An Interface System to Aid the Design of Rapid Prototyping Prosthetic Socket Coated with a Resin Layer for Transtibial Amputee

摘要

For employing the technology of rapid prototyping (RP) to fabricate prosthetic socket for transtibial amputee, a CAD stump model must be constructed. Currently, the commercial CAD systems need experienced skills to define objects. To simplify the construction procedure of stump model and easily used by a prosthetist, an interface system for the specific purpose of defining stump model should be developed. The main objective of this study is to improve the tedious process and quality uncertainty of conventional method to produce prosthetic sockets. This study developed an interface system that allows a prosthetist to modify the shapes of stump model so that the acceptable pressure distribution on pressure tolerant (PT) and pressure relief (PR) areas can be achieved. This study used C++ programming language and Open Graphic Library to develop an interface system. The point data of stump surface obtained by a T-scan system, which includes a hand-held 3D laser scanner and tracking system, is utilized to build the original shape of the stump. The primary shape of stump model is modified based on the requirements at the PT and PR areas of the specified amputee. As soon as the contact pressures between stump and socket are verified by finite element analysis, the modified stump model can be used to design a specific CAD socket model for the production using a RP machine. This interface system directly used a file of scanned points to build a stump shape and also provided the functions to identify the shapes of PT/PR areas. The modification requirements, including designations of the regions to be modified and the distances to be indented or raised, can be easily manipulated through appropriate interface dialogs. After a RP socket model has been designed, the socket is manufactured using an FDM machine. To reinforce the strength, the RP socket is coated with a resin layer. The measurement of contact pressures has been implemented and its trial use is under way.