Long Term Clinical Evaluation of SLS Transtibial Sockets

Successful rehabilitation for the majority of lower extremity amputees includes prosthetic limb fitting and training. Critical to the success of prosthetic fitting is a comfortable, well fitting socket. Accomplishing this remains a clinical challenge with residual limb pain and socket discomfort affecting 20-55% of lower limb amputees. Achieving an acceptable socket fit using conventional prosthetic techniques requires individual custom molding and fabrication in a labor intensive, costly process. Alternative methods of fabricating prosthetic sockets that can improve efficiency in prosthetic provision, enhance comfort and fit, or reduce cost are needed to ensure the continued optimal rehabilitation of the amputee. This project will continue the development of a new promising method of socket fabrication using solid freeform fabrication (SFF) based on selective laser sintering (SLS) technology. SFF allows the direct manufacture of a prosthetic socket without the intermediate molds and laminating process required with conventional techniques.

The overall long-term goal of this project is the development of a clinically practical system for rapid prosthetic limb provision that integrates computer-aided design with solid freeform fabrication techniques. This proposal builds on our previous successful demonstration of the feasibility of SFF socket fabrication and will address several key issues that underlie its clinical viability. The specific objectives of the proposed work are:

1. To develop improved designs for SFF transtibial prosthetic sockets that allow the use of industry standard pylon mounts and incorporate variable compliance elements.
2. Determine the clinical effectiveness of variable wall compliance elements in enhancing the comfort and fit of transtibial prosthetic sockets.
3. Determine the durability and functionality of SFF sockets during extended clinical use.

These objectives will be met over a three-year period. The initial phase of the proposed work will use an iterative engineering design - modeling - evaluation process to develop variable compliance elements and an industry standard pylon mount adapter. During the second phase of the proposed work, clinical evaluations of SFF prosthetic sockets will be studied. The effectiveness of variable compliant elements in enhancing comfort and fit will be determined using a within subject case comparison study of SFF sockets with conventional laminated sockets. Durability of SFF sockets that incorporate an industry standard pylon mounting system will be determined during a 12-month clinical field trial.