Session 12: Sports orthopedics

17. November
13:30 - 15:00
Lokale: Vingsal 3
Chair: Annika Winther and Bjarne Mygind

91. Ten years with a standard treatment algorithm for patellofemoral instability and trochlea dysplasia in a Danish population – general experience and 5 years outcome
Christian Dippmann¹, Peter Lavard¹, Volkert Siersma², Anette Kourakis¹, Michael Rindom Krogsgaard¹
1 Section for Sports Traumatology M51, Bispebjerg and Frederiksberg Hospital. A part of IOC Research Center Copenhagen, Denmark. 2 The Research Unit for General Practice and Section of General Practice, Department of Public Health, University of Copenhagen, Denmark.

Background: Patellofemoral instability is often caused by predisposing factors, of which trochlea dysplasia is the most common. Patellar instability leads to impaired function and increased risk of osteoarthritis. The treatment of trochlea dysplasia has been centralized in Denmark during the last decade at two hospitals. At Bispebjerg Hospital the treatment has been based on a algorithm and more than 350 trochleoplasties have been performed during this period.
Aim: The purpose of this study was to report our experience 10 years after introducing a treatment algorithm in this prospective patient series, including long-term results at 5-years follow-up.
Materials and Methods: Prospectively collected data from August 2009 to August 2016 for all patients undergoing open trochleoplasty (TP) as well as the combinations of accompanying surgical procedures, such as MPFL reconstruction (MPFL-r), medialization/distalization of the tibial tuberosity (ET), femoral/tibial osteotomy, etc., was analyzed. Before surgery patients had clinical examination and MRI-scan and completed four patient-reported outcome measures (PROMs) (Kujala, KOOS, Lysholm and IKDC). One, two, five and ten years after surgery all patients were scheduled for clinical control, MRI-scan and completion of the four PROMs. We report data for the 5-year follow-up.
Results: During the period, 115 TP were performed in 106 patients (36 males, 70 females). Average age: 22 yrs (range 12-41yrs). 3 knees had TP+ET (2,6%), 3 knees (2,6%) had an isolated TP. 49 knees (42,6%) had TP + MPFL-r, while 60 knees (52,2%) received TP+MPFL+1 other procedures. 40 knees (34,8%) had further surgery (19 brisement force, 4 isolated MPFL-r, 8 isolated amotio atellae and 9 other). Following our algorithm only one patient (1%) suffered from re-dislocation of the patella. After five years there was a significant improvement in all PROMS (p<0.01), when adjusted for age, treatment before and treatment after operation.
Interpretation / Conclusion: 10-years after introduction a standard treatment algorithm for patella instability excellent 5-yr results can be seen with high patient satisfaction and a very low dislocation rate.

92. Incidence of arthroscopic resection of cyclops lesions within two years after an ACL reconstruction and the influence of surgical technique changing. An analysis of 2,608 patients in the period 2005-2019.
Lene Lindberg Miller¹ ³ , Torsten Grønbech Nielsen¹ ³ , Inger Mechlenburg¹ ², Martin Lind¹ ²
Department of Orthopedics, Aarhus University Hospital, Denmark¹; Department of Clinical Medicine, Aarhus University, Denmark²; Department of Physiotherapy and Occupational Therapy, Aarhus University Hospital³

