A New Active Shoulder Prosthesis: from the Design to the First Clinical Application

INAIL and DIEM prototyped a new externally-powered prosthetic shoulder developed for interscapulothoracic and first-proximal trans-humeral amputees. The articulation consist of two connected powered joints that allow the elevation of the upper arm in any vertical plane passing through the shoulder centre of rotation. The development of the mechanism is the result of a rigorous approach, which made it possible to systematically combine both the technical and the clinical aspects involved in the design of a prosthetic device. The prototype underwent laboratory tests needed to evaluate the mechanism’s performance (e.g. the maximum payload) and the electrical requirements (e.g. the current draining). Based also on the results retrieved from these tests, an on-board embedded controller was implemented. The electronic unit can control a prosthesis with up to five powered joints and can manage different control strategies, according to the amputees’ preferences. The prototype with the embedded control system has been recently integrated within the prosthesis, provided with hand, wrist and elbow, of a proximal trans-humeral amputee who firstly tested the new device. This paper provides an overview of the development of the actual prosthesis, reports the main patient’s feedback and outlines the future developments