Surgically implantable knee prosthesis with captured keel

Abstract

A unicompartmental knee prosthesis for implantation in a knee joint between a femoral condyle and a corresponding tibia plateau is provided including a generally elliptical body having opposed femoral and tibial face, the body having an anterior end and a posterior end. A keel is provided on the tibial face having a generally anterior-posterior orientation, the keel having an anterior end and a posterior end, where the keel posterior end includes a distal posterior portion that extends farther toward the body posterior end compared with a proximal posterior portion of the keel posterior end.

1 . A unicompartmental knee prosthesis for implantation in a knee joint between a femoral condyle and a corresponding tibia plateau, the prosthesis comprising:
 a generally elliptical body having opposed femoral and tibial faces, the body having an anterior end and a posterior end; and   a keel provided on the tibial face having a generally anterior-posterior orientation, the keel having an anterior end and a posterior end, wherein the keel posterior end includes a distal posterior portion that extends farther toward the body posterior end compared with a proximal posterior portion of the keel posterior end.   
   
   
       2 . The prosthesis according to  claim 1 , wherein the distal posterior portion of the keel posterior end is rounded. 
   
   
       3 . The prosthesis according to  claim 1 , wherein the keel posterior end is step-shaped to form an approximately 90° angle at the keel posterior end. 
   
   
       4 . The prosthesis according to  claim 1 , wherein a distal end of the keel is longer than a proximal end of the keel. 
   
   
       5 . The prosthesis according to  claim 1 , wherein the keel anterior end includes a proximal anterior portion that extends farther toward the body anterior end compared with a distal anterior portion of the keel anterior end. 
   
   
       6 . The prosthesis according to  claim 5 , wherein the distal anterior portion of the keel anterior end is rounded. 
   
   
       7 . The prosthesis according to  claim 5 , wherein the distal anterior portion of the keel anterior end is chamfered. 
   
   
       8 . The prosthesis according to  claim 1 , wherein the keel anterior end includes a distal anterior portion that extends farther toward the body anterior end compared with a proximal anterior portion of the keel anterior end. 
   
   
       9 . The prosthesis according to  claim 8 , wherein the keel anterior end is step-shaped to form an approximately 90° angle at the keel anterior end. 
   
   
       10 . The prosthesis according to  claim 1 , wherein the keel posterior end is hook-shaped to form an obtuse angle at the keel posterior end. 
   
   
       11 . The prosthesis according to  claim 1 , wherein the keel anterior end extends longer distally compared with the keel posterior end. 
   
   
       12 . The prosthesis according to  claim 1 , wherein the keel posterior end extends longer distally compared with the keel anterior end. 
   
   
       13 . The prosthesis according to  claim 1 , wherein the keel tapers such that a proximal end of the keel is wider than a distal end of the keel. 
   
   
       14 . The prosthesis according to  claim 1 , further comprising a surfacing component provided on at least one of the tibial and femoral faces. 
   
   
       15 . The prosthesis according to  claim 1 , further comprising a cross-keel having a generally medial-lateral orientation. 
   
   
       16 . The prosthesis according to  claim 15 , wherein the keel extends longer distally compared with the cross-keel. 
   
   
       17 . The prosthesis according to  claim 15 , wherein the cross-keel extends to approximately the same distal depth as the keel. 
   
   
       18 . The prosthesis according to  claim 15 , wherein a distal portion of the cross-keel extends farther toward the body posterior end compared with a proximal portion of the cross-keel. 
   
   
       19 . The prosthesis according to  claim 15 , wherein the cross-keel extends distally generally orthogonally from the tibial face. 
   
   
       20 . The prosthesis according to  claim 15 , wherein the cross-keel extends distally along the keel anterior end. 
   
   
       21 . The prosthesis according to  claim 1 , the keel further comprising at least one barb member protruding therefrom and having a generally medial-lateral orientation, the barb member having a distal portion that extends farther toward the body anterior end compared with a proximal portion of the barb member. 
   
   
       22 . The prosthesis according to  claim 21 , wherein the at least one barb member tapers such that an end adjacent the keel is wider compared with an end removed from the keel. 
   
   
       23 . The prosthesis according to  claim 1 , further comprising a tab extending distally from the posterior end of the body. 
   
   
       24 . The prosthesis according to  claim 1 , wherein the keel includes a portion which is expandable in a generally medial-lateral direction. 
   
   
       25 . The prosthesis according to  claim 24 , wherein the expandable portion is provided adjacent the keel anterior end. 
   
   
       26 . The prosthesis according to  claim 1 , wherein the body is arranged to receive a fastener. 
   
   
       27 . The prosthesis according to  claim 1 , wherein the keel is constructed from a deformable material. 
   
   
       28 . The prosthesis according to  claim 1 , wherein the prosthesis includes a biologically or pharmaceutically active material associated therewith. 
   
   
       29 . The prosthesis according to  claim 28 , wherein the biologically or pharmaceutically active material is a vasodilator associated with the keel. 
   
   
       30 . The prosthesis according to  claim 28 , wherein the biologically or pharmaceutically active material is a nerve-targeting agent associated with the keel. 
   
   
       31 . The prosthesis according to  claim 1 , further comprising an internal conduit from the body to the keel. 
   
   
       32 . A unicompartmental knee prosthesis for implantation in a knee joint between a femoral condyle and a corresponding tibia plateau, the prosthesis comprising:
 a generally elliptical body having opposed femoral and tibial faces, the body having an anterior end and a posterior end; and   a keel provided on the tibial face having a generally anterior-posterior orientation, the keel having an anterior end and a posterior end, wherein the keel posterior end includes a distal posterior portion that extends farther toward the body posterior end compared with a proximal posterior portion of the keel posterior end, and wherein the keel anterior end includes a proximal anterior portion that extends farther toward the body anterior end compared with a distal anterior portion of the keel anterior end.   
   
   
       33 . A method of implanting a unicompartmental knee prosthesis in a knee joint between a femoral condyle and a corresponding tibia plateau, the method comprising:
 providing a generally elliptical body having opposed femoral and tibial faces, the body having an anterior end and a posterior end, the prosthesis including a keel provided on the tibial face having a generally anterior-posterior orientation, the keel having an anterior end and a posterior end, wherein the keel posterior end includes a distal posterior portion that extends farther toward the body posterior end compared with a proximal posterior portion of the keel posterior end; and   creating a cut in the tibial plateau arranged to at least partially receive the keel.   
   
   
       34 . The method according to  claim 33 , wherein a majority of subchondral bone of the tibial plateau is left intact. 
   
   
       35 . The method according to  claim 33 , further comprising positioning the keel to reach below an underside of subchondral bone of the tibial plateau, thus capturing the prosthesis. 
   
   
       36 . The method according to  claim 33 , further comprising associating a biologically or pharmaceutically active material with the prosthesis. 
   
   
       37 . The method according to  claim 36 , further comprising filling the prosthesis with the active material via an internal conduit between the body and the keel.