Coverage of the femoral head by the acetabular labrum in dysplastic hips

Hip dysplasia is an important cause of osteoarthrosis of the hip, especially in Japanese. Recently, the role of the acetabular labrum in hip diseases has attracted the attention of researchers, but the condition of the labrum in the dysplastic hips has not ben described. We used radial MRI to measure the degree of coverage of the femoral head by the acetabu-lum and the labrum, corresponding to 7 positions on the acetabular rim at every 15° from anterosuperior 45° via midsuperior to posterosuperior 45°. 38 Japanese patients (51 hips) with dysplasia, and 11 healthy controls (22 hips) were studied. In the dysplastic hips, the labrum was larger than in the controls. We found no correlation between the coverage of the acetabulum in the anterosuperior positions and the size of the labrum among the dysplastic hips.