Stump-socket interface pressure as an aid to socket design in prostheses for trans-femoral amputees--a preliminary study.

A system for measuring the stump-socket interface pressure was designed and built using a strain gauged type load cell. The system was utilized to study the pressure distribution in the quadrilateral and ischial containment type sockets. Two volunteer trans-femoral amputees fitted with both types of socket participated in the experiments. Pressures were measured while the subjects were standing and during walking. The maximum pressure recorded for standing was 34 kPa and for walking 95 kPa. Comparison made between the two sockets indicated that higher pressures were recorded at the proximal brim of the quadrilateral socket whereas the ischial containment socket produces a more evenly distributed pressure profile. The pressure distribution on the medial and lateral walls of both types of socket were similar but in the anterior and posterior walls, significant differences were noted. The results obtained from this study were compared with those found in published literature and the biomechanics of the two types of socket is discussed.