Prosthetic Knees for Above-Knee Amputation

Overseen By Jennifer Johansson, MS

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Liberating Technologies, Inc.

Disqualifiers: Injuries, Contralateral amputation, Socket issues, others

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

Compensation: Varies

Number of Visits: 8

26 Participants Needed

Trial Summary

What is the purpose of this trial?

The goal of this proposed project is to gather community-based data from the K2-level Transfemoral Amputee (TFA) population to aid in evidence-based prescription of powered prosthetic knees (i.e., choosing the right device to maximize the benefit for each patient). The investigators intend to use this trial data along with a concurrent study being conducted within the K3-K4 level population to guide the implementation of effective prescriptions towards those that can benefit most from a given device and limit prescription to those who would not see benefit in order to ensure the most judicious use of Department of Defense (DoD) and Veteran's Affairs healthcare dollars. The findings will also be shared with the research community to help drive the design of future devices by identifying what features and functions are most beneficial to which patient populations when the devices are used outside of the laboratory. In summary, more community-based data on how powered prosthetic knees compare with the current standard in TFA populations is needed to allow for improved clinical decision making and clinical outcomes.

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's best to discuss this with the trial coordinators or your healthcare provider.

How does the Ossur Power Knee differ from other prosthetic knee treatments for above-knee amputation?

The Ossur Power Knee is unique because it actively generates power at the knee joint, unlike passive prosthetic knees, which only dissipate energy. This active power generation can improve walking and stair climbing by reducing the strain on the remaining joints and enabling more natural movements. ^{1 2 3 4 5}

Research Team

Jennifer Johansson, MS

Principal Investigator

Liberating Technologies, Inc.

Eligibility Criteria

This trial is for individuals with above-knee amputations, specifically K2-level transfemoral amputees. It's aimed at those who use prosthetic knees and are looking to improve their mobility. The study excludes certain groups based on specific criteria not provided here.

Inclusion Criteria

I use a prosthetic leg that fits between my knee and hip.

My weight is between 110lbs and 256lbs.

I have used a prosthesis for at least six months.

Exclusion Criteria

Socket issues/changes in the last 6 weeks

Users with bone-anchored implants

I have injuries on my remaining limb or the opposite leg that affect my ability to function.

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

1 visit (in-person)

Training and Acclimation

Participants are trained and acclimated to each prosthetic knee condition during the first month of the take-home period

4 weeks

4-8 visits (in-person)

Condition Testing

Participants wear each prosthetic knee at home for three months, with periodic assessments and follow-up calls

3 months per condition

2 visits (in-person) per condition

Follow-up

Participants are monitored for safety and effectiveness after completing all conditions

4 weeks

1 visit (in-person)

Treatment Details

Interventions

• Ossur Power Knee
• Reboocon Intuy Knee

Trial Overview The study compares non-powered (Reboocon Intuy Knee) versus powered (Ossur Power Knee) prosthetic knees in people with leg amputations. It aims to determine which device offers the most benefit in real-world settings outside of a lab environment.

Participant Groups

Group I: Reboocon Intuy Knee Experimental Treatment 1 Intervention

The subject will wear the Reboocon Intuy Knee for 3 months, as well as in the lab to complete outcome measures.

Group II: Ossur Power Knee Experimental Treatment 1 Intervention

The subject will wear the Ossur Power Knee for 3 months, as well as in the lab to complete outcome measures.

Group III: Comparator Baseline Active Control 1 Intervention

The subject will wear the Ossur OFM-2, a passive mechanical knee which is the most commonly used knee for K2 users, for 3 months, as well as in the lab to complete outcome measures.

Ossur Power Knee is already approved in United States, European Union for the following indications:

Approved in United States as Össur Power Knee for:

• Transfemoral amputation in K2-level ambulators

Approved in European Union as Össur Power Knee for:

• Transfemoral amputation in K2-level ambulators

Who Is Running the Clinical Trial?

Liberating Technologies, Inc.

Lead Sponsor

Trials

13

Recruited

100+

Hanger Clinic: Prosthetics & Orthotics

Collaborator

Trials

11

Recruited

520+

Findings from Research

The Power Knee (PK) prosthetic knee unit generates more power during stair descent compared to the C-Leg, potentially reducing the strain on the nondisabled limb during these activities.

While the PK helps lessen the power needed from the nondisabled knee during stair climbing, it does not outperform the C-Leg in other tasks, indicating that further improvements are needed for optimal function.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Assessment of transfemoral amputees using C-Leg and Power Knee for ascending and descending inclines and steps. Wolf, EJ., Everding, VQ., Linberg, AL., et al.[2019]

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 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]

A study involving 10 young adults with unilateral transfemoral amputation found that the weight-activated braking knee resulted in a longer swing-phase duration and greater anterior pelvic tilt compared to the automatic stance-phase lock knee, indicating distinct biomechanical differences between the two prosthetic knee types.

The prolonged swing-phase time for the weight-activated braking knee suggests that it may require more knee unloading to initiate flexion during gait, which could lead to stability issues in early stance-phase and affect overall gait patterns.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Biomechanical responses of young adults with unilateral transfemoral amputation using two types of mechanical stance control prosthetic knee joints. Andrysek, J., García, D., Rozbaczylo, C., et al.[2022]

In a study comparing prosthetic knee systems for U.S. military service members with transfemoral amputations, the Power Knee™ (PK) showed greater peak knee power in the amputated limb during sit-to-stand tasks compared to the C-Leg, suggesting enhanced performance for PK users.

Despite the differences in knee power, both prosthetic systems resulted in greater forces on the intact limb, indicating that while PK may improve certain tasks, it does not significantly reduce impact on the remaining joints compared to the C-Leg.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Comparison of the Power Knee and C-Leg during step-up and sit-to-stand tasks. Wolf, EJ., Everding, VQ., Linberg, AA., et al.[2022]

References

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

Assessment of transfemoral amputees using C-Leg and Power Knee for ascending and descending inclines and steps. [2019]

2. England 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. [2023]

3. England 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? [2023]

4. France pubmed.ncbi.nlm.nih.gov

Biomechanical responses of young adults with unilateral transfemoral amputation using two types of mechanical stance control prosthetic knee joints. [2022]

5. England pubmed.ncbi.nlm.nih.gov

Comparison of the Power Knee and C-Leg during step-up and sit-to-stand tasks. [2022]