Powered Prosthesis for Amputation

Overseen By Robert D Gregg, PhD

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: University of Michigan

Disqualifiers: Pregnancy, Neuromuscular disorders, Cognitive deficits, others

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

Approved in 2 Jurisdictions This treatment is already approved in other countries

Compensation: Varies

Number of Visits: Unknown

40 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores a new powered prosthesis designed for individuals with above-knee amputations. The goal is to enhance how the prosthesis adapts during various movements, making it feel more natural. Researchers will employ machine learning to analyze joint movements and adjustments during tasks like walking. Individuals with an above-knee amputation who have been walking independently for over two months and can walk without an assistive device may be suitable candidates for this study. As an unphased trial, this study provides a unique opportunity to contribute to innovative research that could improve mobility 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. It might be best to discuss this with the trial coordinators or your doctor.

What prior data suggests that this powered prosthesis is safe?

Research has shown that powered prosthetic legs can make life safer and easier for individuals who have lost a leg above the knee. Studies have found that these devices help users move more confidently than non-powered ones because the prosthetic legs adjust to different movements, simplifying everyday tasks.

Users have generally found powered prosthetic legs comfortable, with no major safety issues reported. Designed to mimic the natural movement of a human leg, these devices reduce strain and enhance comfort.

Overall, evidence suggests that powered prosthetic legs are safe and effective for improving the quality of life for those with above-knee amputations. ^{1 2 3 4 5}

Why are researchers excited about this trial?

The powered prosthesis is unique because it integrates advanced robotics to enhance mobility and functionality for individuals with limb amputations. Unlike traditional prosthetics, which rely largely on passive mechanisms or external effort from the user, the powered prosthesis uses motorized components to assist with movement, making everyday tasks easier and more natural. Researchers are excited about this innovation as it holds promise for significantly improving the quality of life for amputees by providing greater independence and mimicking more natural limb movements.

What evidence suggests that this powered prosthesis is effective for amputation?

Research has shown that powered prostheses, like the one under study in this trial, can significantly aid individuals with above-knee amputations in improving mobility. One study found that a powered knee and ankle prosthesis enabled a person with amputations on both legs to walk more naturally. Another study discovered that these prostheses enhanced balance during activities like sitting down, compared to non-powered prostheses. Additionally, knees with microprocessors have demonstrated numerous benefits, enhancing overall function for users. These findings suggest that powered prostheses can offer better balance, mobility, and quality of life than traditional prosthetic options. Participants in this trial will perform various tasks while wearing the powered prosthesis to further evaluate these benefits. ^{1 6 7 8 9}

Who Is on the Research Team?

Robert D Gregg, PhD

Principal Investigator

University of Michigan

Are You a Good Fit for This Trial?

This trial is for adults aged 18-65 who are able-bodied, and those with above-knee amputations aged 18-70 who can walk without assistance. Participants must not be pregnant, have significant disorders that affect movement, or cognitive deficits. Amputees must weigh under 250 lbs and meet certain mobility classifications.

Inclusion Criteria

I have been walking on my own for over two months after losing a leg above the knee.

I am an amputee who can walk with my prosthesis without needing another device.

Exclusion Criteria

I am pregnant.

An excessively long residual limb length, and/or a non-removable cosmetic cover determined by the prosthetist performing the evaluations for subjects with amputation

Co-morbidity that interferes with the study (e.g., pace maker placement, severe ischemia, cardiac disease, etc.) for subjects with amputation

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Initial Testing

Able-bodied subjects are recruited for initial testing of various prosthesis controllers

4 weeks

Multiple visits (in-person)

Validation

Amputee subjects validate the prosthesis controllers and participate in endurance and symmetry studies

8 weeks

Multiple visits (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

What Are the Treatments Tested in This Trial?

Interventions

• Powered Prosthesis

Trial Overview

The study tests a powered prosthesis designed to adapt to varying activities using machine learning based on human joint biomechanics. It aims to improve the control of prosthetic legs by modeling variable joint impedance through measurable quantities in different locomotion tasks.

How Is the Trial Designed?

