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

OBJECTIVES: Participation rates in women’s ice hockey is increasing in North America. Recent studies have demonstrated an increased prevalence of femoroacetabular impingement (FAI) in elite male ice hockey players, yet little is known about hip pathology of players in the National Women’s Hockey League (NWHL). The primary purpose of this study was to determine the prevalence of radiographic FAI in women’s professional ice hockey players. The secondary purpose was to analyze the relationship between the presence of radiographic cam deformity and hip ROM, clinical impingement signs and age of menarche. METHODS: In this IRB-approved study, physical examination and demographic data were prospectively collected for 27 NWHL players. Alpha angles were measured on 45-degree Dunn views with an alpha angle &gt55° defined as cam-positive. Pearson correlations were performed to analyze the relationship between alpha angle and ROM measurements, clinical impingement signs and self-reported age of menarche. Players were grouped into those with and without cam impingement and group differences were assessed using the student’s t-test. Statistical significance was set at p&lt0.05. RESULTS: Twenty-seven athletes were included in the study. Nineteen of the 27 players (70%) had radiologic evidence of cam-type impingement with alpha angle &gt55 degrees; 14 players (52%) had bilateral cam deformity. The average age of menarche was 13.9±1.5 years. There was a significant association between age of menarche and right alpha angle (R=0.57, CI [0.16, 0.81], p=0.011), as well as age of menarche and left alpha angle (R=0.48, CI [0.03, 0.77], p=0.039). There was no statistically significant association between alpha angle and any ROM measurement. Additionally, there was no difference in the incidence of clinical impingement for players with or without an alpha angle &gt55°. CONCLUSION: This study suggests that elite female ice hockey players have a significantly higher prevalence of cam-type morphology than the general population. The clinical significance of this radiographic finding is uncertain as the majority of these deformities seem to be asymptomatic. Interestingly, the positive association between alpha angle and age of menarche lends support to the etiological hypothesis that cam lesions are a result of activity-related stress at the proximal femoral physis. This data suggests that players with earlier menarche (and therefore earlier physeal closure) seem to be less vulnerable to the development of cam deformity of the proximal femur.