UCSF

Osteoarthritis (OA) progression in the contralateral limb after unilateral total knee arthroplasty (TKA) may be related to altered and asymmetrical movement patterns that overload the contralateral joints. The purpose of this study was to determine if biomechanical factors after unilateral TKA were associated with future contralateral TKA. One hundred and fifty-eight individuals who underwent unilateral TKA completed three dimensional motion analysis 6-24 months after unilateral TKA (baseline). Subjects were re-contacted for follow-up (mean 5.89 years after baseline testing) to determine if they had undergone a contralateral TKA. Biomechanical variables from gait at baseline were compared between those who did and did not undergo contralateral TKA at follow-up using one-way ANOVAs. Odds ratios were calculated for variables found to be significant in the ANOVA models. Individuals who underwent contralateral TKA had less knee flexion excursion (10.5° vs. 12.1°; p = 0.032) and less knee extension excursion (8.2° vs. 9.6°; p = 0.035) at baseline on the operated side during walking. Individuals who underwent contralateral TKA also had less knee flexion excursion on the contralateral limb at baseline (11.9° vs. 14.0°; p = 0.017). For every additional degree of knee flexion excursion on the contralateral knee at baseline, there was a 9.1% reduction in risk of future contralateral TKA. Individuals who walked with stiffer gait patterns were more likely to undergo future contralateral TKA. Clinical Significance: Altered movement patterns after surgery may increase the risk for contralateral TKA. Knee excursion is an important metric to include in outcome studies and may serve as a target of rehabilitation after TKA. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:397-402, 2019.