Session 10: Sport Orthopaedics 2

Christian Dippmann, Vokert Siersma, Søren Overgaard, Michael Rindom Krogsgaard ,
Department for Orthopedic Surgery, Bispebjerg and Frederiksberg Hospital University of Copenhagen, Institute of Clinical Medicine Faculty of Health and Medical Sciences, and The Research Unit for General Practice and Section of General Practice, Department of Public Health, University of Copenhagen, Copenhagen.

Background: Patients with femoral-acetabular impingement syndrome (FAIS) in the presence of acetabular retroversion (AR) may be treated surgically by arthroscopy or reverse periacetabular osteotomy (PAO). The short and mid-term results after arthroscopic treatment are promising, but the evidence is mainly based on small, retrospective cohort studies.
Aim: The purpose of the present study was to investigate differences in results after arthroscopic treatment of FAIS between patients with and without radiographic signs of AR in a large, prospective cohort from the Danish Hip Arthroscopy Registry (DHAR). We hypothesized that there are no differences.
Materials and Methods: Data on 4,914 hip arthroscopies performed during 2012-2019 were obtained from DHAR. Patients with radiological signs of osteoarthritis (Tönnis > 1) or hip dysplasia (CE angle < 25 degrees) were excluded. The clinical outcomes for patients with AR (defined by a positive posterior wall sign (PWS) in combination with a positive Ischial Spine Sign (ISS)) and without AR (no PWS, no ISS) were analyzed one and two years after surgery. The primary outcomes were the six domains of the Copenhagen Hip and Groin Outcome score (HAGOS), while secondary outcomes were the Hip Sports Activity Scale (HSAS), a visual analogue pain scale (VAS) and a numeric rating scale (NRS) for pain. A total of 3,135 hip arthroscopies were included, of which 339 had AR, 1876 did not, and 920 had one of the two signs (PWS and ISS) present.
Results: No statistically significant differences (p > 0.05) between patients with and without AR were found in neither the primary outcomes (HAGOS domains) nor the secondary outcomes (HSAS, VAS, NRS), one and two years after surgery. Both groups showed clear improvement at both follow-ups compared to preoperative values.
Interpretation / Conclusion: The short-term outcome one and two years after arthroscopic treatment of FAIS in Denmark is not different for patients with and without AR.

Charlotte Anker-Petersen, Birgit Juul-Kristensen, Jarrod Antflick, Henrik Aagaard, Christopher Myers, Anders Ploug Boesen, Eleanor Boyle, Per Hölmich, Kristian Thorborg
Sports Orthopedic Research Center-Copenhagen, Department of Orthopedic Surgery, Amager-Hvidovre Hospital, Copenhagen University Hospital, Denmark; Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark; Tendon Performance, London, UK; Department of Orthopedic Surgery, Zealand University Hospital, Køge, Denmark; Complete Physio, London, UK

Background: In professional ballet dancers four out of five injuries are related to overuse and Achilles tendinopathy is the second most common overuse problem.
Aim: The objective was to investigate, first, whether six weeks of intensive ballet dance exposure is associated with structural and clinical changes in the Achilles tendon; second, the importance of demographics, self-reported Achilles pain, and generalized joint hypermobility (GJH).
Materials and Methods: Data were collected at baseline and at six weeks’ follow-up, using Achilles tendon ultrasound tissue characteristics (UTC) as primary outcome (percentage distribution of echo-type I-IV; type I=intact and aligned bundles, type II=discontinuous/wavy bundles, type III=fibrillar, type IV=amorphous cells/fluid). Secondary outcomes included clinical signs of Achilles tendinopathy, Achilles tendon pain during single-leg heel raise, self-reported symptoms (VISA-A questionnaire) and GJH.
Results: Sixty-three ballet dancers (aged 18-41) participated. From baseline to follow-up, UTC echo-type I decreased significantly (ß=-3.6, p=0.001; 95% CI: -5.8;-1.4), whereas echo-type II increased significantly (ß=3.2, p<0.0001, 95% CI: 1.6;4.8). Furthermore, a significant effect of limb (left limb showed decreased echo-type I and increased echo-type III+IV) and sex (women showed decreased echo-type I and increased in type II) was found. No significant changes in the remaining secondary outcomes were found.
Interpretation / Conclusion: Ballet dancers showed structural changes in UTC, corresponding to a decreased echo-type I distribution after six weeks of rehearsing for Swan Lake ballet. No changes in self-reported symptoms, clinical signs of Achilles tendinopathy and single-leg heel raise test were seen from pre- to post-rehearsal. Thus, structural changes in the Achilles tendon seem to appear earlier than clinical signs of tendinopathy.

