Arthroplasty of the knee joint. With special reference to complications

Ninety-one arthroplasties of the knee joint--all performed by the same orthopaedic surgeon, were followed for from 6 months to 6 years (mean 3.5 years). At the time of the primary operation the mean age of the patients, most of whom had rheumatoid arthritis, was 60 years. The prostheses most often used were the Geomedic, the modular and the polycentric. The most consistently good results were achieved with the Geomedic prosthesis. The primary arthroplasty failed in 16 knees (17.6%); deep infections developed in four knees (4.4%). In three knees the prosthesis fractured and in two knees the supporting bone fractured. All these fractures occurred in the medial compartment of the knee joint. Loosening of the prosthesis--with or without concomitant infection or fracture of the prosthesis--was the most common local complication (nine knees). Reoperations were performed, during the follow-up period reported on here, on all knees in which complications developed, except one. Eight knees, about 9%, required arthrodesis. In six knees the prosthesis was replaced, and one knee was treated by arthrotomy and closed irrigation. The four deep infections resolved during the follow-up period--one after arthrodesis of the joint and one after arthrotomy and closed irrigation. In the other two knees with deep infection the prosthesis was replaced.