Session 12: Sports Medicine I

Anders Bøvling, Rune D Bech, Bertel Understrup, Bjarke Viberg
Department of Orthopaedic Surgery and Traumatology, Odense University Hospital; Department of Orthopaedic Surgery and Traumatology, Odense University Hospital; Department of Orthopaedic Surgery and Traumatology, Odense University Hospital; Department of Orthopaedic Surgery and Traumatology, Odense University Hospital


Background: Radiographic measurements are frequently used for the assessment of knee dysplasia and patella height especially in patients with patella instability but the literature is scarce on the reliability.
Purpose / Aim of Study: To estimate the reliability of the Dejour Classification (DC), Anterior Translation (AT), Trochlea Depth (TD), Caton-Dechamps Index (CDI), Insall-Salvati Index (ISI), and the Blackburne-Peel Index (BPI).
Materials and Methods: A search for DS830 was conducted in the county database. X-rays were reviewed for applicability and 115 x-rays was acceptable for measurements. 4 raters independently measured the x-rays 2 times with a minimum of 14 days apart according to GRRAS guidelines. The raters were one medical student, two residents, and one consultant in knee arthroscopi. Unweighted kappa statistics was applied and prior to measurements a sample size of minimum 105 x- rays was estimated. The Landis and Koch interpretation of kappa values is <0 poor, 0.01- 0.20 slight, 0.21-40 fair, 0.41-0.60 moderate, 0.61-0.80 substantial, and 0.81-1.00 almost perfect agreement
Findings / Results: Intrarater kappa results ranged from 0.19-0.55 for DC, -0.01-0.70 for AT, 0.31-0.85 for TD, 0.12-0.70 for CDI, 0.63-0.85 for ISI, and 0.24-0.57 for BP. There was a tendency for the medical student in general to have lower kappa values compared to the other raters. Interrater kappa results ranged from 0.07-0.36 for DC, -0.08-0.60 for AT, 0.14-0.70 for TD, 0.10-0.58 for CDI, 0.59-0.71 for ISI, and 0.07-0.30 for BP. There was no tendency for lower kappa values with higher experience.
Conclusions: The only measurement with substantial reliability was ISI. All other measurements seem to be unreliable for use in clinical research.

Emil T. Nielsen, Kasper Stentz-Olesen, Sepp de Raedt, Peter Bo Jørgensen, Ole G. Sørensen, Bart Kaptein, Michael S. Andersen, Maiken Stilling
Orthopedic Research Department, Aarhus University Hospital; Orthopedic Research Department, Aarhus University Hospital; , Nordisk Røntgen Teknik; Orthopedic Research Department, Aarhus University Hospital; Department of Sportstraumatology, Aarhus University Hospital; Biomechanics and Imaging Group at Department of Orthopedic Surgery, Leiden University Medical Center; Department of Mechanical Engineering and Manufacturing, Aalborg University; Department of Clinical Medicine, University of Aarhus


Background: Anterior cruciate ligament (ACL) rupture often occurs during internal rotation knee trauma and may be associated with damage to extracapsular knee rotation-stabilizing structures, such as the anterolateral ligament (ALL).
Purpose / Aim of Study: To investigate knee rotation stability with and without ALL reconstruction as a supplement to ACL reconstruction surgery.
Materials and Methods: Eight cadaver knees were recorded with dynamic radiostereometry during a pivot-like dynamic movement simulated by a constant internal tibial rotation during knee flexion (0° to 50°). The cadavers were tested in five successive ligament situations: intact, ACL lesion, ACL+ALL lesions, ACL reconstruction, and ACL+ALL reconstruction. The knee stability was determined by three-dimensional kinematics and articular surface interactions.
Findings / Results: For the entire motion, resecting the ALL caused increased instability (p<0.014) for all degrees of freedom. The largest effects of ALL resection were found for external-internal rotation (EI), anterior- posterior translation (AP), and proximal-distal (PD) translation. Reconstruction of the ALL caused increased stability (p<0.001) for all degrees of freedom, except varus/valgus. Evaluating knee laxity in 10° ranges of knee flexion for ACL and ALL lesions against ligament intact knees, knee instability was largest for knee flexion below 30° (p<0.035). Combined ACL and ALL reconstructions were unable to completely restore native kinematics/stability at flexion angles below 10° (EI,PD) and 20° (AP) (p<0.02).
Conclusions: Adjuvant reconstruction of the ALL with ACL reconstruction in a cadaver setting provides internal rotation knee stability similar to knee kinematics with intact ligaments, except in knee flexion between 0° to 20°.

