Expanding Powered Leg Access

Body

Amputation of the lower limb affects an estimated 1 million Americans, significantly limiting their mobility and independence. After lower limb loss, individuals walk more slowly and unevenly, are less stable, and use more energy.

Most commercially available prosthetic legs are passive, meaning they do not supply power to compensate for the energy that would be provided by an intact ankle or knee, and therefore provide significantly limited function. Advanced passive prosthetic joints use sensors and a microcomputer to cushion the knee joint and make walking smoother. These computerized prostheses can be programmed with several activity modes, such as walking or descending stairs. However, these modes are not activated automatically so users must select when they are changing activities. Further, since these computerized prostheses are passive, the user still cannot efficiently climb stairs or inclines. 

Body

Powered prostheses can overcome these disadvantages by providing joint power for the more demanding activities of daily living. Unfortunately, patient access to these devices is limited. Current Medicare guidelines allow reimbursement of prosthetic components based on clinician-evaluated levels of mobility. Thus, patients who are evaluated to have better walking potential are typically prescribed more advanced prostheses. However, a patient’s ability determined by in-clinic assessments may not reflect real world mobility, and little information exists on the correlation between clinical measures and community mobility level. Previous studies suggest that more advanced devices provide mobility advantages across a range of patient abilities. 

Body

New powered joints may allow for better outcomes in individuals with leg amputation across ability levels. However, powered devices have been almost exclusively developed for and tested by individuals with high levels of mobility. Our work is focused on comprehensively evaluating the benefits of powered devices for prosthesis users who have historically not be included in such testing. We are comparing the functional performance of patients with a passive microcomputer knee prosthesis versus a prosthesis with both a powered knee and a powered ankle. We are also testing if a prosthesis with only a powered knee or a powered ankle improves walking in this group. Further, we are evaluating if additional clinical training with the powered knee and ankle prosthesis reduces abandonment of the prosthesis. Our hypothesis is that providing powered prosthetic devices will improve patient mobility and that clinical training will magnify those improvements.

Body

• Attend multiple study visits at Shirley Ryan AbilityLab over 8 to 10 months
• Meet with a research prosthetist to make a socket for use in the study
• Be fit for use with socket and study devices
• Receive training with commercially available and study-specific prostheses
• Perform functional testing wearing prostheses

Body

• Residents of the Chicagoland area
• 18-95 years old 
• Individuals with a unilateral transfemoral amputation
• At least 6 months since definitive prosthesis fitting
• Able to walk 50 meters (55 yards) with a prosthesis without the assistance of another person
• Medically cleared by physician to participate in study
• English speaking
• Weigh under 250 pounds 

Body

Participants will receive compensation for each study visit.

Body

National Institute of Health (NIH)