• DOI:10.1089/DIA.2005.7.638
• Corpus ID: 2389589

Wear and biomechanical characteristics of a novel shear-reducing insole with implications for high-risk persons with diabetes.

@article{Lavery2005WearAB,
  title={Wear and biomechanical characteristics of a novel shear-reducing insole with implications for high-risk persons with diabetes.},
  author={Lawrence A. Lavery and Dan R. Lanctot and George Constantinides and Ruben G. Zamorano and Kyriacos A. Athanasiou and Chandra Mauli Agrawal},
  journal={Diabetes technology \& therapeutics},
  year={2005},
  volume={7 4},
  pages={
          638-46
        }
}

• L. Lavery, D. Lanctot, +3 authors C. M. Agrawal
• Published 24 August 2005
• Medicine
• Diabetes technology & therapeutics

OBJECTIVE
This study was designed to measure pressure and shear reduction of a novel insole design.

METHODS
We compared three multilayer viscoelastic insoles to a novel insole design (Glide-Soft, Xilas Medical, Inc., San Antonio, TX). The bottom pad of each insole was fabricated from firm-density Plastazote [Apex Foot Products (now Aetrex), South Hackensack, NJ] with an upper of Plastazote, ethyl vinyl acetate, or PORON (Langer Biomechanics Group, Inc., Deer Park, NY). The GlideSoft design used the same materials with two intervening thin sheets of a low friction material. We measured foot pressures, shear, and material stiffness prospectively as the insoles aged during daily usage in 30 healthy adults. We used the F-Scan (Tekscan, Inc., Boston, MA) to determine in-shoe foot pressures and the Automated Stress-relaxation Creep Indenter System (Xilas Medical) to measure material stiffness. To evaluate shear force, the insole was placed on the slide assembly of a custom-designed shear tester equipped with a reciprocating mechanism and force transducers.

RESULTS
The GlideSoft exhibited 57% less peak shear force than the standard insole (P < 0.05) in laboratory testing under simulated conditions. Ethyl vinyl acetate had higher compressive stiffness values than Plastazote and PORON at all test intervals (P < 0.05). There were no statistical differences between any of the insoles for peak in-shoe pressure measurements (P > 0.05).

CONCLUSIONS
The GlideSoft design demonstrated a significant reduction in shear while maintaining equivalent pressure reduction compared with standard insole designs with three different material combinations for up to 320,000 steps.