Niclas Højgaard Eysturoy, Torsten Grønbech Nielsen, Martin Carøe Lind
Sportstrauma Division, Department of Orthopedics, Aarhus University Hospital, Aarhus.; Sportstrauma Division, Department of Orthopedics, Aarhus University Hospital, Aarhus.; Sportstrauma Division, Department of Orthopedics., Aarhus University Hospital, Aarhus.


Background: The method of graft fixation in primary anterior cruciate ligament (ACL) reconstruction is important for the initial stability of the graft. Poor graft fixation can result in failure of the reconstruction.
Purpose / Aim of Study: This study investigates the early risk of revision depending on graft fixation principle and the most frequently used combinations of graft fixation implants.
Materials and Methods: Revision rates and graft fixation method was extracted from The Danish ACL Reconstruction Registry (DKRR). Analyses included hamstring tendon- (HT) and patellar tendon grafts (BPTB). Revisions after 2 years and multiligament reconstructions were excluded. 14.935 patients were included in the study. Failure outcome was 2-years revision rate. We extracted data from both principle of graft fixation in the femur and all implant combinations represented by more than 175 patients.
Findings / Results: Analysis of fixation principles demonstrated that a non-adjustable suspension technique had a higher higher risk of revision (RR=1,27, P<0,05), while the transfixation technique had a lower risk (RR:0.78). Comparing frequent fixation combinations, Endobutton/Biosure PEEK (RR: 1,36, P<0,05) and Endobutton/Intrafix Bio (RR:1,55, P<0,05) had higher risk for revision (HT). Atlantec metal screw/metal screw (RR: 0,83, P<0,05) and Softsilk/Softsilk (RR:0,73, P<0,05) had a lower risk for revision (BPTB).
Conclusions: A non-adjustable suspension fixation technique has a higher risk, while transfixation has a lower risk of revision within 2 years after a primary ACL reconstruction. For HT reconstructions, the fixation combinations of Endobutton/BioSure PEEK and Endobutton/Intrafix had a higher risk, while for BPTB reconstructions Atlantec metal screw/metal screw and Softsilk/Softsilk screw had a lower risk of revision.

Andrea Mosler, Adam Weir, Cristiano Eirale, Per Hölmich, Kay Crossley
Aspetar, Aspetar, Doha Qatar; Aspetar, Aspetar; Aspetar, Aspetar; SORC-C & Aspetar, Department of Orthopedics, Hvidovre Hospital; La Trobe University, Victoria, Australia, La Trobe University, Victoria, Australia


Background: Football groin injury epidemiology has previously been examined in a single team, or a selection of teams, but not encompassed an entire professional football league.
Purpose / Aim of Study: To investigate the epidemiology and characterize groin injuries sustained in the Qatar Stars league (QSL).
Materials and Methods: All QSL teams were observed prospectively during 2013-15. Time loss injuries, individual training and match play exposure were recorded by club doctors using standardised surveillance methods. Incidence of groin injury per 1000 playing hours was calculated, and descriptive statistics used to determine the prevalence and characteristics of groin injuries. Severity was defined as; minimal (1-3 days), mild (4-7 days), moderate (8-28) days) and severe (>28 days). All groin injuries were categorized using the Doha agreement classification system.
Findings / Results: 606 male footballers from 17 clubs were included. There were 206/1145 (18%) time loss groin injuries sustained by 150 players. Incidence was 1.00/1000 h and prevalence 21% of players (IQR 9-31%) per club per season, equivalent to 6 (IQR 3-9) groin injuries sustained per average club roster. Of the 206 injuries, 15% were minimal, 27% mild, 40% moderate and 18% severe, with a median absence of 10 days/injury (IQR 5-22days). The median numbers of days lost due to groin injury for each team was 88days (IQR 44-215days). Adductor-related groin pain was the most common entity (68%) followed by iliopsoas (12%) and pubic (9%) related groin pain.
Conclusions: Groin injury had high prevalence, significant time loss and adductor-related groin pain was the most common entity. Injury prevention programs should therefore focus on preventing adductor- related groin pain in football.

