Thigh muscle strength, functional capacity, and self-reported function in patients at high risk of knee osteoarthritis compared with controls.

OBJECTIVE: Reduced muscle strength is suggested as a risk factor for knee osteoarthritis (OA). Meniscectomy patients have an increased risk of developing knee OA. The aim of this study was to identify reductions in different aspects of muscle strength as well as objectively measured and self-reported lower extremity function in middle-aged patients who had undergone a meniscectomy compared with controls.
METHODS: Thirty-one patients who had undergone surgery in 2006 and 2007 (mean ± SD age 46 ± 6 years, mean ± SD body mass index [BMI] 26 ± 4 kg/m(2), and mean ± SD postsurgery 21 ± 6 months) and 31 population-based controls (mean ± SD age 46 ± 6 years and mean ± SD BMI 26 ± 4 kg/m(2)) were examined for maximal muscle strength and rapid force capacity, distance achieved during the one-leg hop test, and the maximum number of knee bends performed in 30 seconds. The Knee Injury and Osteoarthritis Outcome Score (KOOS) was used to determine self-reported outcomes.
RESULTS: No differences were detected in any muscle strength variables between the operated and nonoperated leg (mean ± SD quadriceps maximum voluntary contraction of 2.80 ± 0.10 for the operated leg and 2.88 ± 0.10 for the nonoperated leg), between patients and controls (mean ± SD torque of 2.70 ± 0.09 Nm × kg(-1) for the controls; P = 0.26 for main effect leg), or in objectively measured function (P ≥ 0.27). Patients reported 10-26 points worse KOOS scores in all 5 subscales (P < 0.001).
CONCLUSION: Thigh muscle strength is not impaired in middle-aged adults 2 years after resection of a degenerative tear. Our findings indicate that factors other than muscle strength are responsible for the perceived functional limitations and suggest that training to improve strength alone may not be sufficient to improve self-reported function in patients at high risk of knee OA.