The use of conventional immobilization splints can cause a lot of mishaps and discomfort in patients. In addition, it is common the generation of muscle, joint and vascular complications arising from the application of classic restraint devices in this phase of treatment. Currently, it is being observed that these problems could be solved with the use of Advanced Manufacturing techniques based on Additive Manufacturing (AM), industrial digitalization and reverse engineering for the realization of individualized immobilization splints. The present study proposes to give these splints a functional character in their design adapting them to a specific pathology, in this case to the partial rupture of Achilles tendon. It also provides a comparison against the use of conventional plaster splints as an improvement factor for their definitive implementation considering the initial sanitary use for which they were designed. In this way, there have been created therapeutic windows that allow the application of rehabilitation techniques, being the treatment that would be carried out developed in parallel. The designed splint has been made in FilaFlex and Polycarbonate, materials that guarantee comfort and resistance at the same time. In addition, an optimization in terms of material has been executed, lightening the splint and reducing environmental impact and manufacturing costs. As a result of this preliminary study, a prototype on scale printed in PLA has been generated.