Clinical Evaluation of Prosthetic Sockets Manufactured By Selective Laser Sintering

A pilot study was undertaken to evaluate the clinical acceptance of prosthetic limb sockets manufactured using solid freeform fabrication (SFF). The fabrication of sockets for amputees is a natural application for SFF. The socket is the part of the prosthetic limb that fits onto the amputee’s residual limb. Each socket is custom manufactured for each individual amputee. Four amputees were successfully fit with sockets created using selective laser sintering. The scope of the study included software development, finite element analysis, materials testing, and clinical evaluation. This paper discusses socket design issues and clinical testing results. Purpose The purpose of this pilot study is to demonstrate the feasibility of Solid Freeform Fabrication (SFF) using Selective Laser Sintering (SLS) to fabricate variable compliant wall prosthetic sockets for trans-tibial amputees. The study includes an engineering design component and a clinical case controlled comparison of variable compliant wall prosthetic sockets with conventionally fabricated prosthetic sockets. The overall long-term objective of this project is to develop a system to fabricate variable wall compliant prosthetic sockets directly from digital residual limb shape information using freeform fabrication techniques. These sockets are expected to improve prosthetic socket comfort, improve tissue-loading characteristics, reduce skin discomfort and breakdown, and reduce fabrication time and cost compared to conventional socket fabrication techniques. Introduction There are approximately 400,000 lower limb amputees in the United States with 60,000 new major lower extremity amputations performed yearly. The majority of these amputees are fit with a prosthetic limb as part of their rehabilitation and return to independence. Because of changes in the shape and volume of the residual limb following amputation, the typical amputee will require a new prosthesis every two or three years. A prosthetic limb for a transtibial amputee consists of several components (Fig. 1). First there is a socket that fits over the residual limb that is custom fit for each amputee. A fitting is