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Research Company Develops Prosthetic Foot Emulator Emulator technology designed to aid researchers and clinicians in testing new prosthetic devices is being developed at Humotech, a company founded on research from Carnegie Mellon University (CMU). The emulator is a “robotic, wearable device that we program to mimic the behavior of conventional devices or to test novel device ideas,” says Josh Caputo, PhD, president and chief executive officer. The emulator is worn like a conventional device; for prosthetic foot testing, the emulator attaches to the user’s residual limb with a standard pylon. “What makes it very different from other devices is that the emulator is powered and controlled by an offboard motor,” Caputo explains. “For now, the emulator can only be used during walking or running on a treadmill or stairmill, but we are exploring other possibilities.” The offboard actuation Josh Caputo, PhD allows Caputo and his team to make the device that the person wears extremely lightweight, which is necessary for the emulator to accurately mimic passive, nonpowered devices. The technology originated at the Experimental Biomechatronics Lab at CMU, where Caputo earned his doctorate while working under the supervision of Lab Director Steve Collins, PhD. “We were interested in developing a prosthetic foot with actively powered push-off. We recognized that the development process for new O&P devices was rather inefficient; coming up with the idea for a new type of device can happen overnight, but then iteratively prototyping and testing with patients takes years of hard work,” says Caputo. The CMU team sought to create a versatile robotic platform where new ideas could be implemented and tested quickly with patients. “This way we could avoid spending tons of time
SEPTEMBER 2017 | O&P ALMANAC
PHOTOS: Josh Caputo, PhD
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engineering and building feet and instead focus on what we think is a more fundamental challenge for the field: How should a prosthetic device behave in order to optimize outcomes for the patient?” Factors such as whether the device has a motor or is passive, is made of carbon fiber or fiberglass, etc., are secondary considerations. “Let’s first identify what is best for the patient, and then we can think about how to embody that functionality into a physical product they can take home with them,” explains Caputo. “Whether the goal of your work is to invent new technology to improve lives years in the future, or to figure out how to help the patient in your office achieve their goals, Humotech’s emulator technology is a way to quickly reach an evidence-based determination of what works best for the patient.” Caputo is currently working with David Morgenroth, MD, and his team at the Seattle VA Center for Limb Loss and MoBility on a Department of Defense-funded project studying test drive strategies for prosthetic foot prescription using the emulator. The technology is being leveraged in research applications, and clinical applications are forthcoming. “A solution like this is necessary if we are to improve outcomes and reduce costs in O&P,” says Caputo. “We have shown that prosthetic feet are really not one-size-fits-all; a device that works great for one patient may be very suboptimal for a similar patient. The best choice of a device can depend strongly on which outcomes you measure: Patient feedback? Metabolic energy consumption? Aesthetics of gait?” Using the emulator will enable new measurements and drive more informed decision making, says Caputo. Humotech is gathering data to show that the emulator experience is “realistic and predictive, results in better outcomes for the patient, and saves health-care costs,” says Caputo. “We believe if we can establish a new standard of care where patient outcomes data from emulator evaluations becomes integral to cost justification, that we can build trust and payors will be more interested in spending on care for amputees now to save later on reduced longer-term health-care costs.”