[Long-term outcome of a silastic semilunar bone prosthesis]

Eight silastic implants of the lunate bone were inserted between 1980 and 1984 on 8 patients. Seven patients were seen, at a ten year follow-up visit and were satisfied with the results. However, STT osteoarthritis secondary to the carpal collapse had to be stabilized by a triscaph arthrodesis. The clinical course showed a clear improvement of force and mobility in a first phase, followed by progressive deterioration ending in a return to preoperative values. Multiple intracarpal cysts were found radiologically in all wrists as well as in the distal radius in two cases and in the metacarpal bones in 3 cases. The height of the prosthesis was decreased by about 36%. Carpal collapse and ulnar translation showed a statistically significant progression. According to these findings, silastic prostheses should no longer be recommended.