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

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 degrees and 8 degrees), and the laterally wedged insole was fabricated with an inclination of 4 degrees. 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 degrees valgus, in 8 degrees 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 degrees valgus, in 8 degrees 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 degrees valgus adjustment was 30% higher than with 4 degrees 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. (C) 2011 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:11251132, 2012