Prosthetic Foot Stiffness Modulation for Below Knee Amputation

(OSA Trial)

Overseen By Elise Campbell

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Seattle Institute for Biomedical and Clinical Research

Disqualifiers: Gait disorders, Skin irritation, Assistive device use

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 2

Duration: 3 hours

20 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial examines how the stiffness of a prosthetic foot affects balance in individuals with below-knee amputations. The goal is to determine the optimal stiffness level for daily activities such as walking on slopes, carrying loads, and navigating uneven terrain. Participants will test various stiffness levels in a specially designed prosthesis featuring automatic prosthetic foot stiffness modulation. Ideal candidates have used a prosthetic leg for over six months and can walk on a treadmill without additional walking aids. As an unphased trial, this study provides participants the chance to contribute to innovative research that could advance prosthetic technology and improve daily life for many.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications.

What prior data suggests that this prosthetic foot stiffness modulation is safe for individuals with below knee amputations?

Research has shown that adjusting the stiffness of a prosthetic foot is generally well-received. This method aids individuals with below-knee amputations in maintaining better balance by altering the stiffness of the prosthetic foot. Studies suggest that this adjustment can enhance stability and comfort during activities such as walking at varying speeds or on uneven terrain.

While specific safety data is unavailable, the study's "Not Applicable" phase indicates a focus on device adjustment rather than testing a new drug or surgery, suggesting a lower risk of side effects. Participants in similar studies have reported positive results without major safety issues. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about the automatic prosthetic foot stiffness modulation because it offers a new way to enhance mobility for individuals with below-knee amputations. Unlike traditional prosthetic feet, which often have a fixed stiffness, this innovative approach automatically adjusts stiffness in response to different walking conditions. This dynamic adaptation could lead to improved balance and comfort, particularly on uneven terrain or slopes. The potential for personalized and adaptive support makes this approach a significant advancement over current static prosthetic solutions.

What evidence suggests that this prosthetic foot stiffness modulation is effective for improving balance control in individuals with below knee amputations?

Research has shown that altering the stiffness of a prosthetic foot can significantly impact balance and walking ability for people with below-knee amputations. Studies have found that varying stiffness levels affect the energy stored and released with each step, improving walking and reducing muscle strain. In this trial, participants will use an automatic prosthetic foot stiffness modulation system. Previous research discovered that individuals using a microprocessor-controlled prosthetic foot, which adjusts stiffness automatically, achieved better balance and walked more efficiently. Another study found that tailoring prosthetic stiffness to a user's preference resulted in more comfortable and confident walking. These findings suggest that automatic adjustments in prosthetic foot stiffness could enhance balance and walking for those with below-knee amputations. ^{1 6 7 8 9}

Who Is on the Research Team?

Glenn Klute, PhD

Principal Investigator

US Department of Veterans Affairs

Richard Neptune, PhD

Principal Investigator

The University of Texas at Austin

Are You a Good Fit for This Trial?

This trial is for individuals with below knee amputations. Participants should be able to perform daily activities and must not have any additional conditions that could affect balance or require a specific prosthesis stiffness outside the study's range.

Inclusion Criteria

It has been over a year since my amputation.

I can walk on a treadmill.

I have had one leg amputated below the knee.

Exclusion Criteria

I have a condition other than amputation that affects my ability to walk.

I have skin irritation or injury on my amputated limb.

I use a device like a cane or walker to help me walk.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Fitting and Adjustment

Participants are fitted with a novel prosthesis and adjustments are made to the pylon length as needed

1 week

1 visit (in-person)

Treatment

Participants perform nine ambulatory activities with different prosthetic foot stiffness levels to optimize balance control

3 hours

1 visit (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

What Are the Treatments Tested in This Trial?

Interventions

• Automatic Prosthetic Foot Stiffness Modulation

Trial Overview

The trial tests how different levels of prosthetic foot stiffness impact balance during everyday activities. It compares the person's usual foot stiffness with two variations: one stiffer and one less stiff, across nine common tasks.

How Is the Trial Designed?

Group I: Walking up an 8% slope at self-selected speed Experimental Treatment 3 Interventions

All participants will walk on a treadmill, in a straight line, up an 8% slope, at their self-selected walking speed determined while walking overground up an 8% slope.

Group II: Walking on uneven terrain at self-selected speed Experimental Treatment 3 Interventions

All participants will walk on an uneven terrain treadmill, in a straight line, on a 0% slope, at their self-selected walking speed determined while walking on the uneven terrain treadmill.

Group III: Walking on 0% slope at self-selected speed while hand carrying a 5 kg load on their prosthetic side Experimental Treatment 3 Interventions

All participants will walk on a treadmill, in a straight line, on a 0% slope, at their self-selected walking speed determined while walking overground, while carrying a 5 kg load in one hand on their prosthetic side.

