Pivot-Flex Foot: Optimal Coupling Ratio Between Transverse and Sagittal-plane Motions Using a Torsionally Adaptive Prosthesis for Individuals With Lower Limb Amputation
Completed · Not applicable
Conditions studied: Lower Extremity Amputation
In brief
When prescribing a prosthetic foot, clinicians face a dizzying array of choices as more than 200 different prosthetic feet are available. While these conventional prosthetic feet primarily function in the sagittal plane, the intact foot and ankle comprise a complex set of joints that allow rotation in multiple planes of motion. Some of these motions are coupled, meaning rotation in one plane induces motion in another. One such coupling is between the sagittal and transverse planes. For every step, plantar- and dorsi-flexion motion in the sagittal plane is coupled with external and internal rotation of the shank relative to the foot in the transverse plane. There is no prosthetic foot available for prescription that mimics this natural coupling. To investigate the need for this coupling, the investigators have built a torsionally adaptive prosthesis where the coupling ratio between the transverse- and sagittal-planes can be independently controlled with a motor. This research has one specific aim: to identify the optimal coupling ratio between transverse- and sagittal-plane motions using a novel, torsionally adaptive prosthesis for individuals with lower limb amputation. The investigators will conduct a human subject experiment wearing the motor-driven and computer controlled torsionally adaptive prosthesis. Individuals with lower limb amputation will be asked to walk in a straight line and in both directions around a circle while the coupling ratio between transverse- and sagittal-plane motions is varied between trials. Participants will be blinded to the coupling ratio. The investigators hypothesize that: (1) a coupling ratio exists that minimizes undesirable transverse-plane socket torque and (2) there will be a coupling ratio that individuals with lower limb amputation prefer.
Key facts
- Study ID
- NCT03532100
- Run by
- VA Office of Research and Development
- People needed
- 14
- Starts
- 2018-04-18
- Expected to finish
- 2024-11-18
- Last updated by the study team
- 2025-11-19
Who can join
Age: 18 and older, up to 70. Sex: any. Healthy volunteers: not accepted.
You may qualify if…
- Unilateral transtibial amputation
- Been fit with a prosthesis and used it for at least six months
- Wear the prosthesis for four or more hours on an average day
- Prescribed prosthesis can accommodate fitment of the study prosthetic components to be tested (determined at initial visit)
You may not qualify if…
- Improper fit and suspension with current prosthesis and one cannot be achieved with clinical resources (determined at initial visit)
- Current skin irritation or injury on residual limb
- Osteoarthritis, injury, or pain that interferes with walking ability
- Currently incarcerated
- Pregnant (determined via self-report)
- Inadequate cognitive function or language proficiency to consent to participate
Where it is running
- VA Puget Sound Health Care System Seattle Division, Seattle, WA — Seattle, Washington, United States
Full record on ClinicalTrials.gov
Trial information comes from ClinicalTrials.gov and is refreshed daily. TrialsForMe does not provide medical care and does not run the studies it lists.