Methods for Improving Ability to Investigate the Effectiveness of Non-Invasive Treatment Strategies for Medial Knee OA
Osteoarthritis (OA) is the most common form of arthritis, occurring frequently in the medial compartment of the knee. As the onset and progression of medial knee OA has been associated with abnormal and excessive loading of the joint, non-invasive treatment options often focus on joint load reduction to slow the progression of the disease. However, a need persists for further development of methods for analysing the effectiveness of existing and potential treatment strategies. Unloader braces are one common form of treatment for knee OA, which primarily function by applying a moment at the knee to reduce loading and increase joint separation in the medial compartment. We developed a novel method based on measuring brace deflection using motion capture techniques to estimate the mechanical effect of valgus braces. Brace moments computed using the motion capture method for three subjects during static and walking trials were validated using strain gauge instrumentation. A second, promising treatment option we explored was biofeedback-assisted gait retraining, which uses live feedback to guide subjects towards an optimal and novel gait pattern that lessens medial compartment loads. We developed a biofeedback system that uses real-time kinematic and kinetic input measures to provide a live estimate of knee joint loading using a statistical regression model. By using a large group of training subjects with a variety of gait styles to generate the regression model, the system that was developed can provide feedback of an estimate of the joint contact forces in the knee for a variety of gait patterns. In summary, we developed (1) a method for measuring the mechanical effect of valgus bracing and (2) a biofeedback system that can be used in gait retraining to provide live feedback of an estimate of knee joint loads. These developments will provide us with the ability to further investigate the effectiveness of these non-invasive strategies for treating medial knee osteoarthritis. In doing so, we will be able to continue developing these treatment options towards providing more pain relief and improvements in function for a larger group of individuals with knee OA, potentially delaying or preventing the need for surgical interventions.