Last updated: 11/24/2009

Despite the increase in the number of procedures requiring bone grafts, there is no ideal bone graft substitute. However, there are a variety of natural and synthetic replacement materials used instead of bone, including collagen (the protein substance...

of the white fibers of the skin, bone, and connective tissue); polymers, such as silicone and some acrylics; hydroxyapatite; calcium sulfate; and ceramics. Several new products are available or in development. They function as bone graft substitutes or extenders. Demineralized bone matrix (bone that has had its calcium removed) possesses some of the properties that the body uses to induce bone formation. Calcium hydroxyappetite products or coral have structures similar to bone, and act as scaffolding for new bone.

New BMP products are expected to be strong inducers of bone growth (osteoinductive). These new products will be relatively expensive, but will grow bone better than the patient's own bone, eliminating the need for bone graft harvesting. Bone morphogenetic proteins have been extracted from natural tissues and produced in the laboratory to stimulate bone production in animals and humans. Because they do not have the same drawbacks as grafts, surgeons are hopeful that they will soon be able to use BMP and laboratory produced BMP to aid in the generation and repair of bone.

The INFUSE Bone Graft (rhBMP-2) has received Food and Drug Administration approval, and has demonstrated better patient outcomes than hip autografts with regard to length of surgery, blood loss, hospital stay, reoperation rate, median time to return to work, and fusion rates at six, 12, and 24 months following surgery.

Advances in tissue engineering have provided polymer based graft substitutes with degradable, porous, three-dimensional structure. New bone may be grown on these products; the grafts then slowly dissolve, leaving only the new bone behind.