Introduction and Objectives: Synovial osteochondromatosis (SOC) is a benign synovial metaplasia of unknown pathogenesis characterised by the formation of multiple cartilaginous nodules. It is classified in 2 broad groups: primary and secondary. Treatment includes both arthroscopic and open surgical techniques and is directly related to the symptoms caused by these loose bodies in the joints.

Materials and Methods: This is a retrospective study of cases of SOC treated between 1990 and 2002 analysing localisation, number of joints affected, clinical presentation, and radiographic images. Type of treatment used and pathological findings were evaluated. SPSS 10.0 software was used for statistical analysis.

Results: From 1990 to 2002, 25 cases of SOC were treated. Of these, 15 cases were completely followed-up. The most frequent localisation was the knee (8 cases), followed by the hip, shoulder, ankle, elbow, and distal radio-ulnar joint. There was no significant difference in distribution by gender. A predominance was noted of monoarticular over poliarticular occurence. The most common symptoms described were chronic pain and limitation of mobility. The most common treatment was removal of the loose bodies and synovectomy using open surgery.

Discussion and Conclusions: SOC is an uncommon condition that may go undetected for years. It is manifested as slow-evolving pain, limitation in movement, and joint locking. At this stage, it is necessary to remove the loose bodies and perform a complete synovectomy in order to avoid recurrence. This may be done arthroscopically or with open surgery, as long as complete removal of all cartilaginous nodules and the synovial tissue is confirmed.