COMPOSITE MATRICES DESIGNED FOR ENHANCED BONE REPAIR
Osteoconductive synthetic bone grafts are provided in which porous ceramic granules are embedded in a biocompatible matrix material. The grafts, which may also include one or more of a coating, a reinforcing bio-absorbable mesh, and an osteoinductive protein or peptide, are generally porous and may incorporate fenestrations.
1 . A biocompatible implant, comprising:
a matrix comprising cross-linked rhCollagen derived from a plant, said matrix having a density of 10-20 mg rhCollagen per cubic centimeter of the matrix and including a plurality of interconnected pores having a mean cross-sectional dimension between 100 and 300 microns;
a plurality of porous, calcium ceramic granules embedded within the matrix at a ratio of 150-310 milligrams of granules per cubic centimeter of matrix;
a bioresorbable polymer mesh within said matrix; and
a coating comprising rhCollagen and at least partially covering said matrix.
2 . The implant of claim 1 , wherein said matrix includes a plurality of fenestrations.
3 . The implant of claim 2 , wherein each fenestration of the plurality of fenestrations has a mean cross sectional dimension of 1-2 mm.
4 . The implant of claim 3 , wherein at least some of said plurality of fenestrations extend through a thickness of said matrix.
5 . The implant of claim 1 , further comprising a bone morphogenetic protein.
6 . The implant of claim 5 , wherein said bone morphogenetic protein is associated with said granules.
7 . The implant of claim 1 , wherein said granules have an average size within the range of 425 to 800 microns.
8 . The implant of claim 1 , wherein said mesh comprises a plurality of resorbable polymer fibers arranged in a yarn, and said yarn is fabricated into said mesh.
9 . The implant of claim 8 , wherein said mesh is characterized by openings with an average size of 1-2 millimeters.
10 . The implant of claim 9 , wherein said resorbable polymer comprises PGLA.
11 . The implant of claim 1 , wherein said calcium ceramic granules comprise calcium deficit hydroxyapatite.
12 . A method of making a biocompatible implant, comprising the steps of:
forming a solution comprising cross-linked rhCollagen and a plurality of calcium ceramic granules;
transferring at least a portion of said solution within a mold to form a first slurry layer;
placing a bioresorbable polymer mesh onto said first slurry layer;
transferring at least a portion of said solution within the mold to form a second slurry layer and a preform comprising the first slurry layer, the bioresorbable polymer mesh, and the second slurry layer;
lyophilizing the preform;
contacting the preform with a coating material comprising rhCollagen, thereby at least partially coating the preform; and
lyophilizing the at least partially coated preform.
13 . The method of claim 12 , wherein the mold includes a plurality of protrusions.
14 . The method of claim 12 , further comprising the step of cross-linking the preform before said step of contacting the preform with a coating material.
15 . The method of claim 14 , wherein said step of cross-linking comprises soaking said preform with 1-[3-(Dimethylamino) propyl]-3-ethylcarbodiimide.
16 . A kit comprising the implant of claim 1 .
17 . The kit of claim 16 , further comprising a container of lyophilized osteoinductive protein.
18 . A method of treating a patient, comprising the steps of:
contacting a bony tissue of the patient with a biocompatible implant, said implant comprising:
a matrix comprising cross-linked rhCollagen derived from a plant, said matrix having a density of 10-20 mg rhCollagen per cubic centimeter of matrix and including a plurality of interconnected pores having a mean cross-sectional dimension between 100 and 300 microns;
a plurality of porous, calcium ceramic granules embedded within the matrix at a ratio of 150-250 mg granules per cubic centimeter of matrix;
a bioresorbable polymer mesh within said matrix;
a coating comprising rhCollagen and at least partially covering said matrix; and
and an osteoinductive protein associated with the plurality of calcium ceramic granules.
19 . The method of claim 18 , wherein the protein-loaded biocompatible implant includes a plurality of fenestrations.
20 . The method of claim 19 , wherein each of the plurality of fenestrations has a mean cross sectional dimension of between 1-2 mm.
21 . The implant of claim 18 , wherein said granules have an average size within the range of 425 to 800 microns.
22 . The implant of claim 18 , wherein said mesh comprises poly-glycolide-co-lactide.
23 . The implant of claim 18 , wherein said calcium ceramic granules comprise calcium deficit hydroxyapatite.