Clinical Investigation (Beta) of Power Knee Mainstream - Dynamic

NCT04787627 | Completed Results FDA Device

• 1 other identifier: CIP2019050213
• Study Type: interventional
• Target: 17
• Locations: 1 country
• Sites: 2

Brief Summary

Prospective two group cross over investigation, comparing the investigational device (Power Knee, a powered microprocessor controlled prosthetic knee) and subjects prescribed microprocessor prosthetic knee (MPK). The primary objective was to evaluate the efficacy of the investigational device in reducing exertion during walking compared to passive MPKs. Additionally to evaluate the efficacy of the investigational device in the short and long term compared to passive MPKs and previous versions of the Power Knee, during daily living activities i.e. walking on level ground, in stairs and inclines, rising from and sitting down to a chair as well as performance of gait functions and ease of set up for average to highly active transfemoral/knee disarticulation amputees and Certified Prosthetists/Orthotists (CPOs).

Conditions

Prosthesis User; Amputation

Outcome Measures

Primary Outcomes (2)

• Mean Difference in Borg Category Rating Scale Before and After 6MWT at 2 Weeks

  Mean difference in perceived exertion on the Borg rating scale of perceived exertion before and after 6 minute walk test (6MWT) (see outcome 2) with investigational device (Power Knee) compared to comparator (prescribed device). Subjects are asked how exerted they feel on a scale of 0-10 (0 indicating no exertion and 10 indicating the most exertion) at rest before they carry out the 6MWT, and after carrying out the 6MWT, the difference is recorded. The Borg Category Rating 10 scale (CR10) is a validated measure of perceived exertion.

  At baseline, after 2 weeks of either using the Power knee or their own prescription prosthesis, and at the fourth follow-up (at approximately weeks 22-16)

• Average Distance Walked in 6 Minute Walk Test

  Average distance walked in 6MWT with investigational device (Power Knee) compared to comparator (prescribed device) User walk for 6 minutes in their self selected walking speed on a 30 meter track. Shorter time indicates better mobility performance.

  At baseline, after 2 weeks of either using the Power knee or their own prescription prosthesis, and at the fourth follow-up (at approximately weeks 22-16)

Secondary Outcomes (13)

• Total Score of Prosthesis Mobility Questionnaire (PMQ) Questions 9 and 10

  At baseline, after 2 weeks of either using the Power knee or their own prescription prosthesis, and at the fourth follow-up (at approximately weeks 22-16)

• Average Score of Modified Prosthesis Evaluation Questionnaire (PEQ) Question 14F

  At baseline, after 2 weeks of either using the Power knee or their own prescription prosthesis, and at the fourth follow-up (at approximately weeks 22-16)

• Average Score of Modified Prosthesis Evaluation Questionnaire (PEQ) Question 13D

  At baseline, after 2 weeks of either using the Power knee or their own prescription prosthesis, and at the fourth follow-up (at approximately weeks 22-16)

• Satisfaction With Walking Speed

  At baseline, after 2 weeks of either using the Power knee or their own prescription prosthesis, and at the fourth follow-up (at approximately weeks 22-16)

• Prosthetic Limb Users Survey of Mobility (PLUS-M) T-score

  At baseline, after 2 weeks of either using the Power knee or their own prescription prosthesis, and at the fourth follow-up (at approximately weeks 22-16)

Study Arms (2)

Power Knee before prescribed prosthesis

EXPERIMENTAL

Power Knee, the investigational device is fitted on subjects and they use it as their primary prosthesis for 2 weeks before coming in for data collection on the device. After being on the investigational device for 2 weeks subjects go back on their prescribed prosthesis for 2 weeks and comparator data is collected.

Device: Power Knee

Power Knee after Prescribed prosthesis

EXPERIMENTAL

Subjects start the study by using their prescribed prosthesis for 2 weeks, then they come in for data collection of comparator data, in that same visit they are fitted with the investigational device and wear that for 2 weeks before coming in for data collection on that device.

Device: Power Knee

Interventions

Power Knee DEVICE

Powered microprocessor controlled prosthetic knee

Power Knee after Prescribed prosthesis; Power Knee before prescribed prosthesis

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Kg\< body weight \< 116Kg
• K3-K4 amputees with unilateral transfemoral amputation or Knee disarticulation
• Allows for 37mm knee center height to dome of pyramid alignment
• Currently using a MPK or Power Knee
• Older than 18 years old
• No socket issues/changes in the last 6 weeks and no socket changes expected during the duration of the study period.
• Comfortable and stable socket fit
• Willing and able to participate in the study and follow the protocol

You may not qualify if:

• Kg\> body weight \> 116Kg
• Bilateral amputees
• Users with socket problems
• Users with co-morbidities in the contra-lateral limb, which affect their functional mobility
• Younger than 18 years old
• Users with stump pain
• Users with cognitive impairment
• Users not involved in other clinical tests and/or receiving treatment that the testing might affect.

Sponsors & Collaborators

• Össur Iceland ehf: lead
• Medical Center Orthotics and Prosthetics: collaborator

Study Sites (2)

Medical Center Orthotics and Prosthetics

Silver Spring, Maryland, 20910, United States

Location

Medical Center Orthotics and Prosthetics

Boston, Massachusetts, 02134, United States

Location

Limitations and Caveats

Due to Covid restrictions replacement of drop-outs was not attempted.

Results Point of Contact

• Title: Laurine Roussillon
• Organization: Össur Iceland ehf.

lroussillon@ossur.com

+354 822 1812

Study Officials

• Ian Fothergill, CPO

  Medical Center Orthotics and Prosthetics (MCOP) Silver Spring

  PRINCIPAL INVESTIGATOR

• John Warren, CPO

  Medical Center Orthotics and Prosthetics (MCOP) Boston

  PRINCIPAL INVESTIGATOR

Publication Agreements

• PI is Sponsor Employee: No
• Restrictive Agreement: No

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: CROSSOVER
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Model Details: This is a prospective randomized two group cross-over study, within subject comparison.

Study Record Dates

• First Submitted: December 29, 2020
• First Posted: March 8, 2021
• Study Start: November 18, 2019
• Primary Completion: July 6, 2020
• Study Completion: July 6, 2020
• Last Updated: September 22, 2025
• Results First Posted: September 22, 2025

Record last verified: 2025-09

Data Sharing

• IPD Sharing: Will not share

Locations

US (2)