Powered Prosthetic Knee for Below Knee Amputation

Overseen By Michael Davidson, Ph.D.

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Loma Linda University

Disqualifiers: Multiple amputations, Assistive device, Pregnancy, others

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

Approved in 3 Jurisdictions This treatment is already approved in other countries

Compensation: Varies

Number of Visits: 4

12 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial aims to determine if a powered microprocessor-controlled knee (PMPK) can improve walking ease and efficiency for individuals with above-knee amputations. The trial will compare the PMPK with the prosthetic knee currently used by participants. Eligible participants must have one leg amputated above the knee, use a prosthesis daily without issues, and be comfortable walking at various speeds. As an unphased trial, this study provides participants the opportunity to contribute to innovative research that could enhance mobility solutions.

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 this powered microprocessor-controlled knee is safe for below knee amputation?

Research shows that microprocessor-controlled prosthetic knees (MPKs) are generally safe and can aid people with above-knee amputations by enhancing safety, stability, and movement. Studies have found that these knees may reduce the risk of falls and improve balance, which is crucial for daily activities. However, there isn't enough evidence yet to confirm they significantly enhance overall health.

The powered microprocessor-controlled knee (PMPK) under study is already available for purchase, indicating it has passed some safety checks. Although limited safety information exists for below-knee amputations, MPKs are considered essential for some amputees, reflecting trust in their safety and benefits. Overall, while more research is needed, current evidence suggests that PMPKs are generally well-accepted. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about the Powered Microprocessor-controlled Knee (PMPK) because it offers a dynamic and adaptive approach to prosthetic knees for below-knee amputation. Unlike traditional prosthetic knees that rely on passive mechanisms, the PMPK actively powers movement, mimicking natural knee function more closely. This smart technology adjusts in real-time to changes in walking speed and terrain, providing users with improved stability and mobility. By enhancing the user's gait and reducing effort, the PMPK has the potential to significantly improve quality of life for amputees compared to existing prosthetic options.

What evidence suggests that this powered microprocessor-controlled knee is effective for improving metabolic function during walking?

Research shows that microprocessor-controlled prosthetic knees (MPKs) can make life safer and easier for people with above-knee amputations. Studies have found that these knees help users walk on various surfaces, improving mobility. They also reduce the risk of falls, a major concern for many prosthetic users. While results can vary, evidence suggests that MPKs outperform prosthetic knees without microprocessors. This trial will specifically evaluate the effectiveness of the Powered Microprocessor-Controlled Knee (PMPK) for individuals with below-knee amputations, as the benefits for this group remain unclear and require further research. ^{1 2 4 6 7}

Who Is on the Research Team?

Michael Davidson, Ph.D.

Principal Investigator

Loma Linda University Health

Are You a Good Fit for This Trial?

This trial is for men and women aged 18-75 who have lost one leg above the knee, weigh between 49-117 kg, walk or play sports with a prosthesis daily, and have been doing so for at least six months without recent socket issues or limb pain that affects function.

Inclusion Criteria

No socket issues or changes in the last six weeks

No residual limb pain affecting functional ability.

Males and Females with unilateral knee disarticulation or transfemoral (KD/TF) amputation.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

1 week

1 visit (in-person)

Initial Visit

Informed consent, HIPAA authorization, ambulation potential verification, body measurements, balance confidence scale, posture alignment assessment

1 day

1 visit (in-person)

Second Visit

Fit with heart rate monitor and metabolic analyzer, treadmill tests, posture alignment assessment, use PMPK for one week

1 week

1 visit (in-person)

Third Visit

Fit with heart rate monitor and metabolic analyzer, treadmill tests, balance confidence scale, return PMPK, verify alignment

1 day

1 visit (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment

1 week

What Are the Treatments Tested in This Trial?

Interventions

• PMPK

Trial Overview The study aims to determine if a powered microprocessor-controlled knee (PMPK) can improve how efficiently people use energy while walking on flat ground and slopes compared to their usual physician-prescribed prosthetic knees.

How Is the Trial Designed?

Group I: Powered Microprocessor-controlled Knee (PMPK) Experimental Treatment 1 Intervention

the "Power Knee" is a commercially available PMPK.

PMPK is already approved in European Union, United States, Canada for the following indications:

Approved in European Union as PMPK for:

• Lower limb loss
• Mobility assistance

Approved in United States as PMPK for:

• Lower limb loss
• Mobility assistance

Approved in Canada as PMPK for:

• Lower limb loss
• Mobility assistance

Who Is Running the Clinical Trial?

Loma Linda University

Lead Sponsor

Trials

322

Recruited

267,000+

Össur Ehf

Industry Sponsor

Trials

23

Recruited

3,900+

Össur Iceland ehf

Industry Sponsor

Trials

23

Recruited

3,900+

Published Research Related to This Trial

Commercial microprocessor-controlled prosthetic knees (MPKs) are mostly passive and rely on heuristic intent classifiers, while research MPKs are powered and often use machine learning for better intention detection, indicating a significant technological gap.

