Modular knee joint prosthesis

Abstract

A knee joint prosthesis includes a femoral component for engaging the femur having an articular surface and a recess within the articular surface, and a tibial component for engaging the tibia with a bore, and a meniscal component comprising a rotation pin configured for rotatable mounting within the bore of the tibial component. The meniscal component also includes a bearing surface for sliding contact with the articular surface of the femoral component and an elongated channel defined amid the bearing surface. A stabilizing post is provided that includes a base slidably mounted with the elongated channel and a spine post projecting from the base through the channel and into the recess when the articular surface is in contact with said bearing surface. The stabilizing post thus slides within the channel when contacted by the interior of the recess in the femoral component. In a method of the invention, a plurality of stabilizing posts can be provided for temporary mounting within the channel. A stabilizing post can be selected that provides an optimum joint movement.

What is claimed is:  
     
         1 . A joint prosthesis comprising: 
 a first joint component having a bone engaging portion, an articular surface, and a recess defined within said articular surface;    a mating component having a bone engaging portion and defining a bearing surface for sliding contact with said articular surface of said first joint component; and    a stabilizing post slidably mounted to said mating component amid said bearing surface, said post projecting from said mating component and into said recess when said articular surface is in contact with said bearing surface.    
     
     
         2 . The joint prosthesis of  claim 1 , wherein said mating component includes: 
 a second joint component including the bone engaging portion; and    an intermediate component connected to said second joint component, said intermediate component including said bearing surface.    
     
     
         3 . The joint prosthesis of  claim 2 , wherein: 
 said second joint component defines a bore; and    said intermediate component includes a pin sized to be received within said bore.    
     
     
         4 . The joint prosthesis of  claim 3 , wherein said bore and said pin are configured to permit relative rotation therebetween when said pin is received within said bore.  
     
     
         5 . The joint prosthesis of  claim 1 , wherein: 
 said mating component defines an elongated channel; and    said stabilizing post includes a base configured for sliding engagement within said channel and a spine projecting from said base through said channel and into said recess when said articular surface is in contact with said bearing surface.    
     
     
         6 . The joint prosthesis of  claim 5 , wherein: 
 said channel is open at one end; and    said mating component includes a locking member configured to close said one end with said base of said stabilizing post disposed within said channel.    
     
     
         7 . The joint prosthesis of  claim 6 , wherein said locking member is configured for a press-fit within said channel.  
     
     
         8 . The joint prosthesis of  claim 6 , wherein: 
 said channel includes an enlarged groove at opposite sides of said channel,    said base is configured for sliding engagement within said grooves; and    said locking component is configured for locking engagement within said grooves.    
     
     
         9 . The joint prosthesis of  claim 6 , wherein said locking member is selectable from a plurality of locking members having different lengths when disposed within said channel.  
     
     
         10 . The joint prosthesis of  claim 5 , wherein: 
 said channel includes an enlarged groove at opposite sides of said channel; and    said base is configured for sliding engagement within said grooves with said spine projecting through said channel.    
     
     
         11 . The joint prosthesis of  claim 10 , wherein said base has a length and said channel has a length greater than the length of said base.  
     
     
         12 . The joint prosthesis of  claim 1 , wherein said stabilizing post is selectable from a plurality of stabilizing posts having different profiles.  
     
     
         13 . The joint prosthesis of  claim 1 , wherein: 
 said recess includes surfaces at its opposite ends;    said stabilizing post includes a face opposing one of said opposite end surfaces; and    said face and said one of said opposite end surfaces are configured to provide a camming movement of said stabilizing post as said one of said opposite end surfaces moves in contact with said face.    
     
     
         14 . The joint prosthesis of  claim 13 , wherein: 
 said stabilizing post includes an opposite face opposing the other of said opposite end surfaces; and    said opposite face and the other of said opposite end surfaces are configured to provide a camming movement of said stabilizing post as said other of said opposite end surfaces moves in contact with said opposite face.    
     
     
         15 . The joint prosthesis of  claim 14 , wherein said face and said opposite face are differently curved.  
     
     
         16 . In a prosthetic knee joint having a femoral component with femur engaging portion, an articular surface and a recess within the articular surface, and a tibial component with a tibia engaging portion and a bore, a meniscal component comprising: 
 a rotation pin configured for rotatable mounting within the bore of the tibial component;    a bearing surface for sliding contact with the articular surface of the femoral component;    an elongated channel defined amid said bearing surface; and    a stabilizing post including a base slidably mounted with said elongated channel and a spine post projecting from said base through said channel and into the recess when the articular surface is in contact with said bearing surface.    
     
     
         17 . The meniscal component of  claim 16 , wherein: 
 said channel has an open end; and    said meniscal component further comprises a locking member configured for locking engagement at said open end of said channel to trap said stabilizing post within said channel.    
     
     
         18 . A method for fitting a prosthetic joint to a patient comprising the steps of: 
 engaging a first component to a first bone of the patient, the first component having an articular surface and a recess defined within said articular surface;    engaging a mating component to a second bone of the patient, the mating defining a bearing surface for sliding contact with the articular surface of the first component;    selecting one of a plurality of stabilizing posts;    slidably mounting the selected stabilizing post to the mating component amid the bearing surface with the post projecting from the mating component and into the recess when the articular surface is in contact with the bearing surface;    evaluating the movement of the prosthetic joint in situ; and    replacing the selected stabilizing post with another stabilizing post from the plurality of posts to optimize the movement of the joint.    
     
     
         19 . The method of  claim 18 , wherein: 
 the mating component defines a channel having an open end; and    the method further comprises the step of closing the open end when a stabilizing post has been selected to optimize the movement of the joint.    
     
     
         20 . The method of  claim 18 , wherein: 
 the mating component includes a second component and an intermediate component; and    the step of engaging a mating component includes engaging the second component to the second bone and rotatably mounting the intermediate component to the second component.