Component asymmetry in simultaneous bilateral total knee arthroplasty.

Component size asymmetry and knee scores were determined in a review of 253 patients undergoing simultaneous or same-day, bilateral total knee arthroplasty (TKA). Asymmetry in component sizes was found in 22 (8.7%) pairs of femoral components, 17 (6.7%) pairs of tibial components, and 13 (5.1%) pairs of patellar components. Asymmetric and symmetric total knee arthroplasties were seen equally in men and women, and there was no statistical difference in knee scores and range of motion between patients with symmetric or asymmetric arthroplasties. Asymmetry rates for anterior referenced femoral components were significantly higher than posterior referenced components, an unexpected finding of unknown significance. Awareness of the incidence of component asymmetry and the practice of independent sizing of each knee during bilateral TKA is important to continue the success of bilateral TKA in a growing patient population.