Cam morphology is associated with MRI-defined cartilage defects and labral tears: a case–control study of 237 young adult football players with and without hip and groin pain

Abstract

ObjectiveFootball players are at risk of developing hip osteoarthritis (OA). Cam morphology (present in almost two of every three football players) may explain this heightened risk, but there is limited research on its role in hip OA development in younger athletes. Knowledge of this relationship will advance our understanding of the aetiology of hip OA in football players. We aimed to study the relationship between cam morphology size and MRI-defined cartilage defects and labral tears, and if this relationship differs by symptomatic state in young adult football players.MethodsFor this case–control study, 182 (288 hips) symptomatic (hip and/or groin pain >6 months and positive flexion-adduction-internal-rotation (FADIR) test) and 55 (110 hips) pain-free football players (soccer or Australian football) underwent anteroposterior and Dunn 45° radiographs, and 3-Tesla MRI. Cam morphology size was defined using alpha angle, and cartilage defects and labral tears were scored semiquantitatively. Presence, location and score (severity) of cartilage defects and labral tears were determined. Each participant completed the International Hip Outcome Tool 33 and Copenhagen Hip and Groin Outcome Score.ResultsGreater alpha angle was associated with cartilage defects (OR 1.03, 95% CI 1.01 to 1.04) and labral tears (OR 1.02, 95% CI 1.01 to 1.04). Greater alpha angle was associated with superolateral cartilage defects (OR 1.03, 95% CI 1.02 to 1.05) and superior labral tears (OR 1.03, 95% CI 1.02 to 1.05). The association of alpha angle with MRI-defined cartilage defects and labral tears was no greater in football players with symptoms than in those without (p=0.189–0.937)ConclusionCam morphology size was associated with cartilage defects and labral tears in young adult football players with and without pain. This study provides evidence that cam morphology may contribute to the high prevalence of hip OA in football players. Prospective studies of football players are now needed to establish if cam morphology causes progression of cartilage defects and labral tears and development of hip OA.

Are cam morphology size and location associated with self‐reported burden in football players with FAI syndrome?

“…Our findings are consistent with previous reports of a dose-response relationship between cam morphology and physical findings, where those with larger cam morphology had worse chondrolabral pathology 8,9 and restricted ROM. 11 It is unclear why football players with larger cam morphology reported worse perceived impairment to physical function than those with smaller cam morphology, warranting future investigation of the relationship between cam morphology size and hip joint biomechanics during sporting tasks.…”

“…Maximum alpha angle measurements are frequently observed at the anterosuperior region of the femoral head-neck junction, 4,[15][16][17] where larger and more anterior cam morphology has been found to impinge the acetabulum at smaller degrees of hip flexion. 27 While mechanical impingement between the femoral neck and acetabulum may increase hip joint stresses, 28 restrict ROM, 11,29 and cause chondrolabral pathology, 8,9 the effect of cam morphology on reported burden has been less certain. Cam morphology presence 13,14 and size 2,30,31 have been unrelated to PROM scores in various symptomatic populations, including those undergoing hip arthroscopy, 30,31 adults with self-reported hip OA, 13 and football players with hip/groin pain.…”

“…Defining FAI syndrome using an alpha angle threshold value (i.e., ≥60°) may not identify the potential effect of cam morphology size on self-reported hip/groin burden severity. A dose-response relationship was observed between cam morphology size and hip joint physical findings, where people with large cam morphology (alpha angle ≥78°) had worse chondrolabral pathology 8,9 and lesser hip ROM 11 when compared to those with cam morphology (alpha angles 60-78°). However, it is not known whether a similar relationship exists between cam morphology and self-reported pain and symptoms in people with FAI syndrome.…”

“…3 Diagnosis of FAI syndrome requires symptoms, clinical signs, and imaging evidence of cam and/or pincer morphology. 4,5 Primary cam morphology is determined by an alpha angle threshold value of 60°4 ,6,7 and has been associated with chondrolabral pathology, 8,9 lower hip range of motion (ROM), 10,11 and the development of hip OA. 12 However, symptomatic adults with and without cam morphology report similar patient-reported outcome measure scores, 13,14 indicating a less certain relationship between cam morphology and reported burden in people with hip/ groin pain.…”

Prospective evaluation of sport activity and the development of femoroacetabular impingement in the adolescent hip (PREVIEW): results of the pilot study

“…A recent MRI study looking at young football players (mean age 26 years) found an association between cam morphology size and risk of chondrolabral damage. Interestingly, the relationship was similar in symptomatic and asymptomatic patients [ 40 ]. With chondrolabral damage being a continuum, it is likely too early for participants in this study to show any important cartilage damage that may cause hip pain [ 39 ].…”