A 12-year-old boy, diagnosed with osteosarcoma of the left femur, was treated with intercalary resection and massive bone allograft reconstruction. (A) An anteroposterior radiographic view at presentation showing a lytic lesion located at the distal diaphyseal region of the femur, without involvement of the physis. The edema around the lesion seen in the anteroposterior T2 Short-TI Inversion Recovery magnetic resonance image (B) and the axial T2 magnetic resonance image (C) before preoperative chemotherapy disappeared in the anteroposterior T2 Short-TI Inversion Recovery magnetic resonance image (D) and the axial T2 magnetic resonance image (E) after preoperative chemotherapy. (F) Radiograph showing consolidation of the intercalary allograft at the 3-month follow-up. Radiograph showing allograft fracture 2 years after the surgery (G) treated using a new massive bone allograft in combination with a free vascularized fibular graft (H). (I) Radiographic view showing consolidation and integration of the allograft with the fibular graft 2 years after the surgery. The vascularized fibula graft could serve as an alternative for addressing fracture of intercalary massive bone allograft.