A computertomographic study on the congruence of the hip joint

This study describes investigations into the appearance of intra-articular spaces of hip joints. In CT scans of cadaver hip joints in the supine position an increased intra-articular space was found dorsally, while in the prone position the same hip joint showed an increased intra-articular space ventrally. It is assumed generally that the gap between the bone ends seen on plane X-rays represents the cartilage, but this study indicates that there may in fact be a space between the cartilage surfaces in the unloaded joint. Relevance-Osteotomies for reconstructing arthrotic hip joints are based widely on the assumption that the joint space seen on X-rays is a representation of the joint cartilage. This study reveals that the intra-articular space in general is not identical with undamaged layers of cartilage.