Group I: Prosthesis Experimental Treatment 1 Intervention

Participants in this arm of the study will perform various tasks while wearing the powered prosthesis

Powered Prosthesis is already approved in United States, European Union for the following indications:

Approved in United States as Powered Prosthetic Limbs for:

• Above-knee amputations
• Mobility assistance

Approved in European Union as Robotic Prosthetic Legs for:

• Lower limb amputations
• Rehabilitation

Who Is Running the Clinical Trial?

University of Michigan

Lead Sponsor

Trials

1,891

Recruited

6,458,000+

Published Research Related to This Trial

Early rehabilitation measures, including the provision of a prosthesis, are crucial for aged individuals following above-knee amputation to prevent physical and mental decline, as energy consumption for walking with a prosthesis is significantly higher than for non-amputated individuals.

A comprehensive approach to rehabilitation is necessary, considering not just the physical aspects of recovery but also the individual's social environment and personal needs, ensuring that both prosthetic and wheelchair management are tailored to the patient's unique circumstances.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Prosthetic and wheelchair management of elderly patients following above the knee amputation--a decision at the acute hospital]. Dorian, R.[2022]

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]

In a study involving 41 individuals with above-knee amputations, those with higher functional mobility levels showed significant improvements in performance speed when using microprocessor-controlled prosthetic knee joints compared to mechanically controlled ones.

The results indicate that while there is considerable variability in functional performance among MFCL-2 amputees, many can benefit from the advanced technology of microprocessor-controlled knees for daily activities.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Functional added value of microprocessor-controlled knee joints in daily life performance of Medicare Functional Classification Level-2 amputees. Theeven, P., Hemmen, B., Rings, F., et al.[2014]

A case study demonstrated that lightweight powered knee and ankle prostheses can effectively restore natural leg movements for individuals with bilateral above-knee amputations, allowing them to walk and climb stairs with improved gait patterns.

The powered prostheses were able to replicate essential biomechanical functions, such as ankle push-off during walking and knee power generation during stair ascent, which are crucial for enhancing mobility and quality of life.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Powered knee and ankle prostheses enable natural ambulation on level ground and stairs for individuals with bilateral above-knee amputation: a case study. Hood, S., Creveling, S., Gabert, L., et al.[2023]

The use of an active powered microprocessor-controlled prosthetic knee (A-MPK) resulted in greater knee range of motion and reduced hip torque during walking compared to a passive microprocessor-controlled prosthetic knee (P-MPK) in four transfemoral amputees, suggesting improved gait mechanics.

A follow-up case study indicated that using the A-MPK for four weeks increased the amputee's confidence and highlighted the importance of adaptation time for optimizing the benefits of the A-MPK.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Assessment of transfemoral amputees using a passive microprocessor-controlled knee versus an active powered microprocessor-controlled knee for level walking. Creylman, V., Knippels, I., Janssen, P., et al.[2018]

The review highlights the ongoing advancements in transfemoral prosthesis design, focusing on mechanical performance and the integration of modern technologies like sensors and software to enhance functionality and user experience.

Future research aims to create more cost-effective and safer prosthetic components that better restore the capabilities of amputees, addressing both technical and social challenges in prosthetic development.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

An insight into Transfemoral Prostheses: Materials, modelling, simulation, fabrication, testing, clinical evaluation and performance perspectives. Amudhan, K., Vasanthanathan, A., Anish Jafrin Thilak, J.[2022]

Powered exoskeletons, like the ReWalk™, Indego™, and Ekso™, have been approved as medical devices to help individuals with gait disabilities walk upright, but the understanding of their risks and safety is still developing.

There is a significant need for standardized regulations and awareness of potential risks associated with powered exoskeletons to ensure safe and effective use, as current criteria for their use and reported adverse events vary widely.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Risk management and regulations for lower limb medical exoskeletons: a review. He, Y., Eguren, D., Luu, TP., et al.[2020]

In a study involving six unilateral transfemoral amputees, the Rheo Knee XC showed advantages in walking with small steps due to its 'default swing' concept, which provided a consistent swing phase release.

However, the C-Leg demonstrated better safety and load-bearing capacity during activities like walking down stairs and slopes, while the Rheo Knee XC required more compensatory movements, potentially increasing the risk of falls in certain situations.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Comparative biomechanical evaluation of two technologically different microprocessor-controlled prosthetic knee joints in safety-relevant daily-life situations. Bellmann, M., Köhler, TM., Schmalz, T.[2019]

Current lower limb prostheses lack the ability to replicate the energy distribution and function of natural musculature, which is crucial for effective movement.

