The Cam-type Deformity of the Proximal Femur Arises in Childhood in Response to Vigorous Sporting Activity
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- Cite this article as:
- Siebenrock, K.A., Ferner, F., Noble, P.C. et al. Clin Orthop Relat Res (2011) 469: 3229. doi:10.1007/s11999-011-1945-4
The prevalence of a cam-type deformity in athletes and its association with vigorous sports activities during and after the growth period is unknown.
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.
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.
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.