Primary Synovial Chondromatosis of the Knee in a 12-Year-Old Boy: A Case Report

Abstract

Case Presentation12-year-old boy presented to their primary care physician with a 6-month-long experience of symptoms of intermittent pain in the left knee as well as stiffness and a locking sensation when ambulating. The patient denied prior trauma or episodes of joint pain. Physical examination revealed no obvious abnormalities, and the patient was treated conservatively with rest, ice, compression, elevation, and physical therapy. Despite adherence to the recommended therapy, the patient returned to his physician six months later with recurrent knee swelling in addition to the previous symptoms. At this time, physical examination revealed left knee effusion and a palpable, firm mass behind the patellar tendon. Radiography of the left knee revealed a round, 2.5-cm calcified, dense formation in the anterior joint space, slightly hyperdense spots in the posterior joint space, and a small effusion in the suprapatellar region (Figure 1A). These findings were suggestive of synovial chondromatosis. The patient was referred to an orthopedic surgeon and underwent magnetic resonance imaging (MRI) for preoperative planning. The imaging findings (Figures 2A and 2B) were consistent with synovial chondromatosis, and the patient underwent