Distal femur and proximal tibia are the main localization of primary malignant bone tumor. Osteosarcoma and Ewing sarcoma are the most frequent. New techniques in imaging, recent development in chemotherapy protocols and surgery sharpening led to major improvement in their management, which allowed to minimize amputation ratio. The complexity of their treatment and their rarity imply the involvement of multidisciplinary approach, in terms of both surgical and medical points of view. After resection, total knee arthroplasty has become the gold standard of reconstruction in such localizations. It uses press fit against healthy bone, thanks to long centromedullar stems, because of major soft tissues resection due to carcinologic surgery rules. The incision is usually antero-medial and the main difficulty is mostly linked to the care of vascular and nervous systems and the extensor apparatus. The conservation (or not) of the latter modifies the surgical technique. Articular invasion will impose to perform a one-piece-articular resection, which will complicate the conservation of the extensor apparatus. There are lots of different techniques and prosthesis. Arthrodesis indications are seldom because prosthesis reconstructions have made proof of their efficacy and their longevity. Functional and oncologic results of this excision and reconstructive surgery are now clearly established. However, this represents complex and risky interventions which will often lead to secondary surgical revision because of the young age of patients and their functional demands. This can only stress the necessity of addressing patients to specialized, network-organized sarcoma teams.