DESIGN, LATTICE ARCHITECTURE, AND FINITE ELEMENT VERIFICATION OF PATIENT SPECIFIC METAL ADDITIVELY MANUFACTURED ORTHOPAEDIC IMPLANTS: A REVIEW

Abstract

This paper includes an extensive examination of existing design processes for 3D printed orthopaedic implants. We considered many different parts of the design process including creating models from imaging data, designing lattice and porous structures, as well as issues of design constraints with metal additive manufacturing (AM). We put particular focus on how numerical techniques including finite element analysis (FEA) were used to analyse the distribution of stresses, deformations, fatigue, and bone-implant interaction prior to production. The findings of the review showed that patient-specific geometries and customized porosities improved the anatomical fit of the implants and reduced stiffness mismatch, thus enhancing performance. However, design errors due to lack of verification or verification processes can cause localized overstressed areas resulting in failure to perform over the long term. The review also identified challenges to improving the current state of the industry including the need for regulatory standards for designs, the establishment of protocols for validating designs with experimental or clinical data and developing methods for managing defects resulting from additive manufacturing processes. Finally, the review offers suggestions for directions of future research including developing automated optimization procedures for designs, creating multi-material print processes, and providing more accurate biomechanical simulations in the development of safer and more effective 3D printed orthopaedic implants.