Characterizing the Prevalence of Cam-Type Hip Impingement in Professional Women’s Ice Hockey Players

BACKGROUND: Recent studies have demonstrated a high prevalence of femoroacetabular impingement (FAI) in elite men’s ice hockey players, yet little is known about the hips of elite women’s ice hockey players. PURPOSE: The primary purpose of this study was to determine the prevalence of radiographic cam-type FAI in professional women’s ice hockey players in the National Women’s Hockey League (NWHL). The secondary purpose was to analyze the relationship between the presence of cam deformity and both hip range-of-motion (ROM) and age of menarche. METHODS: Clinical, radiographic and demographic data were collected during player pre-participation physicals. ROM measurements were performed with a goniometer. Alpha angles were measured on 45° Dunn radiographs, with alpha angles >55° defined as cam-positive (Figure 1). Measurements were performed 3 separate times by 4 investigators. One-way ANOVA, independent means t-test and Pearson correlation coefficients were calculated, with statistical significance set at p<0.05. RESULTS: Twenty-six female athletes were included. Average menarchal age was 13.8 ±1.5 years. 24 (92%) had alpha angles >55°; 20 (77%) had bilateral cam deformity. Inter-rater reliability was excellent at 0.86. Intra-rater reliability was also excellent, with mean ICC=0.87 (range= 0.82-0.90 for each rater). There was a significant positive association between age of menarche and alpha angle (p<0.02, Figure 2). There was no association between alpha angle and hip ROM. CONCLUSION: Elite female ice hockey players have a higher prevalence of cam morphology than the general population. The positive association between alpha angle and age of menarche supports the etiological hypothesis of the cam lesion resulting from activity-related stress at the proximal femoral physis during a period of physiologic vulnerability. Professional women’s ice hockey players have a high risk of developing cam morphology of the proximal femur, although each player’s age of menarche may mediate her individual risk for cam lesion development.