Bone grafting is a surgery that is used to fix problems in the bones. Sometimes bones may break, get infected, or need to be replaced, and bone grafting helps put the bones back together again. In the surgery, new bone is taken from another part of the body (or sometimes from a donor) and is then placed into the part of the bone that needs to be fixed. The new bone graft helps the bones heal and grow back together again, just like putting together a puzzle.