Prosthesis with compressible stem

Abstract

A series of humeral stems, each stem including an axial bore and longitudinal slots along the distal end to allow for distal compression. The compression force necessary to compress the distal diameter of each stem varies by stem diameter. Thus, as the stem diameter increases through the series, the compression force decreases. The axial bore and longitudinal slots together form a series of stem segments that assume the shape of the medullary canal, reducing the force exerted upon the canal by the humeral stem.

What is claimed is:  
     
         1 . A prosthesis having a stem for insertion in the intramedullary canal of a bone, the stem having a distal end portion with an axial bore formed therein and a plurality of slots formed in the stem and extending generally parallel to the bore axis and extending generally radially therefrom to define a plurality of stem segments, each stem segment being capable of radial compression upon application of a compression force, the stem segments being odd in number to restrain segments on opposite sides of the bore from slipping past each other when compressed together.  
     
     
         2 . The prosthesis of  claim 1 , wherein the stem segments are positioned equiangularly about the bore axis.  
     
     
         3 . The prosthesis of  claim 1 , wherein the stem is manufactured of titanium.  
     
     
         4 . The prosthesis of  claim 1 , further comprising a groove provided along each stem segment for receiving adhesive.  
     
     
         5 . A stem for insertion in the intramedullary canal of a bone, the stem comprising: 
 a proximal end portion having an engagement structure provided thereon; and    a distal end portion having an axial bore and an odd number of slots extending proximally therefrom, at least three slots being provided,    a plurality of elongated, axially extending stem segments being defined by the slots in the distal end portion, the stem segments being configured to enable the stem to conform to the shape of the intramedullary canal of the bone;    each stem segment being capable of radial compression upon application of a compression force.    
     
     
         6 . The stem of  claim 5 , wherein the stem is manufactured of titanium.  
     
     
         7 . The stem of  claim 5 , further comprising a groove provided along each stem segment for receiving adhesive.  
     
     
         8 . A series of sized stems for insertion in the intramedullary canal of a bone, each stem comprising: 
 a proximal end portion having an engagement structure provided thereon; and    a distal end portion having an axial bore and an odd number of slots extending proximally therefrom, at least three slots being provided,    a plurality of elongated, axially extending stem segments being defined by the slots in the distal end portion, the stem segments being configured to enable the stem to conform to the shape of the intramedullary canal of the bone;    each stem of the series having a diameter, the diameter of the stems varying between stems;    each stem segment being capable of radial compression upon application of a compression force, the bore and slots of the series being sized and configured such that the compressive force needed to compress each of the segments decreases as the diameter of the stems increase.    
     
     
         9 . The series of  claim 8 , wherein the stems are manufactured of titanium.  
     
     
         10 . The series of  claim 8 , further comprising a groove provided along each stem segment for receiving adhesive.