Objective. Femoroacetabular impingement may be a risk factor for hip osteoarthritis in men. An underlying hip deformity of the cam type is common in asymptomatic men with nondysplastic hips. This study was undertaken to examine whether hip deformities of the cam type are associated with signs of hip abnormality, including labral lesions and articular cartilage damage, detectable on magnetic resonance imaging (MRI).
Methods. In this cross-sectional, populationbased study in asymptomatic young men, 1,080 subjects underwent clinical examination and completed a selfreport questionnaire. Of these subjects, 244 asymptomatic men with a mean age of 19.9 years underwent MRI.
All MRIs were read for cam-type deformities, labral lesions, cartilage thickness, and impingement pits. The relationship between cam-type deformities and signs of joint damage were examined using logistic regression models adjusted for age and body mass index. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were determined.
Results. Sixty-seven definite cam-type deformities were detected. These deformities were associated with labral lesions (adjusted OR 2.77 [95% CI 1.31, 5.87]), impingement pits (adjusted OR 2.9 [95% CI 1.43, 5.93]), and labral deformities (adjusted OR 2.45 [95% CI 1.06, 5.66]). The adjusted mean difference in combined anterosuperior femoral and acetabular cartilage thickness was ؊0.19 mm (95% CI ؊0.41, 0.02) lower in those with cam-type deformities compared to those without.
Conclusion. Our findings indicate that the presence of a cam-type deformity is associated with MRIdetected hip damage in asymptomatic young men.
Osteoarthritis (OA) of the hip is one of the major causes of pain and disability (1,2), accounting for more than 200,000 hip replacements annually in the US (3). The etiology of OA is multifactorial (4). Current classifications include "idiopathic" OA and "secondary" OA in individuals with clearly visible deformities such as hip dysplasia (5). More than four decades ago, however, Murray suggested that most cases of idiopathic OA were the result of frequently undetected deformities and were therefore secondary OA (6). These deformities were later suggested to cause femoroacetabular impingement and signs of early hip OA (7). Two different types of impingement were distinguished, cam and pincer. (An