Muscle Strength and Osteoarthritis Progression After Surgery or Exercise for Degenerative Meniscal Tears: Secondary Analyses of a Randomized Trial.

Abstract

To evaluate muscle strength changes following partial meniscectomy or exercise therapy for degenerative meniscal tears and the relationship between baseline muscle strength and osteoarthritis progression. Secondary analysis of a randomized trial (n = 140 participants). Isokinetic quadriceps and hamstrings strength (peak torque [Nm/kg] and total work [J/kg]) were assessed at baseline, 3-month, 12-month, and 5-year follow-up. Between-group differences were analyzed using intent-to-treat linear mixed models. The relationship between baseline muscle strength and osteoarthritis progression (Kellgren/Lawrence ≥1 grade increase) were assessed using logistic regression models. We found statistically significant between-group differences favoring exercise therapy at 3 months (quadriceps -0.30 Nm/kg [95% confidence interval (95% CI) -0.40, -0.20]; hamstrings -0.10 Nm/kg [95% CI -0.15, -0.04]) and 12 months (quadriceps -0.13 Nm/kg [95% CI -0.23, -0.03]; hamstrings -0.08 Nm/kg [95% CI -0.14, -0.03]). At 5 years, between-group differences were -0.10 Nm/kg (95% CI -0.21, 0.01) for quadriceps and -0.07 Nm/kg (95% CI -0.13, -0.01) for hamstrings. Quadriceps muscle weakness at baseline was associated with knee osteoarthritis progression over 5 years, with adjusted odds ratio of 1.40 for every 0.2 Nm/kg decrease (95% CI 1.15, 1.71). The adjusted odds ratio for hamstrings was 1.14 (95% CI 0.97, 1.35) for every 0.1 Nm/kg decrease. Exercise therapy was effective in improving muscle strength at 3- and 12-month follow-up compared to partial meniscectomy, but the effect was attenuated at 5 years. Quadriceps muscle weakness at baseline was associated with higher odds of osteoarthritis progression over 5 years.