Graded stiffness offloading insoles better redistribute heel plantar pressure to protect the diabetic neuropathic foot

Abstract

BackgroundDiabetic heel ulceration is a common, detrimental, and costly complication of diabetes. This study investigates a novel “graded-stiffness” offloading method, which consists of a heel support with increasing levels of stiffness materials to better redistribute plantar pressure for heel ulcer prevention and treatment. Research questionIs the novel “graded-stiffness” solution better able to redistribute heel pressure and reduce focal stress concentration areas of the heel? MethodsTwenty healthy young men walked with four, 3D-printed, insole configurations. The configurations included the “graded-stiffness” insoles with and without an offloading hole under the heel tissue at risk for ulcerations and two conventional offloading supports of flat insoles with no offloading and simple holed offloading insoles. In-shoe plantar pressure was measured using the Pedar-X system. Peak pressure and pressure dose were measured at three heel regions: offloaded region, perimeter of offloaded region, and periphery region. ResultsThe simple offloading configuration reduced pressure at the offloaded region; however, pressure at the perimeter of the offloading region significantly increased. With respect to ANOVA, the “graded-stiffness” offloading configurations were more effective than existing tested solutions in reducing and redistributing heel peak pressure and pressure dose, considering all heel regions. SignificanceThe “graded-stiffness” offloading solution demonstrated a novel flexible and customized solution that can be manufactured on-demand through a precise selection of the graded-stiffness offloading location and material properties to fit the shape and size of the ulcer. This study is a follow-up in-vivo pilot study, in a healthy population group, to our previous computation modeling work that reported the efficiency of the “graded-stiffness” configuration, and which emphasizes its potential for streamlining and optimizing the prevention and treatment of diabetic heel ulcers.