Total knee implant

Abstract

A knee prosthesis is provided for use in knee arthroplasty. In one exemplary embodiment, the present invention provides a tibial prosthesis having a tibial baseplate with a fixed medial bearing component and a mobile lateral bearing component. In one exemplary embodiment, the lateral bearing component is secured to the lateral portion of the tibial baseplate utilizing at least one prosthetic ligament. Additionally, in one exemplary embodiment, a stop is provided to limit anterior or posterior movement of the lateral bearing component relative to the tibial baseplate. For example, the stop may be defined by cooperating shoulders formed on the lateral bearing and the tibial baseplate.

1 . A prosthetic knee system, comprising:
 a femoral component having a lateral condyle and a medial condyle;   a tibial component comprising:
 a baseplate having a bone facing surface and an opposing support surface; 
 a medial bearing component having a medial articulation surface and a medial attachment surface, said medial attachment surface coupleable with said support surface of said baseplate to fix said medial component to said baseplate, whereby movement of said medial component relative to said baseplate is substantially entirely prevented; and 
 a lateral bearing component having a lateral articulation surface and a lateral attachment surface, said lateral attachment surface slidingly securable to said support surface of said baseplate, wherein said lateral component is translatable relative to said baseplate 
   a first prosthetic ligament detachably connected to the baseplate and the lateral condyle; and   a second prosthetic ligament detachably connected to the baseplate and the medial condyle.   
     
     
         2 . The prosthetic knee system of  claim 1 , further comprising: a T-shaped projection formed on one of said lateral attachment surface of said lateral component and said support surface of said baseplate, a T-shaped groove formed on the other of said lateral attachment surface of said lateral component and said support surface of said baseplate, said T-shaped projection sized and positioned to cooperate with said T-shaped groove to form a securement mechanism when said lateral attachment surface of said lateral component is slidingly secured to said support surface of said baseplate, said securement mechanism allowing translation of said lateral component in an anterior direction and a posterior direction. 
     
     
         3 . The prosthetic knee system of  claim 1 , wherein said lateral component is translatable relative to said baseplate independent of said medial component. 
     
     
         4 .- 8 . (canceled) 
     
     
         9 . The prosthetic knee system of  claim 3 , wherein:
 the baseplate further comprises a projection extending from the support surface between the medial bearing component and the lateral bearing component, the projection extending in an anterior-posterior direction; and   the first and second prosthetic ligaments connect to the baseplate at the projection.   
     
     
         10 . The prosthetic knee system of  claim 1 , wherein the first prosthetic ligament is the only ligament attaching the lateral condyle to the tibial component and the second prosthetic ligament is the only ligament attaching the medial condyle to the tibial component. 
     
     
         11 . The prosthetic knee system of  claim 1 , wherein each of the first and second prosthetic ligaments comprises:
 an elongate body having a width and extending between a first end and a second end;   a first head connected to the first end; and   a second head connected to the second end;   wherein the first and second heads are wider than the width.   
     
     
         12 . The prosthetic knee system of  claim 11 , further comprising:
 a first groove located in the lateral condyle for receiving the first head of the first prosthetic ligament;   a second groove located in the medial condyle for receiving the first head of the second prosthetic ligament;   a third groove located in the baseplate for receiving the second head of the first prosthetic ligament; and   a fourth groove located in the baseplate for receiving the second head of the second prosthetic ligament.   
     
     
         13 . The prosthetic knee system of  claim 12 , wherein the first and second heads are spherical and the first, second, third and fourth sockets are shaped to mate with the spherical heads. 
     
     
         14 . The prosthetic knee system of  claim 12 , wherein the fourth groove is located anterior of the third groove. 
     
     
         15 . The prosthetic knee system of  claim 14 , wherein the first and second prosthetic ligaments crossover each other in a medial-lateral direction extending between the femoral component and the baseplate. 
     
     
         16 . The prosthetic knee system of  claim 11 , wherein the first and second heads are formed of a resiliently deformable material. 
     
     
         17 . The prosthetic knee system of  claim 1 , wherein the first prosthetic ligament has a first stiffness and the second prosthetic ligament has a second stiffness that is different than the first stiffness. 
     
     
         18 . A prosthetic knee system comprising:
 a femoral component having a lateral condyle and a medial condyle;   a tibial component comprising:
 a medial portion for engaging the medial condyle; 
 a lateral portion for engaging the lateral condyle; and 
 a central portion positioned between the medial and lateral portions; 
   a first prosthetic ligament solely coupling the lateral condyle to the central portion; and   a second prosthetic ligament solely coupling the medial condyle to the central portion.   
     
     
         19 . The prosthetic knee system of  claim 18  wherein:
 the first prosthetic ligament is attached to the central portion posterior of where the second prosthetic ligament is attached to the central portion; 
 the first prosthetic ligament is attached to the central portion closer to a medial side of the central portion than a lateral side of the central portion; and 
 the second prosthetic ligament is attached to the central portion closer to the lateral side of the central portion than the medial side of the central portion. 
 
     
     
         20 . The prosthetic knee system of  claim 18 , wherein the first and second prosthetic ligaments are detachably coupled to the femoral component and the tibial component at attachment points. 
     
     
         21 . The prosthetic knee system of  claim 20 , wherein each attachment point comprises:
 a spherical head attached to an end of one of the first and second prosthetic ligaments; and   a spherical socket positioned on the femoral component or the tibial component to receive the spherical head.   
     
     
         22 . The prosthetic knee system of  claim 21 , wherein each spherical head is resilient. 
     
     
         23 . A prosthetic knee system comprising:
 a femoral component having a lateral condyle and a medial condyle;   a tibial component comprising:
 a medial portion for engaging the medial condyle; 
 a lateral portion for engaging the lateral condyle; and 
 a central portion positioned between the medial and lateral portions; 
   a first prosthetic ligament coupling the lateral condyle to a medial portion of the central portion; and   a second prosthetic ligament coupling the medial condyle to a lateral portion of the central portion.   
     
     
         24 . The prosthetic knee system of  claim 23 , wherein the first prosthetic ligament attaches to the central portion posterior of where the second prosthetic ligament attaches to the central portion. 
     
     
         25 . The prosthetic knee system of  claim 23 , wherein the first prosthetic ligament and the second prosthetic ligament each comprises:
 a first resilient spherical head;   a second resilient spherical head; and   a resiliently deformable elongate body extending between the first resilient spherical head and the second resilient spherical head.