Abstract
The evaluation of prosthetic ankles/feet and the study of the gait of trans-femoral amputees (TFAs) in different walking conditions are essential for improving prostheses design and supporting TFA rehabilitation and prostheses selection. To date limited work has been done in these areas and this study aimed to address some of the existing limitations by investigating the effect of hydraulic ankles/feet (Echelon and Elan) on the gait of conventional TFAs compared with a fixed ankle/foot (Esprit) during common daily activities. Five active male unilateral conventional TFAs and fourteen non-amputees participated in this research. Spatial-temporal, kinematic and kinetic gait data were determined for level ground self-selected normal and fast speed walking, 2.5° camber walking, and ascending and descending a 5° slope. Assessment of gait symmetry was given particular focus in the data analysis. Participant feedback was obtained from questionnaires. The results for the conventional TFAs showed significant improvement with the hydraulic ankles/feet in the sagittal plane ankle moment Trend Symmetry Index. This may support a claim of enhanced prosthetic knee stance stability when using these feet. In addition, greater range in prosthetic ankle dorsiflexion/plantarflexion, and increased first vertical ground reaction force peak at the prosthetic side were found compared with the fixed ankle/foot. The subject questionnaire results supported a preference for the hydraulic ankles/feet over the fixed ankle/foot. There was no significant difference found between the Echelon and Elan foot from the gait or questionnaire data. The strategies of conventional TFAs for adapting to different activities were compared with the non-amputees. When walking on an inclined surface, reduction in impulse at the prosthetic limb is an important requirement, as is improvement of balance control. Future studies with increased number of conventional TFAs and osseo-integrated TFAs are suggested to test the findings on the improvement indicated by the use of hydraulic ankles/feet. Key words: Trans-femoral Amputees; Hydraulic Ankles/Feet; Trend Symmetry Index; Slope Ambulation; Camber Ambulation; Osseo-Integration