Determining the Potential Benefit of Powered Prostheses

Study Overview
=================
Brief Summary
-----------------
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.

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.

Official Title
-----------------
Determining the Potential Benefit of Powered Prostheses

Conditions
-----------------
Unilateral Traumatic Amputation, Amputation, Traumatic

Intervention / Treatment
-----------------
* Device: Powered ankle prosthesis
* Device: Dynamic Response Foot


Participation Criteria
=================
Eligibility Criteria
-----------------
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

Ages Eligible for Study
-----------------
Minimum Age: 21 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Supportive Care
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Powered Ankle Prosthesis<br>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. | Device: Powered ankle prosthesis<br>* This device is a commercially available powered ankle prosthesis, (BioM, Bionx, Bedford, MA) which was given FDA device exempt status.<br>|
| Sham Comparator: Dynamic Response Foot<br>In this arm, participants will wear their clinically prescribed dynamic response foot. This period is 2 weeks long. | Device: Dynamic Response Foot<br>* This condition is a sham condition as the participant will wear the prosthesis they were clinically prescribed and usually wear.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Metabolic Cost of Walking | Metabolic costs will be measured using a portable metabolic system when participants walk on a treadmill at a fixed speed. | Testing took place after wearing the prostheses for two weeks | 
| Total Steps Outside the Home Over a Two Week Period | 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 | 2 weeks | 
| Quality of Life (QoL) on a Short-Form 36 | 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. | Questionnaire completed 2 weeks after wearing each prosthesis | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Prosthetic Evaluation Questionnaire (PEQ) | 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 | Questionnaire completed 2 weeks after wearing each prosthesis | 
| Muscle Activity in the Lower Limb | 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. | Testing took place after the participant wore the prosthesis for 2 weeks | 
| Time to Fatigue | Participants walk on a treadmill at a fast speed until they felt they can no longer continue. The time to fatigue was recorded. | Testing took place after wearing the prostheses for two weeks | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
powered ankle prosthesis, activity monitoring, muscle fatigue, below knee amputation