Investigation of the Effectiveness of Plantar Pressure Redistribution of Customized Insole Structure Designed Based on Plantar Structure

Although both fabricated insoles and customized insoles were designed with varied function components, current knowledge approved that customized insoles worked much better. However, how the customized insoles achieved a better performance in term of load re-distribution was still lacking quantitative assessment. The aim was to determine whether the customized insole structure based on a novel customization procedure proposed in this study performs better than the prefabricated insoles in terms of plantar pressure re-distribution efficiency. This study included ten healthy subjects, each wearing four types of insoles accordingly (control insoles; arch support insoles; orthotic insoles; customized insoles), and plantar pressure was collected in a walking state. The custom insoles are made by determining the subject's plantar surface and key plantar points, then following the customization procedure to finish them. The plantar area was divided into eight zones and then a pressure transfer algorithm was used to gain insight into the plantar pressure. Compared to the control group insoles, the arch support of the customized insoles reduced pressure in the hallux region and transferred pressure from the M4-5 to the MH and LH regions, while the metatarsal pad enhanced the pressure transfer in the mid-foot, and the anterior-posterior height difference of the insole plays a role in pressure transfer. Furthermore, the customized insoles performed close to the professional orthotic insoles. Design strategy with accurate insole's component location and reasonably plantar surface matching, our customized insole demonstrated advantages such as a better loading redistribution and significant pressure relieving on the forefoot.