Andreas Serner, Adam Weir, Johannes L Tol, Kristian Thorborg, Frank Roemer, Ali Guermazi, Per Hölmich
Sports Groin Pain Center, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar; Sports Groin Pain Center, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar; Sports Groin Pain Center, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar; Sports Orthopaedic Research Center–Copenhagen (SORC-C), Department of Orthopedic Surgery, Copenhagen University Hospital, Amager-Hvidovre, Denmark; Department of Radiology, University of Erlangen-Nuremberg, Erlangen, Germany; Quantitative Imaging Center (QIC), Department of Radiology, Boston University School of Medicine, Boston, MA, USA; Sports Orthopaedic Research Center–Copenhagen (SORC-C), Department of Orthopedic Surgery, Copenhagen University Hospital, Amager-Hvidovre, Denmark


Background: MRI can be used in the diagnosis of acute groin injuries in athletes, however, as MRI is not readily available for many clinicians, further investigation of the association between clinical examination tests and the presence of MRI injuries and their location is required.
Purpose / Aim of Study: To investigate whether clinical examination tests predict a positive or negative MRI result (MRI+/-), and to assess accuracy of clinical tests to localise injury in MRI+ cases.
Materials and Methods: We consecutively included 81 male athletes with acute groin injuries. Standardized clinical examination (palpation, resistance, and stretch tests) and MRI were performed within 7 days of injury. Diagnostic statistics including positive and negative predictive values (PPV/NPV) were calculated.
Findings / Results: 85 acute injuries were found on MRI in 64 athletes with 17(21%) athletes having MRI- injuries. Palpation had highest NPV (91-96%, [95%CI 69-99]). Three specific adductor examination tests (resisted outer-range adduction, squeeze test - hip neutral and long lever, and passive adductor stretch) showed 80-81% (95%CI 63-91) probability of an MRI+ adductor lesion when positive, all with high accuracy of a correct MRI location (PPV 93-97% [95%CI 76-100]). Hip flexor tests showed poor ability to predict MRI+ lesions (PPV 34-63% [95%CI 20-84]), and low accuracy (PPV 17-71% [95%CI 7-85]).
Conclusions: 21% of athletes had negative imaging and the absence of palpation pain was best at predicting an MRI- result. Specific adductor examination tests were accurate for confirming MRI+ adductor injuries. Hip flexor clinical tests were poor at predicating and localising MRI+ injuries in the hip flexors. Clinical examination therefore appears sufficient to diagnose acute adductor injuries, whereas MRI could assist in accurately locating acute hip flexor injuries.

Kristoffer Weisskirchner Barfod, Julian A Feller, Ross Clark, Taylor Hartwig, Brian M Devitt, Kate E Webster
OrthoSport Victoria Research Unit, Deakin University and Epworth HealthCare, Australia; OrthoSport Victoria Research Unit, Deakin University and Epworth HealthCare, Australia; School of Health and Sports Science, University of the Sunshine Coast, Australia; OrthoSport Victoria Research Unit, Deakin University and Epworth HealthCare, Australia; OrthoSport Victoria Research Unit, Deakin University and Epworth HealthCare, Australia; School of Allied Health, College of Science, Health & Engineering, La Trobe University, Australia


