Proceedings of the 6 th World Congress on New Technologies (NewTech'20) Prague, Czech Republic Virtual Conference – August, 2020 Paper No. ICBB 107 DOI: 10.11159/icbb20.107 ICBB 107-1 Novel Plantar Surface Design of a Hinged Ankle Foot Orthosis (HAFO) Manufactured by 3D Printing Mariana Ribeiro Volpini Lana 1 , Paulo Henrique Rodrigues Guilherme Reis 1,2 , Anderson Horta 1 , Joana Pimenta Maia 1 ; Mariana Rodrigues Carvalho de Aquino 1 , Juan Carlos Campos Rubio 2 1 AMR – Associação Mineira de Reabilitação Professor Otávio Coelho de Guimarães Street, 111 – Mangabeiras, Belo Horizonte, MG, Brazil marianavolpini@amr.org.br; andersonhorta@gmail.com; joanapimentato@gmail.com; marircaquino@gmail.com 2 UFMG – Universidade Federal de Minas Gerais Antônio Carlos Avenue, 6627 – Pampulha, Belo Horizonte, MG, Brazil paulogsk@gmail.com; juan@ufmg.br Abstract - Ankle foot orthosis manufactured by 3D printing have several benefits in terms of the manufacturing process, such as the diversity of designs and precision of manufacture. However, for the 3D printed orthosis to be functional, it is necessary to observe its mechanical behavior in relation to the forces acting during gait. It is common to observe high stiffness in orthoses manufactured by 3D printing during the foot roll phase, which can interfere with the performance of functional mobility. This study proposes new geometry in the plantar region of the orthosis, based on data from computer simulations, in order to provide its flexibility during gait, helping to improve the performance of this functional activity. The results showed that the new surface deformed 465% more (30.01 mm) compared to the traditional surface (6.45 mm). Keywords: Orthosis; 3D Print; Finite Elements Analysis; Gait. 1. Introduction Ankle-Foot Orthosis (AFO) is a complementary resource in the rehabilitation of individuals with neuromotor disorders used to prevent muscle shortening and bone deformities and to promote biomechanical alignment and improve gait functionality [1,2]; Hinged AFO (HAFO) can be used in different gait patterns such as equine or drop foot [3,4] because it stabilizes the ankle, limiting the plantar flexion movement, without restricting dorsal flexion [5]. Additive Manufacturing (AM), also called 3D printing, has been increasingly considered a promising manufacturing technique for rehabilitation devices due to the possibility of making products with complex and varied shapes quickly and accurately [3,6]. Although it has several advantages, the manufacture of the HAFO by AM must guarantee flexibility so that the functional benefits of the foot roll during the step are maintained. It is common to see in AFOs made by AM high stiffness, especially in the plantar region, which can interfere with gait performance. In this way, new geometric shapes in devices manufactured by AM must be developed to enable, in the same device, areas that present greater rigidity, providing biomechanical alignment and the containment of the desired range of motion, and areas of greater flexibility, enabling kinematics adequate gait [7]. The aim of this study was to improve the HAFO manufactured by the AM process by modifying its plantar surface. For this purpose, simulations by Finite Element Analysis (FEA) were used. 2. Method This is a methodological study with application of numerical simulation by finite elements. The mechanical properties of HAFO's manufacturing material were analyzed by 3D printing, the modeling of the new plantar region of this device and, finally, the influence of these changes on its stiffness and stress distribution. The results obtained by AEF in the traditional model, without modification in the plantar region, and in the new model were then compared.