In-Shoe Innovation: 3D-Printed Foot Orthoses

Breanne Therese Przestrzelski, Clemson University


By the year 2050, one in three adults in the United States will have diabetes. One in three. While countless complications arise with the development of diabetes, one of particular focus is that of diabetic foot ulcers (DFUs), which affect up to 25% of all diabetics at least once in their lifetime. Of these, 2-3% of diabetics will experience a recurring foot ulcer annually, 24% of which require a subsequent amputation. Of all lower-limb amputations, 85% are preceded by a non-healing foot ulcer. This suggests the immediate need for an improved technology to reduce this inexcusable prevalence in the 21st century. Current DFU treatment involves the prescription of a custom foot orthosis that aims to offload the ulcerated area, but simultaneously takes 2-3 weeks to be delivered to the patient, costs the patient upwards of $250 per pair, which is required to be replaced every 3-6 months, and is not at the point-of-care often requiring extensive fabricator interpretation of the developed orthosis without clinical involvement until the conclusion of the process at time of patient fitting. This dissertation describes the development of a novel 3D-printed foot orthosis to fulfill these shortcomings of the current golden standard of care. This novel 3D-printed foot orthosis is comprised of a tri-layer system that uses customizable material offloading capabilities to span the ranges of traditional orthotic material hardness and peak pressures, two measures which are often in direct correlation with development of DFUs. The technology underwent a series of verification testing that determined significant equivalence to the traditional orthotic in addition to validation testing that confirmed the feasibility of projected adoption into the market. While significant enhancements were identified for future design improvement that will extend the durability of the novel geometric voided structures, most notable was the confirmation that through these structures, the 3D-printed orthosis possessed greater capabilities of offloading via a decreased peak pressure gradient, and equivalent patient comfort rating during a short-term clinical trial when compared to the traditional orthosis.