Metabolic Cost of Walking With Passive vs. Powered Prosthetic Knees Among Persons With Limb Loss

The purpose of this industry-initiated research study is to test that a powered microprocessor controlled knee improves metabolic function during walking in level and sloped conditions as compared to the subject's physician prescribed prosthesis.

Study Overview

• Status: Recruiting
• Conditions: Transfemoral Amputation
• Intervention / Treatment: Other: Powered Microprocessor-controlled Knee (PMPK)

Detailed Description

The Procedures include:

Initial Visit:

1. Informed consent
2. HIPAA authorization
3. Determine/verify ambulation potential
4. Take and record body measurements (height, weight, circumferences)
5. Activities-Specific Balance Confidence (ABC) scale
6. L.A.S.A.R. Posture alignment assessment with RxPx

Second Visit

1. Fit with heartrate monitor and metabolic analyzer mask
2. Treadmill Test (level-ground) with RxPx
3. Rest
4. Treadmill Test (incline) with RxPx
5. Fit subject with PMPK
6. L.A.S.A.R. Posture alignment assessment with PMPK
7. Subject uses PMPK for one week as their primary prosthesis

Third Visit (1 week later)

1. Fit with heartrate monitor and metabolic analyzer mask
2. Treadmill Test (level-ground) with PMPK
3. Rest
4. Treadmill Test (incline) with PMPK
5. Activities-Specific Balance Confidence (ABC) scale
6. Return PMPK and refit of RxPx
7. Verify alignment with L.A.S.A.R. Posture alignment
8. Check that all fasteners are secure

• Study Type: Interventional
• Enrollment (Estimated): 12
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Michael Davidson, Ph.D.; Phone Number: 9095586516; Email: mdavidson@llu.edu

Study Locations

• United States
  • California
    • Loma Linda, California, United States, 92354
      • Recruiting
      • Loma Linda University
      • Contact: Michael Davidson, Ph.D.; Phone Number: 909-558-6516; Email: mdavidson@llu.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Males and Females with unilateral knee disarticulation or transfemoral (KD/TF) amputation.
• a body mass greater than 49Kg and less than 117Kg
• 18-75 years of age
• Have an ambulation potential of K3 or K4
• Use a prosthesis daily for walking or sports activities
• No less than six months of experience with a prosthesis
• No socket issues or changes in the last six weeks
• No residual limb pain affecting functional ability.

Exclusion Criteria:

• Cannot walk at different speeds (MCFL K0-K2)
• Limb-loss below the knee or through the hip
• More than one amputation.
• Uses an assistive device for walking
• Uncontrolled edema in leg compartments
• Compromised skin of the residual limb or contralateral foot
• Are 180 days or less post-amputation
• Pregnant (self-reported)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Powered Microprocessor-controlled Knee (PMPK); the "Power Knee" is a commercially available PMPK.	Other: Powered Microprocessor-controlled Knee (PMPK); A microprocessor-controlled Knee with standardized commercial prosthetic foot; Other Names: Power Knee

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
VO2 uptake - level ground	VO2 uptake during ambulation on a treadmill - level ground	Change between Baseline Visit (study enrollment) and Visit 2 (3 weeks post-study enrollment)
VO2 uptake - incline	VO2 uptake during ambulation on a treadmill - 5 degree incline	Visit 2 (3 weeks post-study enrollment)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Balance confidence	Activities based balance confidence survey (0-100%) higher score means more balance confidence	At Baseline Visit (study enrollment)
Exertion	Borg Exertion Scale (0-10) with 10 being maximum exertion	Change between Visit 2 (3 weeks post-study enrollment) and Visit 3 (4 weeks post-study enrollment)

Collaborators and Investigators

• Sponsor: Loma Linda University
• Collaborators: Össur Iceland ehf
• Investigators: Principal Investigator: Michael Davidson, Ph.D., Loma Linda University Health

Study record dates

Study Major Dates

• Study Start (Actual): February 27, 2023
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): December 1, 2026

Study Registration Dates

• First Submitted: February 27, 2023
• First Submitted That Met QC Criteria: April 14, 2023
• First Posted (Actual): April 26, 2023

Study Record Updates

• Last Update Posted (Actual): February 4, 2026
• Last Update Submitted That Met QC Criteria: February 2, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Amputation; Heart Rate; Power Knee; Metabolic Costs
• Other Study ID Numbers: 5220320

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No