For patients who have been diagnosed with osteosarcoma, treatment is planned. If a chemotherapy regimen of three drugs given over five days is used, three courses of preoperative chemotherapy are required, which takes about two and a half months. Of course, this is only a preliminary plan, and if the tumor load is relatively high, four to five sessions of preoperative chemotherapy may be required. The criteria for determining the number of preoperative chemotherapy sessions is to perform X-rays and MRIs to assess the tumor condition. The most we have ever given a patient was seven times of preoperative chemotherapy before surgery was performed. Currently, limb-preserving surgery is the mainstream treatment method, and the rate of limb preservation can reach 90-95%. Of course, limb-preserving surgery requires very good preoperative chemotherapy and a relatively low expected postoperative recurrence rate. If the tumor volume reduction is not obvious after preoperative chemotherapy, or even the tumor continues to grow, or the patient is insensitive or intolerant to chemotherapy, the chemotherapy effect is not satisfactory, and the expected postoperative recurrence rate is relatively high, then consider life preservation as the main concern and recommend amputation surgery. Commonly used limb preservation surgeries include tumor-based prosthesis replacement, allogeneic bone graft, and autologous bone relocation. As for the choice of surgical procedure, the actual condition of the patient needs to be evaluated to decide. However, if the limb preservation surgery is done in a qualified manner, the function of the preserved limb is significantly stronger than that of the prosthesis, and it is basically possible to perform daily life.