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:
 a medial insert comprising a medial articulation surface and a medial bottom surface, the medial articulation surface for articulation with a medial portion of a femoral condylar articulation surface and the medial bottom surface for receipt by a medial portion of a tibial base member, wherein the medial articulation surface comprises a medial posterior portion with a medial posterior slope relative to the medial bottom surface; and   a lateral insert comprising a lateral articulation surface and a lateral bottom surface, the lateral articulation surface for articulation with a lateral portion of the femoral condylar articulation surface and the lateral bottom surface for receipt by a lateral portion of the tibial base member, wherein the lateral articulation surface comprises a lateral posterior portion with a lateral posterior slope relative to the medial bottom surface.   
     
     
         2 . The tibial prosthesis of  claim 1 , wherein the medial posterior slope and the lateral posterior slope are equal. 
     
     
         3 . The tibial prosthesis of  claim 1 , wherein the medial posterior slope and the lateral posterior slope are different. 
     
     
         4 . The tibial prosthesis of  claim 1 , wherein the medial posterior slope is negative in an anterior-posterior direction of the medial insert. 
     
     
         5 . The tibial prosthesis of  claim 1 , wherein the lateral posterior slope is negative in an anterior-posterior direction of the lateral insert. 
     
     
         6 . The tibial prosthesis of  claim 1 , wherein the medial posterior slope increases in an anterior-posterior direction of the medial insert. 
     
     
         7 . The tibial prosthesis of  claim 1 , wherein the medial posterior slope decreases in an anterior-posterior direction of the medial insert. 
     
     
         8 . The tibial prosthesis of  claim 1 , wherein the lateral posterior slope increases in an anterior-posterior direction of the lateral insert. 
     
     
         9 . The tibial prosthesis of  claim 1 , wherein the lateral posterior slope decreases in an anterior-posterior direction of the lateral insert. 
     
     
         10 . The tibial prosthesis of  claim 1 , wherein the medial posterior slope and the lateral posterior slope are configured to provide balance between a medial collateral ligament and a lateral collateral ligament. 
     
     
         11 . A tibial prosthesis implant kit, comprising:
 a first pair of inserts comprising:
 a first medial insert comprising a first medial articulation surface and a first medial bottom surface, the first medial articulation surface for articulation with a medial portion of a femoral condylar articulation surface and the first medial bottom surface for receipt by a medial portion of a tibial base member, wherein the first medial articulation surface comprises a first medial posterior portion with a first medial posterior slope relative to the first medial bottom surface; and 
 a first lateral insert comprising a first lateral articulation surface and a first lateral bottom surface, the first lateral articulation surface for articulation with a lateral portion of the femoral condylar articulation surface and the first lateral bottom surface for receipt by a lateral portion of the tibial base member, wherein the first lateral articulation surface comprises a first lateral posterior portion with a first lateral posterior slope relative to the medial bottom surface; 
 wherein the first medial posterior slope and the first lateral posterior slope are configured to provide a first amount of flexion space; and 
   a second pair of inserts comprising:
 a second medial insert comprising a second medial articulation surface and a second medial bottom surface, the second medial articulation surface for articulation with the medial portion of the femoral condylar articulation surface and the second medial bottom surface for receipt by the medial portion of the tibial base member, wherein the second medial articulation surface comprises a second medial posterior portion with a second medial posterior slope relative to the second medial bottom surface; and 
 a second lateral insert comprising a second lateral articulation surface and a second lateral bottom surface, the second lateral articulation surface for articulation with the lateral portion of the femoral condylar articulation surface and the second lateral bottom surface for receipt by the lateral portion of the tibial base member, wherein the second lateral articulation surface comprises a second lateral posterior portion with a second lateral posterior slope relative to the medial bottom surface; 
 wherein the second medial posterior slope and the second lateral posterior slope are configured to provide a second amount of flexion space different from the first amount of flexion space. 
   
     
     
         12 . The tibial prosthesis implant kit of  claim 11 , wherein the first medial posterior slope is a set number of degrees more than the second medial posterior slope and the first lateral posterior slope is the set number of degrees more than the second lateral posterior slope. 
     
     
         13 . The tibial prosthesis implant kit of  claim 11 , wherein the first medial posterior slope and the first lateral posterior slope are equal. 
     
     
         14 . The tibial prosthesis implant kit of  claim 11 , wherein the first medial posterior slope and the first lateral posterior slope are different. 
     
     
         15 . The tibial prosthesis implant kit of  claim 11 , wherein the second medial posterior slope and the second lateral posterior slope are equal. 
     
     
         16 . The tibial prosthesis implant kit of  claim 11 , wherein the second medial posterior slope and the second lateral posterior slope are different. 
     
     
         17 . The tibial prosthesis implant kit of  claim 11 , wherein the first medial posterior slope is negative in an anterior-posterior direction of the first medial insert and the second medial posterior slope is negative in an anterior-posterior direction of the second medial insert. 
     
     
         18 . The tibial prosthesis implant kit of  claim 11 , wherein the first lateral posterior slope is negative in an anterior-posterior direction of the first lateral insert and the second lateral posterior slope is negative in an anterior-posterior direction of the second lateral insert. 
     
     
         19 . The tibial prosthesis implant kit of  claim 11 , wherein the first medial posterior slope increases in an anterior-posterior direction of the first medial insert and the second medial posterior slope increases in an anterior-posterior direction of the second medial insert. 
     
     
         20 . The tibial prosthesis implant kit of  claim 11 , wherein the first medial posterior slope decreases in an anterior-posterior direction of the first medial insert and the second medial posterior slope decreases in an anterior-posterior direction of the second medial insert.