Clinical Outcomes With Passive MPKs vs. Powered Prosthetic Knees

NCT05267639 | Completed Results FDA Device

• 1 other identifier: 20216190
• Study Type: interventional
• Target: 13
• Locations: 1 country
• Sites: 2

Brief Summary

The goal of this proposed project is to gather community-based data from the K4-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 envision that this Level 1 submission will transition into a larger follow-on Level 2 trial that will explore a larger spectrum of patient populations (K2-K4), as well as testing additional Power Knees currently in development that are expected to become commercialized in the near future. The investigators intend to use this Level 2 trial data 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 MPKs is needed to allow for improved clinical decision making and clinical outcomes.

Conditions

Amputation; Amputation; Traumatic, Leg, Lower; Limb; Absence, Congenital, Lower; Prosthesis User; Lower Limb Amputation Above Knee (Injury); Amputation; Traumatic, Leg: Thigh, Between Hip and Knee

Keywords

amputee; lower limb amputee; transfemoral amputee; prosthetic knee; power knee; microprocessor knee; MPK; Ossur; lower limb prosthesis user

Outcome Measures

Primary Outcomes (3)

• Daily Step Count

  Prior to each condition, each subject will be fit and aligned on the designated knee by a trained certified prosthetist. An activity monitor (such as the GeneActiv™) will be worn by the subject for each intervention period during the final month of the condition. Similar to prior studies, the investigators will use the activity monitor to track the number of steps the subjects take in each condition per day. The number of steps per day are averaged over the final month in each condition. A higher value indicates a better outcome.

  1 Month

• Activities-Specific Balance Confidence Scale (ABC) - Measuring Change From Baseline

  Activities-specific balance confidence (ABC) scale is a structured questionnaire that measures an individual's confidence during ambulatory activities without falling or experiencing a sense of unsteadiness. It consists of 16 questions gauging the individual's confidence while doing activities, from 0 (no confidence) to 4 (complete confidence). Therefore, the total score ranges from 0 to 64, with a higher value indicating a better outcome. This survey will be given at the end of each study condition (2 conditions, 3 months per condition). This survey will be administered as a part of the master questionnaire. Analysis is reported in % of balance confidence, which is found by taking their average of all questions (sum up all questions and divide by total number of questions) and dividing that average by 4.

  At the end of each 3 month condition

• PEQ-Well Being (PEQ-WB) - Measuring Change From Baseline

  The version of the PEQ which will be administered consists of 2 questions in 1 category (well being). For purposes of easier administration, the investigators have adopted the modified 10-point ordinal scale version of the PEQ-WB (scale 1-10, where 1 is the worst and 10 is the best relative to the questions being asked). This survey will be given at the end of each study condition (2 conditions, 3 months per condition). This survey will be administered as a part of the master questionnaire. The reported result is the average of the 2 questions in the PEQ-WB. The range of this reported result is 1-10, where a higher value indicates a better outcome.

  At the end of each 3 month condition

Study Arms (2)

Control (MPK)

NO INTERVENTION

The subject will wear their usual Microprocessor Knee (MPK) for 3 months, as well as in the lab to complete outcome measures.

Power Knee

EXPERIMENTAL

The subject will wear the Ossur PK in place of their usual MPK for 3 months, as well as in the lab to complete outcome measures.

Device: Power Knee

Interventions

Power Knee DEVICE

Newest version of the commercially-available Power Knee developed by Ossur.

Also known as: Ossur Power Knee, Ossur Power Knee III, PK, PK3

Power Knee

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Are at least 18 years old
• Unilateral transfemoral prosthesis user (limb absence between the knee and hip)
• Current user of a microprocessor-controlled knee (MPK)
• Have adequate clearance between distal end and ground for necessary knee and foot components
• Medicare Functional Classification Level (K-Level): 4
• Socket-Comfort Score: 6 or above to ensure adequate socket fit
• PLUS-M T-score of 55 or above
• Six months or more experience on a prosthesis
• Body weight between 50kg and 116kg (110lbs - 256lbs)

You may not qualify if:

• Present injuries to residual limb or contralateral leg affecting functional ability
• Socket issues/changes in the last 6 weeks
• Users with bone-anchored implants
• Subjects can be excluded at the discretion of the investigator for other unforeseen disqualifying criteria (such as specific cognitive issues, etc.). Subjects in this study will not be discriminated by sex/gender or race/ethnicity.
• Using a knee that the subject is unfamiliar with may increase the risk of falling. Therefore, pregnant women should not participate in the study and will be screened by self-disclosure.

Sponsors & Collaborators

• Liberating Technologies, Inc.: lead
• Hanger Clinic: Prosthetics & Orthotics: collaborator

Study Sites (2)

Liberating Technologies, Inc.

Holliston, Massachusetts, 01746, United States

Location

Hanger Clinic

Austin, Texas, 78758, United States

Location

MeSH Terms

Conditions

Wounds and Injuries

Limitations and Caveats

Limited data for the powered knee condition reduces the generalizability of these results

Results Point of Contact

• Title: Jen Johansson
• Organization: Liberating Technologies, Inc.

jen.johansson@liberatingtech.com

774-233-0874

Study Officials

• Jennifer Johansson, MS

  Liberating Technologies, Inc.

  PRINCIPAL INVESTIGATOR

Publication Agreements

• PI is Sponsor Employee: Yes

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: OTHER
• Intervention Model: CROSSOVER
• Sponsor Type: INDUSTRY
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Model Details: Participants will take home two interventional devices for data collection and feedback. One of the interventions will be their usual microprocessor knee to collect as a control, and the other will be the commercially available Ossur Power Knee. Participants will be trained on the interventional knees during the first month of at-home use. Functional outcome measures and self-report surveys will also be completed in-lab before and after each take-home intervention, as well as at the last training visit, in order to form a detailed comparison between the two interventions.

Study Record Dates

• First Submitted: December 9, 2021
• First Posted: March 4, 2022
• Study Start: May 1, 2022
• Primary Completion: August 28, 2024
• Study Completion: August 28, 2024
• Last Updated: June 26, 2025
• Results First Posted: June 26, 2025

Record last verified: 2025-06

Locations

US (2)