Prosthetic Foot-Ankle Mechanisms for Transtibial Amputation

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Massachusetts Institute of Technology

Disqualifiers: Below K3 rating, age outside range

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

Compensation: Varies

Number of Visits: 2

10 Participants Needed

Trial Summary

What is the purpose of this trial?

In summary, subjects will be asked to wear a number of sensors and use different ankle-foot prostheses in place of their customary prosthesis. Data will be collected from the wearable sensors, VICON motion capture system, video cameras, and force sensors in the ground as they walk on level-ground, on a treadmill, and on stairs. The controller of any powered prosthesis will be electronically adjusted between trials or while the subject walks to determine how their gait changes in response to these changes. Trials will also be conducted with a standard passive prosthesis that would be prescribed for a person of similar height and weight.

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 data supports the effectiveness of the treatment Blatchford Elan Variable-Dampening Prosthesis, MIT Sliding Beam Passive Prosthesis, MIT Variable Equilibrium Angle Prosthesis, MIT Variable Stiffness Prosthesis for transtibial amputation?

Research shows that prosthetic devices like the Blatchford Elan, which use microprocessors to adapt to different walking conditions, can improve balance and stability on uneven terrain compared to traditional prostheses. These devices can adjust the ankle angle and energy release, helping users walk more comfortably and efficiently on slopes and level ground. ^{1 2 3 4 5}

Is the prosthetic foot-ankle mechanism safe for humans?

The research does not provide specific safety data for the prosthetic foot-ankle mechanisms, but it discusses various designs and their effects on gait and comfort, suggesting ongoing efforts to improve user experience and functionality. ^{2 3 5 6 7}

How does the Prosthetic Foot-Ankle Mechanism treatment differ from other treatments for transtibial amputation?

This treatment uses a novel non-backdrivable cam-based transmission to create a compact, lightweight ankle-foot prosthesis that actively repositions the foot during walking, improving foot clearance and adapting to ground inclines. Unlike traditional passive prostheses, it offers enhanced gait energetics, symmetry, and comfort without the bulk and weight of fully-powered devices. ^{2 3 4 5 8}

Eligibility Criteria

This trial is for individuals aged 18-65 with a single below-knee (transtibial) amputation who are fairly to very active, as indicated by a K3 or K4 Medicare mobility rating. It's not suitable for those under 18 or over 65, or less active individuals rated below K3.

Inclusion Criteria

I have had one of my legs amputated below the knee.

I have a Medicare mobility rating of K3 or K4.

Exclusion Criteria

I am within the required age range for the trial.

My mobility is rated below K3 by Medicare.

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Familiarization

Participants are given time to become familiar with the equipment and prostheses before beginning any trials

As needed

Experimental Sessions

Participants undergo experimental sessions involving walking on level-ground, treadmill, and stairs with different prostheses. Data is collected using sensors and motion capture systems.

8 hours total per participant, likely over two 4-hour sessions

2 sessions (in-person)

Follow-up

Participants are monitored for feedback and device preference through questionnaires after each session

Immediate post-session

Treatment Details

Interventions

• Blatchford Elan Variable-Dampening Prosthesis
• MIT Sliding Beam Passive Prosthesis
• MIT Variable Equilibrium Angle Prosthesis
• MIT Variable Stiffness Prosthesis

Trial Overview The study tests different prosthetic foot-ankle mechanisms: MIT's Variable Stiffness and Equilibrium Angle Prostheses, the Sliding Beam Passive Prosthesis, Ossur's Pro-flex XC, and Blatchford's Elan Variable-Dampening Prosthesis. Participants will use these while walking on various surfaces and their gait will be analyzed using sensors and motion capture.

Participant Groups

Group I: Unilateral Subject Group Experimental Treatment 5 Interventions

Foot-ankle devices will be given to this group to evaluate and compare the devices.

Who Is Running the Clinical Trial?

Massachusetts Institute of Technology

Lead Sponsor

Trials

104

Recruited

12,810,000+

Findings from Research

Microprocessor Prosthetic Ankles (MPA) provide better ankle angle adaptation for transtibial amputees compared to traditional energy storing and return (ESR) feet, particularly during varied walking conditions like slopes and stairs.

However, while MPAs improve adaptability, they tend to release less energy for propulsion, indicating a trade-off between flexibility and energy efficiency in different prosthetic designs.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Experimental characterization of the moment-angle curve during level and slope locomotion of transtibial amputee: Which parameters can be extracted to quantify the adaptations of microprocessor prosthetic ankle? Davot, J., Thomas-Pohl, M., Villa, C., et al.[2021]

The proposed compact, lightweight ankle-foot prosthesis utilizes a novel non-backdrivable cam-based transmission to actively reposition the foot during swing phases, which can enhance foot clearance and adapt to ground inclines.

Preliminary tests indicate that this new design could improve gait energetics, symmetry, and comfort for transtibial amputees, addressing the limitations of heavier powered devices and the Össur PROPRIO FOOT.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A lightweight robotic ankle prosthesis with non-backdrivable cam-based transmission. Lenzi, T., Cempini, M., Newkirk, J., et al.[2018]

The new robotic leg prosthesis effectively mimics the biomechanics of a biological leg while matching the weight, size, and battery life of traditional prostheses, making it more practical for daily use.

Preclinical tests with three individuals showed that this prosthesis allows for natural walking movements and includes a passive mode for unlimited walking on level ground without needing to recharge, which is a significant advancement over existing powered prosthetics.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A lightweight robotic leg prosthesis replicating the biomechanics of the knee, ankle, and toe joint. Tran, M., Gabert, L., Hood, S., et al.[2023]

References

1. England pubmed.ncbi.nlm.nih.gov

Experimental characterization of the moment-angle curve during level and slope locomotion of transtibial amputee: Which parameters can be extracted to quantify the adaptations of microprocessor prosthetic ankle? [2021]

2. United States pubmed.ncbi.nlm.nih.gov

A lightweight robotic ankle prosthesis with non-backdrivable cam-based transmission. [2018]

3. United States pubmed.ncbi.nlm.nih.gov

Simulation of a slope adapting ankle prosthesis provided by semi-active damping. [2022]

4. United States pubmed.ncbi.nlm.nih.gov

A lightweight robotic leg prosthesis replicating the biomechanics of the knee, ankle, and toe joint. [2023]

5. United States pubmed.ncbi.nlm.nih.gov

Amputee Independent Prosthesis Properties--a new model for description and measurement. [2022]

6. United States pubmed.ncbi.nlm.nih.gov

Effect on gait using various prosthetic ankle-foot devices. [2022]

7. United States pubmed.ncbi.nlm.nih.gov

A Reduced-Order Computational Model of a Semi-Active Variable-Stiffness Foot Prosthesis. [2022]

8. United States pubmed.ncbi.nlm.nih.gov

Powered ankle-foot prosthesis for the improvement of amputee ambulation. [2020]