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

Overview

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.

Full Title of Study: “Functional Assessment of High-profile Crossover Feet in People With Syme’s Amputation”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Crossover Assignment
    • Primary Purpose: Treatment
    • Masking: None (Open Label)
  • Study Primary Completion Date: August 2020

Detailed Description

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.

Interventions

  • Device: Crossover foot
    • A prosthetic foot that features an extended strut (keel) that attaches to the posterior proximal aspect of the prosthetic socket.
  • Device: Energy Storing Foot
    • A prosthetic foot that features a short strut (keel) that attaches to the distal aspect of the prosthetic socket.

Arms, Groups and Cohorts

  • Experimental: Crossover foot
    • Prosthetic foot that attaches to the proximal posterior socket. Relatively long strut length.
  • Active Comparator: Energy Storing Foot
    • Prosthetic foot that attaches to the distal aspect of the socket. Relatively short strut length.

Clinical Trial Outcome Measures

Primary Measures

  • Change in step length asymmetry
    • Time Frame: Sessions 3 (after 2 weeks of prosthesis 1 wear) and 4 (after 2 weeks of prosthesis 2 wear)
    • The difference between prosthetic and sound side step lengths
  • Change in prosthetic ankle range of motion
    • Time Frame: Sessions 3 (after 2 weeks of prosthesis 1 wear) and 4 (after 2 weeks of prosthesis 2 wear)
    • The total angular motion of the ankle in the sagittal plane during stance phase
  • Change in prosthetic-side energy return
    • Time Frame: Sessions 3 (after 2 weeks of prosthesis 1 wear) and 4 (after 2 weeks of prosthesis 2 wear)
    • Intersegmental flow of power out of the prosthesis
  • Change in peak sound-side limb loading
    • Time Frame: Sessions 3 (after 2 weeks of prosthesis 1 wear) and 4 (after 2 weeks of prosthesis 2 wear)
    • Maximum vertical ground reaction force in early stance

Secondary Measures

  • Preference questionnaire
    • Time Frame: Session 4 (after 4 weeks of prosthesis wear, 2 weeks of prosthesis 1 and 2 weeks of prosthesis 2)
    • 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?”).
  • Change in Prosthetic Limb Users Survey of Mobility (PLUS-M) 12-item Short Form version 1.2
    • Time Frame: Sessions 3 (after 2 weeks of prosthesis 1 wear) and 4 (after 2 weeks of prosthesis 2 wear)
    • 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.
  • Change in Activities-Specific Balance Confidence Scale (ABC)
    • Time Frame: Sessions 3 (after 2 weeks of prosthesis 1 wear) and 4 (after 2 weeks of prosthesis 2 wear)
    • Self-reported measure of balance confidence, the ABC is a single measure, scores range from 0-4, higher scores represent better balance confidence.
  • Change in Trinity Amputation and Prosthesis Experience Scales- Revised Functional Satisfaction
    • Time Frame: Sessions 3 (after 2 weeks of prosthesis 1 wear) and 4 (after 2 weeks of prosthesis 2 wear)
    • Self-reported measures of functional prosthetic satisfaction, scores on items are averaged and range from 0-2, higher values represent more satisfaction (better outcome)
  • Change in Trinity Amputation and Prosthesis Experience Scales- Revised Aesthetic Satisfaction
    • Time Frame: Sessions 3 (after 2 weeks of prosthesis 1 wear) and 4 (after 2 weeks of prosthesis 2 wear)
    • Self-reported measures of aesthetic prosthetic satisfaction, scores on items are averaged and range from 0-2, higher values represent more satisfaction (better outcome)
  • Change in Trinity Amputation and Prosthesis Experience Scales- Revised Activity Restrictions
    • Time Frame: Sessions 3 (after 2 weeks of prosthesis 1 wear) and 4 (after 2 weeks of prosthesis 2 wear)
    • Self-reported measures of activity restrictions, scores on items are averaged and range from 0-2, higher values represent more activity restrictions (worse outcome)

Participating in This Clinical Trial

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)

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: N/A

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • University of Washington
  • Provider of Information About this Clinical Study
    • Principal Investigator: Sara Morgan, Assistant Professor – University of Washington
  • Overall Official(s)
    • Sara Morgan, PhD, CPO, Principal Investigator, University of Washington
  • Overall Contact(s)
    • Sara Morgan, PhD, CPO, 206-616-9997, sjmorgan@uw.edu

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