FGF9 and synovial chondromatosis: Treatment of synovial chondromatosis entails synovectomy with removal of the loose bodies in the presence of active synovitis.1, 6, 8 The recurrence rate after surgery ranges from 3.2% to 22.2%.5 Radiotherapy is beneficial for recurrent lesions and inhibition of FGF-9 has been suggested as a nonoperative method of treating primary synovial chondromatosis.4, 9