An implantable medical device includes a porous metal foam or foam-like
structure having pores defined by metal struts or webs wherein the porous
structure has directionally controlled pore characteristics. The pore
characteristics controlled include one or more of the metal structure
porosity, pore size, pore shape, pore size distribution and strut
thickness. The pore characteristics may vary in one or more directions
throughout the structure. Preferably the pore characteristics are
controlled to match the porous metal structure to various mechanical and
biological requirements of different regions of the structure in order to
optimize aspects of the implants performance and may vary not only over
the surface of the porous structure but through the depth of the porous
structure. The thickness of the porous metal structure may also be
modified to establish a thickness profile that optimizes mechanical and
biological requirements of the implants performance. Acetabular cup
embodiments of the invention are described. Various methods of
manufacturing implants having directionally controlled pore
characteristics are described.