Fibrous cortical defect, depending on the degree of defect can be treated without treatment, or take surgical treatment, as follows: 1. No treatment: If the local extent is relatively small, no special treatment is needed, as long as regular observation can be done. 2. Surgical treatment: If the fibrous cortical defect involves a larger extent, resulting in serious thinning of the bone cortex and the risk of fracture, or if the fibrous cortical defect involves the epiphysis, to be surgical treatment. The main method of surgical treatment is to remove the lesion and then perform a strong bone graft, which can also be fixed with plates and screws. It is important to remove as much pathological tissue and lesions as possible during surgery and to perform fluoroscopy, if necessary, to make sure that the lesions are completely removed. Thorough irrigation and local inactivation are also performed, and then the cavity is filled and fixed using autologous iliac bone tissue.