods: A triangulation of qualitative data collection techniques was applied with the purpose of obtaining in depth-knowledge of patients’ perspectives and the context; document analysis, participant observations (n=16 hours), semi-structured interviews with patients before (n=31) and after (n=24) their access to eDialogue, and exploration of usage data.
Results: Patients expressed difficulties in current communication pathways due to a lack of information and inadequate coordination of care after hospital discharge. eDialogue was used by 83.9% and was perceived as adequate to most patients’ communication needs following hospital discharge. They suggested it provided a sense of security, reduced their need for phone calls to the hospital, and that it eased the sharing of knowledge between patients and healthcare professionals across settings.
Interpretation / Conclusion: In conclusion, patients evaluated eDialogue positively and suggested it could support them after returning home following orthopaedic surgery.

Tina Udemark Pasgaard¹, Sidsel Hald Rahlf², Julie Ladeby Erichsen², Christian Færgemann², Bjarke Viberg³, Anders Holsgaard-Larsen²
1. H.C. Andersen Children’s Hospital, Odense University Hospital; 2. Department for Orthopaedic Surgery and Traumatology, Odense University Hospital; 3. Department of Orthopaedic Surgery and Traumatology, Hospital Lillebaelt – University Hospital of Southern Denmark

Background: Determining the cause and severity of idiopathic toe walking (ITW) can be difficult from clinical examination alone. Gait analysis might provide further description of ITW, potentially altering the treatment strategy.
Aim: To test the hypothesis that the treatment strategy of children diagnosed with ITW and considered candidates for achilles lengthening surgery will change once gait analysis is added to the decision- making.
Materials and Methods: A cross-sectional analysis on baseline data from a prospective cohort (powered for another research question). Inclusion: Children (7-15 years) referred to the pediatric orthopedic outpatient clinic at Odense University Hospital or Kolding Hospital and considered candidates for surgical treatment for ITW based upon parent reported and visual signs of toe-walking and passive ankle dorsiflexion <15° with the knee extended. Exclusion: Children with neurological conditions, unilateral toe-walking, previous achilles lengthening surgery, club foot, and not understanding Danish. Following clinical ITW examination children were referred to a confirmatory 3-dimensional gait analysis. Based upon waveforms of the ankle kinematics and kinetics (Vicon, T40, Oxford, England) children were categorized according to Alveraz et al. 2007 into; 1) no – mild signs, 2) moderate – severe signs of ITW.
Results: 23 children (17% girls, age 10 ± 2 years (mean ± sd)) were included. There were 13 children demonstrating moderate - severe signs of ITW whereas 10 children demonstrated no - mild signs of ITW and thus, not considered candidates for achilles lengthening surgery. Differences in dynamic ankle function between the two groups were observed for peak ankle dorsi-flexor degree (4.5 ± 5.8° vs 13.4 ± 1.4°, p < 0.001) and delta of the two peak ankle plantar-flexor moments (0.09 ± 0.29 Nm/BW vs 0.68 ± 0.19 Nm/BW, p < 0.001) (indicating equinus).
Interpretation / Conclusion: Adding objective and quantitative information from a gait analysis to the decision making of ITW altered the treatment strategy for almost half of the children considered to be candidates for achilles lengthening surgery. Moreover, gait analysis revealed that other causes than equinus should be considered in the treatment planning of ITW.

Mathias Hauge Bünger¹, Line Holm Jensen¹, Martin Gottliebsen¹
1. Department of paediatric orthopaedics, Aarhus University Hospital

