Center for Limb Loss and MoBility
Development of an Inverting/Everting Prosthesis
PI: Glenn K. Klute, Ph.D.
Agency: Department of Veteran Affairs
Four-bar linkage driven by an electric linear actuator to enable inversion and eversion. The ankle device measures 250 mm and weighs 1.75 kg.
Objective: Stability while negotiating an ever-changing landscape is a constant concern for lower limb amputees. Although sagittal plane motion is the primary ambulatory component, mediolateral activity plays a very significant role in maintaining dynamic stability during gait. This is particularly the case while traversing uneven or unsteady terrain whereupon the likeliness of unanticipated footfall is considerably increased. The purpose of this research is the development of a prosthesis that will improve the dynamic lateral stability of an amputee.
Research Design: The application of controlled coronal rotation to the ankle of a prosthetic foot will allow an extra degree of freedom providing improvement in the amputee’s mediolateral stability. Coronal plane rotation in the ankle shall improve upon the rigid shank by (1) reducing fall propensity on uneven terrain, (2) facilitating recovery upon a misstep, and (3) enabling a more natural gait for amputees. Furthermore, this research shall work to develop and improve upon existing measures of stability to more accurately gauge effectiveness of the solution.
Methodology: Our research plan includes hardware and software development to control the prosthetic foot inversion angle based on a measured center of pressure. Bench-top laboratory tests assessing simulated mechanism performance shall be accomplished before proceeding to human subjects. Human subjects testing will measure the effectiveness of the new limb design and examine balance-assistance hypotheses by completing a series of standing balance tasks and ambulating during controlled gait disturbances.
Findings: The findings of this project will discover if amputees might benefit from a prosthetic intervention that aims to facilitate balance recovery from a disturbance while walking.
Milestones: The project is currently in the mechanical testing phase and is on schedule to conduct human subject testing in mid-2010. Institutional Review Board approval is in progress. This project is currently supporting one graduate student.
