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

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial tests different prosthetic foot-ankle devices to assess their impact on walking for individuals with a below-the-knee amputation. Participants will wear sensors and try both powered and passive prostheses, such as the Blatchford Elan Variable-Dampening Prosthesis and the MIT Sliding Beam Passive Prosthesis, while walking on flat ground, treadmills, and stairs. The researchers aim to understand how these devices alter walking patterns. This trial suits adults with a below-the-knee amputation and a Medicare mobility rating of K3 or K4, indicating a good level of movement ability. As an unphased trial, it offers participants the chance to contribute to innovative research that could enhance prosthetic technology for future users.

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 these prosthetic foot-ankle mechanisms are safe for transtibial amputation?

Research shows that the Blatchford Elan Variable-Dampening Prosthesis improves knee stability and reduces the risk of tripping. Users generally find it safe and satisfactory. Its availability in stores indicates a certain level of safety for users.

Specific safety information for the MIT Sliding Beam Passive Prosthesis is not yet available. Testing continues to assess its safety.

Similarly, the MIT Variable Equilibrium Angle Prosthesis lacks clear safety data. It remains under study to identify any risks.

Studies have shown that the MIT Variable Stiffness Prosthesis improves walking, but specific safety information is not yet available. Testing is ongoing to evaluate its safety.

Overall, while some prostheses are already in use and show benefits, others are still under safety evaluation. Trial participants play a crucial role in determining the effectiveness and safety of these devices for future use. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about these prosthetic foot-ankle mechanisms because they offer innovative features not typically found in standard prosthetic options, like fixed or limited-adjustability devices. The Blatchford Elan Variable-Dampening Prosthesis, for example, can adjust its dampening levels to suit different walking conditions, offering a more natural gait for users. The MIT Sliding Beam Passive Prosthesis provides enhanced stability and energy efficiency through its unique sliding beam design. Meanwhile, the MIT Variable Equilibrium Angle and Variable Stiffness Prostheses allow users to fine-tune the balance and stiffness, giving them more personalized control and comfort. These advancements are promising because they aim to improve mobility and comfort for individuals with transtibial amputations.

What evidence suggests that these prosthetic foot-ankle mechanisms are effective for transtibial amputation?

Research has shown that the Blatchford Elan Variable-Dampening Prosthesis, which uses microprocessors to adapt to different walking conditions, improves balance and stability for people with below-knee amputations. It mimics natural ankle movement by adjusting hydraulic resistance. In this trial, participants will receive one of several prosthetic devices, including the MIT Sliding Beam Passive Prosthesis and the MIT Variable Equilibrium Angle Prosthesis, which allow users to change the ankle's angle, enhancing comfort and walking performance. The MIT Variable Stiffness Prosthesis, another device under study, is designed to improve body movement by adjusting its stiffness, helping people walk more naturally and efficiently. These devices aim to enhance mobility and comfort for those using prosthetic limbs. ^{1 2 5 6 7}

Are You a Good Fit for This Trial?

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 for a Trial Participant

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

What Are the Treatments Tested in This Trial?

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.

How Is the Trial Designed?

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+

Published Research Related to This Trial

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]

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 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]

Citations

1. blatchfordmobility.com blatchfordmobility.com/media/xdml0nwi/elan-clinical-evidence-study-summary.pdf

Elan - Blatchford Energy cost of ambulation in trans-tibial amputees using a dynamic-response foot with hydraulic versus rigid 'ankle': insights from body centre of mass dynamics ...

2. clinicaltrials.gov clinicaltrials.gov/study/NCT05964855

Comparison of Various Prosthetic Foot-Ankle Mechanisms Device : Blatchford Elan Variable-Dampening Prosthesis. Commercially-available electronically-controlled prosthesis that can vary its effective dampening.

3. withpower.com withpower.com/trial/phase-transtibial-amputation---unilateral-6-2023-d8f8c

Prosthetic Foot-Ankle Mechanisms 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 ...

4. blatchfordmobility.com blatchfordmobility.com/en-us/products/feet-ankles/elan

Elan - Blatchford Elan is a microprocessor controlled foot that mimics natural muscle resistance and ankle motion by adapting hydraulic resistance levels to optimise stability.

5. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC10936261/

A low-power ankle-foot prosthesis for push-off enhancement This study proposes an innovative low-power active prosthetic module that fits on off-the-shelf passive ankle-foot energy-storage-and-release (ESAR) prostheses.

6. clinicaltrials.gov clinicaltrials.gov/study/NCT05964855

Comparison of Various Prosthetic Foot-Ankle Mechanisms Device : Blatchford Elan Variable-Dampening Prosthesis. Commercially-available electronically-controlled prosthesis that can vary its effective dampening.

7. blatchfordmobility.com blatchfordmobility.com/en-us/for-professionals/clinical-evidence-finder/

Clinical Evidence Finder – Lower Limb Prosthetics - Blatchford EchelonVAC. Improvements in Clinical Outcomes using Echelon compared to ESR feet. Safety. Reduced risk of tripping and falls. Increased minimum toe clearance ...