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 - 123 . Canceled.  
   
   
       124 . A method for fabricating an orthopedic implant prosthesis bearing, comprising the steps of: 
 a) pre-annealing a polyethylene preform at a temperature greater than ambient temperature and less than the decomposition temperature of the polyethylene for a period of time greater than about 30 minutes;    b) irradiating the polyethylene preform to crosslink the polyethylene preform; and quenching residual free radicals in the polyethylene preform.    
   
   
       125 . The method of  claim 124 , further comprising the steps of: 
 a) cooling the preform after the quenching step to a temperature below the melting temperature of the polyethylene; and    b) forming the preform into a prosthetic bearing.    
   
   
       126 . A method for fabricating an orthopaedic implant prosthesis bearing comprising the steps of: 
 a) pre-annealing an ultrahigh molecular weight polyethylene preform;    b) irradiating the ultrahigh molecular weight polyethylene preform to crosslink the ultrahigh molecular weight polyethylene preform;    c) quenching residual free radicals in the ultrahigh molecular weight polyethylene preform subsequent to the irradiating step; and    d) forming the ultrahigh molecular weight polyethylene preform into a prosthetic bearing.    
   
   
       127 . A method for fabricating an orthopaedic implant prosthesis bearing comprising the steps of: 
 a) pre-annealing a polyethylene preform;    b) irradiating the polyethylene preform to crosslink the polyethylene preform;    c) quenching residual free radicals in the polyethylene preform subsequent to the irradiating step; and    d) forming the polyethylene preform into a prosthetic bearing.