SBIR-STTR Award

This SBIR Phase I project will create and evaluate a novel, proof-of-concept low-tech Energy-Harvesting Knee Prosthesis, or Assist-Knee Prosthesis, capable of helping geriatric individuals with transfemoral limb loss more effectively and safely perform sit-to-stand-to-sit transitions. Transitioning from a sitting to a standing position is much more difficult for an individual with transfemoral limb loss, especially within the geriatric population, due to declining or absent knee and ankle musculature. When rising from a chair, these individuals heavily rely on their sound limb and upper limb strength to lift their body weight. Geriatric prosthesis users, who often have marginal and declining strength, could retain their independence if a prosthetic knee was capable of assisting with sit-to-stand-to-sit transitions. Unfortunately, the current designs of most commercially available prosthetic knees do not assist with the sit-to-stand-to-sit transition, a task that is fundamental for normal activities of daily living. The Assist-Knee design harvests the prosthesis user's potential energy during the stand-to-sit transition and appropriately returns that energy to assist with the sit-to-stand transition. While harvesting energy, Assist-Knee provides a resistive knee extension moment that imitates eccentric contraction of the quadriceps muscles for a controlled stand-to-sit. The return of energy provides knee extension, imitating concentric activity of the quadriceps muscles, for an assisted sit-to-stand. The technological innovation of this design does not require a large motor, battery, or complex system to provide external power for knee extension assist. Our low-cost, lightweight design is an alternative to externally powered prosthetic devices. Since external power is not being added to the system, Assist-Knee is not intended to replicate maximum moment output at the knee but to provide a useful percentage of knee extension moment to assist with initiation of the sit-to-stand transition. The specific aims of this project involve: designing and constructing Assist-Knee, performing bench testing of the device, and evaluating the proof-of-concept Assist-Knee in prosthesis users. Successful design and implementation of the proof-of-concept Assist-Knee will enable geriatric individuals with transfemoral limb loss to more easily complete sit-to-stand-to-sit transitions, increase independence by reducing the need for caretaker assistance, and help control the lowering of a user during the stand-to-sit maneuver. The commercial application of Assist-Knee is a low-cost, lightweight prosthetic alternative to assist individuals with transfemoral limb loss within the geriatric population to independently complete activities of daily living.

Public Health Relevance Statement:
PROJECT NARRATIVE Geriatric individuals with transfemoral limb loss often have difficulty performing the sit-to-stand-to-sit transition and could benefit from assistance at the knee joint to make activities of daily living easier. We propose a novel, low-tech energy-harvesting knee prosthesis, or Assist-Knee, to help these individuals by harvesting the prosthesis user's potential energy during the stand-to-sit transition and appropriately returning that energy to assist with the sit-to-stand transition. This Assist-Knee project will enable geriatric transfemoral prosthesis users to more easily complete sit-to-stand-to-sit transitions, increase independence by reducing the need for caretaker assistance, and help control the lowering of a user during the stand-to-sit maneuver.

Project Terms:
absorption; Achievement; Activities of Daily Living; Age; Ankle; Body Weight; Clinical; clinical practice; Clinical Research; commercial application; Complex; cost; design; design and construction; Development; Devices; Elderly; Feedback; Generations; Harvest; Individual; Intuition; Knee; Knee joint; Knee Prosthesis; Laboratories; Lifting; light weight; Limb structure; Measures; mechanical properties; Mechanics; Motion; Motor; novel; Output; Performance; Phase; physical therapist; Population; Positioning Attribute; Potential Energy; Prosthesis; Prosthesis Design; prosthesis wearer; prosthetic foot; prototype; quadriceps muscle; research clinical testing; Safety; safety and feasibility; Small Business Innovation Research Grant; sound; System; technological innovation; Testing; Upper Extremity; Walking; Work

This SBIR Phase II project will create and evaluate a novel low-tech Energy-Harvesting Knee Prosthesis, orAssist-Knee Prosthesis, capable of helping geriatric individuals with transfemoral limb loss more effectivelyand safely perform sit-to-stand-to-sit transitions. Transitioning from a sitting to a standing position is muchmore difficult for an individual with transfemoral limb loss, especially within the geriatric population, due todeclining or absent knee and ankle musculature. When rising from a chair, these individuals heavily rely ontheir contralateral limb and upper limb strength to lift their body weight. Geriatric prosthesis users, who oftenhave marginal and declining strength, could retain their independence if a prosthetic knee was capable ofassisting with sit-to-stand-to-sit transitions. Unfortunately, the current designs of most commercially availableprosthetic knees do not assist with the sit-to-stand-to-sit transition, a task that is fundamental for normalactivities of daily living. The Assist-Knee design harvests the prosthesis user's potential energy during thestand-to-sit transition and appropriately returns that energy to assist with the sit-to-stand transition. Whileharvesting energy, Assist-Knee provides a resistive knee extension moment that imitates eccentric contractionof the quadriceps muscles for a controlled stand-to-sit. The return of energy provides knee extension, imitatingconcentric activity of the quadriceps muscles, for an assisted sit-to-stand. The technological innovation of thisdesign does not require a large motor, battery, or complex system to provide external power for knee extensionassist. Our low-cost, lightweight design is an alternative to externally powered prosthetic devices. Sinceexternal power is not being added to the system, Assist-Knee is not intended to replicate maximum momentoutput at the knee but to provide a useful fraction of knee extension moment to assist with initiation of the sit-to-stand transition. The specific aims of this project involve: updating and optimizing the Assist-Knee designbased on our successful Phase I findings and with a user-centered design approach that includes biannualmeetings with stakeholders, and validating Assist-Knee in daily use with a laboratory and at-home clinical trial.Successful design and implementation of Assist-Knee will enable geriatric individuals with transfemoral limbloss to more easily complete sit-to-stand-to-sit transitions, increase independence by reducing the need forcaretaker assistance, and help control the lowering of a user during the stand-to-sit maneuver. The commercialapplication of Assist-Knee is a low-cost, lightweight prosthetic alternative to assist individuals with transfemorallimb loss within the geriatric population to independently complete activities of daily living.

Public Health Relevance Statement:
PROJECT NARRATIVE Geriatric individuals with transfemoral limb loss often have difficulty performing sit-to-stand-to-sit transitions and could benefit from assistance at the knee joint to make activities of daily living easier. We propose a novel, low-tech energy-harvesting knee prosthesis, or Assist-Knee, to help these individuals by harvesting the prosthesis user's potential energy during the stand-to-sit transition and appropriately returning that energy to assist with the sit-to-stand transition. This Assist-Knee project will enable geriatric transfemoral prosthesis users to more easily complete sit-to-stand-to-sit transitions, increase independence by reducing the need for caretaker assistance, and help control the lowering of a user during the stand-to-sit maneuver.

Project Terms: