Synovial chondromatosis is a monoarticular synovial proliferative disease that is characterized by cartilaginous, fibrocartilaginous, or osteochondral vesicles in the synovial membrane of the joints, synovium, and tendon sheaths. The most common group of patients with the disease is young adults, and it often involves one joint, primarily the knee, followed by the hip, elbow, and shoulder joints. The main clinical manifestations of the disease are pain, swelling, and limited joint motion. As the disease progresses, the enlargement of the joint may gradually increase and multiple free bodies may appear in the joint cavity. The principle of treatment is arthroscopic removal of free bodies. If the synovial membrane is hypertrophic and edematous with multiple nodules attached, synovectomy should be performed at the same time, but it is difficult to restore normal joint function. Some scholars believe that synovectomy is not better than free body removal alone. There may be recurrence after surgery, and in rare cases, it may turn into chondrosarcoma.