A bone graft transplants bone tissue. Surgeons use bone grafts to repair and rebuild diseased bones in your hips, knees, spine, and sometimes other bones and joints. Grafts can also repair bone loss caused by some types of fractures (broken bones) or cancers. Once your body accepts the bone graft, it provides a framework for growth of new, living bone.

If the transplanted bone comes from another person, it is called an allograft. Most allograft bone comes from donors who have died. Tissue banks screen these donors and disinfect and test the donated bone to make sure it is safe to use. If the transplanted bone comes from another part of your own body, it is called an autograft. Autograft bone often comes from your ribs, hips or a leg.

A graft in which the replacement bone came from another person. There are several types of allografts:

• Fresh or fresh-frozen
• Freeze-dried
• Demineralized freeze-dried

The terminology of bone transplantation is complicated by the various histologic types of bone grafts. A graft moved from one site to another within the same individual is an autograft; the corresponding adjective is autologous or autogenous. An allograft (adjective, allogeneic) is tissue transferred between two genetically different individuals of the same species. A xenograft (adjective, xenogeneic) is tissue from one species implanted into a member of a different species.

Freeze-dried bone allograft (FDBA) and demineralized freeze-dried bone allograft (DFDBA) materials are widely used in periodontal therapy, and there are no reports of disease transmission during the 30-year history of using FDBA. Although four cases HIV infection were linked to procedures using fresh-frozen bone allografts, these cases involved surgeries of the spine, hip, and knee; fresh-frozen and fresh allografts are not typically used in periodontal therapy. Also, when using FDBA and DFDBA, the delay in processing ensures adequate time for testing for potential pathogens.

Most bone banks adhere to American Association of Tissue Banks (AATB) guidelines to procure, process, and sterilize bone grafts. The AATB advocates excluding collection of bone under the following circumstances:

• Donors from high-risk groups, as determined by medical testing and behavioral risk assessments
• Donors test positive for HIV antibody by ELISA
• Autopsy of donor reveals occult disease
• Donor bone tests positive for bacterial contamination
• Donor and bone test positive for hepatitis B surface antigen or hepatitis C virus
• Donor tests positive for syphilis

Because of donor exclusion criteria, the chance of getting a bone graft from an HIV-infected donor is negligible. These criteria, combined with recommended processing procedures (harvesting in a sterile manner, repeated washings, immersion in ethanol, freezing in liquid nitrogen, freeze-drying, demineralization, and vacuum sealing), render DFDBA and FDBA grafts safe for human implantation.