Background: After an ACL reconstruction (ACLr) scar tissue/arthrofibrosis may develop. This type of arthrofibrosis is named cyclops lesion and was first described in the 1990’s. The cyclops lesion is situated anterior to the reconstructed graft and may cause knee extension deficit, pain, oedema, clicking and reduced knee function.
Aim: To determine the incidence of arthroscopic resection of cyclops lesion within two years after ACLr through a period of 15 years. Furthermore, to investigate which patient demographics and changes in surgical techniques in this period that could be related to the need of arthroscopic resection of cyclops lesion.
Materials and Methods: This cohort study was based on patients who had a primary ACLr with adult surgical technique from 2005-2019 at Aarhus University Hospital. The cohort was identified in the Danish Ligament Reconstruction Register. To identify patients who had resected a cyclops lesion within the first two years after ACLr patients’ surgical records were reviewed. The results will be presented as incidence with a 95% CI.
Results: In the period from 2005-2019 2,608 patients had primary ACLr with two-year follow-up. During the follow-up period, 177 patients had a cyclops lesion arthroscopically resected, equivalent to an incidence of 6.8% (95%CI 5.9;7.8). The incidence in females was 8.3% (95%CI 6.7;10.0) and in men 5.7% (95%CI 4.6;7.0) with a risk ratio of 1.44 (95%CI 1.1;1.9). The incidence of resected cyclops lesion in patients who had ACLr with an anteromedial technique was 8.9 % (95%CI 7.7;10.3) and transtibial technique 1.9% (95%CI 1.0;3.1) with a risk ratio of 4.7 (95%CI 2.8;7.9). The incidence of arthroscopic resection of cyclops lesion was similar among patients with different choice of graft, and with or without cartilage or meniscal lesions.
Interpretation / Conclusion: The incidence of arthroscopic resection of cyclops lesion after ACLr was 6.8%. Females have 44% higher risk of getting resection of a cyclops lesion compared to men. When using the anteromedial technique compared to transtibial technique the risk is almost 5 times higher of receiving an extra arthroscopy with resection of cyclop lesion. These findings are important when deciding on ACLr technique, especially in females.

93. Epiphyseal drilling in Femur reduces growth Disturbance in Pediatric ACL Reconstruction
Peter Faunø, Torsten Grønbech Nielsen, Jannie Bøge Larsen, Michel Bach Hellfritzsch, Mette Mølby Nielsen, Martin Lind
Sports Trauma, Dept of Orthopedics, Aarhus University Hospital.

Background: Anterior Cruciate Ligament Reconstruction (ACLR) in skeletally immature patients can result in growth plate injury, which may cause growth disturbances
Aim: The aim was to evaluate radiological tibial and femoral length and axis growth disturbances as well as clinical outcome in skeletal immature ACLR patients treated with a femoral growth plate sparing ACL- reconstruction technique.
Materials and Methods: Sixty-five skeletal immature patients, who had ACL reconstruction in the period 2013- 2019 were investigated with radiology, knee stability measurements and patient-reported outcomes measures after growth plate closure with a minimum 29 months follow- up. Patients were evaluated with full extremity radiographs, measuring leg length discrepancy and malalignment compared to contralateral leg. Clinical evaluation with KT1000 measurements and KOOS and Tegner scores. The follow-up time was 68 (29-148) months.
Results: There was a statistically significant angular deformity at distal femur compared to contralateral leg. No limb-length discrepancy or angular deformity at tibia was found. We found 2,4 mm side to side difference laxity at follow-up and IKDC score of 86,2.
Interpretation / Conclusion: The present hybrid physis sparing technique did not affect limb-length discrepancy. Despite crossing of tibial physis, no angular deformity at tibia was seen. A small femoral angular deformity was seen despite no crossing of femoral physis.

94. Revision rates and clinical outcomes between fixed- and adjustable-loop devices for femoral fixation in anterior cruciate ligament reconstruction – A systematic review and meta-analysis
Simone Elmholt, Torsten Nielsen, Martin Lind
¹ Department of Orthopedics, Aarhus University Hospital

