Effects of Wearing a Powered Ankle-Foot Prosthesis on Amputee Walking
Amputees wearing a conventional prosthesis require 20-30% more metabolic energy to walk at the same speeds as non-amputees and this discrepancy is more apparent at faster walking speeds. Amputees choose to walk at speeds 30-40% slower than non-amputees. Preferred walking speed is likely influenced by elevated metabolic energy, but the underlying reason for slower preferred walking speeds is not fully understood. Unilateral amputees exhibit highly asymmetrical gait patterns that likely require more metabolic energy and impair functional mobility, increasing the risk of degenerative joint disease, osteo-arthritis and lower back pain. Improvements in prosthetic devices could enhance mobility in amputees, thus positively effecting rehabilitation and ambulation in veterans. A prosthesis that allows amputees to reduce metabolic energy would be especially useful for rehabilitation in older, ill individuals with reduced exercise capacities and could literally restore walking ability in people that are currently non-ambulatory.
Hypotheses. Amputees wearing the MIT Powered Ankle-Foot (PAF) prosthesis will have a lower metabolic cost, faster preferred walking speed, and improved gait symmetry during walking than amputees wearing a conventional prosthesis and will have nearly the same metabolic cost, preferred walking speed, and gait symmetry during walking as age, gender, height, and weight matched non-amputees.
|Study Design:||Endpoint Classification: Efficacy Study
Intervention Model: Factorial Assignment
Masking: Open Label
Primary Purpose: Basic Science
|Official Title:||Effects of Wearing a Powered Ankle-Foot Prosthesis on Amputee Walking|
- Metabolic cost of transport [ Time Frame: After clinical trials are completed ] [ Designated as safety issue: No ]
- Preferred walking speed [ Time Frame: After clinical trials are completed ] [ Designated as safety issue: No ]
- Gait symmetry [ Time Frame: After clinical trials are completed ] [ Designated as safety issue: No ]
|Study Start Date:||March 2009|
|Study Completion Date:||January 2013|
|Primary Completion Date:||June 2011 (Final data collection date for primary outcome measure)|
Experimental: Arm 1
Powered ankle-foot prosthesis
Device: Powered ankle-foot prosthesis
The powered ankle-foot prosthesis is comprised of a series-elastic actuator (SEA) and an elastic leaf spring. This technology has been previously developed for robotic and human rehabilitation applications. The SEA allows for precise force control of the ankle joint, thus mimicking the spring-like behavior of the human ankle, as well as providing adequate energy for forward progression of the body. From the early stance period to the mid-stance period of walking, the SEA will be controlled so that the ankle joint behaves like a spring. During the late stance period, the SEA will be employed to power the forward movement of the body. The elastic leaf spring will provide shock absorption during foot strike, energy storage during early stance, and energy return during late stance.
|United States, Rhode Island|
|VA Medical Center, Providence|
|Providence, Rhode Island, United States, 02908|
|Principal Investigator:||Alena Grabowski, PhD BA||VA Eastern Colorado Health Care System, Denver, CO|