A randomized controlled trial of fixed-versus mobile-bearing total knee arthroplasty

Aims It has been suggested that mobile-bearing total knee arthroplasty (TKA) might lead to better outcomes by accommodating some femorotibial rotational mismatch, thereby reducing contact stresses and polyethylene wear. The aim of this study was to determine whether there is a difference between fixed- and mobile-bearing versions of a contemporary TKA with respect to durability, range of movement (ROM) and function, ten years postoperatively. Patients and Methods A total of 240 patients who were enrolled in this randomized controlled trial (RCT) underwent a primary cemented TKA with one of three tibial components (all-polyethylene fixed-bearing, modular metal-backed fixed-bearing and mobile-bearing). Patients were reviewed at a median follow-up of ten years (IQR 9.2 to 10.4). Results There was no difference in durability, as measured by survivorship free of revision for any reason, nor in mean maximal ROM at ten years (p = 0.8). There was also no difference in function, as measured by Knee Society (KS) function scores (p = 0.63) or the prevalence of patellar tilt (p = 0.12). Conclusion In this clinical RCT, the mobile-bearing design of TKA was found to be reliable and durable, but did not provide better maximum knee flexion, function or durability ten years postoperatively compared with a posterior-stabilized, fixed-bearing design incorporating either an all-polyethylene or a modular-metal-backed tibial component.