Bone erosion in synovial chondromatosis.

Of 30 patients with synovial chondromatosis, nine had prominent pressure defects at the articular margins of the hip and shoulder. Erosions of bone may be extensive, and the patient can be at risk for developing a pathologic fracture. Synovial chondromatosis should be considered in the differential diagnosis of lesions causing erosions of the articular ends of the bones; it is not as uncommon as has been previously suggested.