Comparison of Prosthetic Feet for People With Syme's Amputation (XF Symes Study)

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

Official Title
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Functional Assessment of High-profile Crossover Feet in People With Syme's Amputation

Conditions
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Amputation, Artificial Limb

Intervention / Treatment
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* Device: Crossover foot
* Device: Energy Storing Foot


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 18 years of age or older Have a unilateral Syme's amputation that occurred >1 year prior Owns a crossover foot modified for Syme's use Able to walk in the community without assistance Able to read and write in English Exclusion Criteria: Have other amputations Have a health condition that would limit completion of the study protocol (e.g., skin breakdown, heart disease)

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

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


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Foot 1: Crossover Foot, Foot 2: Energy Storing Foot<br>Participant randomized to crossover foot as first condition, energy storing foot as second condition | Device: Crossover foot<br>* A prosthetic foot that features an extended strut (keel) that attaches to the posterior proximal aspect of the prosthetic socket.<br>Device: Energy Storing Foot<br>* A prosthetic foot that features a short strut (keel) that attaches to the distal aspect of the prosthetic socket.<br>|
| Experimental: Foot 1: Energy Storing Foot, Foot 2: Crossover Foot<br>Participant randomized to energy storing foot as first condition, crossover foot as second condition | Device: Crossover foot<br>* A prosthetic foot that features an extended strut (keel) that attaches to the posterior proximal aspect of the prosthetic socket.<br>Device: Energy Storing Foot<br>* A prosthetic foot that features a short strut (keel) that attaches to the distal aspect of the prosthetic socket.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 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. | 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 | 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 | 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 | Sessions 3 (after 2 weeks of prosthesis 1 wear) and 4 (after 2 weeks of prosthesis 2 wear) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 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?). | 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 | 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. | 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. | 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) | Sessions 3 (after 2 weeks of prosthesis 1 wear) and 4 (after 2 weeks of prosthesis 2 wear) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Ankle disarticulation, Syme, Amputation, Prosthesis, Prosthetic foot, Crossover foot, Biomechanics