Kinetic and kinematic changes with the use of valgus knee brace and lateral wedge insoles in patients with medial knee osteoarthritis

Abstract

The effect of a valgus knee brace and a lateral wedged insole on knee and ankle kinematics and kinetics was evaluated in ten patients with medial knee osteoarthritis (OA). The knee orthosis was tested in two valgus adjustments (4° and 8°), and the laterally wedged insole was fabricated with an inclination of 4°. A motion capture system and force platforms were used for data collection and joint moments were calculated using inverse dynamics. The valgus moment applied by the orthosis was also measured using a strain gauge implemented in the orthosis' rotational axis. For the second peak knee adduction moment, decreases of 18%, 21%, and 7% were observed between baseline and test conditions for the orthosis in 4° valgus, in 8° valgus, and insole, respectively. Similar decreases were observed for knee lever arm in the frontal plane. Knee adduction angular impulse decreased 14%, 18%, and 7% from baseline to conditions for the orthosis in 4° valgus, in 8° valgus, and insole, respectively. Knee angle in the frontal plane reached a more valgus position during gait using the valgus knee brace. The valgus moment applied by the orthosis with 8° valgus adjustment was 30% higher than with 4° valgus adjustment. The valgus knee orthosis was more effective than the laterally wedged insole in reducing knee adduction moment in patients with medial knee OA.