A Biosynthetic Thumb Prosthesis

Abstract

In cases of severe damage to the extremities, the function and structure of compromised biological tissues must be replaced. If biological reconstruction using autologous tissue is not feasible, amputation and replacement with a synthetic prosthesis is often the next best option. Currently, the synthetic materials available for prostheses are limited, especially in their ability to restore skin sensation. Here we show a biosynthetic prosthesis that combines the versatility of titanium with the rich sensory capabilities of biological skin, to both increase movement and restore sensation to an amputated thumb. The prosthesis recreates opposition pinch by linking motion of the prosthetic joint to that of the residual biological joint. The device is enclosed in neurotized skin from the patient's own body, providing natural sensation. We validated the biosynthetic thumb's ability to reproduce opposition pinch on the benchtop and in a cadaver, and showed in vivo viability of the skin interface in an animal model. These results provide a framework for functional reconstruction of amputated digits using a combination of synthetic materials and biological tissues.

One sentence summary: A prosthetic thumb made up of a titanium mechanism and living skin can restore opposition pinch and touch sensation following thumb amputation.