The success of limb preservation treatment depends on a detailed preoperative treatment plan, which is based on advanced imaging, interventional science and other multidisciplinary approaches. The preoperative determination of the extent of tumor infiltration, tumor size, and peri-tumor anatomy is very important for limb-sparing surgery; Trommel et al. used MRI to determine the extent of tumor before surgery, and no local recurrence of tumor was observed in the follow-up cases. CT has the advantage of not overestimating the size of the tumor, while MRI can show areas of tissue edema. MRI has the advantage of showing the soft tissue involvement of the tumor and accurately reflects the relationship of the tumor to adjacent soft tissues, joints, and neurovascular bundles. The T1-weighted images of MRI provide a clear picture of the extent of intramedullary involvement, while the T2-weighted images provide an accurate picture of the soft tissue involvement around the tumor. Therefore, CT scan is a useful complement to MRI for patients with pelvic tumors. 99mTc bone scan can clarify whether there is any other skeletal destruction throughout the body. Frontal and lateral chest radiographs can detect pulmonary metastases in most cases, but CT of the lungs is more sensitive and has become the test of choice for definitive diagnosis of pulmonary metastases. In addition, impactology plays an important role in evaluating the effectiveness of preoperative chemotherapy. Preoperative assessment of chemotherapy efficacy in patients undergoing neoadjuvant chemotherapy can guide the choice of surgical approach and the development of postoperative chemotherapy regimens. Patients with poor response to preoperative chemotherapy should be treated with more extensive surgical borders during tumor resection, and in some cases, amputation is required; while patients with good response to chemotherapy show reduced pain and swelling, decreased alkaline phosphatase levels, healing of pathological fractures, etc. X-rays show increased calcification and ossification in the tumor tissue and significant peritumor sclerosis. If pathological fractures are present, they may heal in the presence of a good response to chemotherapy. Angiography can provide a more definite effect of chemotherapy, if the blood supply of tumor is reduced or disappeared, it indicates a high rate of tumor necrosis and a good response to chemotherapy. Biopsy After clinical history, systematic physical examination and imaging, biopsy of the lesion should be considered, but it is not always necessary in all cases. The first critical step in diagnosis and treatment is to clarify whether the lesion requires biopsy. Sometimes a combination of history, physical examination, imaging data and the experience of the bone tumor surgeon can avoid the corresponding risk by not requiring biopsy. If a biopsy is required, it should be performed by a surgeon with experience in biopsy. The main methods include puncture biopsy and excisional biopsy. The first technique is more commonly used in sarcoma biopsy and is usually performed under local anesthesia. It is a quicker operation and can be performed in a general ward, but care should be taken to choose the location of the access needle before the operation, avoiding the major vascular nerves and the intervening compartments that are not invaded. All puncture biopsy access and incisional biopsy access must be removed during the subsequent procedure. The biopsy procedure can cause bleeding, so it is important to avoid bleeding during the biopsy that may cause tumor spread into the surrounding tissue and around the access. According to Mankin et al, biopsy of malignant bone tumors performed by non-specialists has a significant negative impact on treatment by increasing amputation rates and decreasing survival rates. Because post-biopsy examinations often reveal extensive hematoma formation and often contaminate previously uninvaded structures, if the hematoma formation is too large, complete resection is often not guaranteed and additional radiation therapy to the hematoma area is required. Surgical staging The most widely used staging system for tumors of the bone and soft tissue system is the surgical staging system first proposed by Enneking in 1980 and subsequently supplemented and revised in 1986. This system is used only for staging primary benign and malignant tumors of bone and soft tissue, but not for small round cell lesions such as leukemia, lymphoma, myeloma, Ewing sarcoma, and metastatic lesions. Malignant lesions are 30% stage I, 60% stage II, and 10% stage III. 60% of stage I lesions are intra-interstitial and 33% are extra-interstitial, and 60% of stage II lesions are extra-interstitial and 33% are intra-interstitial.