Fabrication of open-cellular (porous) titanium alloy implants: osseointegration, vascularization and preliminary human trials

Abstract

In this study we describe the fabrication of a variety of open-cellular titanium alloy (Ti-6Al-4V) implants, both reticular mesh and foam structures, using electron beam melting (EBM). These structures allow for the elimination of stress shielding by adjusting the porosity (or density) to produce an elastic modulus (or stiffness) to match that of both soft (trabecular) and hard (cortical) bone, as well as allowing for bone cell ingrowth, increased cell density, and all-matrix interactions; the latter involving the interplay between bone morphogenetic protein (BMP-2) and osteoblast functions. The early formation and characterization of elementary vascular structures in an aqueous hydrogel matrix are illustrated. Preliminary results for both animal (sheep) and human trials for a number of EBM-fabricated, and often patient-specific Tialloy implants are also presented and summarized. The results, while preliminary, support the concept and development of successful, porous, engineered "living" implants.

Advancements in three-dimensional titanium alloy mesh scaffolds fabricated by electron beam melting for biomedical devices: mechanical and biological aspects

“…This demonstrated their potential for clinical application in comparison to PEEK [160]. After three months, post-implantation, micro CT (computer generated) imaging and histological staining showed the growth of neighboring bone tissue into porous Ti mesh, partially fusing the two vertebral bodies.…”

“…The bone tissue bonded closely with Ti mesh/cage, with majority of bone tissue around the struts in the interior and peripheral regions of the mesh (Fig. 9) [160]. A comparative study showed that the culture of human osteoblast-like cells on Ti-6Al-4V led to enhanced osteogenic differentiation in comparison to PEEK implant [167].…”

“…3D printed titanium alloy mesh structure scaffolds have the potential to restore anatomically complex patient specific areas such as spinal fusion, dental, temporomandibular joint and craniomaxillofacial surgery [159,160]. Spinal fusion mesh/cage devices were introduced in 1988 to attain spine interbody (cervical disk) fusion and are now widely practiced.…”

“…But, it does not integrate well with surrounding bone tissue and forms fibrous tissue capsule. To overcome this disadvantage, 3D porous Ti mesh/cage using EBM, was developed [160]. Research is in progress to 3D print titanium alloys to produce customized titanium prosthesis in limb salvage surgery to replace bones lost due to sarcoma [161].…”

Weak fatigue notch sensitivity in a biomedical titanium alloy exhibiting nonlinear elasticity

“…Although commercial pure titanium and Ti6Al-4V alloy are most used for biomedical applications, there are still two remaining problems to be solved [2,3]. One is the potential toxicity of alloying elements, such as V ions released from Ti-6Al-4V alloy.…”