Prevalence of Increased Alpha Angles as a Measure of Cam-Type Femoroacetabular Impingement in Youth Ice Hockey Players.
Philippon, Marc J. MD *,+; Ho, Charles P. MD, PhD +; Briggs, Karen K. MPH +; Stull, Justin BA +; LaPrade, Robert F. MD, PhD +
[Article]
American Journal of Sports Medicine.
41(6):1357-1362, June 2013.
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Background: It has been reported that relative to other sports participants, ice hockey players suffer from cam-type femoroacetabular impingement (FAI) in higher numbers. [alpha] angles have been reported to increase with the likelihood of symptomatic FAI. It is unclear how prevalent increased [alpha] angles, commonly associated with cam FAI, are in asymptomatic young ice hockey players.
Hypothesis: There would be a higher prevalence of [alpha] angles associated with cam FAI in youth ice hockey players than in a non-hockey-playing (skier) youth control group.
Study Design: Cohort study; Level of evidence, 3.
Methods: A total of 61 asymptomatic youth ice hockey players (aged 10-18 years) and 27 youth skiers (controls) (aged 10-18 years) underwent a clinical hip examination consisting of the flexion/abduction/external rotation (FABER) distance test, impingement testing, and measurement of hip internal rotation. The hip [alpha] angle was measured by magnetic resonance imaging, and labral tears and articular cartilage lesions were documented. Hockey players were grouped according to their USA Hockey classification as peewees (ages 10-12 years), bantams (ages 13-15 years), and midgets (ages 16-19 years).
Results: Overall, ice hockey players had significantly higher [alpha] angles than did the control group, and hockey players had a significant correlation between increased age and increased [alpha] angles, while the control group did not. In the ice hockey group, 75% had an [alpha] angle of >=55[degrees], while in the skier group, 42% had an a angle of >=55[degrees] (P < .006). Hockey players were 4.5 times more likely to have an [alpha] angle commonly associated with cam impingement than skiers. Midget players had the highest risk of increased [alpha] angles.
Conclusion: Even at young ages, ice hockey players have a greater prevalence of [alpha] angles associated with cam FAI than do skier-matched controls. Properties inherent to ice hockey likely enhance the development of a bony overgrowth on the femoral neck, leading to cam FAI.
(C) 2013 Sage Publishing