Symmetry in External Work (SEW): A novel method of quantifying gait differences between prosthetic feet

Vibhor Agrawal, Robert Gailey, Christopher O'Toole, Ignacio Gaunaurd, Tomas Dowell

Research output: Contribution to journalArticle

21 Scopus citations

Abstract

Unilateral transtibial amputees (TTAs) show subtle gait variations while using different prosthetic feet. These variations have not been detected consistently with previous experimental measures. We introduce a novel measure called Symmetry in External Work (SEW) for quantifying kinetic gait differences between prosthetic feet. External work is the result of changes in kinetic and potential energy of body center of mass (CoM). SEW is computed by integrating vertical ground reaction forces obtained using F-scan in-sole sensors. Since various prosthetic feet have different designs, we hypothesized that SEW will vary with the type of foot used. This hypothesis was tested with a single unilateral TTA using four prosthetic feet (Proprio, Trias+, Seattle Lite and SACH). The Proprio (mean symmetry 94.5% ± 1.1%) and the Trias+ (92.1% ± 2.5%) feet exhibited higher symmetry between the intact and prosthetic limbs, as compared to the Seattle (67.8% ± 19.3%) and SACH (35.7% ± 11.1%) feet. There was also a good agreement in vertical CoM excursion between the intact foot and prosthetic feet with heel-toe foot plate designs. Results indicate that SEW measure may be a viable method to detect kinetic differences between prosthetic feet and could have clinical applications because of relatively low cost instrumentation and minimal subject intervention.

Original languageEnglish (US)
Pages (from-to)148-156
Number of pages9
JournalProsthetics and orthotics international
Volume33
Issue number2
DOIs
StatePublished - Aug 17 2009

Keywords

  • External mechanical work
  • Gait kinetics
  • Gait symmetry
  • Prosthetic feet comparison

ASJC Scopus subject areas

  • Rehabilitation
  • Health Professions (miscellaneous)

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