Osteitis deformans of the hip joint.

It is estimated that 66% of patients with Paget's disease have involvement of the pelvis and 46% of the proximal femur. Therefore, it is not unexpected that hip pain is one of the major presenting complaints. Analysis of the radiographs of 25 hips with one or more articular sufaces involved by Paget's disease demonstrated narrowing in 24. Unlike the findings in primary degenerative joint disease, the majority of cases had a radiographic pattern characterized by uniform narrowing of the articular cartilage and minimal hypertrophic changes. Pathologic correlation was obtained from specimens of four patients who underwent total hip replacements. The pathogenesis of arthritic changes associated with osteitis deformans is not established. The evidence presented suggest that cartilagenous narrowing results from a disturbance in endochondral bone formation related to the hyperemia of Paget's disease. Secondary deformities of bone produce further derangement of joint mechanics. The secondary degenerative changes which ensue differ mechanically, and therefore radiographically, from primary degenerative joint disease.