Unidirectional mobile bearing knees (RP) were developed to optimise the tibio-femoral articulation in an effort to enhance function and reduce polyethylene wear. The self aligning bearing should also benefit the patello-femoral joint further improving outcome. This study was designed to assess whether these potential benefits are realised in the clinical setting. A total of 352 patients undergoing a PS PFC Sigma TKR were randomly allocated to receive either a Mobile Bearing (176 knees) or a Fixed Bearing (176 knees) tibial tray. Within each group a further randomisation for patella resurfacing versus retention was included. All knees were scored using standard tools (Oxford, AKSS, Patella Score) by independent nurse specialists. At 5 year review there had been 38 deaths (19 in each group), 5 revisions (4 fixed, 1 RP), 7 late patella resurfacings (4 fixed, 3 RP) and a small number of other patients had withdrawn, leaving 142 fixed bearing knees and 144 mobile bearing knees for evaluation.Introduction
Methods
