What is synovial chondromatosis and how does it present?
Synovial chondromatosis is characterized by the development of multiple foci of cartilaginous metaplasia (neoplasia) in the subsynovial compartment. These foci form nodules that may be invaded by blood vessels leading to endochondral ossification (termed osteochondromatosis). The chondral nodules are frequently released as free bodies (joint mice) into the joint space. It most commonly affects men in their 30s to 50s. It is almost always monoarticular affecting the knee (50%) more than the hip, shoulder, ankle, elbow, or other joints. Clinically, there is increasingly limited range of motion with crepitus and often with unexpected locking. Effusions and stiffness may occur.