Patent ID: 8403993

Claim:
A prosthetic knee system comprising: a femoral component having bearing surfaces; a tibial base component comprising a tray having a flat proximal surface, a distal surface and an interior surface defining a bore having a central longitudinal axis, the bore being circular in transverse cross-section along a portion of the length of the bore, a portion of the interior surface of the bore having interior stop surfaces and interior radial surfaces, the interior stop surfaces being perpendicular to the interior radial surfaces and the interior radial surfaces being perpendicular to the longitudinal axis of the bore, the interior stop surfaces and interior radial surfaces defining spaced radial recesses, each radial recess having an arc length; a first tibial bearing component having a proximal bearing surface, a flat distal surface and a protuberance extending distally from the flat distal surface, the protuberance having a longitudinal axis and a distal end spaced from the flat distal surface; and a second tibial bearing component having a proximal bearing surface, a distal surface and a protuberance extending distally from the flat distal surface, the protuberance having a longitudinal axis and a distal end spaced from the distal surface; wherein the first tibial bearing component is sized and shaped so as to be capable of being selectively assembled with the tibial base component with at least a portion of the protuberance received in the bore and the second tibial bearing component is sized and shaped so as to be capable of being selectively assembled with the tibial base component with at least a portion of the protuberance received in the bore; wherein the first tibial bearing component includes a plurality of spaced tabs extending radially outward from the protuberance, each tab including a radial surface perpendicular to the longitudinal axis of the protuberance and a pair of stop surfaces perpendicular to the radial surface of the protuberance, each tab having an arc length; wherein the tabs of the first tibial bearing component are receivable within the radial recesses of the tibial base component, the arc length of each tab being less than the arc length of each radial recess to allow for limited rotation of the first tibial bearing component on the tibial base component; wherein the second tibial bearing component is shaped so as to be rotatable about the longitudinal axis of the stem when assembled with the tibial base component; and wherein no part of the second tibial bearing component is received within the radial recesses of the tibial base component when the second tibial bearing component is assembled with the tibial base component.