Total Condylar Knee Replacement: Preliminary Report

Since 1970, approximately 750 knee replacements of various types have been performed at The Hospital for Special Surgery. The designs used have included both condylar and hinge type prostheses. The results, while satisfactory, have not approached the consistency or general excellence of hip arthroplasty. In particular there are certain problem areas which continue to present difficulty. These include:

Patellofemoral Joint. It has become apparent that unsatisfactory pain relief following knee arthroplasty is often due to the patellofemoral articulation. About 15 per cent of the patients with arthroplasties have severe and disabling pain from this source and many more have minor or intermittent symptoms. The problem is greater in osteoarthritis than rheumatoid arthritis. Patellectomy has not proved a solution.

Fixation of the Tibial Component. A radiolucent line develops around the plastic tibial component with great frequency, often becoming more pronounced with time. While the significance of such radiolucencies is not fully determined, it is probable that they represent insecure fixation. Wilde has reported 10 per cent of clinical loosening of the tibial component requiring reoperation and our experience has been similar. The frequency of radiolucency is much greater for the tibial component than the femoral and this is consistent with the observed loosening of the component.

Surgical Technique. Knee arthroplasty is a difficult technical procedure. Moreover, the problems of accurate placement increase with the degree of preoperative deformity and contracture making hinge type arthroplasty attractive in these circumstances. The disadvantages of hinges are well known and it is evidently desirable that a non-hinge prosthesis should have wide applicability without presenting insuperable difficulties during insertion.

The Total Condylar Prosthesis (TCP) was developed as our solution to these problems. This paper presents the preliminary experience with particular emphasis on design feature and technique.