Patent ID: 7691149

Claim:
A patellar implant comprising: a posterior portion having an outboard face that includes an articulating surface and an inboard face that includes one of a stem and a recess, and one of an annular central hub and an annular radial pocket and one of a protrusion and a depression that extends from said annular central hub or said annular radial pocket alone said inboard face; a ring-lock: an anterior portion defining a tissue engaging surface and a posterior portion engaging surface, said anterior portion being formed entirely of porous metal from said tissue engaging surface to said posterior portion engaging surface, said anterior portion having the other of said stem and said recess wherein said stem, said recess and said ring-lock attain a mechanical interlock in an assembled position upon advancement of said stem into said recess, said anterior portion further having the other of said annular central hub and said annular radial pocket that extends from said annular central hub or said annular radial pocket along said inboard face, wherein complementary tapered surfaces formed on said annular central hub and said annular radial pocket, respectively, continuously surround said stem and said recess and engage each other when said annular radial pocket receives said annular central hub in said assembled position; and wherein said mechanical interlock between said stem, recess and ring-lock, as well as engagement of said complementary tapered surfaces of said annular central hub and said annular radial pocket cooperate to resist separation of said posterior and anterior portions and wherein said protrusion and said depression mate and resist rotation of said posterior portion relative to said anterior portion in said assembled position.