Background Clarification of the indications for patellar resurfacing in total knee arthroplasty (TKA) is still necessary. Few studies of adequate power have evaluated functional differences between total knee arthroplasty with and without patellar resurfacing, in particular walking gait. This study aimed to identify clinically relevant differences in knee kinematic or kinetic parameters during level walking between total knee arthroplasty with and without patellar resurfacing, after controlling for pre-surgery gait parameters.Methods. Kinematic and kinetic gait analysis of level walking was performed on 34 subjects (41 knees) before and 12-18 months after total knee arthroplasty with patellar resurfacing performed randomly. Linear regression analysis was used to examine the influence of patellar resurfacing upon gait variables whilst controlling for the corresponding pre-surgery measure.Findings. The pre-surgery value was a moderate to strong significant predictor of all post-surgery temporal-spatial and kinetic gait parameters (p < 0.001-0.008), and most kinematic parameters (p < 0.001-0.066). The addition of patellar resurfacing to the regression models did not improve the predictive power in any case. Only one parameter, knee flexion at heel-strike, displayed a difference near statistical significance between total knee arthroplasty with and without patellar resurfacing (10 degrees versus 7 degrees respectively, p = 0.023).Interpretation. Pre-surgery gait patterns are an important determinant of post-surgery gait. There are no clinically relevant differences in walking gait between total knee arthroplasty performed with or without patellar resurfacing, using the Profix design. (c) 2005 Elsevier Ltd. All rights reserved.