SILASTIC IMPLANTS OF THE SCAPHOID AND LUNATE - A LONG-TERM CLINICAL-STUDY WITH A MEAN FOLLOW-UP OF 13 YEARS

39 implant replacement arthroplasties were reviewed with a mean follow -up of 13 years. The study includes nine cases of partial replacement of the proximal pole of the scaphoid, 16 cases of total replacement of the scaphoid and 14 cases of replacement of the lunate. In 33 cases t he conventional silicone elastomer (CSE) was used and in six the high performance elastomer (HP). Subjective, clinical and radiological eval uations gave different results. Respectively the results were excellen t in 41, 23 and 5%, satisfactory in 41, 49 and 39% and poor in 18, 28 and 56% of the cases. Lytic lesions in carpal and/or pericarpal bones were present in all except two cases. Study of the X-rays chronologica lly revealed that they increased in number and size. Six cases had the ir implant removed. All had histologically proven silicone synovitis. A major secondary operation has been performed or is foreseen in all c ases except one. We do not recommend implant replacement arthroplasty for the scaphoid or the lunate bone.