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 for at least partially replacing a proximal portion of a tibia, the tibial prosthesis comprising:
 (a) an inferior surface for contact with a resected surface on the proximal portion of the tibia; and   (b) a keel for penetration into a cavity formed in the proximal tibia, wherein the keel extends at an inferior-posterior angle away from the inferior surface.   
     
     
         2 . The tibial prosthesis of  claim 1 , wherein the keel includes an anterior keel portion, a medial keel portion, and a lateral keel portion, and wherein the anterior keel portion extends at the inferior-posterior angle away from the inferior surface. 
     
     
         3 . The tibial prosthesis of  claim 2 , wherein the tibial prosthesis further comprises a medial baseplate portion, a lateral baseplate portion, and a connecting baseplate portion extending between and connecting the medial baseplate portion and lateral baseplate portion; wherein at least a part of the anterior keel portion extends in a generally medial-lateral direction on the connecting baseplate portion; wherein at least a part of the medial keel portion extends in a generally anterior-posterior direction on the medial baseplate portion; and wherein at least a part of the lateral keel portion extends in a generally anterior-posterior direction on the lateral baseplate portion. 
     
     
         4 . The tibial prosthesis of  claim 3 , wherein the anterior keel portion joins the medial and lateral keel portions at areas of increased thickness. 
     
     
         5 . The tibial prosthesis of  claim 3 , wherein the anterior keel portion joins the medial and lateral keel portions at areas of increased width. 
     
     
         6 . The tibial prosthesis of  claim 3 , wherein the connecting baseplate portion increases in thickness in an anterior to posterior direction. 
     
     
         7 . The tibial prosthesis of  claim 3 , wherein the medial and lateral keel portions decrease in height as the medial and lateral keel portions extend in an anterior to posterior direction. 
     
     
         8 . The tibial prosthesis of  claim 2 , wherein the anterior keel portion includes an anterior face and a posterior face, wherein the anterior face extends at an inferior-posterior anterior face angle away from the inferior surface; and wherein the posterior face extends at an inferior-posterior posterior face angle away from the inferior surface. 
     
     
         9 . The tibial prosthesis of  claim 2 , wherein the anterior keel portion extends across the connecting baseplate portion in an anterior-medial to a posterior-lateral direction. 
     
     
         10 . The tibial prosthesis of  claim 9 , wherein the tibial prosthesis defines a central notch extending between the medial and lateral baseplate portions posterior to the connecting baseplate portion, wherein the central notch has a sufficient width and length to receive a portion of a tibial eminence including an anterior cruciate ligament attachment site and a posterior cruciate ligament attachment site. 
     
     
         11 . The tibial prosthesis of  claim 10 , wherein the central notch comprises a medial edge and a lateral edge; wherein an angle defined by the medial edge and a base of the anterior keel portion is acute; and wherein an angle defined by the lateral edge and the base of the anterior keel portion is obtuse. 
     
     
         12 . The tibial prosthesis of  claim 3 , wherein a posterior face of the anterior keel portion is offset from a posterior face of the connecting baseplate portion. 
     
     
         13 . The tibial prosthesis of  claim 2 , wherein a superior surface of the tibial prosthesis includes at least one lock member for securing a tibial insert. 
     
     
         14 . The tibial prosthesis of  claim 2 , wherein a superior surface of the tibial prosthesis includes at least two lock members for securing a medial tibial insert and a lateral tibial insert. 
     
     
         15 . A tibial prosthesis for at least partially replacing a proximal portion of a tibia, the tibial prosthesis comprising:
 (a) a medial baseplate portion, the medial baseplate portion having a medial inferior surface for contact with a medial resected surface on the proximal portion of the tibia;   (b) a lateral baseplate portion, the lateral baseplate portion having an lateral inferior surface for contact with a lateral resected surface on the proximal portion of the tibia; and   (c) a connecting baseplate portion extending between the medial and lateral baseplate portions;   wherein the tibial prosthesis is asymmetric about a midline extending in an anterior-posterior direction between the medial and lateral baseplate portions and the medial baseplate portion extends further anteriorly than the lateral baseplate portion.   
     
     
         16 . The tibial prosthesis of  claim 15 , wherein an area defined by the medial baseplate portion in a transverse plane is greater than an area defined by the lateral baseplate portion in the transverse plane. 
     
     
         17 . The tibial prosthesis of  claim 15 , wherein the tibial prosthesis is a bicruciate-retaining tibial prosthesis. 
     
     
         18 . The tibial prosthesis of  claim 15 , wherein the tibial prosthesis defines a notch extending in a generally anterior-posterior direction between the medial and lateral baseplate portions and is positioned posterior to the connecting baseplate portion; and wherein the notch is of sufficient length to receive at least a portion of an eminence of the tibia including an anterior cruciate ligament attachment site and a posterior cruciate ligament attachment site. 
     
     
         19 . The tibial prosthesis of  claim 18 , wherein the notch comprises a medial edge, a lateral edge, and an anterior edge;
 wherein an angle defined by the medial and anterior edges is acute; and   wherein an angle defined by the lateral and anterior edges is obtuse.   
     
     
         20 . A tibial prosthesis for at least partially replacing a proximal portion of a tibia, the tibial prosthesis comprising:
 (a) a medial baseplate portion comprising a medial inferior surface for contact with a medial resected surface on the proximal portion of the tibia;   (b) a lateral baseplate portion comprising a lateral inferior surface for contact with a lateral resected surface on the proximal portion of the tibia;   (c) a connection baseplate portion extending between the medial and lateral baseplate portions, the connection baseplate portion comprising a connection inferior surface;   (d) a keel for penetration into a cavity formed in the proximal tibia, wherein the keel extends at an inferior-posterior angle away from at least one of the medial inferior surface, the lateral inferior surface, and the connection inferior surface.