Manufacture and experience of endoskeletal functional upper arm prosthesis

Abstract

An endoskeletal functional upper arm prosthesis has been used in clinical practice to enable patients with shoulder disarticulation or high-level amputation such as forequarter amputation to regain the ability to grasp objects. We successfully built an endoskeletal functional upper arm prosthesis for a transhumeral amputee who wanted a functional upper arm prosthesis with an improved appearance. During the manufacturing process, we noted that ① the fingers of the hand would open when the elbow hinge was flexed over 90° while unlocking it. We addressed this issue by adjusting the spring tension in the body-powered hand. Related to this issue, ② the elbow hinge would sometimes not flex completely. We developed a cable that also functions as a spring to address this issue. The cable uses a spring to assist in elbow flexion, thus improving the angles of elbow flexion. These improvements enabled manufacture and use of an endoskeletal functional upper arm prosthesis with improved design that is also user-friendly.