Synovial Chondromatosis

Epidemiology

Synovial chondromatosis is a benign disorder in which foci of cartilage develop in a joint due to chondrometaplasia of the synovial membrane. The cartilaginous nodules may remain attached to the synovial membrane or dislodge into the joint space to form loose bodies. Synovial chondromatosis is more common in large diarthrodial joints (knee, hip, elbow, etc.) with involvement of the temporomandibular joint (TMJ) being less common. Involvement of the TMJ is slightly more common in females, has a predilection for the right, and typically presents between the fourth and fifth decades of life. This is in contradistinction to involvement of the larger joints, which is more common in males between the second and third decades of life. The etiology is unknown and may be due to trauma to the synovium, degenerative joint disease, or abnormal loading due to malocclusion or a displaced disc. This is a benign disease with malignant transformation being exceedingly rare.