Radiation and melt treated ultra high molecular weight polyethylene prosthetic devices

Abstract

A medical prosthesis for use within the body which is formed of radiation treated ultra high molecular weight polyethylene having substantially no detectable free radicals, is described. Preferred prostheses exhibit reduced production of particles from the prosthesis during wear of the prosthesis, and are substantially oxidation resistant. Methods of manufacture of such devices and material used therein are also provided.

1 . A medical prosthesis for use within the body, said prosthesis being formed of radiation treated ultra high molecular weight polyethylene having substantially no detectable free radicals.  
   
   
       2 - 123 . (canceled)  
   
   
       124 . An implantable bearing component made by the process comprising the steps of: 
 (a) crosslinking, by irradiation, a preformed polymer in its solid state;    (b) remelting the crosslinked polymer; and    (c) fashioning the implantable bearing component from the crosslinked and remelted polymer, wherein the polymer is selected from the group consisting of: polyester, poly(methylmethacrylate), nylon, polycarbonates, and polyhydrocarbons.    
   
   
       125 . The implantable bearing component of  claim 124 , wherein the polymer is crosslinked by gamma radiation at a dose of from about 1 to about 100 Mrad.  
   
   
       126 . The implantable bearing component of  claim 125 , wherein the gamma radiation dose is from about 4.5 to about 25 Mrad.  
   
   
       127 . The implantable bearing component of  claim 126 , wherein the gamma radiation dose is from about 4.5 to about 10 Mrad.  
   
   
       128 . The implantable bearing component of  claim 127 , wherein the implantable bearing component is for use in a joint prosthesis.  
   
   
       129 . The implantable bearing component of  claim 128 , wherein the joint prosthesis is selected from the group consisting of: hip, knee, ankle, elbow, jaw, shoulder, finger and spine joint prostheses.  
   
   
       130 . The implantable bearing component of  claim 129 , wherein the joint prosthesis is selected from the group consisting of: hip and knee joint prostheses.  
   
   
       131 . The implantable bearing component of  claim 124 , wherein the implantable bearing component is for use in a joint prosthesis.  
   
   
       132 . The implantable bearing component of  claim 124 , wherein the implantable bearing component is selected from the group consisting of: an acetabular cup, an insert of an acetabular cup, and a liner of an acetabular cup.  
   
   
       133 . A joint prosthesis comprising: 
 a first member adapted to be secured to a first bone constituting a first portion of a joint;    an articulating surface on the first member;    a second member adapted to be secured to a second bone constituting a second portion of the joint; and    the implantable bearing component of  claim 124 , said implantable bearing component being adapted for disposition between the second member and the articulating surface, said implantable bearing component being adapted to receive said articulating surface for movement therein.    
   
   
       134 . The joint prosthesis of  claim 133 , wherein the joint prosthesis is selected from the group consisting of: hip, knee, ankle, elbow, jaw, shoulder, finger and spine joint prostheses.  
   
   
       135 . The joint prosthesis of  claim 134 , wherein the joint prosthesis is selected from the group consisting of: hip and knee joint prostheses.  
   
   
       136 . The joint prosthesis of  claim 133 , wherein the joint prosthesis is for use in a hip joint replacement wherein: 
 (a) the first bone is a femur;    (b) the second bone is a pelvic bone;    (c) the first member is a prosthetic stem;    (d) the second member is a prosthetic acetabular shell;    (e) the articulating surface is a prosthetic femoral head; and    (f) the implantable bearing component is selected from the group consisting of: an acetabular cup liner and an acetabular cup insert.    
   
   
       137 . The joint prosthesis of  claim 133 , wherein said articulating surface and said first member are separate units.  
   
   
       138 . The joint prosthesis of  claim 133 , wherein the implantable bearing component is made of polyethylene.  
   
   
       139 . The joint prosthesis of  claim 136 , wherein the implantable bearing component is made of polyethylene.  
   
   
       140 . A joint prosthesis comprising: 
 a first member adapted to be secured to a first bone constituting a first portion of the joint;    an articulating surface on the first member;    the implantable bearing component of  claim 124  adapted to be secured to a second bone constituting a second portion of the joint, said implantable bearing component being adapted to receive said articulating surface for movement therein.