The knee is the most common location for malignant bony tumors as well as a number of soft-tissue sarcomas. The clinical presentation of these lesions usually involves pain and swelling, often associated with a palpable mass. This can occur rapidly or take a more indolent course. Proper evaluation and staging prior to biopsy of these tumors is necessary. This should be done by a surgeon experienced in the treatment of these tumors and at a facility where a multispecialty team can provide patient care. The primary surgical choices for treating malignant musculoskeletal tumors are limb salvage and amputation. One of the major difficulties in performing limb salvage about the knee is the lack of soft-tissue coverage after resection. Local or even free flaps are often necessary. Additionally, reattachment of the extensor mechanism is necessary. These problems and the use of allografts often lead to a high incidence of complications including infection, wound breakdown, allograft fracture, or extensor mechanism problems with resultant poor functional result.