Effect of a carbon reinforcement for maximizing shoe outsole bending stiffness on plantar pressure and walking comfort in people with diabetes at high risk of foot ulceration.

BACKGROUND: Different shoe design features can reduce peak plantar pressure to help prevent foot ulcers in people with diabetes. A carbon reinforcement of the shoe outsole to maximize bending stiffness is commonly applied in footwear practice, but its effect has not been studied to date. RESEARCH QUESTION: What is the effect of a carbon shoe-outsole reinforcement on peak plantar pressure and walking comfort in people with diabetes at high risk of foot ulceration? METHODS: In 24 high-risk people with diabetes, in-shoe regional peak pressures were measured during walking at a comfortable speed in two different shoe conditions: an extra-depth diabetes-specific shoe with a non-reinforced outsole and the same type of shoe with a 3-mm-thick full-length carbon reinforcement of the outsole. The same custom-made insole was worn in both shoe conditions. Walking comfort was assessed using a Visual Analogue Scale (0-10, 10 being highest possible comfort). RESULTS: Significantly lower metatarsal head peak pressures (by a median 10-22 kPa) were found with the reinforced shoe compared to the non-reinforced shoe (p < .001). In >83% of cases with the reinforced shoe and >71% with the non-reinforced shoe metatarsal head peak pressures were <200 kPa. At the hindfoot, peak pressures were significantly higher (by a median 24 kPa) with the reinforced shoe (p = .001). No significant shoe effects were found for the toes. No significant shoe effects were found for walking comfort: median 6.1 for the reinforced shoe versus 5.6 for the non-reinforced shoe. SIGNIFICANCE: Adding a full-length carbon reinforcement to the outsole of a diabetes-specific shoe significantly reduces peak pressures at the metatarsal heads, where ulcers often occur, in high-risk people with diabetes, and this does not occur at the expense of patient-perceived walking comfort.

Optimizing footwear for the diabetic foot: Data-driven custom-made footwear concepts and their effect on pressure relief to prevent diabetic foot ulceration.

AIMS: To assess the effect of data-driven custom-made footwear concepts on plantar pressure relief to prevent diabetic foot ulceration. METHODS: Twenty-four neuropathic diabetic patients at high risk of foot ulceration were measured for in-shoe plantar pressures during walking in four data-driven custom-made footwear conditions, an athletic shoe and an off-the-shelf non-therapeutic shoe. Two evidence-based footwear conditions (Shoe-A; Insole-A) follow a scientific-based design protocol, are handmade, and use in-shoe plantar pressure guided optimization. One evidence-based insole condition (Insole-B) uses a barefoot plantar pressure and 3D foot shape-based computer-assisted design and manufacturing (CADCAM) routine. And one insole condition (Insole-C) uses a barefoot and in-shoe plantar pressure and 3D foot shape-based CADCAM design and optimization routine. Patient satisfaction was scored on walking comfort, shoe fit, weight and appearance. RESULTS: All data-driven footwear conditions significantly reduced metatarsal head peak pressure compared with the non-therapeutic shoe (17-53% relief). Shoe-A and Insole-A showed the lowest metatarsal head peak pressures (mean 112-155 kPa, 90-98% of cases <200 kPa), significantly lower than for Insole-B and Insole-C (mean 119-199 kPa, 52-100% <200 kPa). Patient satisfaction was not significantly different between footwear concepts. CONCLUSIONS: This study proves the offloading efficacy of a scientific-based, handmade, and in-shoe plantar pressure data-driven approach to custom-made footwear design, and advocates its implementation to optimize diabetic footwear for plantar foot ulcer prevention.