Stair ambulation in persons with transtibial amputation: an analysis of the Seattle LightFoot

The purpose of this study was to document gait patterns in a group of individuals with transtibial amputations (TTA) during stair ambulation, and to identify the functional limitations associated with this task. Ten persons with TTA fitted with a Seattle LightFoot prosthetic component, and 14 nondisabled subjects participated in this study. Electromyographic activity (EMG) of the vastus lateralis (VL), rectus femoris (RF), gluteus maximus (GMAX), semimembranosus (SMEMB), biceps femoris long head (BFLH), and biceps femoris short head (BFSH) was assessed using indwelling wire electrodes during ascending and descending stairs. Lower limb kinematics (VICON) and stride characteristics (Footswitch Stride Analyzer System) also were collected. Stride characteristics revealed that those with TTA had a significantly slower rate of stair ambulation and demonstrated stance phase asymmetry between limbs compared to the nondisabled. Kinematic analysis determined significant limitations in prosthetic ankle motion, which necessitated compensatory functions at the hip and knee to accomplish stair ascent and descent and resulted in significantly greater muscular effort (increased EMG intensity and duration) compared to nondisabled.