Background: Treatment of development dysplasia of the hip (DDH) in infants is often debated. There seem to be consensus that unstable hips require treatment to stabilize the hip in the socket. However, when it comes to treatment of residual dysplasia of the hip at radiographs taken age 6 month opinions are much more diverse and evidence sparse. The effect of bracing after the age of 6 month is unknown.
Aim: The aim of the study was to describe a cohort of children with radiographic DDH at 6 months old treated with part time abduction bracing.
Materials and Methods: The cohort included 50 infants (5 boys/45 girls) with DDH determined as acetabular index (AI) > 30 degrees at age 6 month treated at our institution from 2020-2023. Our treatment regime included a removable abduction brace with parents advised to use it for 12h/24h or more. Children were followed up with radiographs at age 9 and 12 months. 26% were breech babies and 15% had a family history of DDH. 33% had not received any prior treatment, while 24% and 22% had been treated with a Pavlik Harness or a Denis Brown splint, respectively. A further 20% of the children had been treated with closed reduction in a general anesthesia and spica cast.
Results: Good compliance >12h/24h was reported in 90% of the patients at 9 months. This percentage dropped to 54% at 12 month. The mean AI at the beginning of treatment was 29±3 degrees/33±5 (dx/sin) improving to 25±5/28±4 at age 9 month (p<0.001 -paired T-test). No further improvement in AI was found at 12 months. Prior to treatment, 40 children had a previous ultrasound hip examination at a mean age of 3.75 months (2-6 months) with a mean alfa angle of 66±4/62±6 (dx/sin) , coverage 64±7/61±12) and pubo-femoral distance of 4±2/6±3.
Interpretation / Conclusion: In the present cohort children treated with part-time abduction bracing showed improvement in acetabular index from age 6 to 9 month of approximately 5 degrees, while no improvements were found after 9 months. These findings suggest that bracing should stop at 9 month. Surprisingly, a large proportion of the dysplastic hips had a normal USS prior to radiograps at 6 months of age. This finding suggests that residual dysplasia cannot be ruled out based on a normal ultrasound.

Jan Duedal Rölfing^1,3, Harpreet Chhina^2,3, Anne Klassen³, Björn Vogt³, Mohan Belthur³, Melissa Esparanza³, David Bade³, Alicia Kerrigan³, Jonathan Wright³, Ashish Ranade³, Louise Johnson³, David Podeszwa³, James Fernandes³, James Messner³, Christopher Iobst³, Sanjeev Sabharwal³, Jussi Repo³, Sharon Eylon³, Anthony Cooper^2,3
1. Department of Orthopaedics, Aarhus University Hospital, Denmark 2. Department of Orthopaedic Surgery, BC Children’s Hospital, Vancouver, Canada 3. International LIMB-Q Kids collaborators

Background: LIMB-Q Kids is a new patient-reported outcome measure (PROM) for children with Lower limb differences (LLDs). A mixed method multiphase approach was used to develop LIMB-Q Kids including a systematic review informing a conceptual framework. Cognitive debriefing interviews (CDIs) with children were performed multiple times.
Aim: The aim of this study was to assess the psychometrical validity of the items and to perform Rasch analysis.
Materials and Methods: We conducted an international field test study where LIMB-Q Kids was completed by children with lower limb differences from several sites across the world. Clinical data was also collected for all children who completed LIMB-Q Kids. The final field-test version consists of 11 scales (159 items) that measure appearance, physical function, symptoms (hip, knee, ankle, foot, and leg), leg-related distress, and school, social and psychological function. This version was rigorously translated into Danish and German. Translations that are in progress include Arabic, Finnish, Hindi, Hebrew, Portuguese and Spanish.
Results: An international field-test study is underway in 15 countries (25 sites with a target recruitment of 150 participants per country). 310 completed LIMB-Q Kids have been received to date with the target of 500 before the final analysis. A preliminary analysis of the available data using Rasch Measurement Theory analysis provided evidence that the scales in the LIMB-Q Kids work as hypothesized.
Interpretation / Conclusion: No internationally applicable PROM exists for children with LLDs. Data from the international field-test study will be used to reduce items and perform psychometric testing of LIMB-Q Kids. The rigorous translation and cultural adaptation process provided versions of LIMB-Q Kids in different languages. Once completed, the LIMB- Q Kids will provide a common metric for outcome assessment for children with lower limb differences internationally.

Katrine Rønn Abildgaard¹, Peter Buxbom¹, Ole Rahbek², Martin Gottliebsen³, Per Hviid Gundtoft³, Bjarke Viberg⁴, Stig Brorson¹
1. Centre for Evidence-Based Orthopedics, Department for Orthopedic Surgery, Zealand University Hospital, Køge, Denmark; 2. Children´s orthopedics, Department of Orthopedics, Aalborg University Hospital; 3. Danish Paediatric Orthopaedic Research, University Hospital Aarhus, Denmark; 4. Department of Orthopaedic Surgery and Traumatology, Odense University Hospital, Odense, Denmark.

