Hybrid fabrication and biomechanical validation of a patient-specific therapeutic footwear with a replaceable insole for Charcot deformity

Purpose This study aims to introduce a hybrid fabrication protocol for patient-specific therapeutic footwear [ankle-foot orthoses (AFOs) and insoles] to address biomechanical challenges of Charcot neuroarthropathy (CNA), aiming for enhanced customization and precision over traditional methods. Design/methodology/approach The protocol integrates medical imaging [three-dimensional (3D) segmentation], dynamic gait analysis, computer-aided design and manufacturing (CAD/CAM) and additive manufacturing [AM; ethylene-vinyl acetate, fused deposition modeling polylactic acid, mask stereolithography (MSLA) resin]. Finite element analysis (FEA) and material testing were conducted. A clinical case (a 69-year-old female with midfoot CNA) validated the workflow. Findings The results demonstrated that the custom-designed 5-mm-deep off-loading insoles achieved a significant reduction in pressure in the targeted midfoot regions, decreasing lateral pressure by 55.4% and medial pressure by 62.6%. However, this off-loading led to a compensatory increase in pressure on the lateral forefoot (+11.9%), highlighting the necessity for iterative design adjustments based on individual biomechanical responses. Material testing indicated that MSLA resin, when cured for 10 min, exhibited mechanical properties comparable to traditional polypropylene, successfully mimicking its biomechanical function and reducing displacements by 8.7% during midstance phases. Furthermore, the hybrid manufacturing approach proved cost-effective and time-efficient, with insoles costing $13.16 to produce in 25 min and AFOs costing between $5.88 and $9.08 with production times ranging from 12 to 40 h, offering substantial advantages over conventional fabrication techniques. Research limitations/implications Single-subject validation limits generalizability. Simulations were static; real-world durability under dynamic loading remains unverified. Material testing excluded other potential polymers. Future studies should involve diverse cohorts and long-term clinical trials to assess functional outcomes. Practical implications The protocol offers clinics a scalable, cost-efficient alternative to traditional methods, enabling rapid production of customizable devices. Replaceable insoles extend footwear lifespan, reducing long-term costs. MSLA resin’s tunable properties allow tailored stiffness, enhancing adaptability for varying patient needs. Social implications By mitigating ulcer recurrence and amputation risks, this approach improves mobility and quality of life for diabetic patients. Lower healthcare costs and reduced dependency on labor-intensive methods benefit resource-constrained settings, addressing a critical public health challenge. Originality/value This study presents a novel, integrated hybrid protocol combining imaging, gait analysis, CAD/CAM, AM, FEA and material science for customized CNA footwear, which offers significant advantages in cost, time and precision. It highlights the need for balancing off-loading and durability, advocating patient-specific simulations to manage compensatory pressures.