The continuity and integrity of normal human bone is very good, due to trauma or other reasons, the bone is damaged or missing, causing the loss of integrity, the structural integrity of the bone is destroyed, mainly due to trauma, infection, tumor, osteomyelitis surgical debridement, removal of bone tumors, arthroplasty after revision, and a variety of congenital diseases, in this case is called bone defects. The most important cause of bone defects is trauma, which causes fractures, and if the fracture is open, the localized fragments may fall into the surrounding space and cause bone defects.