Biomechanical Characterisation of 3D Printed Comfort Insoles

This study investigated force distribution, biomechanical changes, and user satisfaction after 3 weeks of wearing three dimensional (3D)-printed personalised comfort insoles in healthy and flat-footed adults. Institutional approval was obtained and participants (age 18-65) able to walk independently were enrolled, excluding pregnancy, neurologic gait disorders, or distal foot wounds. Baseline and follow-up static and dynamic plantar pressure and gait analyses were performed using Diers Pedoscan, Pedogait, and a pressure-integrated treadmill, with forces measured on ten plantar regions normalized to body weight plus spatio-temporal and kinematic parameters and center-of-pressure trajectories. Full-weight-bearing 3D foot scans were captured with an iQube E500 scanner, meshes processed in Foot3D, and anonymized for design. Insoles were digitally designed using LeoInsole artificial intelligence software that auto-detected anatomical landmarks and adjusted a base template, with manual tweaks as needed, targeting comfort features (arch, metatarsal pad, sulcus length) and 2.5-3.5 mm thickness. Final insole pairs were additively manufactured in Polyamide12 nylon via Hewlett-Packard Multi Jet Fusion, finished with a glued textile cover, and checked/adjusted by an orthotic technician at delivery. Participants wore the insoles at least 3 hours daily for 3 weeks and completed a 12-item 5-point Likert satisfaction questionnaire after follow-up testing. Flat foot was diagnosed from 3D models using the Chippaux-Smirak Index, but the same comfort insole design was used regardless of flat-foot status.