To examine thigh muscle strength, functional performance, and self-reported outcome in patients with nontraumatic meniscus tears 4 years after operation, and to study the impact of a strength deficit on self-reported outcome and evaluate the feasibility of 3 performance tests in this patient group.The study group comprised 45 patients (36% women, mean age 46.7) who had an arthroscopic partial meniscectomy a mean of 4 years (range 1-6 years) previously. Main outcome measures included isokinetic strength of knee extensors and flexors, functional performance (1-leg hop, 1-leg rising, and square-hop tests), and a self-reported questionnaire (Knee Injury and Osteoarthritis Outcome Score).We found lower knee extensor strength and worse 1-leg rising capacity in the operated leg, but no difference between operated and nonoperated leg for knee flexors (P < or = 0.004 and P > 0.3, respectively). Patients with a stronger quadriceps of the operated leg compared with the nonoperated leg had less pain and better function and quality of life (r = 0.4-0.6, P < or = 0.010). We found the 1-leg rising and 1-leg hop tests to be suitable performance tests in middle-aged meniscectomy patients.Quadriceps strength is reduced in the meniscectomized leg compared with the nonoperated leg 4 years after surgery. This relative quadriceps weakness significantly affects objective and self-reported knee function, pain, and quality of life, indicating the importance of restoring muscle function after meniscectomy in middle-aged patients.