The purpose of this study is to compare the functional differences between two types of foot prostheses for people with ankle disarticulation (Syme's) amputations. The two feet being tested are low- and high-profile feet, with the difference being the latter has an extended keel and attaches to the posterior of the prosthetic socket, rather than the distal end. The hypothesis is that the high-profile foot (i.e., the crossover foot) will lead to functional and biomechanical improvements compared to low-profile feet.
Syme's prostheses are typically limited to low-profile prosthetic feet due to clearance restrictions below the prosthetic socket. As a result, the functional benefits provided by the long residual limb are mitigated by prosthetic design limitations. Recently, high-profile, posteriorly-attaching crossover feet have been modified for use with people who have Syme's amputation. Crossover feet theoretically improve motion and energy storage-and-return compared to traditional foot options for the Syme's level. Crossover feet also have the potential to broaden the range of high-impact activities that can be performed with a single prosthesis. However, to date there is no empirical evidence that compares functional differences when walking with high-profile crossover feet compared to low-profile feet for people with Syme's amputation. This mixed-method pilot research will use a randomized, controlled within-participants design. Investigators will assess gait biomechanics, self-reported health outcomes, and qualitative interviews to compare relative advantages and disadvantages of traditional low-profile Syme's feet and high-profile crossover feet. This proposed work will create a foundation for future research that examines the potential benefits of crossover feet in people with Syme's amputation. In addition, results from this research will be used clinically to inform prosthetic options for people with limited clearance for distally-attached prosthetic feet.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
A prosthetic foot that features an extended strut (keel) that attaches to the posterior proximal aspect of the prosthetic socket.
A prosthetic foot that features a short strut (keel) that attaches to the distal aspect of the prosthetic socket.
University of Washington, Amplifying Mobility and Performance Laboratory
Seattle, Washington, United States
Ratio Between Sound and Prosthetic Side Step Lengths
The symmetry between prosthetic and sound side step lengths. Step lengths were calculated as the distance between heels from heel strike of the contralateral foot to heel strike of the ipsilateral foot.
Time frame: Sessions 3 (after 2 weeks of prosthesis 1 wear) and 4 (after 2 weeks of prosthesis 2 wear)
Total Prosthetic Ankle Range of Motion
The change in total angular motion of the ankle in the sagittal plane (e.g., dorsiflexion \& plantarflexion) during stance phase between prosthetic feet, in degrees
Time frame: Sessions 3 (after 2 weeks of prosthesis 1 wear) and 4 (after 2 weeks of prosthesis 2 wear)
Prosthetic-side Energy Return
Intersegmental flow of power out of the prosthesis
Time frame: Sessions 3 (after 2 weeks of prosthesis 1 wear) and 4 (after 2 weeks of prosthesis 2 wear)
Peak Sound-side Limb Loading
Maximum vertical ground reaction force in early stance
Time frame: Sessions 3 (after 2 weeks of prosthesis 1 wear) and 4 (after 2 weeks of prosthesis 2 wear)
Preference Questionnaire
At the end of the study, participants will engage in a preference questionnaire with open-ended follow-up questions to elicit preferences and experiences with both feet. Questions will ask about overall preference, and preference for a range of mobility activities (e.g., "Which foot did you prefer overall, and why?" and "Which foot did you prefer for walking up stairs, and why?").
Time frame: Session 4 (after 4 weeks of prosthesis wear, 2 weeks of prosthesis 1 and 2 weeks of prosthesis 2)
Change in Prosthetic Limb Users Survey of Mobility (PLUS-M) 12-item Short Form Version 1.2
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Enrollment
5
Self-reported measure of mobility, the PLUS-M 12-item Short Form is a single measure, scores range from 17.5-76.6, higher scores represent better mobility.
Time frame: Sessions 3 (after 2 weeks of prosthesis 1 wear) and 4 (after 2 weeks of prosthesis 2 wear)
Change in Activities-Specific Balance Confidence Scale (ABC)
Self-reported measure of balance confidence, the ABC is a single measure, scores range from 0-4, higher scores represent better balance confidence.
Time frame: Sessions 3 (after 2 weeks of prosthesis 1 wear) and 4 (after 2 weeks of prosthesis 2 wear)
Change in Trinity Amputation and Prosthesis Experience Scales- Revised Aesthetic Satisfaction
Self-reported measures of aesthetic prosthetic satisfaction, scores on items are averaged and range from 0-2, higher values represent more satisfaction (better outcome)
Time frame: Sessions 3 (after 2 weeks of prosthesis 1 wear) and 4 (after 2 weeks of prosthesis 2 wear)