Which patients are suitable for limb-preserving surgery? With the development of reconstructive technology and the improvement of surgical skills and experience of orthopedic oncologists, limb-preserving treatment has become a mainstream trend in the surgical treatment of osteosarcoma. However, not all patients with osteosarcoma can choose limb-preserving surgery, and certain indications are required. For example, the implementation of limb-preserving surgery can be considered in cases where the tumor can reach the surgical margin without tumor residue and distant metastasis based on comprehensive assessment of imaging and other factors; it is estimated that the function after limb-preserving surgery should be stronger than the installation of prosthesis after amputation; the surgeon has rich experience, familiar with the principles of bone tumor surgical staging and resection, and has good reconstructive techniques and conditions; the body and economy can bear the high dose of preoperative and postoperative The surgeon should be physically and financially able to tolerate preoperative and postoperative high-dose chemotherapy, because preoperative neoadjuvant chemotherapy is a prerequisite for limb-preserving surgery; pathological fracture at diagnosis or during treatment is not a contraindication to limb-preserving treatment, provided that the tumor can be extensively resected. Age is also one of the factors affecting limb preservation surgery. Patients of young age, especially those with primary lower limbs, are not advocated for limb preservation because postoperative growth and development can cause limb inequality and affect the quality of survival. What are the current limb-sparing surgeries? There are many types of limb preservation surgeries reported in the literature, and the main methods currently used are artificial prosthesis replacement, autologous or (and) allogeneic bone grafting and tumor segment bone inactivation and reuse. What are the advantages and disadvantages of each type of limb preservation surgery? I. Artificial prosthesis replacement: It can achieve better early clinical results, restore the function of the affected limb immediately after surgery, with few early complications and no need to worry about fracture and non-healing, and is suitable for tumors around the proximal femur and knee joint. Tumors of the humeral head and proximal humerus have also been widely used. Conventional artificial prosthesis, special artificial prosthesis and combined prosthesis are commonly used. However, there are many problems with the material, design and process of domestic prosthesis, and it is difficult to popularize the imported prosthesis in China because of its high price. Moreover, most of the bone tumor patients are young patients, and if they can survive for a long time, their long term loosening and other problems should be considered. Second, autologous or (and) allogeneic bone and joint transplantation: including autologous fibula and clavicle transplantation with or without blood vessels, allogeneic large segment bone and bone and joint transplantation, is a biologically active arthroplasty, which can restore the continuity of bone and reconstruct the joint structure. The advantages of allogeneic bone grafts are the ability to restore bone volume and provide soft tissue attachment sites. Allogeneic bone has the advantages of wide source and convenient use, but the problems of rejection reaction, infectious toxic diseases and matching difficulties remain unsolved in China because the system of bone banking is not yet perfect. Tumor segment bone inactivation and reuse: The use of tumor segment bone for reconstruction can avoid allogeneic bone graft and artificial joint replacement and the complications caused by them. There are more domestic researches in this area, which can be broadly divided into two types: (1) in vitro inactivation and replantation: the tumor segment bone is truncated and the tumor cells are inactivated in vitro by alcohol, radiotherapy, freezing and boiling, and then the tumor segment bone is replanted and fixed in the original place; (2) in vivo in situ inactivation: after the tumor segment bone is exposed, the tumor segment bone is not truncated and kept in situ, and the tumor segment bone is inactivated by microwave and radiotherapy. (2) in situ inactivation: after the tumor segment bone is exposed, the tumor cells in the tumor segment bone are inactivated by microwave and radiotherapy without truncating the bone and keeping it in situ. The advantages of tumor segment bone reuse are: simple surgery, low cost, no need to consider bone matching, which is more suitable for China’s national conditions, especially for young patients with long survival time, and the inactivated tumor cells can play an immune role. The greatest shortcomings are the susceptibility to pathological fractures and difficulty in healing during the process of bone reparation.