Comparison of the Effects of Two Prosthetic Feet on the Biomechanics of a Unilateral Trans-femoral Amputee Gait in Slope Walking

Biomechanical behavior of prosthetic feet on slope is a challenging and important issue to study. The goal of this case study was to determine the effects of two different types of prosthetic feet on lower limb kinematics and kinetics during up and down slope walking. A male unilateral trans-femoral amputee walked at a self-selected speed on a ramp at each of the two slopes (-15%, +15%). The prosthetic feet tested were SACH and Trustep. Two-dimensional gait analysis was carried out to derive the time curves of the knee and ankle joints angles and ground reaction forces (GRFs) at both the prosthetic and sound sides. The results indicate that although the overall gait pattern was similar for both feet, less dorsiflexion in early stance was noticed when walking with Trustep. There was a higher peak of plantar angle for prosthetic ankle in up-slope than in down-slope with either foot. A lower second peak of the vertical ground reaction forces (VGRFs) at residual limb with Trustep, compared with SACH, may be due to Energy Storing and Return (ESAR) quality of the former. At sound side, there was a higher first peak for the VGRF with SACH compared with Trustep. Having said all these, it’s not yet totally clear how the prosthetic knee and the prosthetic foot contribute to producing mentioned effects.