What is an autologous bone graft? During surgery, normal bone tissue is often removed from other parts of the patient’s body to help heal the bone discontinuity. The autologous iliac bone is the most commonly used bone graft due to the superficial nature of the site and the high concentration of osteoblasts and growth factors. The cancellous bone within it can be used to fill the broken ends of the bone, and the cortical iliac bone block can also be used as a structural support for the bone graft. Sometimes, some bone flaps or bone segments with blood vessels can also be used as autologous bone graft material in order to provide bone healing. Autologous bone grafting mostly results in good osteogenesis and is regarded as the “gold standard” of bone grafting. However, its shortcomings are also obvious: 1) the normal bone tissue is sacrificed at the expense of the body, i.e., the east wall is torn down to make up for the west wall; 2) it can cause side damage such as pain, structural and functional impairment to the bone extraction site; 3) the amount of bone is limited and cannot be used indefinitely, and it is not suitable for the elderly with osteoporosis and children with underdeveloped bones. What is allogeneic bone graft Due to the insurmountable deficiencies of autologous bone graft, allogeneic bone graft was born. As the name implies, allogeneic bone grafting is a form of treatment in which a bone component is obtained from another person (usually cadaveric bone) and implanted into the patient. Allogeneic bone grafting avoids the need to remove bone from the patient’s own body and reduces the patient’s pain. As with traditional autologous bone grafts, allograft bone grafts can provide support at the site of bone discontinuity. Over time, the allograft bone is replaced with autologous bone. The greatest advantage is that the allograft bone can be selected as a replacement for the same area based on the characteristics of the injured site, maximizing the effectiveness of the grafted bone. The disadvantage is that there is a degree of risk of rejection and infection with potentially infectious diseases, for which deantigenization and sterilization are usually required. Can allogeneic bone be used? Allogeneic bone is bone of animal origin. Compared to autologous bone and allogeneic bone, allogeneic bone is also a natural mineral/collagen complex. Therefore, allogeneic bone can also be used as bone graft material if properly treated. The most commonly used allogeneic bone grafts are mostly derived from bovine and coral bone. Of course, the greatest risk of allogeneic bone grafts is the transmission of zoonotic diseases, such as mad cow disease. For this reason, the handling and approval of allogeneic bone materials are quite demanding and cautious. Bone graft substitutes, bone biomaterials To overcome the shortcomings of autologous, allogeneic or xenograft bone grafts, bone graft substitutes (bone biomaterials, etc.) have begun to be used for the treatment of bone discontinuities. Although bone graft substitutes do not provide the fresh bone cells needed for normal bone healing, they can provide the support signals needed for bone growth, such as mechanical stimulation and structural stimulation. Also, bone graft substitutes can provide scaffolding for autologous new bone growth. When constructing bone graft substitutes in vitro, growth factors or autologous cells can be simultaneously compounded on them to enhance bone repair. Because a bone graft (or bone graft substitute) cannot provide stability for a fracture alone unless the discontinuity itself is relatively stable, the use of internal or external fixation to improve the stability of the discontinuity is essential. Depending on the type of bone discontinuity, the broken end may also be properly treated with debridement and marrow expansion prior to bone grafting.