The proposed above-knee prosthesis incorporates a self-energized mechanism that captures and stores energy from passive movements at the knee and ankle, enabling active plantar-flexion and improving locomotion efficiency.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Active plantar-flexion above-knee prosthesis: concept and preliminary design. Rigas, C.[2017]

The study of two transfemoral amputees showed that powered knee-ankle prostheses (PKA) can enable walking patterns that closely resemble normal gait, improving mobility and reducing asymmetry in mechanical loading and muscle activation.

Compared to advanced microprocessor-controlled knee prostheses (MPK), the PKA allowed for a greater range of walking speeds and cadence, suggesting enhanced safety and adaptability in various environments for users.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Impact of Powered Knee-Ankle Prosthesis on Low Back Muscle Mechanics in Transfemoral Amputees: A Case Series. Jayaraman, C., Hoppe-Ludwig, S., Deems-Dluhy, S., et al.[2020]

The study demonstrated that a powered knee-ankle prosthesis significantly improved weight-bearing symmetry by 42.1% during sit-down movements compared to passive prostheses, indicating enhanced stability for above-knee amputees.

Despite the improvement in weight-bearing symmetry, there was no significant reduction in muscle effort from the intact quadricep muscle, suggesting that while powered prosthetics improve balance, they may not lessen the physical demands on the user's intact limb.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Can a powered knee-ankle prosthesis improve weight-bearing symmetry during stand-to-sit transitions in individuals with above-knee amputations? Hunt, GR., Hood, S., Gabert, L., et al.[2023]

Citations

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nature.com

nature.com/articles/s41598-022-19701-8

Powered knee and ankle prostheses enable natural ...

Here we show a case study with an individual with bilateral above-knee amputations using a pair of lightweight powered knee and ankle prostheses for walking ...

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pmc.ncbi.nlm.nih.gov

pmc.ncbi.nlm.nih.gov/articles/PMC9396752/

Functional Mobility Training With a Powered Knee and ...

Limb loss at the transfemoral or knee disarticulation level results in a significant decrease in mobility. Powered lower limb prostheses have the potential ...

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tandfonline.com

tandfonline.com/doi/full/10.1080/09638288.2025.2530172

ASsessing Clinical outcomes with microprocEssor kNee ...

The advent of the microprocessor knee (MPK) brought multiple clinical benefits for individuals with above-knee amputation (AKA) [1–6].

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jneuroengrehab.biomedcentral.com

jneuroengrehab.biomedcentral.com/articles/10.1186/s12984-023-01177-w

Can a powered knee-ankle prosthesis improve weight ...

In this study, we found that a powered knee-ankle prosthesis significantly improved weight-bearing symmetry during sit-down compared to passive prostheses.

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pmc.ncbi.nlm.nih.gov/articles/PMC9894662/

A Lightweight Robotic Leg Prosthesis Replicating the ...

Robotic leg prostheses promise to improve the mobility and quality of life of millions of individuals with lower-limb amputations by imitating the ...

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pmc.ncbi.nlm.nih.gov

pmc.ncbi.nlm.nih.gov/articles/PMC10079568/

Effect of Increasing Assistance From a Powered Prosthesis ...

These results show that powered prostheses can improve functional mobility, potentially increasing quality of life for millions of people living with above-knee ...

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clinicaltrials.gov

clinicaltrials.gov/study/NCT06194838

NCT06194838 | Clinical Outcomes With Non-Powered vs. ...

The results of this study will (1) provide initial evidence to guide clinical prescription and use of powered knee technologies for K2-level individuals with ...

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pmc.ncbi.nlm.nih.gov

pmc.ncbi.nlm.nih.gov/articles/PMC11974485/

The effects of microprocessor prosthetic knee use in early ...

Microprocessor‐controlled prosthetic knees (MPKs) improve safety, stability, and mobility for people with transfemoral amputation.

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academic.oup.com/milmed/article/188/11-12/3432/6650769

Functional Performance Outcomes of a Powered Knee–Ankle ...

Clinical knowledge surrounding functional outcomes of a powered knee–ankle (PKA) device is limited, particularly among younger and active ...