Bone implant and method of securing

Abstract

The present invention is an implant for securing to a bone to form a plurality of cement cells. The implant has a bone engagement portion for engagement with the bone. The implant has surfaces defining a first plurality of cement compartments in the bone engagement portion for alignment with a second plurality of cement compartments in the bone to form a plurality of cement cells extending between the implant and the bone when the implant is secured to the bone. The cement cells receive cement therein to form plugs of cement extending between the implant and the bone to secure the implant to the bone.

I claim:  
     
         1 . An implant for securing to a bone, said implant having a bone engagement portion for engagement with the bone and having surfaces defining a first plurality of cement compartments in said bone engagement portion for alignment with a second plurality of cement compartments in the bone to form a plurality of cement cells extending between said implant and the bone when said implant is secured to the bone, said cement cells for receiving cement therein to form plugs of cement extending between said implant and the bone to secure said implant to the bone.  
     
     
         2 . An implant as set forth in    claim 1    including surface means for defining at least one fill port in fluid communication with at least one of said cement compartments in said implant, said fill port for receiving cement through said fill port and for communicating the cement to said at least one cement compartment.  
     
     
         3 . An implant as set forth in    claim 2    including a plurality of fill ports numbering one for each respective cement compartment in said implant.  
     
     
         4 . An implant as set forth in    claim 1    wherein said cement compartments in said implant are each generally cylindrical in shape, having a cylindrical wall extending about an axis extending generally in a direction between said implant and the bone.  
     
     
         5 . An implant as set forth in    claim 1    including means for allowing excess cement to flow from said cement cells away from the interface between said bone engagement portion of said implant and the bone, comprising at least one exit channel in said implant extending from said first plurality of cement compartments in a direction away from said bone engagement portion of said implant.  
     
     
         6 . An implant as set forth in    claim 1    including ridge portions around said cement compartments in said implant to block flow of cement out of said cement compartments and between said implant and the bone.  
     
     
         7 . In combination, 
 an implant having a bone engagement portion for engagement with a bone, said implant having surfaces defining a first plurality of cement compartments in said bone engagement portion;    a bone having surfaces defining a second plurality of cement compartments;    said cement compartments in said implant being aligned with said cement compartments in said bone to form cement cells extending between said implant and said bone; and    plugs of cement in said cement cells extending between said implant and said bone and securing said implant to said bone.    
     
     
         8 . A combination as set forth in    claim 7    including respective alignment markers on said bone and on said implant for aligning said cement compartments in said implant with said cement compartments in said bone.  
     
     
         9 . A combination as set forth in    claim 7    including means for dividing the interface between said implant and said bone into at least two discrete parts, comprising a portion of a surface of said bone engagement portion of said implant in abutting engagement with the bone whereby there is not a continuous layer of cement between said implant and said bone across the full extent of the interface between said implant and said bone.  
     
     
         10 . A combination as set forth in    claim 7    wherein said implant includes surface means for defining at least one fill port in fluid communication with at least one of said cement compartments in said implant, said fill port for receiving said cement through said fill port and for communicating said cement to said cement compartment.  
     
     
         11 . A combination as set forth in    claim 7    wherein said implant includes ridge portions around said cement compartments in said implant to block flow of cement out of said cement cells and between said implant and said bone.  
     
     
         12 . A method of securing an implant to bone comprising the steps of: 
 providing an implant having a bone engagement portion for engagement with the bone and having surfaces defining a first plurality of cement compartments in the bone engagement portion;    making a second plurality of cement compartments in the bone;    placing the bone engagement portion of the implant adjacent the bone;    aligning the cement compartments in the implant with the cement compartments in the bone to form cement cells extending between the implant and the bone; and    placing cement in the cement cells to form plugs of cement extending between the implant and the bone to secure the implant to the bone.    
     
     
         13 . A method as set forth in    claim 12    including the step of limiting the amount of cement entering between the bone engagement portion of the implant and the bone to ensure that there is not a continuous layer of cement between the implant and the bone over the full extent of the interface between the implant and the bone.  
     
     
         14 . A method as set forth in    claim 13    wherein said step of filling the cement cells through one or more fill ports in the implant includes filling the cement cells after performing said step of placing the bone engagement portion of the implant adjacent the bone.  
     
     
         15 . A method as set forth in    claim 14    wherein said step of filling the cement cells through one or more fill ports includes filling each cement cell through its own respective fill port.  
     
     
         16 . A method as set forth in    claim 12    wherein said step of placing cement in the cement cells includes the steps of placing a quantity of cement between the implant and the bone and moving the implant and the bone toward each other to squeeze the cement into the cement cells while the cement compartments in the implant and in the bone are aligned.  
     
     
         17 . A method as set forth in    claim 12    including the steps of providing at least one exit channel in the implant extending from the cement compartments and allowing excess cement to flow through the at least one exit channel.  
     
     
         18 . A method as set forth in    claim 12    wherein said step of aligning the cement compartments in the implant with the cement compartments in the bone includes the steps of placing an alignment marker on the bone and aligning it with a second alignment member on the implant.  
     
     
         19 . A method as set forth in    claim 12    wherein said step of placing cement in the cement cells includes the step of filling the cement cells through one or more fill ports in the implant.  
     
     
         20 . A method as set forth in    claim 12    wherein said step of making a second plurality of cement compartments in the bone includes drilling or broaching or pressing the cement compartments in the bone.  
     
     
         21 . A method of securing an implant to bone comprising the steps of: 
 placing a bone engagement portion of an implant adjacent a bone to form cement cells extending between the implant and the bone; and    placing cement in the cement cells to form plugs of cement extending between the implant and the bone, while preventing formation of a continuous slab of cement between the bone engagement portion of the implant and the bone.    
     
     
         22 . A method as set forth in    claim 21    wherein said step of placing a bone engagement portion of an implant adjacent a bone includes providing an implant having a bone engagement portion for engagement with the bone and having surfaces defining a first plurality of cement compartments in the bone engagement portion, and said step of placing a bone engagement portion of an implant adjacent a bone includes making a second plurality of cement compartments in the bone and aligning the cement compartments in the bone engagement portion of the implant with the cement compartments in the bone.