Association of Idiopathic Cam Morphology With Femoral and Acetabular Version: Analysis of 986 Cadaveric Hips

Background: Studies have correlated symptomatic femoroacetabular impingement (FAI) with femoral retroversion and cam lesions.Purpose: To investigate any association between femoral and acetabular versions with cam deformity in a largely asymptomatic population.Study Design: Descriptive laboratory study.Methods: A total of 986 cadaveric hips were selected from a historical osteologic collection. Each hip was assessed to determine the femoral and acetabular versions, anterior offset, and alpha angle. Cam morphology was defined as an alpha angle >60(degrees). Multiple regression analysis was performed to determine the relationship between age, femoral version, acetabular version, and either alpha angle or anterior femoral offset.Results: The mean alpha angle and anterior offset for the sample population were 48.1 degrees +/- 10.4 degrees and 0.77 +/- 0.17 cm, respectively, with cam morphology in 149 of the 986 (15.1%) specimens. No significant difference was observed between hips with and without cam morphology with respect to the femoral (10.8 degrees +/- 10 degrees vs 10.3 degrees +/- 9.6 degrees; P = .58) or acetabular versions (17.4 degrees +/- 6 degrees vs 18.2 degrees +/- 6.3 degrees; P = .14). Multiple regression analysis did not demonstrate an association between the femoral or acetabular versions and the alpha angle, and it showed a small association between the increasing femoral and acetabular versions and a decreased anterior femoral offset (both P < .01).Conclusion: In a large random sample of cadaveric hips, cam morphology was not associated with femoral or acetabular retroversion. Combined with the existing literature, these findings suggest that retroversion is not associated with cam development.Clinical Relevance: This study provides insight into the development of cam morphology, which may eventually aid in the evaluation and treatment of FAI.