Replacement of the knee in rheumatoid arthritis using the Imperial College London Hospital prosthesis (ICLH) 1977-1979.

The Imperial College London Hospital (ICLH) technique and prosthesis for the total replacement of the knee was evolved over the period 1968 to 1977. The results now reported were obtained at The London Hospital on rheumatoid knees operated upon in the period 1977 to 1979. These knees were reviewed and the results published with a one to 2 year follow-up in 1981. In the present paper this review has been extended to 3 to 5 years. We find that in successfully replaced knees the quality of the clinical result has remained unchanged over the extended period of review. Certain further complications have been encountered which are described. These complications have led us to the conclusion that whereas we previously accepted post-operative alignments between one and 10 degrees of valgus, we should now adjust these limits. We now regard a knee having anything less than 5 degrees of valgus post-operatively as having been incorrectly replaced. The limits of valgus can perhaps be extended to 15 degrees. Experience over the period 1977 to 1980 suggested the possibility of further improvements in both the operative technique and the prosthesis. Accordingly the ICLH prosthesis has now been modified. The modified prosthesis (the Freeman-Samuelson prosthesis) is described in this paper but results with it are not reported.