3D-printed custom-designed prostheses for partial hand amputation: Mechanical challenges still exist

Study Design This is a technical report involving evaluation of two 3D-printed custom-designed prosthetic prototypes for an adult male with partial amputation of his dominant hand. Introduction Prosthetic solutions for partial hand amputations have progressed modestly in comparison with advances in full hands for transradial and higher amputations. 3D-printing technology allows Bespoke prosthetic design and rapid prototyping, but evidence regarding functional performance and consumer ratings of devices is lacking. Purpose of the Study The purpose of this study was to compare grip strength, dexterity, and consumer perceptions for two novel 3D-printed devices with a myoelectric prosthesis. Methods This study involves a 2-year iterative design process with an input from the participant, engineers, a prosthetist, and a hand therapist. The evaluation involved standardized tests of grip/pinch strength and dexterity and participant ratings of key criteria. Results Both 3D-printed devices had very poor grip and pinch strength but comparable dexterity with the myoelectric prosthesis. The participant was more satisfied with the weight and thermal attributes of the 3D-printed devices. Discussion Aspects of both 3D-printed designs showed the potential for future refinements; however, the mechanical solutions to minimize force required at the wrist to activate grip are still required. Conclusion(s) Future design efforts should be client-centered and involve professionals with specialist prosthetic and engineering knowledge.