Three-dimensional modeling of cartilage thickness in hip dysplasia.

The cartilage thickness in both normal hips and in coxarthrosis secondary to hip dysplasia was examined using a computer model. The hip cartilage thickness was calculated in three dimensions from computed tomographic images of the hip joint. In normal hip joints, the anterior cartilage was thicker than the posterior cartilage. In hip joints affected by secondary coxarthrosis, the cartilage thinned as the disease progressed. Approximately 80% of patients demonstrated thinning of the anterior apical cartilage, resulting in a forward and upward displacement of the femoral head.