Glenoid anchor for a shoulder joint prosthesis

Abstract

A glenoid anchor for a shoulder joint prosthesis, fixed to a glenoid cavity of a shoulder blade. The glenoid anchor consists only of a structurally independent pin, with an internally hollow conical sleeve, which has a tapered distal end configured for being directly fixed to the glenoid cavity and an open proximal end configured for being removably attached to a prosthesis component. The prosthesis component is a lug of either one of an anatomical prosthesis or a reverse prosthesis. The glenoid anchor is configured for removal of said lug in order to convert the anatomical prosthesis to the reverse prosthesis or vice-versa, while keeping the structurally independent pin inside the glenoid cavity. An outer surface of the sleeve of said pin has a trabecular structure for favouring osteogenesis and bone integration. The pin further comprises an annular recess formed inside an internal cavity of the pin, for receiving by means of mechanical interference an edge of the lug of the prosthesis component, substantially locking the lug inside the internal cavity.

1 . A glenoid anchor for a shoulder joint prosthesis, of the type intended to be fixed to a glenoid cavity of a shoulder blade,
 wherein the glenoid anchor consists only of a structurally independent pin, with an internally hollow conical sleeve, which has a tapered distal end configured for being directly fixed to the glenoid cavity and an open proximal end configured for being removably attached to a prosthesis component,   wherein said prosthesis component is a lug of either one of an anatomical prosthesis or a reverse prosthesis,   wherein said glenoid anchor is configured for removal of said lug in order to convert the anatomical prosthesis to the reverse prosthesis or vice-versa, while keeping the structurally independent pin inside the glenoid cavity,   wherein an outer surface of the sleeve of said pin has a trabecular structure for favouring osteogenesis and bone integration;   wherein said pin further comprises an annular recess formed inside an internal cavity of the pin, for receiving by means of mechanical interference an edge of the lug of the prosthesis component, substantially locking the lug inside the internal cavity.   
     
     
         2 . The anchor according to  claim 1 , further comprising notches formed in the vicinity of a mouth of the internal cavity for engagement with teeth at a base of the lug by coming into respective bearing contact. 
     
     
         3 . The anchor according to  claim 2 , wherein said notches are anti-rotation notches inside the internal cavity configured to receive the corresponding teeth which are arranged with regular spacing on the base of the lug. 
     
     
         4 . The anchor according to  claim 1 , further comprising at least one pair of oppositely arranged anti-rotation notches in the proximity of said annular recess for receiving oppositely arranged teeth of the same lug intended to be engaged together with said pin. 
     
     
         5 . The anchor according to  claim 1 , wherein said annular recess is configured for receiving by means of snap-engagement an edge of said lug. 
     
     
         6 . The anchor according to  claim 1 , comprising a conical coupling with controlled mechanical interference between the conical lug of a bearing flange and the internal cavity of the pin. 
     
     
         7 . The anchor according to  claim 1 , wherein a surface of said internal cavity of the pin and an outer surface of said lug of the prosthesis component are engaged with each other by means of mechanical interference. 
     
     
         8 . The anchor according to  claim 7 , wherein the surface of the internal cavity of the pin is inclined with respect to the longitudinal axis of said pin at a predefined angle with a reduction in an internal diameter towards the distal end of the pin, while the outer surface of the lug of the prosthesis component is inclined with respect to the same longitudinal axis at an angle smaller than said predefined angle. 
     
     
         9 . The anchor according to  claim 1 , wherein the distal end of said pin is provided with a threaded through-hole for receiving a securing screw of the shoulder joint prosthesis. 
     
     
         10 . The anchor according to  claim 1 , wherein the prosthesis component is structurally independent of said pin. 
     
     
         11 . The anchor according to  claim 1 , wherein the proximal end of the pin defines a flared proximal opening which allows access to the internal cavity. 
     
     
         12 . The anchor according to  claim 11 , wherein a narrower diameter is provided adjacent to the flared proximal opening, inside the internal cavity of the pin, said narrower diameter defining an edge or internal step for seating, in bearing contact, a surface of said lug of the prosthesis component. 
     
     
         13 . The anchor according to  claim 1 , wherein said prosthesis component is structurally independent of said pin and is made of a different material. 
     
     
         14 . The anchor according to  claim 13 , wherein said prosthesis component comprises a portion situated opposite said lug and intended to be engaged with a shoulder-blade component of a reverse prosthesis provided with a convex articular surface. 
     
     
         15 . The anchor according to  claim 14 , wherein the shoulder-blade component of the reverse prosthesis is associated with said prosthesis component by means of a screw engaging inside a threaded hole formed in the distal end of the pin.