Design and Evaluation of a Soft Knee Exosuit for Reducing Knee Medial Compartment Load During Walking

The knee joint experiences substantial moment in the frontal plane during walking, with the medial compartment bearing a greater load, potentially contributing to the development of knee osteoarthritis. The knee adduction moment (KAM) is a critical factor in this process. In this study, we introduce a novel knee exosuit that directly provides an abduction moment in the frontal plane by cable actuation, aiming to reduce the KAM and the knee medial compartment load. Unlike existing exosuits or exoskeletons, our exosuit addresses the knee stability in the frontal plane. The exosuit features a moment arm extension device and corresponding control strategies. Multiple wearer walking experiments were conducted to evaluate its efficacy. Experimental results demonstrated that with the exosuit's assistance, the first peak of the net KAM was reduced by 28.71%, and the second peak decreased by 39.56%. Additionally, lateral muscle activity was reduced. Biomechanical computations conducted in OpenSim revealed that the first peak of knee medial compartment contact force decreased by 19.93%, and the second peak by 21.28%. This study highlights the importance of knee stability in the frontal plane and suggests that the exosuit has positive implications for the prevention of knee osteoarthritis.