Group IV: Walking on 0% slope at self-selected speed Experimental Treatment 3 Interventions

All participants will walk on a treadmill, in a straight line, on a 0% slope, at their self-selected walking speed determined while walking overground.

Group V: Walking on 0% slope at 15% slower than self-selected speed Experimental Treatment 3 Interventions

All participants will walk on a treadmill, in a straight line, on a 0% slope, at a speed that is 15% slower than their self-selected walking speed determined while walking overground.

Group VI: Walking on 0% slope at 15% faster than self-selected speed Experimental Treatment 3 Interventions

All participants will walk on a treadmill, in a straight line, on a 0% slope, at a speed that is 15% faster than their self-selected walking speed determined while walking overground.

Group VII: Walking down an 8% slope at self-selected speed Experimental Treatment 3 Interventions

All participants will walk on a treadmill, in a straight line, down an 8% slope, at their self-selected walking speed determined while walking overground up an 8% slope.

Group VIII: Walking around a 2-meter diameter circle with the prosthesis on the outside of the circle Experimental Treatment 3 Interventions

All participants will walk overground while following the outline of a 2-meter diameter circle, at their self-selected walking speed determined while walking around the circle, with their prosthetic limb on the outside of the circle.

Group IX: Walking around a 2-meter diameter circle with the prosthesis on the inside of the circle Experimental Treatment 3 Interventions

All participants will walk overground while following the outline of a 2-meter diameter circle, at their self-selected walking speed determined while walking around the circle, with their prosthetic limb on the inside of the circle.

Who Is Running the Clinical Trial?

Seattle Institute for Biomedical and Clinical Research

Lead Sponsor

Trials

55

Recruited

13,700+

Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)

Collaborator

Trials

2,103

Recruited

2,760,000+

Published Research Related to This Trial

A structured protocol for testing lower limb prostheses emphasizes safety, requiring users to meet specific graded safety levels before progressing to more challenging environments.

This approach aims to reduce the risk of falls and injuries, thereby enhancing user confidence and overall experience with active prosthetic legs.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Design of a stepwise safety protocol for lower limb prosthetic risk management in a clinical investigation. Thesleff, A., Ahkami, B., Anderson, J., et al.[2022]

A robotic prosthetic foot emulator (PFE) can accurately replicate the effective ankle stiffness of various commercial prosthetic forefeet, achieving an average accuracy within 1% of the actual feet tested.

This technology allows prosthesis users to trial different foot types based on their mechanical characteristics, potentially improving the decision-making process for prosthetic foot selection and enhancing user satisfaction.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Emulating the Effective Ankle Stiffness of Commercial Prosthetic Feet Using a Robotic Prosthetic Foot Emulator. Halsne, EG., Curran, CS., Caputo, JM., et al.[2022]

Citations

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The goal of this clinical trial is to identify prosthesis stiffness that optimizes balance control in individuals with below knee amputations.

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pmc.ncbi.nlm.nih.gov/articles/PMC8796559/

Benefits of a microprocessor-controlled prosthetic foot for ...

The influence of energy storage and return foot stiffness on walking mechanics and muscle activity in below-knee amputees. Clin Biomech ...

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sciencedirect.com

sciencedirect.com/science/article/abs/pii/S0003999305011366

The Effects of Prosthetic Foot Design on Physiologic ...

The effects of prosthetic foot design on physiologic measurements, self-selected walking velocity, and physical activity in people with transtibial amputation.

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jneuroengrehab.biomedcentral.com

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Understanding patient preference in prosthetic ankle stiffness

Subjects with unilateral below-knee amputation walked on a custom variable-stiffness prosthetic ankle and manipulated a dial to determine their ...

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Choosing appropriate prosthetic ankle work to reduce the ...

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pmc.ncbi.nlm.nih.gov

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Considering passive mechanical properties and patient ...

This review presents methods for optimizing passive below-knee prosthesis designs to maximize rehabilitation outcomes and how considerations on patient motor ...

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mdpi.com

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Reported Outcome Measures in Studies of Real-World ...

This scoping review aims to provide an overview of the purpose of use of wearable activity monitors in people with a Lower Limb Amputation (LLA) in the real ...

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nature.com

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Continuous neural control of a bionic limb restores ...

Our previous reports demonstrated that the below-knee AMI amputation improves volitional free-space control in a benchtop setting. Preliminary ...

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Improving Walking Energy Efficiency in Transtibial ...

One of these functionalities is to modulate the foot stiffness to improve the stability and comfort of the user: for example, the Variable- ...