Biomechanical investigation of the efficacy and perceived performance of a knee brace

Abstract: The most prevalent joint disease in adults is osteoarthritis. The knee joint is the joint which is the most affected by osteoarthritis, with mechanical overloading being one of the causes. While no cure exists for osteoarthritis, many different treatment options are available. One alternative is to wear a knee brace on the affected leg. This aims to slow down the progression of osteoarthritis to postpone, or remove the need for, more invasive surgical treatments. Several studies reported that knee braces can lower the perceived pain in patients. However, there is no consensus regarding the biomechanical effect of wearing knee braces, both at the level of the affected knee and in terms of overall effects on gait. The aim of this thesis was to see how the knee brace OA Nano (Enovis) affects gait kinematics and the forces associated with gait. Gait analysis was performed on seven healthy subjects when wearing a knee brace, using video recording for retrieving kinematic data and a force plate for kinetic data. In addition, a design investigation was also conducted to evaluate the knee brace and determine any design improvements. Our results indicates that the gait is not affected by the knee brace, as no significant changes was found in neither ground reaction forces nor any of the investigated gait parameters. When wearing a knee brace, the gait speed varied from 0.75 – 1.20 m/s with brace to 0.78-1.21 m/s without brace. The step length differences varied from -8 to +4 cm in both legs when wearing the brace. The range of motion in the brace wearing leg decreased slightly, between 0° and -11° when wearing the brace. The overall appearance of the graph of the knee angle was similar for all subjects and some differences were found, ranging from 4° lower to 8.3° higher during the gait cycle when wearing the brace. The greatest differences in the ground reaction forces were found to range from -11.6% to 13.9% in the peaks when wearing a knee brace. We conclude that the knee brace does not affect the investigated gait parameters in healthy subjects, as all differences either lie within the standard deviations or are of the same magnitude as the error of the measuring systems. As for the design of the knee brace, the overall design was appreciated by the participants. However, the straps were often fastened in the wrong order and more distinct numbering of the straps was suggested in the design.