Niels Christian Kaldau, Stewart Kerr, Steve McCaig, Per Hölmich
Sports Orthopedic Research Center - Copenhagen, Department of Orthopedic Surgery, Copenhagen University Hospital, Amager & Hvidovre Hospital, Denmark; Life Fit Wellness, Healthcare & Exercise Centre, Falkirk, Scotland, UK; Athlete Health Directorate, English Institute of Sport, Loughborough University, United Kingdom; Sports Orthopedic Research Center - Copenhagen, Department of Orthopedic Surgery, Copenhagen University Hospital, Amager & Hvidovre Hospital, Denmark

Background: In high demand sports like soccer and ice hockey there is a high prevalence of femoroacetabular impingement syndrome (FAIS) in youth populations which may predispose to OA. Internal rotation deficit in the hip of football players is a predictor of hip and groin pain compared to an asymptomatic population and differences in range of motion (ROM) of the hip may be a contributing risk factor for differences in lower extremity injuries between women and men. There are no published reference values for ROM and impingement in the hip of badminton players
Aim: To report ROM and impingement of the hip in elite junior badminton players and to report any differences between sex and between Asian and non-Asian players. Secondly to determine if any correlation exists between ROM, impingement and injury history
Materials and Methods: Players at the World Junior Badminton Championship in 2018 were examined in supine for hip flexion, internal- and external rotation and the impingement tests FADIR and FABER. Injury history was obtained from a questionnaire from the World Olympic Association
Results: Two hundred and eighty four players of 433 aged 16-18 years were examined. One hundred and forty three players answered the questionnaire. Females demonstrated greater hip ROM than boys in both sides. In the dominant side hip flexion was (137.7? (± 9.1) vs. 132.2? (± 11.1), p<0.001), IROM (60.0? (± 10.9) vs. 49? (±11.1), p<0.001) and EROM (57.9? (± 9.9) vs. 54.7? (± 8.9), 0.004). Hip flexion was higher in Asian players compared with non-Asian players (139.1? (± 8.4) vs. 130.3? (± 10.7), p<0.001). One hundred (35 %) players had at least one positive impingement test in the dominant or the non-dominant hip. A possible relationship between a positive FADIR and a decrease in hip flexion was found in the dominant hip, OR 1.06 (1.02- 1.11) p=0.005. A total of 104 injuries were reported with five hip related injuries. No correlation between injury and examinations was found
Interpretation / Conclusion: Females and Asians demonstrated higher ROM in the hip than males and non-Asians. Impingement of the hip is frequent and may be related to low hip flexion. Future studies are needed to examine if impingement is correlated with x-ray findings

Lasse Ishøi, Kristian Thorborg, Otto Kraemer, Bent Lund, Bjarne Mygind-Klavsen , Per Hölmich
Sports Orthopedic Research Center – Copenhagen (SORC-C), Department of Orthopedic Surgery, Copenhagen University Hospital, Amager-Hvidovre, Denmark ; H-HiP Research Center, Horsens Regional Hospital, Horsens, Denmark ; Department of Orthopedic Surgery, Aarhus University Hospital, Denmark

