Development of a 3D-printed transhumeral prosthesis for assistive technology applications

Over the past few years, several prosthetic solutions have been produced using Additive Manufacturing (AM). e-NABLE community has been developing these devices, which, despite low cost, are often uncomfortable, less functional and aesthetically unpleasing. This study aimed to develop a functional and anthropomorphic body-powered transhumeral device by redesigning an e-NABLE prosthesis, combining rigid and flexible materials. The process involved analyzing a clinical case of an 8-year-old girl with a transhumeral malformation, assessing her needs and anatomy through measurements and 3D scanning. Testimonies from children with similar conditions and healthcare professionals were also gathered. In the design stage, multiple prototypes were created using Computer-Aided Design (CAD) software and 3D printing, and then tested for performance and resistance. Additionally, Finite Element Analysis (FEA) was performed to study the device's behavior, while an ongoing study focused on identifying optimal materials. The final prosthesis weighs 400 g, balancing affordability, comfort, aesthetics and functionality, despite some limitations. The terminal device fully closes, requiring between 85.3 N and 163.2 N of force, powered by the amputee's shoulder movements. It performs shoulder internal/external rotation, elbow flexion/extension and forearm supination/pronation. While it can support a maximum load of at least 0.9 kg, maintaining a grip remains a challenge.