Massive synovial chondromatosis of the knee managed with open excision with excellent postoperative functional outcome

A male patient in his 50s presented with complaints of pain, swelling and restriction of movement in his right knee for 7 years. Examination revealed a 10 degree flexion deformity with diffuse swelling and tenderness, as well as a range of motion (ROM) of 10-30 degrees. X-ray showed a 'ring and arc' appearance. MRI showed circumferential disease extending into the subcutaneous plane and encasement of posterior compartment vessels by 270 degrees, extending through the knee joint. The patient underwent open synovectomy and excision of the mass, which measured 15×7×4 cm. At 2 years postoperative follow-up, the patient has had no recurrence of disease and achieved a Musculoskeletal Tumor Society score of 28/30 on clinical examination. The patient reported no flexion deformity and demonstrated knee ROM of 0-90 degrees.