Increased asphericity of the femoral head-neck junction in professional breakers compared to hobby athletes - a retrospective case-control study.

Objective: Breaking has gained public attention as a form of sports activity. The associated intense movements of the hip joints are possibly linked to the development of femoroacetabular impingement (FAI). Therefore, this study aimed to assess clinical and radiographic FAI measures in professional breakers compared to hobby athletes.

Methods: The study cohort consisted of professional breakers with persisting hip pain who were 1:1 matched to a cohort of FAI patients without professional sports careers from our outpatient clinic. The primary endpoint assessed on standardized plain radiographs was the alpha angle (AA). Further measures were the acetabular index (AI), lateral center-edge angle (LCEA), crossover sign, ischial spine sign, and femoral head extrusion index (FHEI). The modified Harris Hip Score (mHHS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score were used to obtain patient-reported measures.

Results: We recruited ten professional breakers and matched them to ten hobby athletes. The median AA was significantly higher in the breakers compared with the hobby athletes (73° [IQR 66.5°, 84.2°]) vs. 61.8° [IQR 59.5°, 64.8°], p = 0.0004). There was a significant reduction in weekly training hours in breakers after diagnosis (13.0 hours [interquartile range [IQR] 9.5, 32.4] to 1.5 hours [IQR 0, 4.8], p = 0.0039). There were no inter-group differences regarding mHHS, WOMAC, and additional radiographic measurements.

Conclusion: Breakers have higher AA in cam-type FAI compared to nonprofessional athletes. The corresponding hip pain significantly reduced training hours and caused the end of their breaking career. The potentially high prevalence of FAI in breakers and the corresponding consequences need to be considered early when athletes present with hip pain.