Design and evaluation of a hydraulic mechanism with available components for passive knee prostheses

Abstract

Background Hydraulic knee prosthesis can provide stance phase control and swing phase control suitable for active persons with an amputation. However, typical commercial hydraulic knees are costly and require frequent maintenance making them inaccessible for persons with an amputation in low-income countries. The objective of this article is to present a new design for a low-cost hydraulic knee prosthesis. Method The prototype hydraulic knee is made of simple hydraulic components. The hydraulic system was designed to provide flexion locking during the stance phase and damping during the swing phase of gait. Results The prototype was tested and results show that the hydraulic knee can prevent flexion of the knee at stance phase when the highest external knee flexion moment in the gait cycle occurs. The prototype mechanism is capable of resisting flexion torque of 60 N-m. Conclusions The prototype hydraulic knee can be assembled from available hydraulic components for low cost and ease of maintenance which is feasible for persons with an amputation in low-income countries. IMPLICATIONS FOR REHABILITATION A new design hydraulic knee which assembled from simple hydraulic components which provide both stance control and swing control. The use of simple hydraulic components makes the knee feasible for low-income country where service and maintenance staff is inadequate.