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

Area of Science:

• Orthopedics
• Biomechanics
• Osteoarthritis Research

Background:

• Knee osteoarthritis (OA) affects millions globally, often leading to total knee arthroplasty (TKA).
• Muscle strength imbalances, particularly in knee extensors, may influence OA progression and TKA risk.

Purpose of the Study:

• To investigate the association between knee extensor strength asymmetry and the likelihood of undergoing TKA.
• To determine if limb-specific strength deficits correlate with TKA risk.

Main Methods:

• Longitudinal cohort study of 3,860 individuals from the Osteoarthritis Initiative.
• Categorization of participants based on a 10% difference in knee extensor strength between limbs.
• Kaplan-Meier curves and Cox regression analysis over a 10-year period, controlling for key covariates.

Main Results:

• Asymmetrical knee extensor strength elevated TKA risk by 30% over 10 years (HR: 1.30).
• A 10% strength deficit in the right leg increased right TKA risk by 40%.
• A 10% strength deficit in the left leg increased left TKA risk by 80%.

Conclusions:

• Knee extensor strength asymmetry is a significant predictor of TKA in knee OA patients.
• Interventions promoting quadriceps strength symmetry may be crucial for reducing TKA incidence.