Method and apparatus for a knee implant

A prosthesis for replacing an articulating portion of bone comprising:

• a cylindrical sleeve extending along a central longitudinal axis and defining a first bore extending along an offset coupling axis;
• an adaptor positionable substantially entirely within the bone to replace a portion of the bone, the adaptor defining a second bore that receives the sleeve, the second bore having an inner cylindrical sidewall and an endwall, the sleeve fully positioned within the second bore such that the sleeve does not extend beyond the sidewall, the sleeve rotatable within the second bore, the adaptor having a surface and an apex, with at least one cylindrical sidewall adjacent to the surface and at least one tapered sidewall coupled between the at least one cylindrical sidewall and the apex, and the second bore is defined through the surface;
• an articulating portion operable to replace the articulating portion of the bone including a projection having a plurality of grooves, the projection received within the first bore to couple the articulating portion to the sleeve;
• and
• at least one augment, the at least one augment having an outer semi-circular sidewall removably coupled to a complementary portion of the at least one cylindrical sidewall of the adaptor and coupled to the adaptor with a fastener extending into the at least one cylindrical sidewall of the adaptor, and wherein the adaptor is composed of a porous metal material and a bone cement inserted into the first bore couples the projection of the articulating portion to the adaptor.

A prosthesis for replacing an articulating portion of bone comprising:

• a stem having first end and a second end, the first end of the stem defining a tapered coupling portion, the second end of the stem adapted to be coupled to a portion of bone,
• a cylindrical sleeve defining an offset coupling axis, the sleeve having a first terminal end and a second terminal end;
• a conical adaptor positionable within the bone to replace a portion of the bone, the adaptor including a substantially planar first surface, a substantially planar second surface opposite the first surface;
• an outer cylindrical sidewall adjacent to the first surface, an outer tapered sidewall extending from the cylindrical sidewall to the second surface, a first bore formed through the first surface, the first bore having an inner cylindrical sidewall and an endwall, with the sleeve positionable within the first bore such that the first terminal end is adjacent to the endwall of the first bore and the second terminal end is coplanar to the first surface, and a second tapered bore extending inward from the second surface and not communicating with the first bore, the second bore receiving the tapered coupling portion of the stem;
• an articulating portion operable to replace the articulating portion of the bone, the articulating portion coupled to the adaptor via the offset coupling axis;
• and
• a first augment having an outer semi-circular sidewall removably coupled to a complementary portion of the cylindrical sidewall of the adaptor, the first augment having a substantially planar augment surface, the augment surface being coplanar with the first surface of the adaptor when the first augment is coupled to the portion of the cylindrical sidewall, the first augment coupled to the adaptor with a fastener extending into the cylindrical sidewall of the adaptor.