Posted September 28, 2018
Brian Hafner, Ph.D., University of Washington

Brian Hafner, Ph.D., University of Washington

Brian Hafner, Ph.D.,
University of Washington

Transtibial amputation (amputations below the knee) significantly increase the energy needed to walk, restricting an individual’s mobility. Dr. Hafner was awarded a Fiscal Year 2014 Orthotics and Prosthetics Outcomes Research Award by the Orthotics and Prosthetics Outcomes Research Program (OPORP) in order to conduct a large-scale, randomized crossover study to compare outcomes associated with use of a modified running-specific foot, termed a “crossover foot” (XF), to outcomes associated with use of a traditional energy-storing foot (ESF). Dr. Hafner’s team compared the performance of these two prosthetic feet across a number of different health domains, including metabolic energy cost, endurance, perceived exertion, gait quality, and step activity. The researchers found that, on average, users had only slightly lower oxygen consumption when using the XF compared to the ESF. Other functional outcomes, (endurance, walking speed, and step activity) were, on average, comparable between the feet. However, participants in the study who used the XF reported about 20% less exertion when walking long distances and generally walked with a more even step pattern. Dr. Hafner’s team also measured users’ perception of performance while they wore each foot as their daily prosthesis. Users reported that the XF improved their mobility, balance, and functional satisfaction. It also reduced perceptions of fatigue and restrictions in activity due to the prosthesis. Results of the study collectively indicate that the XF and ESF prostheses are generally equivalent in function during level ground walking, but the XF may offer users additional benefits in real-life conditions. Dr. Hafner suggests that the XF may provide a unique, “all-in-one” solution for Service members, Veterans, and civilians with transtibial amputations who wish to engage in a wide range of activities. Dr. Hafner’s team next plans to study the relative performance of the XF and ESF under more rigorous real-world conditions—such as walking on stairs and inclines, jogging, and carrying loads—in order to inform development of an improved XF, including a version for Service members who wish to return to active duty.


Public and Technical Abstracts: A Novel Prosthetic Foot Designed to Maximize Functional Abilities, Health Outcomes, and Quality of Life in People with Transtibial Amputation

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