Background: Treatment of displaced distal forearm fractures (DFF) in children have traditionally been closed reduction and optional pin fixation, although they might heal and remodel without manipulation, with no functional impairment. Earlier studies focus on radiographic outcome or range of motion. No randomized controlled trials (RCTs) have been published comparing the patient-reported functional outcome after non-surgical and surgical treatment of displaced DFF in children.
Aim: To investigate the patient-reported functional outcome after non-surgical versus surgical treatment of displaced DFF in children aged 4-10 years.
Materials and Methods: This is a multicenter RCT on four Danish university hospitals. Children aged 4-10 years with open physes and a displaced DFF (overriding or 20-40° angulation) will be offered inclusion, if the on-duty orthopedic surgeon finds indication for surgical intervention. They will be allocated equally to non-surgical treatment or surgical treatment of surgeon’s choice. Follow-up will be 4 weeks, 3, 6 and 12 months for questionnaires, photographs and radiographs. The primary outcome is the between-group difference in 12 months QuickDASH score. A sample of 40 patients will allow us to show a 15- point difference with 80% power and a one-sided type I error rate of 2.5%.
Results: Not yet recruiting. Expected inclusion period is June 2023 to June 2025.
Interpretation / Conclusion: The design of this RCT offers an opportunity to compare patient-reported outcome after non-surgical versus surgical treatment of pediatric displaced DFF. If non-surgical treatment proves non-inferior to surgical treatment, unnecessary anesthesia and surgery may be avoided, and treatment may be carried out with limited radiation exposures, fewer control visits, and less pin-related complications.

Zabane Zakaria¹, Hartig Andreasen Charlotte ¹, Hauge Bünger Mathias ¹, Bach Hellfritzsch Michel ¹
Zakaria: Medical school, Aarhus University Charlotte: Department of Orthopaedics, Aarhus University Hospital Mathias: Department of Orthopaedics, Aarhus University Hospital Michel: Department of Radiology, Aarhus University Hospital

Background: Four year old boy, suffers a forearm fracture which is treated with closed reduction and conservatively with an orthopaedic cast for 4 weeks. Immediately postoperatively, the patient is affected by pain and median nerve affection. It was at the time interpreted as neuropraxia. A year later, the patient still has median nerve affection. Ultrasonographic examination of the forearm reveals that the median nerve is trapped in callus at the radius fracture site. The patient undergoes a second operation with neurolysis and nerve grafting.
Aim: To highlight the use of ultrasonography as a tool in the diagnostics of nerve entrapment syndrome. Although nerve entrapment syndrome after closed fracture reduction is a rare condition, it is a serious condition which can lead to nerve damage. In some rare cases, nerve entrapment syndrome can be misinterpreted as neuropraxia. This abstract will also elucidate red flags that a physician must be aware of.
Materials and Methods: The patient’s journal was used to describe the background of the abstract. Pictures from the ultrasonography examination and reconstructive surgery were used to describe location of the radius callus fracture and the median nerve entrapment site in the bone. Other case reports about nerve entrapment from public libraries were used to further describe details in the abstract.
Results: Posttrauma x-ray of the patient’s forearm presented a fracture of the distal third of ulna and radius. A year later, a new x-ray revealed complete bone healing and bone remodelling. The x-ray also showed a slight bone irregularity which was seen as a bony spike on the distal third of caput radius. Ultrasonography was performed and showed an osseous defect on caput radius at the place of the fracture in which the median nerve was trapped.
Interpretation / Conclusion: Nerve entrapment syndrome in forearm fractures in children is uncommon, however it is a serious condition. Ultrasonography is a non- invasive, quick and an easily accessible diagnostic tool. In the hands of an experienced user, ultrasonography should serve a role in the diagnostics of nerve entrapment syndrome soon after trauma or surgery where symptoms exceed what normally is expected.

Simone Trøst Bylund^1,2, Ali K. K. Al-Hamdani^1,2, Nils Wolfram³, Morten Jon Andersen^1,2
1. Dept of Orthopedic Surgery, Copenhagen University Hospital - Herlev and Gentofte 2. Dept of Clinical Medicine, University of Copenhagen 3. Dept of Neurology, Zealand University Hospital - Roskilde

