Interventional Study on the Evaluation of Functionality, Safety of a Robotic Prosthesis for Transtibial Amputations

The goal of this multicenter interventional pilot is to verify the functionality of a prosthesis for trans-tibial amputees. The main question it aims to answer are: * Is to verify the technical functionality, safety and reliability of the propulsive lower limb prosthesis prototype, with active ankle, so as to provide indications regarding the technical and functional developments to be implemented in the finalization of the device. * Provide an indication of the functional effectiveness of the device and its satisfaction by patients. Participants will perform: * walking tests inside parallel bars on flat and/or inclined terrain; * walking tests on treadmill; * stair climbing/descent tests.