CLINICAL OUTCOMES AND WALKING ANALYSIS AFTER TOTAL KNEE ARTHROPLASTY WITH AND WITHOUT PATELLAR RESURFACING: A PROSPECTIVE RANDOMISED TRIAL

Introduction and Aims: It is probable that the success of total knee arthroplasty without patellar resurfacing is influenced by the design of the femoral trochlea. The aim of this study was to compare measures of clinical outcome including gait analysis between total knee arthroplasty with and without patellar resurfacing using a prosthesis compatible with the native patella. Method: A prospective trial of 78 patients was performed, with 43 total knee arthroplasty randomised to receive patellar resurfacing and 48 to receive patellar retention. The mean duration of follow-up was 3.2 years (range 2.0–4.7 years). Patients were assessed pre- and post-surgery using the Knee Society Clinical Rating System, the Knee Pain Scale, and a Patellar Function Score. A subset of 34 patients also underwent pre- and post-surgery analysis of knee kinematics and kinetics during walking. Results: At a minimum two-year follow-up, total knee arthroplasty with patellar resurfacing had significantly lower Knee Society knee scores (Mann Whitney U test; p = 0.036). Total knee arthroplasty with patellar resurfacing exhibited a greater degree of knee flexion contracture (Mann-Whitney U test; p = 0.020) and significantly less knee extension at heelstrike during walking in those subjects undergoing gait analysis (Independent t-test; p = 0.013). The presence of a knee flexion contracture was a significant predictor of post-surgery anterior knee pain (Exp β = 4.1, CI: 1.1 to 14.9, p = 0.033). Post-surgery Knee Society function scores and Patellar Function Scores were significantly better in those patients with total knee arthroplasty without patellar resurfacing (Mann-Whitney test; p = 0.031 and 0.017 respectively). Conclusion: In this study using an anatomically designed femoral component with a domed patellar prosthesis, total knee arthroplasty with patellar resurfacing exhibited inferior clinical results as compared to total knee arthroplasty with patellar retention. Total knee arthroplasty with patellar resurfacing exhibited significant limitation of knee extension, which was significantly associated with the presence of post-surgery anterior knee pain (p = 0.033).