Prosthetic element

Abstract

A removable prosthetic element having an elongated stem with a smooth outer surface, a portion of which defines, when the element is implanted in a subject, a contact interface between the stem and surrounding bone and/or fibrous tissue. One or more longitudinal guide channels in the form of longitudinal circular bores are located to the interior of the outer surface of the stem, the bore being adapted for receiving and laterally retaining a drill bit. One or more anchoring cavities comprising pores or passages having an opening with a distal perimeter at the outer surface of the stem lead to a longitudinal guide channel. At least a portion of the distal perimeter is formed as a sharp or pointed cutting edge that cuts the ingrown tissue upon upward removal of the element.

1 . A removable prosthetic element comprising
 an elongated stem having a smooth outer surface, a portion of which defines, when the element is implanted in a subject, a contact interface between the stem and surrounding bone and/or fibrous tissue;   one or more longitudinal guide channels located to the interior of the outer surface of the stem, each of said channel or channels comprising a longitudinal circular bore arranged in the interior of the stem, the bore being adapted for receiving and laterally retaining a drill bit; and   one or more anchoring cavities comprising pores or passages having openings with a distal perimeter at the outer surface of the stem and leading to a longitudinal guide channel, wherein at least a portion of said a distal perimeter comprises a sharp or pointed cutting edge.   
     
     
         2 . A removable prosthetic element according to  claim 1 , wherein the size of the openings of the anchoring cavities are chosen so as to hinder the ingrowth of bone tissue yet permit the ingrowth of fibrous tissue. 
     
     
         3 . A removable prosthetic element according to  claim 2  wherein the openings have a diameter of less than 0.1 mm. 
     
     
         4 . A removable prosthetic element according to any one of  claims 1 - 3 , wherein the sharp or pointed cutting edges are arranged at portion of the openings opposite an intended direction of removal, and are adapted for severing ingrown tissue upon removal of the prosthetic element in said direction. 
     
     
         5 . A removable prosthetic element according to  claim 4 , wherein the sharp or pointed portions of the distal perimeters are formed by arranging at least a portion of each of the anchoring cavities at an oblique angle with respect to the outer surface of the stem. 
     
     
         6 . A method for the removal of a previously implanted prosthetic element of the type according to  claim 4 , comprising:
 surgically gaining access to an end of the guide channels,   passing a drill bit along the guide channels,   withdrawing the prosthetic element with sufficient force such that the sharp or pointed edges of the anchoring cavities sever the ingrown tissue entering into the anchoring cavities, thus allowing removal of the prosthetic element.