Background: Hip arthroscopy is effective for treatment of hip pain, but a detailed overview is lacking.
Aim: We aimed to classify causes of hip pain based on bony morphologies in patients having hip arthroscopy, and investigate corresponding cartilage injuries, 1-year outcomes, and surgical rates from 2012 to 2020.
Materials and Methods: In total, 5294 hip arthroscopies (no previous hip surgery) were identified in the Danish Hip Arthroscopy Registry. Six classifications were made: normal; cam; pincer; borderline dysplasia; cam and pincer; cam and borderline dysplasia. These were defined based on alpha angle (AA) (normal [AA <55] or cam [AA =55°]) and lateral center-edge angle (LCEA) (normal [25= LCEA =39°], pincer [LCEA >39°], or borderline dysplasia [LCEA <25°; 10 patients <20°]). Cartilage injuries were rated during surgery as none-to-mild (grade 0-2) and moderate-to-severe (grade 3-4). Self-reported symptoms were assessed with The Copenhagen Hip And Groin Outcome Score (HAGOS) 1-year post-surgery. Surgical rates were calculated for each classification as surgeries per year relative to total surgeries the same year.
Results: In total, 82.5 % had bony morphologies: cam (66.9 %); cam and pincer (6.3 %); cam and borderline dysplasia (5.9 %); pincer (1.9 %); borderline dysplasia (1.5 %). Remaining patients (17.5 %), all without deviant bony morphologies, were classified as normal. Patients with cam morphology had the highest proportion of grade 3-4 acetabular cartilage injuries: cam and borderline dysplasia (54.6 %); cam (46.5 %); cam and pincer (42.0 %). At 1-year, patients with pincer morphology had the highest HAGOS subscale scores (46.5 to 75.4 points), while borderline dysplasia patients had the lowest scores (22.4 to 56.9 points). Hip arthroscopies in patients with normal morphology showed a gradual increase from 7.7 % in 2012 to a plateau of 25 % in 2017-2020.
Interpretation / Conclusion: Data on hip arthroscopies in Denmark show that cam is the most prevalent morphology and is associated with the highest proportion of grade 3-4 cartilage injuries. Patients with borderline dysplasia have the worst 1-year outcome. Surgical rates in patients with normal morphology have increased from 2012 (<10 %), and now constitute 25 % of surgeries.

Signe Kierkegaard, Inger Mechlenburg, Ulrik Dalgas, Bent Lund
H-HiP, Department of Orthopaedic Surgery and Physio and Occupational Therapy, Horsens Regional Hospital; Department of Orthopaedics, Aarhus University Hospital and Department of Clinical Medicine, Aarhus University; Section for Sport, Department of Public Health, Aarhus University, Aarhus; H- HiP, Department of Orthopaedic Surgery, Horsens Regional Hospital

Background: Patients with femoroacetabular impingement syndrome (FAIS) often experience pain, decreased function and quality of life (QoL). Hip arthroscopy is used to treat the patients but long-term data on the surgical outcome are sparse.
Aim: We aimed to investigate clinical examination, radiographic assessment and patient-reported outcomes in patients with FAIS five years after hip arthroscopy.
Materials and Methods: Sixty patients (aged 36±9, 63% females) participated in the original HAFAI cohort and had hip arthroscopy in 2015-2016. Five years after surgery, patients were invited for a follow-up which included clinical examination by the surgeon (pain provocation test of m. psoas major, FADIR test (flexion, adduction and internal rotation) and FABER test (flexion, abduction and external rotation), standing anterior-posterior pelvic radiograph for assessment of the lateral joint space width (LJSW) and completion of the Copenhagen Hip and Groin outcome score (HAGOS) and the Hip Specific Sports Activity scale (HSAS).
Results: Twelve (20%) of 60 patients, had re- operations and 6 patients (10%) had a total hip replacement (THR). Forty-three patients were seen for clinical examination and x- ray. 53% of those had a positive pain provocation test, 36% had a positive FADIR test and 25% had a positive FABER test. In patients who did not convert to THR, LJSW was average 3.7±1.1 mm. Forty-seven patients completed HAGOS (Median [25th, 75th quartile]); Pain: 76 [65;93] , Symptoms: 71 [57;86], Activities of daily living: 85 [65;100], Sport: 66 [50;84], Participation in sport: 50 [25;75], QoL: 60 [45;80]. All HAGOS subscales improved compared with before surgery (p<0.001). The median [25th, 75th quartile] HSAS was 2 [1;3]. Patients with a positive FADIR test had significantly worse HAGOS subscales.
Interpretation / Conclusion: Five years after surgery, patients experienced mild pain and symptoms, were able to participate in physical activities and had radiographs showing an acceptable LJSW. However, clinical examination and scores for participation in sport and QoL indicated that patients still have problems related to the hip. This highlights the need for further research aiming to improve rehabilitation of these patients.

