Finite Element Analysis of Ventral Ankle-Foot Orthosis Under Cuff and Ground Reaction Force Loading

The patient with a spinal TB that has kyphosis will be prone to falling. Ankle Foot Orthosis (AFO) is proposed as a medical instrumentation that can help the patient's gait rehabilitation become more stable and reduce excessive leg movement. However, the design of AFO is not specified for spinal TB cases, and the fabrication process is mainly trial and error. This study aims to do a simulation based on finite element analysis on the AFO model for spinal TB patients. There were two variations in thickness (5 and 7 cm) and four types of materials (Polypropylene (PP), Carbon Fiber (CF) 230, 290, and 395) based on the available AFO used by the patient with gait disorder. The AFO model is subjected to loading according to the gait phase and cuff loading to analyze the stress, deformation, deflection, and safety factors. PP-based AFO model has the highest deformation among other materials. AFO with 7 mm thickness had lower deformation of up to half of the deformation in AFO with 5 mm thickness. The AFO model made from CF 395 at 547 MPa owns the most considerable maximum von Mises stress. In conclusion, AFO made from CF 395 with a thickness of 7 mm is considered suitable for rehabilitating spinal TB patients to provide stability. For future studies, the most suitable model of this study could be fabricated by a 3D printing process to be used by spinal TB patients.