Background: Although quadriceps weakness is a common impairment following anterior cruciate ligament reconstruction (ACLR), there is limited research examining its association with functional outcomes.
Purpose / Aim of Study: The purpose of the study was to determine the proportion of patients with strength deficits at 6 and 12 months and the association between strength outcomes and single limb hop tests.
Materials and Methods: The study was performed as a prospective cohort study following the STROBE guidelines. There were 123 patients (74 male, 49 female). Quadriceps strength and hop test measurements were made at 6- and 12-months following primary ACLR with hamstring grafts. Normal strength and hopping distance were defined as >85% of the contralateral limb.
Findings / Results: At 6- and 12-months 29% and 53% of patients had recovered normal quadriceps strength respectively. The majority of patients who had recovered normal strength also had a normal hopping distance at 6 (91%) and 12 (93%) months. However, at 6- and 12- months 39% and 29% of patients respectively had recovered normal hopping distance without recovering normal quadriceps strength.
Conclusions: Only 1 in 3 patients had recovered normal QF strength 6 month after ACLR, at the time when they are often expecting to resume sporting activity. This had only improved to 1 in 2 at 12 months. Approximately 1 in 3 patients recover normal hopping distance without having normal quadriceps strength.

Signe Kierkegaard, Bent Lund, Kjeld Søballe, Ulrik Dalgas, Inger Mechlenburg
Department of Orthopaedic Surgery, Horsens Hospital; Department of Orthopaedic Surgery, Horsens Hospital; Department of Orthopaedic Surgery, Aarhus University Hospital; Section for Sport Science, Department of Public Health, Aarhus University; Department of Orthopaedic Surgery, Aarhus University Hospital


Background: Patients with femoroacetabular impingement (FAI) undergoing hip arthroscopy show reduced hip pain following surgery. However, it is, less well documented how pain levels in the knee and the back are affected by surgery, despite both joints could be affected by altered hip motion due to hip pain and decreased hip range of motion.
Purpose / Aim of Study: The aim of the study was, therefore, to investigate hip, back and knee pain in patients with FAI before and after hip arthroscopy in a consecutively included cohort.
Materials and Methods: Sixty patients (age 36±9, 63% females) with FAI scheduled for hip arthroscopic surgery at Horsens Hospital were included in the study. On a 100-mm visual analog scale (VAS), patients scored their resting hip pain, hip pain during activity, knee pain and back pain during the past 24 hours. Patients scored their pain preoperatively, 3, 6 and 9 months postoperatively. Time development in the scores was investigated with a mixed effects model. Results are presented as medians and quartiles.
Findings / Results: Back VAS pain was present before surgery (16 [5;49] mm) and increased after surgery: 3 months: 15 [2;44] mm; 6 months: 25 [5;61] mm; 9 months: 21 [4;55] mm (p = 0.04). Knee VAS pain was present before surgery (19 [1;51] mm) and seemed to decrease over time, but this was not significantly: 3 months: 5 [1;45] mm; 6 months: 4 [0;38] mm; 9 months: 2 [0;18] mm (p = 0.16). Preoperative resting hip pain was 19 [7;38] mm and hip pain during activity was 37 [20;62] mm which both decreased significantly after surgery (p < 0.001).
Conclusions: Hip arthroscopy can alleviate hip pain in patients with FAI, but some patients experience increased back pain after surgery and some knee pain. To improve pain outcomes for the knee and back after surgery, the underlying causes of pain need to be investigated.

Andreas Serner, Frank Roemer, Per Hölmich, Kristian Thorborg, Jingbo Niu, Adam Weir, Johannes L Tol, Ali Guermazi
Sports Groin Pain Center, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar; Department of Radiology, University of Erlangen-Nuremberg, Erlangen, Germany; Sports Orthopaedic Research Center–Copenhagen (SORC-C), Department of Orthopedic Surgery , Copenhagen University Hospital, Amager-Hvidovre, Denmark; Sports Orthopaedic Research Center–Copenhagen (SORC-C), Department of Orthopedic Surgery , Copenhagen University Hospital, Amager-Hvidovre, Denmark; Clinical Epidemiology and Training Unit, Department of Medicine, Boston University School of Medicine, Boston, MA, USA; Sports Groin Pain Center, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar; Sports Groin Pain Center, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar; Quantitative Imaging Center (QIC), Department of Radiology, Boston University School of Medicine, Boston, MA, USA


