BACKGROUND: Decreased quadriceps and hamstring muscle function appears to be greater in the elderly population with knee osteoarthritis. This may be due to lower physical activity levels or to pain and swelling. OBJECTIVE: To compare quadriceps and hamstring performance in elderly people with and without knee osteoarthritis and to correlate this with pain and swelling. METHOD: The sample was composed of 15 elderly people with bilateral knee osteoarthritis (osteoarthritis group) and 15 asymptomatic elderly people (asymptomatic group). The Biodex System 3-Pro® isokinetic dynamometer was used to evaluate muscle performance, and a visual analog scale (VAS) to register the pain. The swelling was assessed by a manual test. Student's t test was applied to compare the demographics, anthropometric variables, quadriceps work, hamstring work and hamstring/quadriceps ratio. The chi-squared test was used to compare physical activity levels and Spearman coefficients to verify correlations between the swelling and pain variables and the quadriceps work, hamstring work and hamstring/quadriceps ratio. RESULTS: No statistically significant differences were detected between the anthropometric variables, demographics and physical activity levels (p > 0.05). Quadriceps work was statistically smaller (p = 0.001) in the osteoarthritis group and the hamstring/quadriceps ratio was statistically larger in this group (p = 0.04). There was no correlation between the pain and swelling variables and the quadriceps work, hamstring work and hamstring/quadriceps ratio (rho < -0.468; p > 0.229). CONCLUSION: The reduced muscle function among elderly people with knee osteoarthritis cannot solely be attributed to the lower physical activity levels of this population.
elderly people; knee osteoarthritis; physical activity; pain; swelling; muscle dysfunction
