mechanical and Metabolic Work of Persons with Lower-extremity Amputations Walking with Titanium and Stainless Steel Prostheses : a Preliminary Study

A total of 15 subjects with unilateral amputations (8 transfemoral and 7 transtibial) performed treadmill walking with prostheses assembled from titanium and stainless steel components to determine if mass differences had an effect on walking. Standardized components (knees, pylons, adapters, feet) made from each material were added below the level of the socket. Metabolic cost from submaximal oxygen consumption and mechanical power estimates allowing transfers within and between segments were calculated during steady-state walking at self-selected velocities. Results showed that despite significant mechanical power differences, the decreased mass associated with the use of titanium materials did not have a significant effect on the metabolic costs of walking, stride rate, or stride length. Further division of subjects by age and experience walking on a prosthesis suggested that older persons and established walkers benefit most from the use of titanium components, both metabolically and mechanically.