Background: Groin injuries are common in sports medicine as they frequently occur in high intensity team sports, such as football, where they are considered the second most frequent injury location. Most published literature on groin pain in athletes focuses on long-standing symptoms. An assessment system for acute groin injuries is still lacking.
Purpose / Aim of Study: To describe a multi-dimensional MRI assessment approach with a focus on acute musculotendinous groin injuries, and to evaluate scoring reproducibility.
Materials and Methods: Male athletes who participated in competitive sports and presented within 7 days of an acute onset of sports-related groin pain were included. All athletes underwent MRI (1.5 T) according to a standardized groin-centred protocol. From several calibration sessions, a system was developed assessing grade, location and extent of muscle strains, peri-lesional hematoma, as well as other non-acute findings commonly associated with long-standing groin pain. Kappa (𝓚) statistics and intraclass correlation coefficients (ICCs) were used to describe intra- and inter-rater reproducibility.
Findings / Results: 75 athletes (mean age 26.6 ± 4.4 years) were included in the analyses, and 85 different acute lesions were observed. Adductor longus lesions were most common (42.7%) followed by rectus femoris lesions (16.3%). Kappa values ranged between 0.70 and 1.00 for almost all categorical features for acute lesions, with almost perfect intra- and inter-rater agreement (𝓚=0.89-1.00) for presence, number, location and grading of lesions. ICCs ranged between 0.77 and 1.00 for continuous measures of acute lesion extent.
Conclusions: A standardized MRI assessment approach of acute groin injuries was described and showed good intra- and inter-rater reproducibility.

Søren Winge, Bjarne Mygind-Klavsen, Bent Lund, Torsten Grønbech Nielsen, Niels Maagaard, Otto Kraemer, Per Hölmich, Martin Lind
, CFR Private Hospital; Div. of Sports Traumatology, Dept. of Orthopedics, Aarhus University Hospital THG, 8000 Aarhus C, Denmark; Dept. of Orthopedics, Horsens Regional Hospital, 8700 Horsens, Denmark; Div. of Sports Traumatology, Dept. of Orthopedics, Aarhus University Hospital THG, 8000 Aarhus C, Denmark; Dept. of Orthopedics, Odense University Hospital, 5000 Odense, Denmark; Arthroscopic Center, Dept. of Orthopedics, Copenhagen University Hospital, Amager-Hvidovre, 2300 Copenhagen S, Denmark; Arthroscopic Center, Dept. of Orthopedics, Copenhagen University Hospital, Amager-Hvidovre, 2300 Copenhagen S, Denmark; Div. of Sports Traumatology, Dept. of Orthopedics, Aarhus University Hospital THG, 8000 Aarhus C, Denmark


Background: Capsular closure in FAI patients during hip arthroscopy procedures are still debated. The Danish Hip Arthroscopy Registry (DHAR) contains data to perform matched- cohort analyses.
Purpose / Aim of Study: The purpose of this study was to describe data from DHAR after FAI surgery associated with capsular closure, report outcome data and compare these outcome data with a matched-cohort study group. Our primary hypothesis was that patients undergoing hip arthroscopy would not benefit in subjective outcome from capsular closure compared with no closure.
Materials and Methods: We identified FAI patients in DHAR where the capsule was closed during the hip arthroscopy. A matched cohort of patients who did not have capsular closure performed were selected. Matching criteria were age, gender, radiological parameters (lateral centre edge angle and alpha angle). We compared the two groups according to HAGOS, HSAS, EQ-5D and VAS. We identified 247 patients in each group.
Findings / Results: Both groups improved significantly in all postoperative PROMs at one and two year follow-up. When comparing the improvements between the two groups we found a significant better improvement in the capsular closure group in VAS and all HAGOS sub scales at both one and two year follow-up. HSAS demonstrated improvement in the closure group at one year but no difference at two year follow-up. EQ-5D showed difference at two year follow-up.
Conclusions: This study showed that FAI-patients undergoing capsular closure during hip arthroscopy had a significant improvement in outcome when compared to a matched control group at two year follow-up. We also found improvement in physical activity and quality of life scores. We therefore conclude that capsular closure might positively affect the outcome in FAI-patients during hip arthroscopy.

