A patient with juxtacortical osteosarcoma of the upper extremity of the left tibia which encased the popliteal neurovascular bundle was treated by monobloc resection of the superior extremity of the tibia and the tibial nerve. The knee joint was replaced by a Guepar prosthetic knee. Arterial and venous continuity was reestablished by a double bypass using the contralateral greater saphenous vein. One year later the patient had good lower limb function and was free of local or general disease. This observation confirms that preservation of lower limb function is possible using reconstruction techniques of bone, nerves, and vessels in sarcoma of the musculoskeletal system.