Patellofemoral problems are a common cause of morbidity and reoperation after total knee arthroplasty. We made a prospective study of 52 patients who had bilateral arthroplasty (104 knees) and in whom the patella was resurfaced on one side and not on the other. A movable-bearing prosthesis with an anatomical femoral groove was implanted on both sides by the same surgeon using an otherwise identical technique. The mean follow-up was 5.24 years (2 to 10). In the 30 available patients (60 knees) there was no difference between the two sides in subjective preference, performance on ascending and descending stairs or the incidence of anterior knee pain. Radiographs showed no differences in prosthetic alignment, femoral condylar height, patellar congruency or joint line position. The use of an appropriate prosthetic design and careful surgical technique can provide equivalent results after knee arthroplasty with or without patellar resurfacing. Given the indications and criteria, which we discuss, retention of the patellar surface is an acceptable option.

When aseptic failure of the bond between the cement and the prosthesis of a total joint replacement occurs, complete removal of the cement has been advocated before the insertion of a new prosthesis. The present study questions this practice. Both laboratory tests on variously prepared specimens of cement and clinical experiences demonstrate that recementing over old cement is a practical alternative if the technique employed includes the removal of blood from the old cement surface, rasping of this surface and the early application of fresh cement.