Mechanical Analysis of a Novel 3D-printed External Fixator Design Versus Industry-standard External Fixators.

Abstract

External fixation is a critical component of orthopaedic fracture management and is used for various conditions, including trauma and pediatric orthopaedics. However, the availability and high cost of external fixation devices are a concern, especially in rural and developing countries. 3D printing technology has shown promise in reducing manufacturing costs and improving accessibility to external fixation devices. The purpose of this study was to evaluate the mechanical properties of a fully 3D-printed desktop external fixation device and compare the results with the mechanical properties of commonly used, clinically available external fixators. A fully 3D printable external fixator was designed and printed in polylactic acid at two infill densities, 20% and 100%. The mechanical properties of the 3D-printed external fixators and several commercially available fixators were tested according to applicable sections of the American Society for Testing and Materials F1541 standard protocol in axial, medial-lateral, and anterior-posterior orientations. The primary outcomes measured included failure load, safe load, rigidity, and yield load. The mean differences between experimental and control groups were calculated using one-way analysis of variance and Tukey tests. The 20% infill 3D-printed construct showed poor performance compared with commercially available external fixators in all testing conditions and across most variables. The 100% infill 3D-printed construct was comparable with or superior to all commercially available devices in most testing conditions. The cost for printing a single 3D-printed 100% infill external fixator was $14.49 (United States Dollar). This study demonstrates that a low-cost desktop 3D printer can create an entirely 3D-printed external fixator that resists clinically relevant forces similar to medical-grade industry-standard external fixators. Therefore, there is potential for customizable and low-cost external fixators to be manufactured with desktop 3D printing for use in remote areas and other resource-constrained environments for fracture care.