63 – A RANDOMISED CLINICAL TRIAL COMPARING PATELLAR RESURFACING VERSUS PATELLAR RETENTION IN TOTAL KNEE ARTHROPLASTY

Abstract

Purpose: Despite the excellent results of total knee arthroplasty (TKA), controversy over whether or not to resurface the patella persists. Anterior knee pain, which occurs with variable frequency, continues to be a problem in a subset of the TKA patient population. Some clinicians advocate resurfacing all patellae while others cite the complications attributed to patellar resurfacing as reasons to avoid this aspect of the procedure. Still others favour selective resurfacing based on subjective criteria. To address this clinical controversy, we prospectively randomized patients receiving TKA into two groups, those receiving patellar resurfacing and those left without resurfacing to determine clinical outcomes and revisions at five and 10 years postoperatively. Our primary objective was to compare the revision rate following TKA between the two study groups. Secondarily, we compared pain and function at five and 10 years and knee range of motion (ROM) over the first year.

Method: Patients receiving TKA were prospectively enrolled in the study and randomized intraoperatively to either receive patellar resurfacing or have no patellar intervention. All surgeries were performed through the standard medial parapatellar approach. The Smith and Nephew Profix TKA system was implanted in all cases and all subjects followed a standardized post-operative regimen. Subjects were assessed pre-operatively and at 6 months, 1, 3, 5 and 10 years postoperatively for knee ROM, function, and pain using the WOMAC and SF-36 questionnaires. Re-operations and revisions were also documented.

Results: Thirty-nine patients were enrolled in the study. There was 83% patient retention at five years and 74% at 10 years. Study groups were similar in baseline characteristics. At five years, three (18%) revisions had been performed in the retained patella group and one (5%) in the resurfaced group (p=0.31). There were no further revisions between five and 10 years. ROM was similar between the groups at all evaluations (p> 0.05). SF-36 and WOMAC scores demonstrated that both groups improved their pain and function significantly following surgery (p< 0.04).

Conclusion: The decision whether or not to resurface the patella during TKA remains controversial. This study demonstrated that initial results with either technique are comparable, but it appears that there may be clinically significant differences by five years postoperatively. These trends continued throughout the study and were statistically significant at the 10 year mark. Revision surgery was required in 18% of the retained group compared to 5% in the re-surfaced group.