Background: Elbow dislocation in children is not common and constitute only 3-6% of all elbow injuries. Associated injuries are common and fracture of the medial epicondyle the most frequent. Neurological compromise is rare (<5%) and usually transient due to traction neurapraxia. Intraarticular entrapment of the median nerve is described as a very rare complication. The median nerve can be entrapped as described by Fourrier et al. with or without a concomitant medial epicondyle fracture.
Aim: To present this rare but clinically important condition.
Materials and Methods: We present a case together with a literature review.
Results: A 10-year-old boy presented to the ED after a fall complaining of left elbow pain and tingling sensation in the second finger. Vascular status was normal. Plain radiographs showed elbow dislocation with avulsion of the medial epicondyle. The elbow was reduced by closed means in the ED. Post reduction radiographs and CT showed a congruent joint. Sensory deficits and inability to flex first and second finger's distal interphalangeal joint (DIJ) were present. ORIF of the epicondyle was performed. Follow up at six weeks was without clinical improvement. EMG showed severe affection of median nerve function. Ultrasound showed an irregular path of the nerve. Intraarticular entrapment of the nerve was suspected and surgery was performed. The median nerve was identified proximally and followed medially where it was buried under new bone formation. The nerve continued medial to the epicondyle and entered the ulnohumeral joint. To free the nerve, the medial soft tissues were released and the nerve was removed from the joint. Distal to the joint the nerve was further released anteriorly hereafter the nerve followed the anatomical path. 3 months postoperative motor function was partially restored and active flexion over the first and second DIJ was observed. Sensory function was also improved.
Interpretation / Conclusion: Elbow dislocation in children is a rare injury and nerve entrapment a very rare complication. Post reduction median nerve affection should lead to further investigation by ultrasound. If nerve entrapment is suspected urgent surgical exploration is warranted and should not await EMG or spontaneous recovery.

Hans-Christen Husum^1,2, Michel Bach Hellfritzsch^2,3, Rikke Damkjær Maimburg^2,5, Bjarne Møller-Madsen^2,4, Mads Henriksen^2,3, Natallia Lapitskaya^2,3, Søren Kold^1,2, Ole Rahbek^1,2
1 Interdisciplinary Orthopaedics, Aalborg University Hospital, Denmark; 2. Danish Paedatric Orthopaedic Research, Aarhus University Hospital, Denmark www.dpor.dk; 3. Department of Radiology, Aarhus University Hospital, Denmark; 4. Department of Children’s Orthopaedics, Aarhus University Hospital, Denmark; 5. Department of Midwifery, University College of Northern Denmark, Aalborg

Background: The pubo-femoral distance (PFD) ultrasound (US) measurement has been proposed as a more accessible measurement for hip dysplasia (DDH) screening. While PFD US is implicitly correlated to current gold standard US measurements for DDH through its reported high sensitivity for DDH, the exact correlation of these measurements is not clear. The gold standard measurements quantify acetabular morphology and sonographic hip instability by measuring the acetabular inclination angle and coverage of the femoral head by the bony acetabulum. Conversely, the PFD measurement relies on a single distance measurement between the medial femoral epiphysis and the ossification center of the pubic bone while lateralizing stress is applied to the hip joint.
Aim: The present study seeks to investigate the correlation of PFD to the gold standard alpha angle and the femoral head coverage (FHC) at rest and during manual provocation.
Materials and Methods: We prospectively included all newborns referred for follow up hip US at our institution based on primary risk factor-, clinical- and PFD screening. Alpha angles, PFD, FHC and FHC during provocation at follow-up ultrasound for referred newborns were measured and compared using scatter plots, linear regression, t-tests and box-plots.
Results: We included 2,735 newborns of which 754 received a follow-up hip ultrasound within six weeks of age. After exclusion 752 newborns were included for analysis (372 male/380 female), mean age at examination was 36.6 days (range 4-87 days). We found a negative linear correlation of PFD to alpha angles (p<0.001), FHC(p<0.001) and FHC during provocation (p<0.001) with a 1mm increase in PFD corresponding to a -2.1 degree (95% CI -2.3;-1.9) change in alpha angle and a -3.4% (95% CI -3.7;-3.0) change in FHC and a -6.0% (-6.6;-5.5) change in FHC during provocation. The PFD was significantly higher with increasing Graf types and in displaceable hips (FHC <50%) (p<0.001)
Interpretation / Conclusion: PFD is strongly correlated to both alpha angles and hip displaceability, as measured by FHC and FHC during provocation, in ultrasound of newborn hips. The PFD increases as the hips become more dysplastic and/or displaceable.