Pyrolytic Carbon Implants With Porous Fixation Component And Methods Of Making The Same

Abstract

An orthopedic implant including an articulation portion having a pyrolytic carbon bearing surface and a porous bone on- or in-growth structure, and methods of making the same.

1 . An orthopedic implant, comprising:
 an articulation portion having a pyrolytic carbon bearing surface; and   a bone-fixation portion extending from the articulation portion and having a porous structure configured for bone on-growth or bone in-growth.   
     
     
         2 . The implant of  claim 1  wherein the articulation portion further includes a substrate and the bone-fixation portion is bonded to the substrate. 
     
     
         3 . The implant of  claim 2  further including a metal interlayer positioned at least partially between the bone-fixation portion and the substrate. 
     
     
         4 . The implant of  claim 3  wherein the metal interlayer and the bone-fixation portion are comprised of the same metal material. 
     
     
         5 . The implant of  claim 3  wherein the interlayer is comprised of a first metal and the bone fixation portion is comprised of a second metal, and the first metal is soluble with the second metal. 
     
     
         6 . The implant of  claim 3  further including a metal outer layer at least partially covering the bone fixation portion and the interlayer, wherein the interlayer and metal outer layer bond the bone fixation portion to the substrate. 
     
     
         7 . The implant of  claim 1  wherein the bone fixation portion is comprised of porous tantalum. 
     
     
         8 . The implant of  claim 2  wherein the substrate is comprised of isotropic graphite. 
     
     
         9 . A method of forming an orthopedic implant, comprising:
 providing a carbon member having an articulation portion and a bone fixation portion with a porous region;   applying a layer of pyrolytic carbon on an outer surface of the articulation portion;   applying a metal coating to the porous region of the bone fixation portion.   
     
     
         10 . The method of  claim 9  in which the metal coating is selected from the group consisting of tantalum, titanium, niobium or alloys or combinations thereof. 
     
     
         11 . The method of  claim 9  wherein the pyrolytic carbon is applied by chemical vapor deposition. 
     
     
         12 . A method of forming an orthopedic implant, comprising:
 providing a substrate having a first surface and a second surface;   applying a layer of pyrolytic carbon to the first surface of the substrate;   placing an interlayer comprising a metal between the second surface of the substrate and a porous metal structure; and   bonding the porous metal structure and the substrate together to form the orthopedic implant.   
     
     
         13 . The method of  claim 12  wherein the bonding comprises applying heat and pressure to the substrate, interlayer and porous metal structure for sufficient time to achieve solid-state diffusion between the interlayer and the porous metal structure. 
     
     
         14 . The method of  claim 12  wherein one of the porous metal structure and the interlayer is comprised of tantalum and the other is comprised of titanium. 
     
     
         15 . The method of  claim 12  wherein the interlayer is applied to the second surface of the substrate by chemical vapor deposition. 
     
     
         16 . The method of  claim 12  wherein the pyrolytic carbon is applied by chemical vapor deposition. 
     
     
         17 . A method of forming an orthopedic implant, comprising:
 applying a layer of pyrolytic carbon to a first surface of a substrate;   applying a metal interlayer to a second surface of the substrate;   contacting a porous metal structure with the metal interlayer; and   applying a second outer layer of metal to the substrate, interlayer and porous metal structure.   
     
     
         18 . The method of  claim 17  in which the metal interlayer, metal outer layer and porous metal structure all comprise the same metal. 
     
     
         19 . The method of  claim 18  in which the metal is selected from the group consisting of titanium, tantalum, niobium or alloys or combination of the same. 
     
     
         20 . The method of  claim 17  in which the pyrolytic carbon is applied to the substrate by chemical vapor deposition. 
     
     
         21 . The method of  claim 17  in which the metal interlayer is applied to the substrate by chemical vapor deposition. 
     
     
         22 . The method of  claim 17  in which the metal outer layer is applied by chemical vapor deposition. 
     
     
         23 . A method of forming an orthopedic implant, comprising:
 applying a layer of pyrolytic carbon to a first surface of a substrate;   applying an interlayer comprised of a metal to a second surface of the substrate;   providing a porous metal structure;   placing a metal foil between the interlayer and the porous metal structure; and   diffusion bonding the porous metal structure, the metal foil and the interlayer.