Background: Button implants with either fixed-loop device (FLD) or adjustable-loop device (ALD) are used frequently in Anterior Cruciate Ligament Reconstruction (ACLR). Since revision, ACLR is associated with poorer clinical outcomes, investigating the difference in risk of revision between FLDs and ALDs is important.
Aim: To systematically assess the risk of revision ACLR between ALDs and FLDs, as well as secondary outcomes of knee stability and patient-reported outcomes (PROMs).
Materials and Methods: The online databases Embase, Medline (PubMed) and SPORTDiscus were searched to identify studies, comparing FLDs and ALDs for femoral fixation in patients undergone primary ACLR with hamstring autografts. Risk of bias was assessed with the Robin-I tool for non- randomized studies. The risk of revision ACLR is presented as an Odds Ratio (OR). The mean difference (MD) in knee side-to- side stability (SSD) was assessed at 2- years follow-up. The MD in PROMs was evaluated with the Lysholm score and the International Knee Documentation Committee (IKDC) score at 2-years follow- up. A random-effect meta-analysis were performed for the secondary outcomes and the quality of evidence was evaluated by the GRADE approach.
Results: Fifteen cohort studies were included with a total of 2686 patients. One study with 1654 patients compared the risk of revision ACLR with an OR of 0.521 (95% CI: 0.240-1.132) lower for the ALD. Four studies with 357 patients reported the knee SSD at 2-years follow-up and the ALDs had an SSD of -0.15mm lower (95% CI: -0.54-0.24) compared to FLD. The MD in IKDC score was 0.48 points higher for ALDs reported by six studies with 446 patients. For the Lysholm score the ALDs had a 0.17 points higher score compared to the FLDs reported by seven studies with 563 patients. The quality of evidence was either low or very low due to study designs, risk of bias and heterogeneity.
Interpretation / Conclusion: There was no difference in knee stability and PROMs between the ALDs and FLDs, however, the interpretation of these results is challenging due to low quality of evidence. More studies investigating the risk of revision ACLR between ALDs and FLDs are needed.

95. Knee-related Quality of Life, Symptoms, Pain, and Function in Sport and Recreational activities in adults with a history of adolescent Osgood-Schlatter: A registry-based cross-sectional study
Amalie Bjerre Jørgensen¹,² , Per Hölmich²,³ , Kristian Thorbrg²,³ , Lasse Christensen4, Mathias Nielsen², Kasper Krommes²
¹Faculty of Physiotherapy, Center of Nutrition and Rehabilitation, University College Absalon, Roskilde, Denmark. ²Sports Orthopedic Research Center – Copenhagen (SORC-C), Department of Orthopedic Surgery, Copenhagen University Hospital, Amager- Hvidovre, Denmark. ³Department of Clinical Medicine, University of Copenhagen, Denmark. 4Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark

Background: Osgood-Schlatter is a common growth-related injury in adolescence and can cause persistent pain, decreased function, and reduced participation in physical activity. However, little is known about the long-term consequences for knee-related health for these patients in adulthood
Aim: To investigate long-term consequences for self- reported knee health of adults diagnosed with Osgood-Schlatter in adolescence compared to normative values from healthy age-matched populations
Materials and Methods: We included patients aged 18-55y, diagnosed in Danish secondary care with Osgood-Schlatter during the years 1977-2020, from the Danish National Patient Registry. They were invited to complete a survey. Knee-related health was self- reported on the Knee Injury and Osteoarthritis Outcome Score (KOOS) on four subscales: Quality of Life (QoL), Symptoms, Pain, and Sport/Rec. Mean responses were grouped according to pre-specified age groups (18-24, 25-34, 35-44, 45-55 years) and compared to age-matched normative KOOS values derived from a healthy cohort (Williamson et al., 2015, n=1000)
Results: 400 participants completed the survey (mean age 33.8±13y, 65% men). All mean subscale scores were lower for the surveyed group compared to the healthy cohort. Mean differences between the two groups were (female/male): QoL subscale: 36/19 points (18-24y), 25/27 points (25-34y), 26/33 points (35-44y), 25/23 points (45-55y); Symptom subscale: 15/8 points (18-24y), 8/9 points (25-34y), 18/11 points (35-44y), 10/11 points (45-55y); Pain subscale: 19/9 points (18-24y), 11/12 points (25- 34y), 13/15 points (35-44y), 16/10 points (45-55y); Sport/Rec subscale: 36/19 points (18-24y), 30/28 points (25-34y), 38/31 points (35-44y), 33/26 points (45-55y)
Interpretation / Conclusion: People diagnosed with Osgood-Schlatter in adolescence have decreased self-reported knee health in adulthood when compared to healthy populations. Clinically relevant differences were seen, especially in terms of Quality of Life and Function in Sport and Recreational activities. Future studies should address the need for mitigating the potential long-term consequences of this condition and investigate a potential causal relationship between exposure from Osgood-Schlatter and long-term outcomes

