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

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial aims to identify the best prosthetic knee for individuals with an above-knee amputation. Researchers will compare powered prosthetic knees, such as the Ossur Power Knee and Reboocon Intuy Knee, with the current standard mechanical knee. They seek data from regular prosthesis users to help doctors determine which device best suits different patients. Individuals who have used a mechanical knee prosthesis for at least six months and have a K2 mobility level may qualify for this study. As an unphased trial, this study provides a unique opportunity to advance prosthetic technology and improve future patient 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.

What prior data suggests that these prosthetic knees are safe for above-knee amputees?

Research shows that the Ossur Power Knee aids users in movements like standing up from a chair by providing extra power. Some studies have shown mixed results, mainly due to the device's hardware and control systems. Importantly, no strong evidence of serious side effects exists, suggesting it is generally well-tolerated by users.

For the Reboocon Intuy Knee, available information does not reveal any major safety concerns. This knee also assists users with movements, and there are no significant reports of negative effects from its use.

Both devices aim to help people with above-knee amputations, and current studies do not indicate any major safety issues. This suggests both are generally safe options, but discussing personal health considerations with a healthcare provider is always advisable. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about the Ossur Power Knee and the Reboocon Intuy Knee because they offer advanced functionality for individuals with above-knee amputations, unlike traditional passive mechanical knees. The Ossur Power Knee is unique because it actively assists with movements, providing powered support that can help users walk more naturally and with less effort. Meanwhile, the Reboocon Intuy Knee features smart adaptive technology, meaning it can adjust in real-time to different walking speeds and terrains, enhancing stability and comfort. These innovations promise to improve mobility and quality of life, addressing limitations of current passive knee prosthetics.

What evidence suggests that these prosthetic knees are effective for above-knee amputees?

This trial will compare the Ossur Power Knee and the Reboocon Intuy Knee, both powered prosthetic knees, to improve mobility for people with above-knee amputations. Participants in one arm of the trial will use the Ossur Power Knee, which assists with bending and straightening the knee to make walking feel more natural. However, results have varied, possibly due to its control mechanism and design. Another arm will involve the Reboocon Intuy Knee, designed to support a more natural walking motion and reduce stress on the other leg. Known for being quiet and easy to use, it is a good choice for those needing a prosthetic knee. Both options have shown promise in enhancing ease and comfort of movement. ^{1 2 3 6 7}

Who Is on the Research Team?

Jennifer Johansson, MS

Principal Investigator

Liberating Technologies, Inc.

Are You a Good Fit for This Trial?

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 for a Trial Participant

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)

What Are the Treatments Tested in This Trial?

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.

How Is the Trial Designed?

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+

Published Research Related to This Trial

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 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]

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 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]

Citations

1. ossur.com ossur.com/en-us/prosthetics/knees/power-knee

Power Knee™. Ossur.com The Power Knee is the world's first motor-powered microprocessor knee. Active assistance powers flexion and extension to mimic concentric and eccentric muscle ...

2. clinicaltrials.gov clinicaltrials.gov/study/NCT05267639

Clinical Outcomes With Passive MPKs vs. Powered ... This study will focus on investigating the tradeoffs between the commercially available Ossur Power Knee and traditional MPKs to identify the prosthetic knee ...

3. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/41024213/

The clinical effects of the Össur Power Knee with phase- ... Previous studies have demonstrated mixed results, potentially due to a combination of limitations in prosthetic hardware, control algorithms, ...

4. jneuroengrehab.biomedcentral.com jneuroengrehab.biomedcentral.com/articles/10.1186/s12984-025-01729-2

The clinical effects of the Össur Power Knee with phase-based ... Previous studies have demonstrated mixed results, potentially due to a combination of limitations in prosthetic hardware, control algorithms, ...

5. 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 ...

6. ossur.com.ua ossur.com.ua/Media/ossur/Instructions/Brochures/knee/POWER%20KNEE%20Reimbursement%20guide.pdf

POWER KNEE™ POWER KNEE data post-delivery to document patient progress. ... Finally, POWER KNEE's motor helps lift above-knee amputees out of a chair to a standing position.

7. withpower.com withpower.com/trial/phase-amputation-traumatic-8-2023-0cc68

Prosthetic Knees for Above-Knee Amputation This N/A medical study run by Liberating Technologies, Inc. is evaluating whether Ossur Power Knee and Reboocon Intuy Knee will have tolerable side effects ...