Femoral head resurfacing apparatus and methods

Abstract

A femoral head resurfacing apparatus includes a cap of hemispherical shape and stabilization structure (e.g., one or more non-shear fixation bars) that inserts into slots cut into the femoral head, so that the cap remains substantially immovable other than due northerly. A method of resurfacing the femoral head of a hip joint includes removing longitudinal slots or holes of bone in the femoral head, and attaching a hemispherical cap to the head, the cap having non-shear fixation bars or other stabilizing structure for mating engagement with the slots or holes.

1 . Femoral head resurfacing apparatus, comprising 
 a cap of substantially hemispherical shape;    a center post for insertion into a center hole in the femoral head, the center post forming one or more grooves; and    stabilizing structure for insertion into one or more corresponding holes in the femoral head, the stabilizing structure comprising one or more dowels, each dowel configured to fit into a corresponding groove;    wherein the cap remains substantially immovable other than due northerly.    
   
   
       2 . Apparatus of  claim 1 , an inner surface of the cap comprising hydroxyapatite porocast to promote bone ingrowth-penetration into the cap and facilitate fixation of the cap to the femoral head.  
   
   
       3 . Apparatus of  claim 1 , the cap being sized to minimize bone removal from the femoral head.  
   
   
       4 . A method for capping a femoral head with a shell, comprising the steps of: 
 drilling a central hole in the femoral head;    forming one or more additional openings in the femoral head;    inserting a centering post of the shell into the central hole; and    inserting stabilizing structure, which is formed monolithically with the centering post, into the one or more additional openings to prevent migration of the shell.    
   
   
       5 . Femoral head resurfacing apparatus, comprising: 
 a cap of substantially hemispherical shape;    a centering post for insertion into a central hole in the femoral head; and    fins, extending from the centering post, for insertion into one or more corresponding openings in the femoral head;    wherein the cap remains substantially immovable other than due northerly.    
   
   
       6 . Apparatus of  claim 1 , the center post being 3 to 4 centimeters long.  
   
   
       7 . Apparatus of  claim 1 , a diameter of the one or more dowels being 10% to 50% of a diameter of the center post.  
   
   
       8 . Apparatus of  claim 1 , the one or more dowels comprising a plurality of dowels, the one or more grooves comprising a plurality of grooves such that each dowel corresponds to a selected one of the grooves.  
   
   
       9 . Apparatus of  claim 8 , wherein at least one of the dowels is sized differently than at least one other of the dowels.  
   
   
       10 . Method of  claim 4 , further comprising a step of down size reaming the femoral head so that the femoral head fits within the shell.  
   
   
       11 . Method of  claim 4 , wherein at least one of the steps of drilling and forming comprises utilizing a template.  
   
   
       12 . Apparatus of  claim 5 , one or more of an inner surface of the cap, a surface of the centering post and a surface of the fins comprising hydroxyapatite porocast.  
   
   
       13 . A method for capping a femoral head with a shell, comprising the steps of: 
 drilling a central hole in the femoral head;    drilling one or more secondary holes in the femoral head such that each of the secondary holes adjoins the central hole;    inserting, for each of the one or more secondary holes, a corresponding dowel into a corresponding groove formed by a centering post of the shell;    inserting the centering post into the central hole; and    inserting each corresponding dowel into each of the one or more secondary holes, to prevent migration of the shell.    
   
   
       14 . Method of  claim 13 , further comprising a step of down size reaming the femoral head so that the femoral head fits within the shell.  
   
   
       15 . Method of  claim 13 , wherein at least one of the steps of drilling the central hole and drilling one or more secondary holes comprises utilizing a template.