96. Factors increasing the risk of ACL-reconstruction after ACL-injury
Hanne Hornshøj¹, Carsten Juhl¹ ², Bob Fjelstad Larsen¹,
¹Department of Physiotherapy and Occupational Therapy, Copenhagen University Hospital, Herlev and Gentofte, Copenhagen, Denmark ²Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark

Background: Knee trauma resulting in anterior cruciate ligament (ACL) injury are treated with inter- disciplinary rehabilitation (based on exercise and information) or ACL-reconstruction (ACLR) followed by rehabilitation.
Aim: To identify factors associated with increased risk of ACLR after an ACL-injury and evaluate patient satisfaction.
Materials and Methods: Included patients were offered a 6-weeks in- hospital rehabilitation at Herlev & Gentofte Hospital. The factors investigated included patient characteristics (age, sex), specific tests (Rolimenter, Lachmans test, pivot shift test, anterior drawer test) and patient reported outcomes (Patient Specific Function Score (PSFS), Knee Injury and Osteoarthritis Outcome Score (KOOS), Lysholm, Tegner and functional test (single leg hop test and side-hop test). Risk of ACLR was investigated in a univariate logistic regression analysis and presented as Odds Ratio (OR) with 95% CI. Patient satisfaction was evaluated as the patient acceptable symptom state (PASS) and treatment failure (TF).
Results: From February 2015 to February 2017, 152 participants were included in the cohort. Of these 49 received ACLR. The ACLR group was younger (29 vs. 37 years, were predominately male (61 vs. 39 %), had higher pre-injury activity (Tegner 6.82 vs 6.22), higher laxity (Rolimeter 4.1 mm vs 3.0 mm), had more often swelling after the in- hospital evaluation (58% vs. 33%) compared to the non-ACLR group. There was increased risk of ACLR being male (OR: 2.49, 95% CI 1.24 to 5.00), had higher pre- injury activity (Tegner) (OR: 1.37, 95% CI 1.06 to 1.77), had higher laxity (Rolimeter) OR: 1.27, 95% CI 1.07 to 1.50) and reduced risk with increasing age (OR: 0.93, 95% CI 0.90 to 0.96). The PASS was 61% after rehabilitation and 65% after ACLR. The corresponding values for TF was 5 and 8%. Only 3 of the 103 in the exercise-based intervention changed decision and received ACLR at follow-up (after 1-2 years).
Interpretation / Conclusion: Younger age, male sex, higher pre-injury activity level, higher laxity and swelling at 6 weeks (follow-up after rehabilitation) increase the risk of ACLR in participants with ACL injury following a 6 weeks in-hospital rehabilitation and evaluation. Similar patient satisfaction was achieved

97. Objectively measured knee instability during Pivot-shift test. An experimental Dynamic RSA study
Tobias Vind¹ ², Emil Toft Petersen¹ ², Ole Gade Sørensen³ 4, Lars Lindgren5, Maiken Stilling¹ ² ³
Department of Clinical Medicine, Aarhus University¹; AutoRSA Research Group, Orthopaedic Research Unit, Aarhus University Hospital²; Department of Orthopaedic Surgery, Aarhus University Hospital³; Division of Sports Trauma, Orthopaedic Department, Aarhus University Hospital4; Department of Radiology, Aarhus University Hospital5

