Custom Therapeutic Insoles Based on Both Foot Shape and Plantar Pressure Measurement Provide Enhanced Pressure Relief

  1. Tammy M. Owings, DENG1,
  2. Julie L. Woerner, BS1,
  3. Jason D. Frampton1,
  4. Peter R. Cavanagh, DSC, PHD12 and
  5. Georgeanne Botek, DPM3
  1. 1Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
  2. 2Orthopaedic Research Center, Cleveland Clinic, Cleveland, Ohio
  3. 3Department of Orthopaedic Surgery, Cleveland Clinic, Cleveland, Ohio
  1. Corresponding author: Georgeanne Botek, DPM, Department of Orthopaedic Surgery–A40, Cleveland Clinic, 9500 Euclid Ave., Cleveland, OH 44195. E-mail: botekg{at}ccf.org

Abstract

OBJECTIVE—The purpose of this study was to determine whether custom insoles tailored to contours of the barefoot pressure distribution and shape of a patient's foot can reduce plantar pressures in the metatarsal head (MTH) region to a greater extent than conventional custom insoles.

RESEARCH DESIGN AND METHODS—Seventy regions of elevated barefoot pressures (mean peak 834 kPa under MTHs) were identified in 20 subjects with diabetes. Foam box impressions of their feet were sent to three different orthotic supply companies for fabrication of custom insoles. One company was also given plantar pressure data, which were incorporated into the insole design. Measurements of in-shoe plantar pressures were recorded during gait for the three custom insoles in a flexible and a rocker-bottom shoe. Peak pressure and force-time integral were extracted for analysis.

RESULTS—In 64 of 70 regions, the shape-plus-pressure–based insole in the flexible shoe achieved superior unloading compared with the two shape-based insoles. On average, peak pressure was reduced by 32 and 21% (both P ≤ 0.0001) and force-time integral by 40 and 34% (both P < 0.0001) compared with the shape-based insoles. At the midfoot, force-time integral was increased by 51 and 33% (both P < 0.01). Similar trends were found using the rocker-bottom shoe.

CONCLUSIONS—Compared with insoles based only on shape, the use of foot shape with barefoot plantar pressure measurements in designing custom insoles results in enhanced offloading of high-pressure areas under the forefoot. This offloading was achieved by a greater transfer of load to the midfoot without additional loading of other forefoot structures.

Footnotes

  • Published ahead of print at http://care.diabetesjournals.org on 5 February 2008. DOI: 10.2337/dc07-2288.

    P.R.C. has received honoraria for serving as a speaker and consultant for and owns stock in DIApedia LLC and is a named inventor on U.S. patents 6,610,897, 6,720,470, and 7,206,718, the last of which elucidates the method of insole manufacture described in this article. His participation in this study was regulated by a Conflict of Interest Management Plan approved by Cleveland Clinic's Conflict of Interest Committee.

    The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C Section 1734 solely to indicate this fact.

    • Accepted January 17, 2008.
    • Received December 3, 2007.
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  1. Published online before print February 5, 2008, doi: 10.2337/dc07-2288 Diabetes Care May 2008 vol. 31 no. 5 839-844
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