A 3-dimensional finite element model of the human foot and ankle for insole design

Jason Tak Man Cheung, Ming Zhang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

137 Citations (Scopus)

Abstract

Objective: To investigate the effect of material stiffness of flat and custom-molded insoles on plantar pressures and stress distribution in the bony and ligamentous structures during balanced standing. Design: A 3-dimensional (3-D) finite element model of the human ankle-foot complex and a custom-molded insole were developed from 3-D reconstruction of magnetic resonance images and surface digitization. The distal tibia and fibula, together with 26 foot bones and 72 major ligaments and the plantar fascia, were embedded in a volume of soft tissues. Setting: Computational laboratory in a rehabilitation engineering center. Participant: A healthy man in his mid twenties (weight, 70kg). Interventions: Not applicable. Main Outcome Measures: Foot-support interfacial pressure, von Mises stress in bony structures, and strain of the plantar fascia were predicted using the finite element model. Results: A custom-molded, soft (Young modulus, E=0.3MPa) insole reduced the peak plantar pressure by 40.7% and 31.6% at the metatarsal and heel region, respectively, compared with those under a flat, rigid (E=1000MPa) insole. Meanwhile, a 59.7% increase in the contact area of the plantar foot was predicted with a corresponding peak plantar pressure increase of 22.2% in the midfoot. Conclusions: The finite element analysis implies that the custom-molded shape is more important in reducing peak plantar pressure than the stiffness of the insole material.
Original languageEnglish
Pages (from-to)353-358
Number of pages6
JournalArchives of Physical Medicine and Rehabilitation
Volume86
Issue number2
DOIs
Publication statusPublished - 1 Jan 2005

Keywords

  • Ankle
  • Finite element analysis
  • Foot
  • Pressure
  • Rehabilitation

ASJC Scopus subject areas

  • Physical Therapy, Sports Therapy and Rehabilitation
  • Rehabilitation

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