Background: The Pivot-shift test is a clinical test for knee instability for patients with Anterior cruciate ligament (ACL) lesions, however the test has low inter-observer reliability. Dynamic radiostereometry (dRSA) imaging is a highly precise non-invasive method for objective evaluation of joint kinematics.
Aim: The aim of this study was to quantify precise knee kinematics by use of dRSA imaging during Pivot-shift test in knees with intact ligaments, in knees with ACL lesion, and in knees with a combined ACL and ALL lesion.
Materials and Methods: Eight human donor legs with hemipelvis were evaluated. Ligament lesion intervention of the ACL was performed during arthroscopy and anterolateral ligament (ALL) section was performed as a capsular incision. Pivot-shift test examination was recorded with dRSA on ligament intact knees, ACL-deficient knees and ACL+ALL-deficient knees.
Results: A Pivot-shift pattern was identifyable after ligament lesion as a change in tibial posterior drawer velocity from 7.8 mm/s (CI95 3.7; 11.9) in ligament intact knees, to 30.4 mm/s (CI95 23.0; 38.8) after ACL lesion, to 35.1 mm/s (CI95 23.4; 46.7) after combined ACL-ALL lesion. The anterior- posterior drawer excursion increased from 2.8 mm (CI95 2.1; 3.4) in ligament intact knees, to 7.2 mm (CI95 5.5; 8.9) after ACL lesion, to 7.6 mm (CI95 5.5; 9.8) after combined lesion. Furthermore a change in tibial rotation was found, with increasing external rotation at the end of the Pivot-shift motion going from intact to ACL+ALL- deficient knees.
Interpretation / Conclusion: This experimental study demonstrates the feasibility of dRSA to objectively quantify the kinematic laxity patterns of the knee during the Pivot-shift test. The dynamic parameters found through dRSA displayed the kinematic changes from ACL to combined ACL-ALL ligament lesion.

98. Microfragmentation for processing stem cells from adipose tissue is promising when compared to enzymatic digestion for the treatment of osteoarthritis
Jasmin Bagge¹ , Per Hölmich¹, Jan Nehlin², Lars Blønd³, Lisbet Rosenkrantz Hölmich4, Kristoffer Weisskirchner Barfod¹
Sports Orthopedic Research Center – Copenhagen (SORC-C), Department of Orthopedic Surgery, Copenhagen University Hospital – Hvidovre, Denmark¹, Department of Clinical Research, Copenhagen University Hospital – Hvidovre, Denmark², Department of Orthopedic Surgery, Zealand University Hospital – Køge, Denmark³, Department of Plastic Surgery, Copenhagen University Hospital – Herlev and Gentofte, Denmark4

Background: Intraarticular treatment of knee osteoarthritis with adipose tissue-derived stem cells has shown promising results. Until now, standard processing of lipoaspirates for therapeutic use consists of enzymatic digestion (ED) and cell expansion prior to injection. However, complex regulatory issues related to the application of enzymatically treated and expanded cells have led to development of microfragmentation (MF) to harvest stem cells ready for treatment.
Aim: To assess quantity and viability of stem cells from abdominal adipose tissue (AT) when processed with MF compared to ED.
Materials and Methods: Abdominal AT from knee osteoarthritis patients was processed with MF and ED, respectively. Cell type, quantity, and viability was investigated using trypan blue staining and flow cytometry. Statistical analysis was performed using paired t- tests. p-values <0.05 were considered statistically significant.
Results: AT from 15 patients, age (mean (SD) 50.9 (8.5)), were analyzed. ED provided more nucleated cells 3.9x10^6/mL (2.5x10^6) than MF 1.0x10^6/mL (0.5x10^6), p<0.01. Also, ED gave higher nucleated cell viability 90% (4%) compared to MF 80% (6%), p<0.01. Using flow cytometric gating on stem cells, equally high viability was identified for ED 82% (4%) and MF 84% (3%), p=0.17. There was higher stem cell content per total nucleated cell count for MF 10% (2%) compared to ED 6% (2%), p<0.01. Adventitial stem cells (CD31-/CD45-/CD34+/CD146-), pericytes (CD31-/CD45-/CD34-/CD146+), mesenchymal stem cells (CD34-/CD45-/CD146-/CD90+/CD105+), and CD271+ stem cells (CD31-/CD45-/CD90+/CD271+) were identified in microfragmented AT.
Interpretation / Conclusion: Microfragmentation is a promising method to harvest clinically relevant stem cells from adipose tissue for treatment of osteoarthritis.

