Multidisciplinary co-creation, design and clinical evaluation of a two-material 3D printed ankle-foot orthosis: Preliminary clinical findings in a case report of fibular hemimelia

Lower-limb orthoses are often either standardized, lacking personalization for individual clinical needs, or custom-made, which is time-consuming and labor-intensive for orthotists. To address this gap, this study proposes a co-creation methodology for developing a customized orthosis, integrating 3D scanning, computer-aided design (CAD), and 3D printing with feedback from both the clinical team and the patient's caregivers. The methodology was applied to a fibular hemimelia case study, where the orthosis was designed based on 3D scans and printed using two materials: thermoplastic polyurethane (TPU) for flexibility and polyethylene terephthalate glycol (PETG) for rigidity. Usability and satisfaction assessments were conducted using the System Usability Scale (SUS) and the Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST 2.0). The orthosis met the clinical requirements, allowing the child to take a normal stride without discomfort (SUS: 92.5/100; QUEST 2.0: 4.2/5). Although the orthosis fractured at the ankle after a few hours of use, the study provided crucial insights for future design improvements. These findings highlight the utility of this co-creation approach in developing personalized orthotic models and demonstrate the advantages of using multi-material 3D printing to enhance orthosis functionality.