Digital design and fabrication of multi-material hand orthoses to allow an athlete with scleroderma to play sitting volleyball

• Hand orthoses fabrication for a sitting volleyball athlete affected by scleroderma. • These devices have to be rigid, to hit the ball, and soft, to limit skin damages. • The devices integrate an external carbon fibre shell and an internal silicone layer. • An HTV silicone layer with a promoting agent allows to bond carbon to RTV silicone. • This method involves the use of 3D scanners, mesh editing software and 3D printer. Scleroderma is a chronic and progressive autoimmune disorder of connective tissues often causing lesions and deformities of the hands. Individuals affected by this condition experience daily life limitations and are typically unable to take part in sport activities that involve impacts on the hands. In this article we describe the design and manufacturing of custom-made hand orthoses to play sitting volleyball, for an elite paralympic athlete affected by scleroderma. The devices consist of a carbon fibre shell with an internal silicone padding and an external polymeric multilayer cover. The manufacturing of the orthoses involves digital modelling, 3D printing, composite lamination and an innovative method to create a strong and durable chemical bonding between silicone and carbon fibre. The internal silicone padding proved to be effective in hosting and protecting the hands, whereas the external shell with polymeric multilayer cover allowed to dampen the ball shocks while effectively hitting the ball. Indeed, these devices allowed the athlete to take part in the 2020 Tokyo Paralympic games and were used for two years without showing any damage.