Wednesday, April 2, 2025
4/2/2025
A new clinical device to enable informed prosthesis prescription decision-making. - Abstract The selection of a prosthetic foot that best suits an individual's unique gait patterns and mobility needs is currently an overwhelmingly challenging process. There are over 100 prosthetic feet available on the market, each with a different combination of mechanical behaviors, such as forefoot stiffness, heel stiffness, and energy return. Adding to the difficulty, the current prescription process in the US creates major barriers for patients to pilot multiple prosthetic feet, which often results in most patients being fitted with a sub-optimal prosthesis given their gait biomechanics and ambulation goals. Unfortunately, sub-optimal prosthesis fit can result in long-term complications such as low back pain, knee osteoarthritis, discomfort, reduced community ambulation, and decreased quality of life. Prosthetists, the clinical experts that select and align prosthetic feet to the socket, use informal systems based on both patient feedback and visual assessment of gait quality to improve prosthesis alignment—but tools and techniques for quickly finding the patient-optimal prosthesis model are currently not available. To address this issue, this project aims to develop the Ankle-Foot Optimization Tool (A-FOOT), a robotic device that can accurately and quickly replicate the behavior of any commercially available ankle-foot prosthesis. This new technology will consist of a wearable mechatronic platform that will allow the emulated prosthesis’s mechanical properties to be adjusted by prosthetists using a simple tablet-based app. Specifically, the app will enable prosthetists to make adjustments to the emulator's heel stiffness, forefoot stiffness, series damping, and parallel damping, providing them with the ability to customize the emulator's behavior to the specific needs of each patient. The device performance will be validated through a series of benchtop tests, and by comparing the just-noticeable difference, or limit of patient perception, for plantar/dorsiflexion alignment, forefoot stiffness, and hindfoot stiffness to values found with quasi-passive systems. Additionally, a pilot n=3 study will be conducted, in which three prosthetist-patient pairs will work together to select their preferred setting, and repeated testing (with random re-seeding of the start point) will provide a metric of prescription consistency. The long-term vision of this project is to revolutionize the prosthesis prescription process by enabling prosthetists to rapidly find the optimal foot model and alignment using this robotic emulator, improving the quality of life for individuals who have lost their leg, and reducing risk of long-term secondary complications. This proposal takes a major step towards realizing this future by creating and validating the mechatronic system upon which this new future will be built.
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