Inter-Limb Strength Asymmetry and Risk of Total Knee Replacement: A Survival Analysis

The current study explored the association between knee extensor strength asymmetry and the risk of total knee arthroplasty in individuals with or at risk of knee osteoarthritis.

This longitudinal cohort study analyzed data from the Osteoarthritis Initiative, including 3860 individuals with or at risk for knee osteoarthritis. Participants were categorized as having symmetrical or asymmetrical knee extensor strength based on a 10% difference between limbs. Kaplan-Meier curves and Cox regression assessed the risk of total knee arthroplasty over 10 yrs, adjusting for age, sex, body mass index, baseline Kellgren-Lawrence grade, absolute weakness, and baseline pain.

Participants with asymmetrical knee extensor strength had a 30% greater risk of undergoing total knee arthroplasty over 10 yrs compared to those with symmetrical strength (hazard-ratio: 1.30, 95% CI [1.05,1.62]). Limb-specific analyses revealed that a 10% reduction in right and left knee extensor strength were associated with a 40% and 80% increased risk of right and left total knee arthroplasty, respectively.

Knee extensor strength asymmetry was associated with the risk of total knee arthroplasty in individuals with or at risk for knee osteoarthritis. Findings support the need to further examine if an intervention targeted at quadriceps strengthening aimed at achieving and maintaining strength symmetry can reduce total knee arthroplasty risk.