The cam-type deformity of the proximal femur arises in childhood in response to vigorous sporting activity

Clin Orthop Relat Res. 2011 Nov;469(11):3229-40. doi: 10.1007/s11999-011-1945-4. Epub 2011 Jul 15.


Background: The prevalence of a cam-type deformity in athletes and its association with vigorous sports activities during and after the growth period is unknown.

Questions/purposes: We therefore compared the prevalence and occurrence of a cam-type deformity by MRI in athletes during childhood and adolescence with an age-matched control group.

Patients and methods: We retrospectively reviewed 72 hips in 37 male basketball players with a mean age of 17.6 years (range, 9-25 years) and 76 asymptomatic hips of 38 age-matched volunteers who had not participated in sporting activities at a high level.

Results: Eleven (15%) of the 72 hips in the athletes were painful and had positive anterior impingement tests on physical examination. Internal rotation of the hip averaged 30.1° (range, 15°-45°) in the control group compared with only 18.9° (range, 0°-45°) in the athletes. The maximum value of the alpha angle throughout the anterosuperior head segment was larger in the athletes (average, 60.5° ± 9°), compared with the control group (47.4° ± 4°). These differences became more pronounced after closure of the capital growth plate. Overall, the athletes had a 10-fold increased likelihood of having an alpha angle greater than 55° at least at one measurement position.

Conclusions: Our observations suggest a high intensity of sports activity during adolescence is associated with a substantial increase in the risk of cam-type impingement. These patients also may be at increased risk of subsequent development of secondary coxarthrosis.

Level of evidence: Level II, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

MeSH terms

  • Adolescent
  • Adult
  • Athletic Injuries / epidemiology
  • Athletic Injuries / pathology*
  • Athletic Injuries / physiopathology
  • Basketball
  • Child
  • Femur / pathology*
  • Hip Injuries / epidemiology
  • Hip Injuries / pathology*
  • Hip Injuries / physiopathology
  • Hip Joint / pathology*
  • Hip Joint / physiopathology
  • Humans
  • Male
  • Pain / etiology
  • Pain / physiopathology
  • Prevalence
  • Range of Motion, Articular
  • Retrospective Studies
  • Switzerland / epidemiology
  • United States / epidemiology
  • Young Adult