Isokinetic Strength and Functional Status in Knee Osteoarthritis

Muscle function and functional performance are affected in patients with osteoarthritis (OA). The aim of the study was to investigate and compare the concentric torque of knee muscles (quadriceps and hamstring) and functional status in two matched groups: one group of patients with low grade of tibiofemoral OA, and one group of matched healthy subjects. Concentric peak torques of quadriceps and hamstring were measured in both groups at an angular velocity of 90 and 150 degree/second. In addition, selected functional tests, selected lower extremity range of motion (ROM) and thigh girth were assessed in both groups. The independent t-test revealed statistically significant differences between the two groups with regard to isokinetic concentric peak torque at different angular velocities and for the timed walking test, as a measure of functional status. However, no significant difference in lower extremity joints’ ROM and thigh girth were seen. In conclusion, patients with knee OA, even in low grades and with minimum symptoms and signs, had muscle weakness and functional limitation in comparison with the matched healthy subjects. This weakness may result from a variety of factors, leading to muscle strength loss and functional limitation.