Evaluation of Multidensity Orthotic Materials Used in Footwear for Patients with Diabetes

Abstract

Selected combinations of multidensity orthotic materials were tested under simulated walking conditions found in the forefoot of diabetic patients. Materials were compared for therapeutic effectiveness by their stress/strain properties and dynamic compression set. Results showed that all of the multidensity materials experienced losses in performance throughout the testing period of 100,000 cycles, with the greatest losses occurring within the first 10,000 cycles. Of the materials tested, Poron + Plastazote #2 and Spenco + Microcel Puff Lite had the highest dynamic material strain and the lowest dynamic compression set over 100,000 cycles. In comparison, these are better multidensity combinations than the others tested to use as therapeutic orthoses in footwear for diabetic patients.

Therapeutic footwear for people with diabetes

“…Use decision rules for insole and rocker Step 3 Use CAD-CAM to machine insole precisely Step 4 Measure in-shoe pressure to ensure efficacy Step 5 Dispense socks, insoles, shoes, and sandals Step 6 Educate the patient Step 7 Follow up frequently Step 8 Replace footwear regularly shoes with soft insoles, which may rapidly lose their initial pressure distribution and cushioning properties [44].…”

Compact and portable digitally controlled device for testing footwear materials: Technical note

“…This is a nominal thickness that is readily available and effective for acquiring material properties without compressing beyond the materials' functional strain limits, commonly referred to as "bottoming out." Foto et al tested 100,000 cycles and determined that plastic deformation of foam materials generally begins after 10,000 cycles [22]. The authors chose 50,000 cycles to accomplish plastic deformation to any applicable materials tested.…”

“…The diabetic forefoot is modeled mathematically, suggesting no impact during the foot-flat to toe-off phase of gait. Dynamic compression testing using a determined number of cycles, loading rate, and pressures equivalent to the conditions found in the footwear forefoot better characterizes the useful service life of materials [22].…”

The Biomechanics of the Foot in Diabetes Mellitus

“…Values for these quantities are not common knowledge at the present time, although, as will be discussed in the next subsection, information on the material properties of insoles is now available, 292,297,298 and it is expected that compression and shear moduli will become the basis for a more quantitative approach to footwear design and manufacture in the near future.…”