ABSTRACT
Porous tantalum represents an alternative metal for primary and revision total knee
arthroplasty (TKA) with several unique properties. Tantalum is a transition metal,
which in its bulk form has shown excellent biocompatibility and is safe to use in
vivo as evidenced by its current application in pacemaker electrodes, cranioplasty
plates, and as radiopaque markers. Current designs for orthopedic implants maintain
a high volumetric porosity (70%-80%), low modulus of elasticity (3 MPa), and high
frictional characteristics, making this metal conducive to biologic fixation. The
low modulus of elasticity of such components allows for more physiologic load transfer
and relative preservation of bone stock. Its more bioactive nature and ingrowth properties
have led to its use in primary as well as revision knee components with good early
clinical results reported. In revision arthroplasty, it has been used as a structural
bone graft substitute. Formation of a bone-like apatite coating in vivo affords strong
fibrous ingrowth properties and allows for substantial soft-tissue attachment with
the potential for use in cases such as mega-prostheses and patella salvage. Although
porous tantalum is in its early stages of evolution, the initial clinical data and
basic science studies support its use as an alternative to traditional orthopedic
implant materials.
