Enabling a Screw Fastener System for Orthopedic Implants Made by Additive Manufacturing

Abstract

This research study explores the feasibility of an additively manufactured screw locking system that allows for the fixation of patient-specific orthopedic implants without applying pressure onto the bone. This is beneficial for the prevention of porosis underneath the implant. Grade 23 Titanium and 316L Stainless Steel, two commonly used biocompatible metals, are chosen as the materials for this research. A parameter study was conducted to produce high-density 3D-printed parts. Heat treatment was performed to get different microstructures and hardness. A PAX advanced locking system was reverse engineered using a high power X-Ray CT and sample specimen were produced. The strength of the system was evaluated by measuring the force needed to push the screw out of the locking plate. Annealed 316L stainless steel locking plate was found to have a high strength while the push-out force is not dependent on the build orientation.