Patent ID: 7708782

Claim:
A mobile bearing knee prosthesis, comprising: a tibial tray for interfacing with a tibia of a patient, wherein the tibial tray comprises an upper surface; and a tibial insert disposed adjacent the tibial tray, wherein the tibial insert comprises a lower surface; wherein substantially the entire upper surface of the tibial tray is defined by an arbitrary shape, wherein the arbitrary shape is fully rotated around an axis of rotation, the arbitrary shape being non-planar along the upper surface of the tibial tray; wherein the lower surface of the tibial insert is configured to be substantially complementary to the upper surface of the tibial tray when the tibial insert and the tibial tray are aligned in both: (a) a medial-lateral axis of the tibial tray and the tibial insert; and (b) an anterior-posterior axis of the tibial tray and the tibial insert; wherein the tibial insert is capable of movement relative to the tibial tray and the movement of the tibial insert relative to the tibial tray includes at least pivotal movement around the axis of rotation; wherein the axis of rotation is the only axis around which the tibial insert is capable of pivoting relative to the tibial tray; and wherein the pivotal movement of the tibial insert relative to the tibial tray is guided by a cooperating interface between the tibial tray and the tibial insert around the axis of rotation such that: (a) the tibial insert utilizes no male member, distinct from the cooperating interface, extending into the tibial tray through the upper surface of the tibial tray to guide the pivotal movement; and (b) the tibial tray utilizes no post or peg to guide the pivotal movement.