Patent ID: 7462198

Claim:
A mobile bearing unicondylar tibial knee prosthesis configured to be positioned in a knee joint, the knee joint having a central plane that divides the knee joint into medial and lateral compartments, said prosthesis comprising: a tibial base plate having a superior surface, an inferior surface, an inside edge configured to be positioned adjacent the central plane of the knee joint, an outside edge, an anterior aspect, a posterior aspect, and a stop projecting superiorly from the superior surface adjacent at least one of the inside edge and the outside edge, the stop having a curved surface having a first terminal end, a second terminal end, and a midpoint, the curved surface curving away from the inside edge of the tibial base plate from the midpoint to each of the terminal ends; and a tibial articular surface component comprising a superior surface, an inferior surface, an inside edge, an outside edge, an anterior aspect, and a posterior aspect, the inferior surface of the articular surface component engaging the superior surface of the base plate in sliding relationship, the curved surface of the stop of the tibial base plate and the tibial articular surface component defining a tab and groove engagement between them, the tab and groove engagement permitting the tibial articular surface component to slide anteriorly-posteriorly on the tibial base plate in a generally arc-shaped motion toward the outside edge of the base plate near the anterior and posterior aspects of the base plate, the articular surface component rotating about an axis offset from the central plane when the prosthesis is positioned in the knee joint, while restricting movement of the tibial articular surface component superiorly away from the base plate.