Novel Clinical Applications of 3D-Printed Highly Porous Titanium for Off-the-Shelf Cementless Joint Replacement Prostheses.

In total joint replacement, early aseptic loosening of implants caused by inadequate initial fixation and late aseptic loosening due to stress shielding-related periprosthetic bone remodeling are the main causes of failure. Over the last two decades, additive manufacturing has been revolutionizing the design of cementless orthopaedic implants by enabling biomimetic, highly porous titanium structures that enhance bone ingrowth and osseointegration while reducing stress shielding. The synergy between optimized selective laser-melted highly porous titanium bearing components, ceramic-coated titanium articular surfaces, and vitamin E-stabilized polyethylene liners delivers several benefits essential for implant longevity: reliable initial fixation, improved biological fixation, reduced bone resorption caused by stress shielding, and lower osteolytic reactivity. These benefits have encouraged the synergetic use of these technologies in joint replacement in novel clinical applications. In recent years, novel off-the-shelf, 3D-printed, highly porous titanium implants have been introduced into hip and knee arthroplasty. These newly introduced implants appear to offer an innovative and promising solution, and are particularly indicated for young active patients, elderly patients with osteoporotic bones, and in complex cases. Future clinical research should confirm these novel implants' superior results in comparison to the current state of the art in cementless joint replacement. The possibility of extending these technologies in the future to other clinical applications such as partial knee prosthesis is discussed.