Synovial osteochondromatosis of the elbow.

We present 12 patients with synovial osteochondromatosis of the elbow treated by synovectomy. Histological review showed that seven cases were primary and five secondary osteochondromatosis. The patients with primary disease had a mean improvement in the flexion arc from a preoperative value of 40 degrees to 123 degrees to 5 degrees to 128 degrees when reviewed at a mean of nine years after operation. The secondary group had a mean improvement in the flexion arc from a preoperative value of 21 degrees to 98 degrees to 4 degrees to 131 degrees at a mean of 6.8 years after operation. There was recurrence in two of seven patients in the primary group and three of five in the secondary group. Osteoarthritis developed in six elbows in the primary and in three in the secondary group. Osteoarthritis secondary to synovial osteochondromatosis is progressive. In the established condition, the distinction between primary and secondary disease may be of greater histological than clinical relevance.