Veterans with below-knee amputations are limited by prosthetic feet that cannot adapt to sloped and uneven terrain. This limitation results in reduced mobility, reduced balance confidence, and a higher risk of falls among some individuals who use below-knee prostheses, which have been shown to negatively impact participation in daily and recreational activities. The investigative group has designed a novel Slope Adaptive Foot (SAF) that is mechanically passive, capable of slope adaption on every step of walking, and maintains high levels of energy storage and return. Pilot testing of the SAF with Veterans has generated excellent results to date, with comments suggesting potential improvements in participation. This study will evaluate the extent to which participation and fall-related health outcomes are influenced by using the SAF versus a typical hydraulic foot in a cross-over randomized controlled trial. Using mixed-methods, the investigators will also collect long-term data of Veterans using their preferred foot to inform the development of evidence-based education materials for use in clinical decision making.
US military Veterans willing to travel to the Minneapolis VA Health Care System
Unilateral, below-knee amputation
Use of a definitive prosthesis for at least 12 months (limb volume has stabilized and has accommodated to prosthesis use post-amputation)
Medicare Functional Classification Level K3 ambulator (unlimited community ambulator)
Residual-limb skin problems
Not a regular prosthesis user
Mass over 125 kg (275 lbs)
Residual limb too long to accommodate the study feet (104 mm of build height)
Crossover
Fillauer Slope Adaptive Foot
DeviceThe SAF uses an articulated ankle and damped plantarflexion to accommodate slopes and uneven terrain. It locks when the forefoot reaches the ground at the beginning of stance phase, which allows the SAF to re-align, or adapt, to the walking surface. After the SAF locks, the laminated foot plate can deflect and store energy as dorsiflexion occurs, returning that energy to the user in late stance for forward propulsion. Finally, at the end of stance phase, when the toe leaves the ground, the SAF unlocks and actively dorsiflexes the ankle to increase toe clearance during swing.
Fillauer Motion Foot SLX
DeviceThe SLX is an articulated, hydraulic ankle that provides passive ankle motion through damped plantarflexion and dorsiflexion to facilitate slope accommodation.
PROMIS Ability to Participate in Social Roles and Activities (APSRA)
This Patient Reported Outcome Measurement Information System (PROMIS) short form is an 8-item self-report survey instrument, developed from PROMIS item banks, that provides T scores (mean = 50, SD = 10) based on a normative sample from a general population of healthy US adults. The PROMIS-APSRA specifically measures the frequency with which one has trouble with completing or needs to limit participation in social roles and activities, including leisure activities and activities with friends and family. This PROMIS measure uses a 5-point ordinal response scale, where higher values indicate a higher degree of ability to participate.
PROMIS Satisfaction with Social Roles and Activities (SSRA)
This Patient Reported Outcome Measurement Information System (PROMIS) short form is an 8-item self-report survey instrument, developed from PROMIS item banks, that provides T scores (mean = 50, SD = 10) based on a normative sample from a general population of healthy US adults. The PROMIS-SSRA measures the level of satisfaction with one's ability to participate in recreational activities, activities of daily living, and to meet the needs of friends and family. This PROMIS measure uses a 5-point ordinal response scale, where higher values indicate a higher degree of satisfaction with participation.
Prosthetic Limb Users Survey of Fall-Related Health (PLUS-FRH)
Each domain of the PLUS-FRH (fall-related self-efficacy, anxiety, avoidance behavior, and interference) corresponds to a 15-item instrument that provides T scores (mean = 50, SD = 10) based on a normative sample of lower-limb prosthesis users. The items on the PLUS-FRH use a 5-point ordinal response scale, where higher values correspond to better or worse fall-related health outcomes, depending on the domain.
Timed Up and Go (TUG)
The TUG is test protocol for balance function. From a seated position in a standard armchair, the participant is asked to do the following: 1) stand up from the chair, 2) walk to a line on the floor 10 feet away at a normal pace, 3) turn, 4) walk back to the chair at a normal pace, 5) sit down again. Performance is measured as the time it takes to complete the test.
10-meter Walk Test (10MWT)
Gait speed (10-meter walk using the middle 6 meters) is assessed under two conditions: 1) normal speed and 2) fastest speed. A difference of 0.10 m/s is defined as the minimal clinically important difference.
Modified Five-Time Sit-to-Stand (m5xSTS)
The m5xSTS test assesses functional lower extremity strength and transitional movements. The participant is instructed to sit with arms resting on their lap and back against a chair. They are instructed to stand up and sit down five times as quickly as possible when prompted. The time taken to complete the test is recorded. If needed, the participant can use armrests or a walker, the use of which should be documented.
Prosthetic Limb Users Survey of Mobility (PLUS-M)
The PLUS-M is a 12-item instrument that measures prosthesis users' mobility (i.e., their ability to move intentionally and independently from one place to another). Individual PLUS-M questions assess respondents' perceived ability to carry out specific activities that require use of both lower limbs. PLUS-M questions cover movements that range from basic ambulation (e.g., walking a short distance indoors) to complex activities (e.g., hiking for long distances over uneven ground). The items on the PLUS-M use a 5-point ordinal response scale that reflects the degree of difficulty with which respondents report they can carry out these activities. PLUS-M T scores (mean = 50, SD = 10) are based on a normative sample of lower-limb prosthesis users.
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VA Office of Research and Development
Lead sponsor
University of Washington
Collaborator
