A Simplified Integration System for the Fabrication of Total Surface Bearing Transtibial Socket by Employing Rapid Prototyping Technology

Abstract

This project is to validate the preliminary result of rapid prototyping (RP)-based transtibial socket that was reinforced by wrapping a layer of unsaturated polyester resin. By employing contemporary technologies including a scanner, computer-aided engineering systems, a rapid prototyping machine, together with the expertise of a prosthetist, RP-based prosthetic sockets with a comfortable fit to volunteer amputees can be fabricated. However, the expensive cost and complex procedure of using current commercial scanners and CAD systems will be barriers experienced by clinical professionals. As the existing service bureau infrastructure and cheaper RP technology are easily accessed, fabrication and technology cost barriers will be reduced. The remaining problems include the availability of easily-used CAD systems for designing prosthetic sockets, simple scanner and stump duplicating tool. This study therefore focuses on the integration of simplified systems including a vacuum forming tool, compact scanner and an interface system for designing prosthetic sockets. Although the type of PTB (patella tendon bearing) transtibial socket is widely adopted in plaster-based manual process, TSB (total surface bearing) sockets are more acceptable by amputees. Since the concept of TSB socket should obtain the stump mold of an amputee under appropriate pressure by using a specific stump forming tool, editing complex surfaces can be avoided when using a TSB-based stump model to design a socket. The quality of socket fit is expected to improve by a simplified design process in which an interface system based on grid-editing algorithms is utilized. In addition, cheaper RP technology, such as 3-D printing or droplet binding process, can be alternative means to fabricate RP-based prosthetic sockets. By combining TSB stump mold, simplified design process and a cheaper RP machine, this study proposes a simplified integrating system to manufacture RP stump mold. Using this RP stump mold together with the traditional lamination method of infiltrating resin into cotton layers, the RP-based transtibial sockets will then be fabricated easily. The expected result will demonstrate the feasibility of employing cheaper emerging technologies to assist an unskilled prosthetist who will be able to produce good quality of prosthetic socket.