Camilla Richter, Lasse Ishøi, Otto Kraemer, Per Hölmich, Kristian Thorborg
Sports Orthopedic Research Center (SORC-C) – Copenhagen, Arthroscopic Center Hvidovre, Department of Orthopedic Surgery. Amager-Hvidovre University Hospital, Copenhagen, Denmark

Background: Specific bony hip morphologies, such as severe cam, dysplasia, and cartilage injuries result in inferior short-term patient-reported outcomes (<2 years), while their effect on mid- and long-term (=5-years) outcomes are unknown.
Aim: To investigate if changes in patient-reported outcome from pre- to 5 years post-surgery, is associated with pre-surgery bony hip morphology and cartilage status in patients with FAIS.
Materials and Methods: Patients were identified in the Danish Hip Arthroscopy Registry. Patient reported outcome was assessed with Copenhagen Hip and Groin Outcome Score (HAGOS). Hip and groin function were specifically assessed with HAGOS (ADL and Sport) at pre- and 5 years post-surgery. Multiple regression analyses assessed the adjusted associations between hip morphology and cartilage injuries with HAGOS ADL and Sport. Morphology was defined using Alpha Angle (AA) and (LCEA) in the following way: cam (55°78°); pincer (LCEA>39°); borderline dysplasia: (20º< LCEA<25°). Hip OA was defined by Joint Space Width (JSW): mild (3.1 mm.2 cm2.
Results: The study included 281 patients (mean ± SD age 35.53 ± 10.1 years, 52.3% females). For bony morphologies, no cam (ADL: ?16 points) and cam (ADL: ?7 points) was associated with larger improvements in HAGOS compared with severe cam, and so was no hip OA (HAGOS ADL: ?21 points) compared to OA. For cartilage injuries, femoral head cartilage injury area <1cm2 was associated with larger improvements in HAGOS (ADL: ?17 points, Sport: ?21 points) compared to patients with femoral cartilage area of >2cm2 (p<.05).
Interpretation / Conclusion: No severe cam morphology, no OA, and femoral head cartilage injury area <1 cm2 were associated with larger improvements in patient- reported outcome 5 years after hip arthroscopy compared to severe cam morphology, OA, and femoral cartilage injury area >2cm2.

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

Background: Approximately 50 % do not have acceptable symptoms (PASS) 1 year post hip arthroscopy. It is unknown whether pre-operative clinical information can be used to stratify care, so patients likely to have unsuccessful outcomes are not offered surgery. The first steps towards this is development and validation of reliable clinical prediction models.
Aim: We aimed to develop and validate clinical prediction models to identify patients with an unsuccessful or successful outcome 1 year post hip arthroscopy.
Materials and Methods: Patient records were extracted from the Danish Hip Arthroscopy Registry (DHAR). Outcomes were defined as unsuccessful/successful if patients did not have/had a score corresponding to PASS in any of the six subscales of the Copenhagen Hip and Groin Outcome Score (HAGOS) at 1-year post hip arthroscopy. A-priori, 26 common clinical variables from DHAR were selected, including demographics, radiographic parameters of hip morphology, and self-reported measures. We used a separate cohort of 1082 hip arthroscopy patients (surgery performed 25th April 2012 to 4th October 2017). to develop the clinical prediction models. Subsequently, we externally validated predictive performance of the models in a separate cohort of 464 hip arthroscopy patients (surgery performed 5th October 2017 to 13th May 2019).
Results: For unsuccessful outcomes, predictive performance on the external validation dataset showed adequate calibration and acceptable discrimination (AUC: 0.75, 95 % CI [0.70-0.80]) with sensitivity and specificity ranging 0.0-0.97 and 0.2-1.0, respectively, depending on the risk threshold. For successful outcomes, predictive performance showed adequate calibration, but poor discrimination (AUC: 0.679, 95 % CI [0.625-0.733]).
Interpretation / Conclusion: Common clinical variables were able to predict patients with an unsuccessful outcome 1-year after hip arthroscopy. This clinical prediction model can be used to support clinical evaluation and shared decision making by informing the orthopedic surgeon and patient about the risk of an unsuccessful outcome, and thus when surgery may not be appropriate. This may reduce unsuccessful outcomes and could therefore improve the overall outcome of hip arthroscopy in the future.