Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Orthop. Jun 18, 2021; 12(6): 376-385
Published online Jun 18, 2021. doi: 10.5312/wjo.v12.i6.376
Off-the-shelf 3D printed titanium cups in primary total hip arthroplasty
Francesco Castagnini, Filippo Caternicchia, Federico Biondi, Claudio Masetti, Cesare Faldini, Francesco Traina
Francesco Castagnini, Filippo Caternicchia, Federico Biondi, Claudio Masetti, Francesco Traina, Department of Ortopedia-Traumatologia e Chirurgia Protesica e dei Reimpianti di Anca e Ginocchio, IRCCS Istituto Ortopedico Rizzoli, Bologna 40136, Italy
Cesare Faldini, Department of Clinica I di Ortopedia e Traumatologia, Rizzoli Orthopedic Institute, University of Bologna, Bologna 40136, Italy
Cesare Faldini, Francesco Traina, Department of DIBINEM Scienze Biomediche e Neuromotorie, Alma Mater Studiorum Università di Bologna, Bologna 40139, Italy
Author contributions: Castagnini F, Caternicchia F and Traina F collected the papers, analyzed the data and wrote the manuscript; Masetti C and Faldini C provided a critical evaluation and the iconographical material; Biondi F and Traina F supervised and corrected the manuscript.
Conflict-of-interest statement: The authors declare that they have no conflicts of interest.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Corresponding author: Francesco Castagnini, MD, Research Fellow, Department of Ortopedia-traumatologia e Chirurgia Protesica e dei Reimpianti di Anca e Ginocchio, IRCCS Istituto Ortopedico Rizzoli, Via Pupilli 1, Bologna 40136, Italy.
Received: January 17, 2021
Peer-review started: January 17, 2021
First decision: March 8, 2021
Revised: April 2, 2021
Accepted: May 22, 2021
Article in press: May 22, 2021
Published online: June 18, 2021

Three-dimensional (3D)-printed titanium cups used in primary total hip arthroplasty (THA) were developed to combine the benefits of a low elastic modulus with a highly porous surface. The aim was to improve local vascularization and bony ingrowth, and at the same time to reduce periprosthetic stress shielding. Additive manufacturing, starting with a titanium alloy powder, allows serial production of devices with large interconnected pores (trabecular titanium), overcoming the drawbacks of tantalum and conventional manufacturing techniques. To date, 3D-printed cups have achieved dependable clinical and radiological outcomes with results not inferior to conventional sockets and with good rates of osseointegration. No mechanical failures and no abnormal ion release and biocompatibility warnings have been reported. In this review, we focused on the manufacturing technique, cup features, clinical outcomes, open questions and future developments of off-the-shelf 3D-printed titanium shells in THA.

Keywords: Socket, Highly porous, Additive manufacturing, Ultraporous, Trabecular, Beam melting

Core Tip: Three-dimensional printed titanium cups theoretically provide a porous, rough surface that improves local vascularization and osseointegration, while avoiding stress shielding because of the low elastic modulus. We herein discuss the manufacturing, main features, and clinical results obtained with 3D-printed titanium cups, with a focus on the open questions and possible future developments to improve this newborn device and technology.