Mobile knee reconstructions after resection of malignant tumors of the distal femur. Limb-salvage surgery involving mobile knee reconstructions for malignant tumors about the distal femur is a desirable and achievable goal. With limb salvage, the survival rate does not decrease significantly, and the resulting function is superior to when an amputation plus a prosthesis are used. Immediate and delayed morbidity is greater after limb-salvage surgery than after amputation. However, with thorough preoperative planning, use of neoadjuvant chemotherapy as indicated, and an experienced team of surgeons, limb-salvage surgery can provide a mobile knee with excellent function in the vast majority of cases for patients with malignant tumors of the distal femur. 