99. Prolonged effect (>1 day) after ultrasound guided intraarticular injection with local anesthesia and glucocoricosteroids prior to hip arthroscopy for femoro-acetabular impingement syndrome (FAIS) is not associated with suboptimal outcome
Christian Dippmann1, Finn Johansen3, Volkert Siersma2, Michael Rindom Krogsgaard1
1 Section for Sports Traumatology M51, Bispebjerg and Frederiksberg Hospital. A part of IOC Research Center Copenhagen, Denmark. 2 The Research Unit for General Practice and Section of General Practice, Department of Public Health, University of Copenhagen, Denmark 3 Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery , Bispebjerg-Frederiksberg Hospital, Denmark

Background: Ultrasound guided intraarticular injection (UGII) with local anesthesia (LA) is frequently used to confirm joint related hip pain in patients with femoro- acetabular impingement syndrome (FAIS). In combination with glucocorticosteroid (GCS) a prolonged pain relief (>1 day) can be seen, which may indicate concomitant inflammatory or degenerative joint pathologies.
Aim: In a previous study we could show that individuals with a steroid effect presented a significant higher prevalence of severe cartilage injuries (IKDC grad 3+4) intraoperatively. The purpose of this study was to analyze if a pre-operative steroid effect prior to hip arthroscopy is associated to a less favorable outcome.
Materials and Methods: From June 2016 to June 2021 194 consecutive patients with clinical and/or radiological signs of FAIS and a positive UGII with LA and GCS underwent hip arthroscopy. 184 patients (68 males, 116 females) were included in this study. Two patients did not meet the inclusion criteria. For 8 patients the HAGOS scores at 1-year follow-up were disregarded as they had new surgery within the one year post-operatively. Intraoperative findings were documented and all patients completed HAGOS pre- and 12 months post-operatively.
Results: 112 patients had a prolonged UGII effect, while 72 patients had an isolated LA effect. Intraoperatively patients with a prolonged UGII had a significantly higher prevalence of severe cartilage injuries (IKDC 3+4) compared to those with an isolated LA effect. However, adjusted for age, sex and underlying pathologies no clinical difference in HAGOS (n.s.) could be seen 1 yr after surgery.
Interpretation / Conclusion: Pain relief beyond the effect of local anesthesia after an UGII with local anesthesia and glucocorticosteroid may indicate severe cartilage injuries. However, this seems not to affect the clinical outcome after one year.

100. Screw resorption and tibial tunnel changes after Biosure Regenesorb absorbable interference screw hamstring graft fixation for anterior cruciate ligament reconstruction
Martin Lind 1, Torsten Nielsen 1, Flemming Kromann Nielsen 2, Peter Faunø 1, Ole Gade Sørensen, Bjarne Mygind-Klavsen
1. Aarhus University Hospital Dept of Orthopedics 2. Aarhus University Hospital Dept of Radiology

Background: Absorbable interference screws for graft fixation during anterior cruciate ligament reconstruction (ACLR) can lead to tunnelwidening and cyst formation due polymer degradation. A novel absorbable Interference screw Biosure Regenesorb (Smith&Nephew) has been developed with an optimized calcium phosphate/polymer composition to promote bone formation during its resorption.
Aim: The present study aims to investigate bone formation, tunnel geometry and screw resorption in tibial tunnels after ACLR.
Materials and Methods: The study is a prospective single-center case series of 11 patients with ACL lesion and with objective symptomatic knee instability treated with ACL reconstruction using hamstring tendon autograft with Biosure Regenesorb tibial fixation with 1 year follow-up. The Biosure Regenesorb consist of 65 % PLGA poly, 20 % calcium sulphate, 15 % tricalciumphosphate. The primary endpoint: Tunnel volume, Implant volume and new bone formation in the tibial tunnel is evaluated by quantitative CT scanning. The secondary endpoints: Objective Lachman knee side-to-side laxity measured by KT- 1000 arthrometry, subjective outcome by IKDC and KOOS scores, and Tegner Activity scale.
Results: Tunnel volume increased 1 % after one year. Only minor amount (< 1 % of tunnel volume) of new bone formation in the screw remnants and screw treads was see. The screw volume decreased to 46 % with in the first year. For secondary outcomes sagittal knee laxity at one year was 0.9 mm. IKDC score increased 15 points and KOOS sport and KOOS QoL scores increased 25 and 26 points respectively.
Interpretation / Conclusion: ACLR with tibial graft fixation using Biosure Regenesorb does not result in tunnel widening with a screw resorption of 46 % after one year and with only minor new bone formation. Knee stability and subjective outcome improvements are excellent and reflects best results after other ACLR methods.