Cystic osteolysis induced by silicone rubber prosthesis

Synovitic symptoms and radiologically documented cystic lesions in several carpal bones and distal radius developed two years after the implantation of silicone rubber scaphoid prosthesis for pseudoarthrosis. Open biopsy revealed granulomatous synovitis and osteitis and foreign material in carpal tissues. Ultrastructurally dense material was found in the cytoplasm of histiocytic, often multinucleated cells. Electron-probe analysis of the material showed a definite peak for silicon, proving the causal relationship of symptoms and signs to the silicone rubber prosthesis.