  Additive manufacturing (AM) of titanium (Ti) and Ti-6Al-4V lattices has been
proposed for bone implants and augmentation devices. Ti and Ti-6Al-4V have
favourable biocompatibility, corrosion resistance and fatigue strength for bone
applications; yet, the optimal parameters for Ti-6Al-4V lattice designs
corresponding to the natural micro- and meso-scale architecture of human
trabecular and cortical bone are not well understood. A comprehensive review
was completed to compare the natural lattice architecture properties in human
bone to Ti and Ti-6Al-4V lattice structures for bone replacement and repair. Ti
and Ti-6Al-4V lattice porosity has varied from 15% to 97% with most studies
reporting a porosity between 50-70%. Cortical bone is roughly 5-15% porous and
lattices with 50-70% porosity are able to achieve comparable stiffness,
compressive strength, and yield strength. Trabecular bone has a reported
porosity range from 70-90%, with trabecular thickness varying from 120-200
{\mu}m. Existing powder bed fusion technologies have produced strut and wall
thicknesses ranging from 200-1669 {\mu}m. This suggests limited overlap between
current AM of Ti and Ti-6Al-4V lattice structures and trabecular bone
architecture, indicating that replicating natural trabecular bone parameters
with latticing is prohibitively challenging. This review contributes to the
body of knowledge by identifying the correspondence of Ti and Ti-6Al-4V
lattices to the natural parameters of bone microarchitectures, and provides
further guidance on the design and AM recommendations towards addressing
recognized performance gaps with powder bed fusion technologies.
