Xiao Li (pseudonym) was diagnosed with osteosarcoma of the left femur in our hospital 10 years ago. After neoadjuvant chemotherapy, he underwent limb-sparing surgery. After surgery, the patient’s limbs functioned well, and he could take care of himself and walk without any obstacles. However, the disease was relentless. 8 years ago, Xiao Li had obvious pain in the affected knee joint, and the X-ray examination indicated that the bone around the artificial prosthesis was resorbed significantly. However, 6 months ago, the patient again developed pain in the affected knee joint with significant limitation of movement, and X-ray examination suggested that the knee prosthesis was fractured, making limb preservation surgery difficult. According to tradition, this patient could only undergo amputation at this time, but our department boldly innovated the treatment concept, cleverly improved the artificial prosthesis, and gave the patient limb-preserving surgery, which eventually preserved the patient’s limb function. Osteosarcoma is one of the common malignant bone tumors around the knee joint, mostly occurring in adolescents, and its incidence ranks first among primary bone tumors. Amputation surgery was the standard treatment for osteosarcoma before the 1970s, but this surgery has a great impact on the limb function of the patient and brings immeasurable psychological damage, and the survival rate within 5 years is also low. With the rapid development of medical technology, surgery, chemotherapy drugs and adjuvant radiotherapy have made great progress, and limb preservation therapy has gradually become the main treatment method for osteosarcoma, especially neoadjuvant chemotherapy combined with limb preservation surgery has achieved great success in clinical practice, eliminating the pain of amputation and increasing the survival rate to more than 80% within 5 years. For the treatment of peri-knee osteosarcoma, with the improvement of medical technology, limb-preserving treatment has now become a trend, and more than 90% of patients can successfully preserve their limbs. The current limb preservation surgical treatment methods include: 1) resection of tumor segment combined with joint fusion 2) autologous or allogeneic bone grafting 3) inactivation of tumor segment bone reimplantation 4) rotational molding 5) artificial prosthesis replacement, among which the function of the affected limb can be quickly restored after artificial prosthesis replacement, which is more widely used in hip and knee joints and has better results.