1. Osteochondromatosis of the synovial membrane is one of the causes of osteocartilaginous loose bodies in the joints, and probably the sole cause of the bodies in the bursae and tendon sheaths.
2. We believe that the condition should be classified as a benign neoplasm. Trauma is a secondary factor.
3. One of our cases was associated with a malignant chondrosarcoma in the lower end of the femur. No malignancy was discovered in the knee-joint.
4. Removal of all the bodies relieves the patient in the majority of instances. We have not found amputation or resection necessary for synovial osteochondromatosis.