Determining the Potential Benefit of Powered Prostheses


The goal of this research is to determine the effectiveness of a powered prosthesis compared to an unpowered prosthesis during short bouts of walking, extended periods of walking (to fatigue), and performance in the community.

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Crossover Assignment
    • Primary Purpose: Supportive Care
    • Masking: None (Open Label)
  • Study Primary Completion Date: August 2019

Detailed Description

Many individuals are living in the United States with limb loss. With the use of a prosthetic device many individuals can stay active, but most do not achieve a medically desired physical activity level. This creates a risk for cardiovascular disease. It is thought that individuals with amputation walk less because it is more difficult to get around, and recent advances in robotic prosthetic technology may make such activities easier. However, these prostheses have not yet been evaluated to determine their effectiveness during extended periods of walking. Despite the goals in design of new devices it is unclear whether individuals using them are able to incorporate them into making daily activities easier. Therefore, the goal of this research is to determine the effectiveness of a powered prosthesis compared to an unpowered prosthesis during long periods of walking.


  • Device: Powered ankle prosthesis
    • This device is a commercially available powered ankle prosthesis, (BioM, Bionx, Bedford, MA) which was given FDA device exempt status.
  • Device: Dynamic Response Foot
    • This condition is a sham condition as the participant will wear the prosthesis they were clinically prescribed and usually wear.

Arms, Groups and Cohorts

  • Experimental: Powered Ankle Prosthesis
    • In this condition, the participant is fitted with a powered prosthetic ankle by a certified prosthetist. The ankle is the BiOM which is manufactured by Bionx (which used to be named iWalk). This device was given 510(K) Exempt status by the FDA under (regulation number: 890.3500). Participants will wear the device for 2 weeks.
  • Sham Comparator: Dynamic Response Foot
    • In this arm, participants will wear their clinically prescribed dynamic response foot. This period is 2 weeks long.

Clinical Trial Outcome Measures

Primary Measures

  • Metabolic Cost of Walking
    • Time Frame: Testing took place after wearing the prostheses for two weeks
    • Metabolic costs will be measured using a portable metabolic system when participants walk on a treadmill at a fixed speed.
  • Total Steps Outside the Home Over a Two Week Period
    • Time Frame: 2 weeks
    • Activity data we be collected using activity monitors and GPS with both the regular prosthesis and the powered ankle prosthesis. Each activity monitoring period will last 2 weeks and will be done within in a 2 month period. Daily step count taken outside of the home, determined using an activity monitor and GPS device
  • Quality of Life (QoL) on a Short-Form 36
    • Time Frame: Questionnaire completed 2 weeks after wearing each prosthesis
    • Participants completed the Medical Outcomes Study 36 Items Short-Form Health Survey (SF-36) after each condition. Each scale is directly transformed into a 0-100 scale on the assumption that each question carries equal weight. The lower the score the more disability.

Secondary Measures

  • Prosthetic Evaluation Questionnaire (PEQ)
    • Time Frame: Questionnaire completed 2 weeks after wearing each prosthesis
    • Participants completed a survey to evaluate their prosthetic satisfaction (Prosthetic Evaluation Questionnaire) after each condition. Most questions in the PEQ use a visual analog scale format. Each visual analog scale is scored as a continuous numerical variable measured as the distance in millimeters from the left endpoint of the line (0 mm) to the point at which the respondent’s mark crosses the line (up to 100 mm). The questions are all worded so that a higher number (toward the right) will correspond with a more positive response. Ambulation – Greater number = increased perceived ambulation Appearance – Greater number = better appearance Frustration – Greater number = less frustration Perceived Response – Greater number = increased perceived response Residual Limb Health – Greater number = better residual limb health Social burden – Greater number = less social burden Sounds – Greater number = less sound Utility – Greater
  • Muscle Activity in the Lower Limb
    • Time Frame: Testing took place after the participant wore the prosthesis for 2 weeks
    • Participants walk on a treadmill while muscle activity from various lower limb muscles are monitored using electromyography. We calculated the integrated EMG (iEMG) for each muscle collected as the total activity in that muscle as a percentage of the maximum signal.
  • Time to Fatigue
    • Time Frame: Testing took place after wearing the prostheses for two weeks
    • Participants walk on a treadmill at a fast speed until they felt they can no longer continue. The time to fatigue was recorded.

Participating in This Clinical Trial

Inclusion Criteria

  • Adult (over 21 years old), Has unilateral transtibial amputation, has used prosthesis for at least 6 months, is currently using an unpowered prosthesis, can walk unassisted for at least 10 minutes Exclusion Criteria:

  • History of orthopedic or neurologic disorders to their intact limb, history of cardiovascular disease that prevents them from safely completing requested activities, unable to walk for 30 minutes at a time

Gender Eligibility: All

Minimum Age: 21 Years

Maximum Age: N/A

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • Deanna H Gates
  • Provider of Information About this Clinical Study
    • Sponsor-Investigator: Deanna H Gates, Assistant Professor – University of Michigan
  • Overall Official(s)
    • Deanna H Gates, Ph.D., Principal Investigator, University of Michigan

Clinical trials entries are delivered from the US National Institutes of Health and are not reviewed separately by this site. Please see the identifier information above for retrieving further details from the government database.

At, we keep tabs on over 200,000 clinical trials in the US and abroad, using medical data supplied directly by the US National Institutes of Health. Please see the About and Contact page for details.