Synovial Chondromatosis.

Synovial chondromatosis is a rare, benign condition of unknown etiology in which the synovium undergoes metaplasia leading to cartilaginous nodules that ultimately break free, mineralize, and even ossify. The most commonly involved joint is the knee. Patients may be asymptomatic or may present with pain, swelling, and limited range of motion. Plain radiographs can be diagnostic and mineralized nodules are pathognomonic. Recommended treatment involves arthroscopic or open removal of loose bodies with or without a synovectomy to prevent further articular and periarticular destruction and to relieve symptoms.