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Marcel Betsch, Joshua Kubach and Mario Pasurka

University Hospital Erlangen, Department of Trauma Surgery and Orthopaedics, Friedrich-Alexander-University Erlangen-Nuremberg, Krankenhausstr. 12, 91054 Erlangen, Germany 

Introduction

Our feet are as unique as our fingerprints, yet we encase them in standard shoes with standard insoles. So far, traditional shoe insoles often fail to accommodate the distinct contours and pressure distribution patterns of each person's feet, leading to discomfort and potential foot health issues. This study introduces and clinically evaluates a highly innovative method to produce individualized shoe insoles using 3D-printing technology.

(Forthcoming)

Wieke Philippart
VU University Amsterdam - Department of Human Movement Sciences

Sicco Bus
University of Amsterdam - University Medical Center

Jaap H. van Dieën
VU University Amsterdam - Department of Human Movement Sciences

Abstract

3D-printing allows customization of density and shape of silicon meshed midsoles to optimize the biomechanical interaction with the user. The purpose of this study was to assess the biomechanical effects of such midsoles with varying density and arch support. Two experiments were performed with 12 and 9 young, able-bodied participants, who walked on 6 midsoles with three different densities, with and without arch support. In the first experiment, peak ground reaction forces, initial vertical loading rate, RMS of ankle inversion/eversion, and power absorbed and produced by the ankle-foot complex were assessed in treadmill walking. In the second experiment, peak pressure, contact area and pressure time integral over rearfoot, mid-foot and forefoot were assessed in overground walking. The data were analyzed at group as well as individual level. No group level effects were found in the first experiment. In the second experiment, lower midsole density reduced peak pressure on the rearfoot and forefoot and arch support increased the contact area at the mid-foot, which reduced peak pressures on the mid-foot and the pressure time-integral on the mid- and forefoot. At the individual level, significant effects of midsole design were found, which were however variable between subjects, explaining to the lack of group level effects. In conclusion, midsole density and arch support affected gait biomechanics, but these effects were clearly subject dependent. The results presented support the notion to customize midsoles to fit individual users or group of users and demonstrate the utility of 3D printed meshed midsoles towards this end.

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