Signe Kierkegaard, Ulrik Dalgas, Bent Lund, Kjeld Søballe, Inger Mechlenburg
Department of Orthopaedic Surgery, Horsens Hospital; Section for Sport Science, Department of Public Health, Aarhus University; Department of Orthopaedic Surgery, Horsens Hospital; Department of Orthopaedic Surgery, Aarhus University Hospital; Department of Orthopaedic Surgery, Aarhus University Hospital


Background: Clinical and disease specific characteristics for symptomatic femoroacetabular impingement (FAI) may be gender specific. Some studies report muscle weakness in patients with FAI while other studies do not, which may be explained by gender specific impairments.
Purpose / Aim of Study: We aimed to investigate gender differences in maximal hip flexion and extension strength when compared to a matched healthy reference group.
Materials and Methods: 60 patients (36 ±9years, 38 females) scheduled for arthroscopic hip surgery for FAI and 30 age and gender matched reference persons were included in the study. Participants had their maximal hip flexion and extension strength tested using dynamometry. All participants completed two submaximal familiarization trials followed by 3–4 maximum voluntary contraction trials. Tests were performed isometrically at 45° of hip flexion, concentric at 60°/s and eccentric at -60 °/s. Maximal peak torque divided by body mass was the main outcome. Comparisons between genders and patients vs. reference persons were performed with multiple regression analysis. The level of significance was set to < 0.05.
Findings / Results: The affected leg of the patients was significantly weaker than the leg of references persons for all testing conditions (75-91% of reference leg). When analyzing males and females separately, this relationship was only found in the female patients (females: 64-92% of reference vs. males: 98-113% of reference).
Conclusions: These data suggest that, muscle strength of the affected leg of female FAI patients is significantly weaker than reference persons, as opposed to male FAI patients. Further studies should investigate these relationships in larger samples and also relate findings to radiographic parameters.

Kasper Skriver Gravesen, Anders Troelsen, Lars Blønd, Kristoffer Weisskirchner Barfod
Dept. of Orthopedic Surgery, Clinical Orthopedic Research Hvidovre (CORH), Copenhagen University Hospital Hvidovre; Dept. of Orthopedic Surgery, Clinical Orthopedic Research Hvidovre (CORH), Copenhagen University Hospital Hvidovre; Dept. of Orthopedic Surgery, Zealand University Hospital Køge and Aleris-Hamlet Parken; Dept. of Orthopedic Surgery, Clinical Orthopedic Research Hvidovre (CORH), Copenhagen University Hospital Hvidovre


Background: Reliable epidemiological data on patellar dislocation is lacking.
Purpose / Aim of Study: The purpose of this study was to investigate the Danish population as a whole from 1994 to 2013 to find the incidence of acute and recurrent patellar dislocation. The risk of acquiring a recurrent dislocation or a dislocation in the opposite knee was investigated with 10 years of follow up after primary dislocation.
Materials and Methods: The study was performed as a descriptive epidemiological study. The Danish National Patient Registry was retrospectively searched from 1994 to 2013 to find the number of acute and recurrent patellar dislocation. National population data were collected at the services of Statistics Denmark.
Findings / Results: From 1994 to 2013 a total of 24.154 primary patellar dislocations were registered. A mean incidence of 72 (95% CI: 63 - 81) per 100.000-person years at risk (PYRS) was found, young females aged 10-17 had an incidence of 108 (95% CI: 101-116). In a 10- year follow up patients had an overall risk of 22.7% (95% CI: 22.2 – 23.2) of suffering a recurrent dislocation, with young girls aged 10-17 athe t highest risk with 36.8% (95% CI: 35.5 – 38.0). The overall risk of suffering a patellar dislocation in the contralateral knee was 5.8% (95% CI: 5.5 – 6.1) and 11.1% (95% CI: 10.4 – 11.7) for patients aged 10-17.
Conclusions: A high incidence rate of primary patellar dislocation was found both as a mean in the population (72/106) but especially in patients aged 10-17 (108/106). The risk of recurrent dislocation in the affected knee (22.7%) and the contralateral knee (5.8%) was high, which could indicate the influence of an underlying pathomorphology.