Method and apparatus for preparing a glenoid surface

Abstract

A method and apparatus for facilitating shoulder arthroplasty by providing a reference to establish version of the glenoid. In one form of the invention, a guide for positioning a guide pin to facilitate implantation of a glenoid prosthesis is provided. To properly position the guide pin, the guide is first oriented with respect to the scapula. A portion of the guide is positioned over the approximate center of the glenoid surface and another portion of the guide is positioned against the anterior surface of the scapula. After the guide is properly positioned, the guide pin is inserted through an aperture in the guide and anchored in the glenoid. Thereafter, the guide pin can serve as an alignment guide for other devices used to modify the glenoid surface. For example, a reamer having a cannulated central shaft can be placed over the guide pin and utilized to resurface the glenoid.

1 . A guide for establishing the orientation of a guide axis relative to a glenoid surface, the guide comprising: 
 a body including a guide portion and a reference portion, said guide portion configured to extend over the glenoid surface, said guide portion including a guide aperture, said guide aperture defining the guide axis, said reference portion configured to extend over an anterior surface of a scapula, said reference portion including a contact point for contacting the anterior surface of the scapula, wherein said contact point is substantially located on the guide axis.    
   
   
       2 . The guide of  claim 1 , further comprising a bushing positioned in said guide aperture, said bushing including a bushing aperture defining a bushing aperture axis, said bushing aperture axis substantially collinear with said guide axis.  
   
   
       3 . The guide of  claim 2 , wherein one of said body and said bushing includes a projection and the other of said body and said bushing includes an alignment aperture, said projection positioned in said alignment aperture to substantially prevent relative rotation between said bushing and said body when said bushing is positioned in said guide aperture.  
   
   
       4 . The guide of  claim 1 , further comprising a bushing positioned in said guide aperture, said bushing including a bushing aperture defining a busing aperture axis, said bushing aperture axis substantially parallel to and eccentric with said guide axis.  
   
   
       5 . The guide of  claim 4 , wherein one of said body and said bushing includes a projection and the other of said body and said bushing includes an alignment aperture, said projection positioned in said alignment aperture to substantially prevent relative rotation between said bushing and said body when said bushing is positioned in said guide aperture.  
   
   
       6 . The guide of  claim 1 , said body further comprises a slot transverse to said guide aperture, said slot extending from said guide aperture through an outside surface of said body.  
   
   
       7 . A system for locating a position on a glenoid surface of a scapula, the scapula including an anterior surface, comprising: 
 a guide, comprising: 
 a body including a guide portion and a reference portion, said guide portion including an aperture, said guide portion configured to extend over the glenoid surface, said reference portion configured to extend over the anterior surface of the scapula; and  
 a bushing, said bushing positioned in said body aperture, said bushing including an aperture; and  
   a guide pin passable through said bushing aperture, said guide pin including an insertion end for engaging the glenoid surface and a shaft, wherein said bushing is removable from said body when said guide pin is positioned in said bushing aperture by passing said bushing along said shaft.    
   
   
       8 . The system of  claim 7 , wherein one of said body and said bushing includes a projection and the other of said body and said bushing includes an alignment aperture, said projection positioned in said alignment aperture to substantially prevent relative rotation between said bushing and said body when said bushing is positioned in said body aperture.  
   
   
       9 . The system of  claim 8 , wherein said alignment aperture is substantially concentric with said body aperture.  
   
   
       10 . The system of  claim 8 , wherein said alignment aperture is substantially parallel to and eccentric with said body aperture.  
   
   
       11 . The system of  claim 7 , wherein said body further comprises a slot transverse to said guide portion aperture, said slot extending from said guide portion aperture through an outside surface of said body.  
   
   
       12 . The system of  claim 7 , said reference portion including a projection extending from said body and wherein said bushing aperture defines a bushing aperture axis, said projection substantially located along said bushing aperture axis.