Adjustable Prosthetic Foot for Lower Extremity Amputation

Recruiting in Palo Alto (17 mi)

Overseen byGlenn K Klute, PhD

Age: 18+

Sex: Any

Travel: May Be Covered

Time Reimbursement: Varies

Trial Phase: Academic

Waitlist Available

Sponsor: VA Office of Research and Development

No Placebo Group

Trial Summary

What is the purpose of this trial?

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.

Research Team

Glenn K Klute, PhD

Principal Investigator

VA Puget Sound Health Care System Seattle Division, Seattle, WA

Eligibility Criteria

This trial is for individuals with a single below-knee amputation who wear their prosthesis at least four hours daily and have been using it for over six months. Their current prosthesis must be compatible with the study's components, and they should not have any skin issues on the residual limb or conditions affecting walking ability.

Inclusion Criteria

I have had one lower leg amputated below the knee.

I wear my prosthesis for at least 4 hours daily.

My prosthesis can be fitted with the study's prosthetic parts.

See 1 more

Exclusion Criteria

Pregnant (determined via self-report)

Inadequate cognitive function or language proficiency to consent to participate

My current prosthesis doesn't fit well and can't be adjusted.

See 3 more

Treatment Details

Interventions

Torsionally Adaptive Prosthesis (Prosthesis)

Trial OverviewThe study tests different torsionally adaptive prostheses that mimic natural foot motion by varying coupling ratios between transverse (side-to-side) and sagittal (forward-backward) plane motions. Participants will walk straight and in circles while these ratios are adjusted without knowing which ratio they're testing.

Participant Groups

3Treatment groups

Experimental Treatment

Group I: Straight line walkingExperimental Treatment5 Interventions

All participants will walk in a straight line while wearing the study prosthesis.

Group II: Circle walking with prosthesis outsideExperimental Treatment5 Interventions

All participants will walk around a 1-meter radius circle with their prosthesis on the outside of the circle.

Group III: Circle walking with prosthesis insideExperimental Treatment5 Interventions

All participants will walk around a 1-meter radius circle with their prosthesis on the inside of the circle.