Patellar resurfacing in total knee replacement: five-year clinical and economic results of a large randomized controlled trial.

BACKGROUND There is conflicting evidence regarding the merits of patellar resurfacing during total knee arthroplasty, as many of the previous randomized controlled trials have not been adequately powered. METHODS A pragmatic, multicenter, randomized controlled trial was initiated in 1999 in the United Kingdom. Within a partial factorial design, 1715 patients were randomly allocated to receive or not receive patellar resurfacing during total knee arthroplasty. The primary outcome measure was the Oxford Knee Score; secondary measures included the Short Form-12, the EuroQoL 5D, cost, cost-effectiveness, and the need for subsequent knee surgery. RESULTS The mean Oxford Knee Score was 35 points at five years postoperatively in both groups. There was no significant difference between the groups with respect to the mean Oxford Knee Score (difference, 0.59 point; 95% confidence interval, -0.58 to 1.76 points) or any other outcome measure at five years postoperatively. The outcome was not affected by whether the patella was domed or anatomic. There was no significant difference between the two groups with respect to the prevalence of knee-related readmission, of minor or intermediate reoperation, or of subsequent patella-related surgery. The total health care cost for the primary arthroplasty, subsequent monitoring, and any revision surgery did not differ significantly between the two groups. CONCLUSIONS In the largest randomized controlled trial of patellar resurfacing reported to date, the functional outcome, reoperation rate, and total health care cost five years after primary total knee arthroplasty were not significantly affected by the addition of patellar resurfacing to the surgical procedure.