Prevalence of increased alpha angles as a measure of cam-type femoroacetabular impingement in youth ice hockey players

Am J Sports Med. 2013 Jun;41(6):1357-62. doi: 10.1177/0363546513483448. Epub 2013 Apr 5.


Background: It has been reported that relative to other sports participants, ice hockey players suffer from cam-type femoroacetabular impingement (FAI) in higher numbers. α angles have been reported to increase with the likelihood of symptomatic FAI. It is unclear how prevalent increased α angles, commonly associated with cam FAI, are in asymptomatic young ice hockey players.

Hypothesis: There would be a higher prevalence of α 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 α 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 α angles than did the control group, and hockey players had a significant correlation between increased age and increased α angles, while the control group did not. In the ice hockey group, 75% had an α angle of ≥55°, while in the skier group, 42% had an α angle of ≥55° (P < .006). Hockey players were 4.5 times more likely to have an α angle commonly associated with cam impingement than skiers. Midget players had the highest risk of increased α angles.

Conclusion: Even at young ages, ice hockey players have a greater prevalence of α 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.

Keywords: cam lesion; femoroacetabular impingement; ice hockey; magnetic resonance imaging; α angle.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Cartilage, Articular / injuries
  • Child
  • Femoracetabular Impingement / classification
  • Femoracetabular Impingement / epidemiology
  • Femoracetabular Impingement / physiopathology*
  • Hip Injuries / physiopathology*
  • Hip Joint / physiopathology*
  • Hockey / injuries*
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Prevalence
  • Rotation
  • Skiing / injuries