In order to understand the role and efficacy of vascularized fibular graft and massive allograft in reconstruction of the knee, we have analyzed and review 25 patients of primary malignant bone tumours within 5 cm around the knee, that were managed primarily by this technique. In 4 patients the distal femur was affected while the proximal tibia was affected in 21 patients. There were 16 male and 9 female with an average age at the time of surgery of 19.7 years (range; 5 to 52), 17 patients (68%) were skeletally immature. The pathology was mostly represented by Osteosarcoma and Ewing sarcoma (15) and 18 patients (72%) received pre-operative chemotherapy. The resection of the tumor was transepiphyseal in 13 patients (52%) and intercalary in 12 patients (48%). The method of reconstruction was mainly concentric (allograft and fibula inside in 22 patients, 88%), while fixation was done principally by diaphyseal plate and metaphyseal screws (14 patients, 56%). Only three flaps failed (12%) detected by postoperative bone scan and confirmed by the clinical follow up. Twelve patients (48%) had 17 local complications (68%). Management of these complications succeeded to control them in nine patients (75%). The average time of union of fibula was 5.6 month (range: 3–10). The average time of union of allograft was 19.6 month (range: 10–34). All allograft united primarily (92%) except two cases; one case required bone graft and re-platting at 13 month postoperative after implant failure to achieve union 2 months later ; the other had infected non-union of allograft and amputation was done. Functional results were evaluated using the modified 30-points Musculoskeletal Tumor Society rating score (MTSRS) at final follow up of average 143 month (range; 28–213): the average total score was 27.4 (range; 18 to 30). All patients had good functional range of motion of the knee with stable knee at final follow up and were able to perform sport. Long term results of this study clearly indicates that allograft and vascularized fibular graft is a useful limb salvage procedure providing a biological long-term solution especially in skeletally immature. This technique provides single stage life long reconstruction. The allograft shell provide early stability and fixation to support a small epiphyseal fragment to preserve the articular surface and the vascularized fibula provides revascularization and osteointgration with the allograft to finally offer a long lasting durable reconstruction with full rang of motion of the knee.