OBJECTIVE: To determinethe correlation between performance of the knee muscles and pain, stiffness, and functionality, through theWestern Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Questionnaire applied to an elderly population with osteoarthritis of the knee (OA). METHODS: This study uses an observational, cross-sectional approach applied to a convenience sample of 80 elderly individuals (71.2 ± 5.3 years of age) with a clinical diagnosis of OA of the knee. Muscle strength, resistance, and balance of the knee were evaluated using the Biodex System 3 Pro isokinetic dynamometer at angularspeedsof 60º/s and 180º/s. The self-reported functionality, presence of pain, and stiffness were evaluated by the WOMAC questionnaire. The correlation between the variables was analyzed bySpearman's coefficient of correlation (α = 0.05). RESULTS: A significant inverse correlation was observed between muscle strength and resistance of the quadriceps muscle (Q) and the hamstring muscle (H) at speeds of 60º/s and 180°/s, respectively, as well as in the relation between H/Q muscle balance at 180°/s and all domains of the WOMAC (p?0.05). CONCLUSIONS: The reduction in strength, resistance, and presence of imbalance in the knee muscles are inversely correlated with all the domains of the WOMAC in elderly individuals with OA. These results indicate a need for intervention that involves strengthening, resistance, and balance of the knee extensor and flexor muscles, aimed at reducing the impact of OA in relation to pain, stiffness, and functionality in elderly individuals. Level I, diagnostic studies - investigating a diagnostic test.
Osteoarthritis; Muscle strength; Aged
