The issue of utilizing a temporary cement spacer after a knee resection arthrodesis of a highly malignant bone tumor is discussed. In our experience, this is the first type of reconstruction performed in the early days of the limb salvage. Now, after more than 12 years of follow-up based on the results of 84 patients, the usefulness and mechanical performance of this type of reconstruction are considered. Of these patients, 45 died of disease. Wound complications were present in 31% of the patients and led to amputation in 7 and healing failure in 6. Mechanical complications occurred in 39%, but radiographic analysis of the implant showed 32 cases (38%) with an inadequate spacer. Only 9 patients are still walking on the original reconstruction, 6 of them uncomplicated (the remaining 3 had rod migrations and shortening). The survival curve showed no statistical difference between the two groups (adequate vs inadequate spacer). In 33 patients who are still alive and retain their limb, the final functional results were excellent in 6, good in 8, fair in 14, and poor in 5. This type of reconstruction can still be considered in developing countries, or when a definitive arthrodesis is planned where there is a lack of a bone source (children, no bone bank). In our institution, reconstruction with cement is still suggested for patients with a large tumor around the knee, when the quadriceps is completely sacrificed, and the patient prognosis is markedly unfavorable.