The main challenges for the commercial viability of active MPKs include demonstrating their benefits over passive models, evaluating their performance in real-world settings, and ensuring that control parameters remain practical for users.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A Comparison of Control Strategies in Commercial and Research Knee Prostheses. Fluit, R., Prinsen, EC., Wang, S., et al.[2021]

Microprocessor prosthetic knees (MPKs) significantly improve functional status and quality of life for patients with lower limb amputation compared to non-microprocessor prosthetic knees (NMPKs), based on a systematic review of 18 studies involving up to 602 participants.

While MPKs show clear advantages over NMPKs, the specific benefits of more advanced models like the Genium® compared to others like the C-leg® and Rheo knee® are not well established, indicating a need for further research.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Impact of microprocessor prosthetic knee on mobility and quality of life in patients with lower limb amputation: a systematic review of the literature. Thibaut, A., Beaudart, C., Maertens DE Noordhout, B., et al.[2023]

Microprocessor-controlled prosthetic knees (MPKs) significantly reduce falls and fear of falling in limited community ambulators, based on a systematic review of 13 studies involving 2366 patients, with 704 classified as limited community ambulators.

MPKs also improve mobility, walking speed, and patient-reported ambulation, making them a valuable therapeutic option for individuals with transfemoral amputations.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The effect of microprocessor controlled exo-prosthetic knees on limited community ambulators: systematic review and meta-analysis. Hahn, A., Bueschges, S., Prager, M., et al.[2023]

In a study of 45 low-activity transfemoral amputees transitioning from mechanical knees to microprocessor knees (MPKs), significant improvements were observed in balance, walking distance (measured by the two-minute walk test), and confidence, despite no significant changes in health-related quality of life or gait profile score.

The findings suggest that while MPKs may not drastically change overall quality of life or gait metrics, they can enhance functional mobility and reduce falls, indicating potential benefits for low-activity users.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Comparison of patient-reported and functional outcomes following transition from mechanical to microprocessor knee in the low-activity user with a unilateral transfemoral amputation. Davie-Smith, F., Carse, B.[2023]

A study involving 35 individuals with transfemoral amputation showed that microprocessor-controlled knees (MPKs) significantly improved dynamic balance and functional mobility compared to non-MPKs, as evidenced by faster Timed-Up and Go test times and higher Locomotor Capability Index scores.

Participants using MPKs reported higher satisfaction and improved quality of life, particularly in mental health, with no significant difference in fall rates between the two types of prostheses, suggesting that MPKs can be beneficial for amputees with moderate activity levels.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Mobility and satisfaction with a microprocessor-controlled knee in moderately active amputees: A multi-centric randomized crossover trial. Lansade, C., Vicaut, E., Paysant, J., et al.[2022]

The pilot study involving five elderly transfemoral amputees showed that using a microprocessor-controlled knee prosthesis (MPK) improved perceptions of safety and resulted in more natural gait patterns compared to standard non-microprocessor-controlled knee prostheses (NMPK) after just 4 to 6 weeks of familiarization.

However, the study suggests that without structured training and a longer acclimation period, the functional benefits of the MPK may not be fully realized, indicating that additional support may be necessary for optimal use.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Safety and function of a prototype microprocessor-controlled knee prosthesis for low active transfemoral amputees switching from a mechanic knee prosthesis: a pilot study. Hasenoehrl, T., Schmalz, T., Windhager, R., et al.[2018]

Citations

1. 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.

2. tandfonline.com tandfonline.com/doi/full/10.1080/09638288.2025.2530172

ASsessing Clinical outcomes with microprocEssor kNee ... Impact of a stance phase microprocessor-controlled knee prosthesis on level walking in lower functioning individuals with a transfemoral amputation.

3. clinicaltrials.gov clinicaltrials.gov/study/NCT06937242

Effects of Microprocessor-controlled Prosthetic Knees on ... This study aims to assess the effects of microprocessor-controlled prosthetic knees on fall-related health outcomes in prosthesis users classified as limited ...

4. mdpi.com mdpi.com/2673-1592/7/4/89

Comparing Microprocessor-Controlled and Non- ... Multiple studies have compared the effectiveness of MPKs to NMPKs based on different aspects and outcome measures, but results vary between studies and raise ...

5. southcarolinablues.com southcarolinablues.com/web/public/brands/medicalpolicy/external-policies/microprocessor-controlled-prosthetic-for-the-lower-limb/

Microprocessor-Controlled Prosthetic for the Lower Limb The evidence is insufficient to determine that the technology results in an improvement in the net health outcome. For individuals who have a tibial amputation ...

6. clinicaltrials.gov clinicaltrials.gov/study/NCT04112901

Effects of Microprocessor-controlled Knee Joints on ... Although past studies indicate that MPKs could result in reduced risk of falls, improved balance and activity in limited mobility amputees, there is a lack of ...

7. medicalpolicy.bcbstx.com medicalpolicy.bcbstx.com/content/dam/bcbs/medicalpolicy/pdf/dme/DME104.012_2024-09-01.pdf

Lower-Limb Prosthetics, Including Microprocessor- ... Microprocessor-Controlled and Powered Knees (MPK; MCK; PK). An MPK may be considered medically necessary in amputees who meet ALL of the ...