Foot clearance strategy for step-over-step stair climbing in transfemoral amputees

Abstract

Stair ascent is a particularly challenging task for transfemoral amputees. The aim of this clinical note was to describe the kinematic features of foot clearance in transfemoral amputee who can ascend stairs using a step-over-step strategy. The marker trajectories of the first metatarsophalangeal joint (Mt1) and clearance height were measured in two transfemoral amputees who could (TF1) and could not (TF2) climb stairs using a step-over-step strategy. The Mt1 marker trajectories of the TF1 moved backward in the early swing phase, and the trajectory followed an off-centered parabolic arc to achieve a similar clearance height as able-bodied subjects. TF2 could not climb the stairs without tripping in each step. An effective compensatory strategy to avoid tripping during stair climbing may be to use the hip joint for a backward extension and rapid flexion of the prosthetic leg during the early swing phase. The foot clearance strategy in transfemoral amputees who can climb stairs using a step-over-step strategy will help us better understand adaptive prosthetic control and thus develop more effective gait rehabilitation programs.