Bone grafting is a surgical procedure by which new bone or a replacement material is placed into spaces between or around broken bone (fractures) or holes in bone. Bone grafting is used to repair bone fractures that are extremely complex, pose significant risk to the patient, or fail to heal properly. Bone grafts are also used to help fusion between vertebrae, correct deformities, or provide structural support for fractures of the spine. In addition to fracture repair, bone grafts are used to repair defects in bone caused by birth defects, traumatic injury, or surgery for bone cancer.

Bone is composed of a matrix, mainly made up of a protein called collagen. It is strengthened by deposits of calcium and phosphate salts, called hydroxyapatite. Within and around this matrix are four types of bone cells. Osteoblasts produce the bone matrix. Osteocytes are mature osteoblasts and maintain the...