SBIR-STTR Award

The vision of this project is to improve the functional physical mobility of people with lower extremity amputations so that they can more fully and confidently participate in a wider range of activities. This will enhance their personal satisfaction thereby improving their quality of life. People using prostheses have significant mobility disability compared to their potential, partly because commercially available prosthetic feet are unable to meet their day-to-day needs. Also, research has shown a high incidence of falls reported by amputees, often due to the prosthesis or environment. Current prosthetic feet are designed and optimized for level-ground forward walking. Consequently, prosthetists align the prosthetic foot to a single preferred position for this activity. During everyday activities, including quiet standing, feet move about in different positions. When the prosthesis user ambulates around their community, they are faced with many obstacles that do not conform to the level-ground forward walking paradigm. Thus there is a need to fundamentally rethink prosthetic foot design to restore adaptability to body-ground position. The innovative approach pursued in this project is to develop an Adaptable Foot prototype which restores spontaneous adaptability through biomimicry allowing the prosthesis user to ambulate over various terrains. The novel, spontaneously adaptable foot allows a range of alignments relative to the ground during postures and gait. This is achieved by specific linkages that respond to environmental forces with predictable results, moving the center of rotation so that it aligns to the resultant forces. Rather than incorporating compliant surfaces, which can cause postural and gait instability and higher energy cost of gain, the Adaptable Foot restores adaptability without sacrificing stability. During the Phase I effort, the project team will evolve an Adaptable Foot prototype to pass engineering benchmarks that indicate the prototype is ready for extended community use and evaluation. Computer simulation will be used to enhance the design of the existing foot and inform engineering aspects of foot prototypes. Rapid prototyping and conventional prosthetic manufacturing methods will be integrated to create proof of concept foot designs for standardized performance tests and questionnaire feedback. Finally, standardized materials testing devices will provide data on energy return and failure modes.

Public Health Relevance Statement:
Project Narrative Currently available prosthetic feet are designed by manufacturers and fit by prosthetist to be optimal for level ground walking and are unable to adapt to various terrains including sloped or uneven ground. This lack of adaptability can lead to severe mobility impairment for people using prostheses through a lack of confidence in their prosthetic limb, ultimately reducing their community involvement and overall quality of life. Here, we seek to restore confidence and functionality by creating a prosthetic foot that can spontaneously adapt to the surface geometry and uncertain placement of the foot thereby improving community participation and quality of life.

Project Terms:
Amputation; Amputees; Anatomy; Ankle; base; Benchmarking; Biomechanics; Body Weight; Characteristics; clinical practice; Communities; Community Participation; Computer Simulation; Consult; cost; Data; design; Development; Devices; disability; Elements; Engineering; Environment; Equipment Malfunction; Evaluation; Evolution; experience; Failure; falls; Feedback; foot; Future; Gait; Geometry; Goals; Guidelines; Height; Home environment; Human; Impairment; improved; Incidence; innovation; interest; Laboratories; Lead; Leg; Length; Limb Prosthesis; Lower Extremity; Maintenance; Manufacturer Name; materials science; Materials Testing; Mechanics; Methods; models and simulation; Motion; Movement; novel; Performance; performance tests; Periodicity; Personal Satisfaction; Phase; Positioning Attribute; Posture; Property; Prosthesis; prosthesis wearer; prosthetic foot; prototype; Quality of life; Questionnaires; Reporting; Research; Research Infrastructure; Rotation; satisfaction; Side; Small Business Technology Transfer Research; Standardization; Stress; Surface; System; Testing; Toes; Universities; Vision; Visit; Walking; Washington; Work

Evolution of an Adaptable Prosthetic Foot Design for Normalization of Biomechanics During Community Participation Summary/Abstract The vision of this project is to improve the functional physical mobility of people with lower extremity amputations especially on uneven ground, side-slopes or when foot placement varies from side-to-side. People with amputations will be enabled to confidently participate in a wider range of activities. This will enhance their personal satisfaction thereby improving their quality of life. People using prostheses currently have significant mobility disability and a high incidence of falls, partly because commercially available prosthetic feet are unable to meet their day-to-day needs. Current prosthetic feet are designed and optimized for level-ground, forward walking. Consequently, prosthetists align the prosthetic foot to a single preferred position for this activity. During everyday activities, including quiet standing, feet are placed in different positions. When the prosthesis user ambulates around their community, they are faced with many obstacles that do not conform to the level-ground forward walking paradigm. When people engage in tasks while they walk, or if they have poor limb function, the placement of the foot becomes less controlled. Thus there is a need to fundamentally rethink prosthetic foot design to restore adaptability to body-ground position. The innovative approach pursued in this project is to develop the Ankentro which restores spontaneous adaptability, allowing the prosthesis user to ambulate over various terrains. The novel, spontaneously adaptable foot allows a range of alignments relative to the ground to accommodate a variety of postures and gait. This is achieved by specific linkages that respond to environmental forces with predictable results, moving the center of rotation so that it aligns to the resultant forces. Rather than incorporating compliant surfaces, which can cause postural and gait instability and higher energy cost, the Adaptable Foot restores adaptability without sacrificing stability. During the Phase II effort, the project team will develop a new prosthetic foot called the Ankentro that includes the linkage system resulting from the Phase I milestone achievements and then use that refined prototype for extended community use and evaluation. Ankentro development includes optimizing the linkage mechanism, developing a new toe and heel spring, refining foot covering dimensions, and validating the design with standardized mechanical tests. The clinical evaluations include controlled laboratory tests that challenge side-to-side adaptability, in parallel with community trials. Quantitative and qualitative outcomes will be generated to evaluate the clinical benefit of the Ankentro.

Public Health Relevance Statement:
Project Narrative Currently available prosthetic feet are generally designed by manufacturers and fit/aligned by prosthetists to be optimal for level ground walking and are unable to adapt to various terrains including sloped or uneven ground due to limited ankle range of motion. This lack of adaptability can lead to severe mobility impairment for people using prostheses because of unstable contact with the ground, resulting in a lack of confidence in their prosthetic limb and ultimately reducing their community involvement. We seek to restore confidence and functionality by creating a prosthetic foot that can spontaneously adapt to the ground surface geometry and uncertain placement of the foot thereby improving community participation and quality of life.

Project Terms:
Achievement; Amputation; Amputees; Anatomy; Ankle; Articular Range of Motion; base; Biomechanics; carbon fiber; Characteristics; Clinical; Communities; community involvement; Community Participation; Community Trial; Control Groups; cost; design; Development; Dimensions; disability; Engineering; Evaluation; Evolution; falls; foot; functional outcomes; Gait; Geometry; Goals; Heel; Home environment; Human; Impairment; improved; improved outcome; Incidence; Individual; innovation; kinematics; Kinetics; Laboratories; Lead; Limb Prosthesis; Limb structure; Lower Extremity; Manufacturer Name; Mechanics; Motion; Movement; novel; Outcome; Participant; Performance; Personal Satisfaction; Phase; Population; Positioning Attribute; Posture; preservation; Prosthesis; prosthesis wearer; prosthetic foot; prototype; Quality of life; research clinical testing; Rotation; satisfaction; Side; simulation; Small Business Technology Transfer Research; Standardization; Surface; System; Test Result; Testing; Toes; Universities; Validation; Vision; Walking; Washington