Stance-Control-Orthoses with Electromechanical Actuation Mechanism: Usefulness, Design Analysis and Directions to Overcome Challenges

Abstract

Engineers and researchers have devotedly sought to improve and develop the design of lower limb orthosis in the last few decades to enhance the mobility, strength, and endurance of impaired individuals. The achievements in design are impressive, but a myriad of design challenges are still appended in making these designs biomechanically user-friendly and commercially viable. Individuals with weak quadriceps have limited orthotic option to allow independent ambulation. Knee–ankle–foot orthosis (KAFO) are typically prescribed. KAFOs lock the knee in full extension to provide knee stability during walking and keep locked throughout the gait cycle. Locked knee in the swing phase leads to an abnormal gait pattern and causes hip hiking of the braced leg, circumduction and contralateral foot vaulting. Stance control orthosis is designed to release the knee during the swing phase to allow free knee motion and keep the knee locked in full extension during stance. The gait pattern of users then becomes more natural by overcoming the limitations of KAFO. This article analyses designs of various stance control orthosis and prototype with electromechanical actuation mechanism and discusses the design challenges.