Cruciate-retaining knee prosthesis

Abstract

Certain embodiments generally provide an improved tibial base member comprising keel portions that allow one or both cruciate ligaments to be preserved. Other embodiments provide improved lateral and/or medial inserts having a mesial lip that helps relieve and or prevent impingement between the femoral component and the tibial eminence. Other embodiments provide improved femoral components having various chamfers to provide additional clearance with respect to the tibial eminence and posterior cruciate ligament without decreasing bone coverage.

1 . A tibial prosthesis, comprising:
 an insert with a tibial articulation surface for articulation with a femoral condylar articulation surface, the tibial articulation surface comprising:
 an anterior-mesial portion, the anterior-mesial portion curved to conform to the femoral condylar articulation surface; and 
 a mesial lip extending in an anterior to posterior direction along a mesial edge of the articulation surface, wherein a height of the mesial lip at the extent of the mesial lip in the anterior direction is greater than a height of a central portion of the tibial articulation surface. 
   
     
     
         2 . The tibial prosthesis of  claim 1 , wherein a height along the mesial lip decreases in the anterior to posterior direction. 
     
     
         3 . The tibial prosthesis of  claim 1 , wherein the tibial articulation surface comprises a flat portion and the flat portion includes at least part of the central portion. 
     
     
         4 . The tibial prosthesis of  claim 3 , wherein the flat portion includes at least part of a lateral portion of the tibial articulation surface. 
     
     
         5 . The tibial prosthesis of  claim 3 , wherein the flat portion is at the height of the central portion. 
     
     
         6 . The tibial prosthesis of  claim 1 , wherein the tibial articulation surface comprises a curved surface connecting the mesial edge to a flat surface of the central portion. 
     
     
         7 . The tibial prosthesis of  claim 1 , wherein the tibial articulation surface defines a plurality of contours in a plurality of planes. 
     
     
         8 . The tibial prosthesis of  claim 1 , comprising a chamfer extending circumferentially around the tibial articulation surface. 
     
     
         9 . The tibial prosthesis of  claim 1 , wherein a posterior-outer portion of the tibial articulation surface is substantially flat. 
     
     
         10 . The tibial prosthesis of  claim 1 , wherein the height of the mesial lip at the extent of the mesial lip in the anterior direction is between 0.025 inches and 0.125 inches greater than the height of the central portion of the tibial articulation surface 
     
     
         11 . The tibial prosthesis of  claim 1 , comprising a locking mechanism to secure the insert to a tibial base member. 
     
     
         12 . An insert for a tibial prosthesis, comprising:
 a tibial articulation surface for articulation with a femoral condylar articulation surface, the tibial articulation surface comprising:
 an anterior-mesial portion, the anterior-mesial portion curved to conform to the femoral condylar articulation surface, and 
 a mesial lip extending in an anterior to posterior direction along a mesial edge of the articulation surface, wherein a height of the mesial lip at the extent of the mesial lip in the anterior direction is greater than a height of a central portion of the tibial articulation surface; and 
 a chamfer extending circumferentially around the tibial articulation surface. 
   
     
     
         13 . The insert of  claim 12 , wherein a height along the mesial lip decreases in the anterior to posterior direction. 
     
     
         14 . The insert of  claim 12 , wherein a posterior-outer portion of the tibial articulation surface is substantially flat. 
     
     
         15 . The insert of  claim 12 , wherein the tibial articulation surface comprises a flat portion and the flat portion includes at least part of the central portion. 
     
     
         16 . The insert of  claim 15 , wherein the flat portion includes at least part of a lateral portion of the tibial articulation surface. 
     
     
         17 . The insert of  claim 15 , wherein the flat portion is at the height of the central portion. 
     
     
         18 . The insert of  claim 12 , wherein the tibial articulation surface comprises a curved surface connecting the mesial edge to a flat surface of the central portion. 
     
     
         19 . The insert of  claim 12 , wherein the tibial articulation surface defines a plurality of contours in a plurality of planes. 
     
     
         20 . The insert of  claim 12 , comprising a locking mechanism to secure the insert to a tibial base member.