April 2018

Crossover prosthetic design

Activities along with mobility spectrum that ESF, RSF, and XF are estimated to span for most prosthetic limb users. The black sections of the arrows indicate that the foot is well designed for these activities, the faded section indicates that the foot design can be used for these activities, however, performance may be suboptimal.

Prosthetic feet are typically optimized for a narrow range of activities, meaning active prosthetic users may need more than 1 prosthesis to fully participate in activities with varying degrees of impact. Modern energy-storing feet (ESF) support users’ ability to walk at differing speeds, as well as support static standing, but they can limit aerobic activities and running speeds. Running-specific feet (RSF), while ideal for running and sprinting, do not support low impact activities, particularly standing or walking.

Now, researchers from the University of Washington at Seattle have developed a crossover foot (XF) designed with a split keel for managing uneven terrain, heel springs, and the ability to fit a regular shoe. Its extended stiff keel allows users to walk and stand as well as run and jog, essentially letting users experience the full spectrum of mobility with a single prosthesis.

In a randomized crossover study published recently in PLoS One, the researchers followed 30 participants with transtibial amputation as they wore custom-made XF and ESF interventions for 30 days each and provided feedback through a variety of measures. Participants reported improved health outcomes in mobility, balance, functional satisfaction, fatigue, and activity limitations using the XF compared to the ESF. The key difference? Sound side-step length improved significantly with XF use, which the authors indicated could provide benefit to the sound limb. Most important to the authors, the participants preferred the XF to the ESF overall.

Clinical relevance:  Prosthetic limb users often report lower quality of life scores due to activity limitations. Based on these findings, prostheses that can accommodate users’ participation in a wider range of activities present a cost-effective opportunity to improve health outcomes for this population.


Morgan SJ, McDonald CL, Halsne EG, et al. Laboratory- and community-based health outcomes in people with transtibial amputation using crossover and energy-storing prosthetic feet: A randomized crossover trial. PLoS ONE. 2018: 13(2): e0189652.

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