Gait recovery is a major objective in the rehabilitation of patients who experience a stroke. For many, the inability to bend the knee sufficiently to stride forward can result in falls or awkward locomotion. A lightweight device incorporating a spring-cam mechanism was designed for use with an ankle foot orthosis to help these patients regain normal walking function.The device is designed to help stroke patients by improving their walking and preventing falls. Source: Tohoku University

As the wearer steps forward, ankle movement in the affected leg induces an elliptical-shaped cam in the device to roll against an integrated coil spring, compressing it. As weight is taken off that leg in preparation for a forward stride, the spring is released, pushes the heel up and supports ankle push-off and strengthens knee flexion forces.

The device developers from Tohoku University and NEC Corporation, Japan, tested the spring-cam system with 11 stroke patients. All demonstrated increased knee flexion and walking stability as the device generated adequate ankle power. Continued use of the walking aid is expected to help users regain the muscle memory needed to sustain a normal gait.