Synovial chondromatosis of the shoulder: open synovectomy and insertion of osteoarticular allogaft with internal fixation to repair intraoperative glenohumeral joint instability.

Synovial chondromatosis is a rare benign disorder characterized by chondroid metaplasia with multinodular proliferation of the synovial lining of a diarthroidal joint, bursa, or tendon sheath. These cartilaginous nodules may become embedded within the proliferating synovium and may extend into the surrounding soft tissues. They also can detach from the synovium, where they can calcify and may present as intra-articular loose bodies. Presence of these nodules leads to joint pain, dysfunction, and ultimately, destruction. Clinically, patients often present with a chronic monoarthropathy. In this article, we report a case of extensive synovial chondromatosis of the right shoulder and surrounding soft tissues with extensive erosion of the humeral head, discuss combined anterior and posterior surgical excision of the cartilaginous fragments, and describe insertion of an osteoarticular allograft to repair the humeral head defect and secondary anterior glenohumeral joint instability.