Synthetic bone grafts constructed from carbon foam materials

Abstract

A porous, self-sustaining body useful as a scaffold for bone grafting is provided. The scaffold comprises a carbonaceous matrix comprising a continuous phase having a surface and defining a plurality of open spaces throughout the matrix. The internal and external surfaces of the matrix are coated with a layer or film selected from the group consisting of osteogenic materials, therapeutic agents, and combinations thereof. The porous body comprises organic materials and is substantially free of metals. Methods of making and using the porous self-sustaining body are also provided, along with kits for facilitating the same.

We claim: 
     
         1 . An implant for bone grafting in a subject comprising a porous self-sustaining body comprising:
 a carbonaceous matrix formed of carbon foam and/or graphite foam, said matrix comprising a continuous phase having a surface and defining a plurality of open spaces throughout said matrix, wherein said open spaces comprise pores in said matrix, and   a coating immobilized on the continuous phase surface of the matrix, said coating being selected from the group consisting of osteoconductive materials, osteoinductive materials, biologics, small molecule drugs, and combinations thereof;   wherein said porous body is substantially free of metal structures or supports in, on, or through the body.   
     
     
         2 . The implant of  claim 1 , wherein said metal is selected from the group consisting of titanium, titanium alloys, steel, tantalum, copper, silver, and cobalt chromium alloy. 
     
     
         3 . The implant of  claim 1 , wherein said porous body is substantially free of polypropylene, polymethylmethacrylate, polyethylene, and/or polyoxymethylene. 
     
     
         4 . The implant of  claim 1 , wherein said carbon or graphite foam has a porosity of at least about 80%. 
     
     
         5 . The implant of  claim 1 , wherein said carbon or graphite foam has an average pore diameter of at least 50 μm. 
     
     
         6 . The implant of  claim 1 , wherein said carbon or graphite foam has a pore density of at least about 50 PPI. 
     
     
         7 . The implant of  claim 1 , wherein said porous, self-sustaining body has an ultimate compressive stress of from about 0.2 to about 15 MPa. 
     
     
         8 . The implant of  claim 1 , wherein said porous, self-sustaining body is readily shapeable. 
     
     
         9 . The implant of  claim 1 , wherein said porous body contains less than 1% by weight inorganic materials, based upon the total weight of the body taken as 100% by weight. 
     
     
         10 . The implant of  claim 1 , wherein at least about 75% of said continuous phase surface is covered by said coating. 
     
     
         11 . The implant of  claim 1 , wherein said coating is not covalently or chemically bonded to said continuous phase surface. 
     
     
         12 . The implant of  claim 1 , wherein said coating comprises at least one material selected from the group consisting of allogenic or autogenic bone fragments, calcium phosphate, hydroxyapatite, coralline, sintered bone, and porous polycaprolactone. 
     
     
         13 . The implant of  claim 1 , wherein said coating comprises at least one material selected from the group consisting of vancomycin, tobramycin, gentamicin, COX-1, COX-2, steroidal anti-inflammatories, conjugated heparin, and warfarin. 
     
     
         14 . The implant of  claim 1 , wherein said coating comprises at least one material selected from the group consisting of collagen, albumin, bone morphogenetic proteins, epithelial growth factors, recombinant human cytokines, estrogen, lamellen, monoclonal antibodies, immunoglobulins, fusion proteins, stem cells, osteoblasts, osteocytes, chondrocytes, subcellular fractions, tissues, whole blood, plasma, fibrin, fibrinogen, vitronectin, platelet rich plasma, plasma components, enzymes, DNA, and cDNA. 
     
     
         15 . The implant of  claim 1 , wherein said porous body consists essentially of said carbonaceous matrix and said coating. 
     
     
         16 . A method of repairing or replacing in a subject a bone void having a given size and shape comprising:
 providing an implant according to  claim 1 , said implant having an initial size and shape;   shaping said implant to yield a shaped implant having a second size and shape that substantially fits said bone void size and shape; and   implanting said shaped implant into said subject, said implanting comprising fitting said shaped implant into said bone void, and optionally further shaping said implant after said fitting.   
     
     
         17 . The method of  claim 16 , wherein said shaping is selected from the group consisting of cutting, carving, shaving, slicing, grinding, boring, sanding, and combinations thereof to change the shape and size of said implant. 
     
     
         18 . The method of  claim 16 , wherein said bone void is in a limb of said subject, wherein said subject returns to reduced ambulatory weight-bearing within less than about 4 days after said implanting. 
     
     
         19 . The method of  claim 16 , wherein said implant is at least about 75% resorbed about 6 weeks after said implanting, said implant being displaced by new bone growth in said subject. 
     
     
         20 . The method of  claim 16 , wherein said implanting further comprises fixing said implant in said bone void using pins, screws, friction-fit engagement, sutures, adhesives, wires, cables, and combinations thereof.