Synovial osteochondromatosis is a rare disease characterized by cartilaginous and osseous metaplasia of the joint synovium. While it may affect practically any synovial joint, the knee is most often affected. An imperforate suprapatellar plica is also a rare finding in the knee. We report an exceptionally rare case of synovial osteochondromatosis of the knee characterized by isolated multiple loose bodies in the suprapatellar bursa caused by imperforate suprapatellar plica in a 52-year-old woman. The case was successfully treated by arthroscopic surgery. A worse-case scenario and possible diagnostic and therapeutic challenges are discussed.