Reconstruction of a High-Grade Osteosarcoma in the Proximal Tibia With Transphyseal Resection Using an Extracorporeal Irradiation and Vascularized Fibula Autograft: A Case Report.

This case report presents the treatment of a 13-year-old male patient diagnosed with high-grade osteosarcoma of the proximal tibia. Management involved a combination of transphyseal resection, extracorporeal irradiation, and reconstruction using a vascularized fibula autograft. The tumor was excised with clear margins, as confirmed intraoperatively through frozen section analysis. The resected tibial segment was sterilized using 50 Gy extracorporeal irradiation and subsequently reimplanted. To restore structural integrity and vascularization, a 14 cm pedicled fibula graft was harvested and inserted intramedullary, then stabilized with plates and screws. This multidisciplinary approach, involving orthopedic oncology and microsurgical reconstruction, demonstrates an innovative limb-salvage strategy that preserves function while minimizing the risk of recurrence. The case highlights the feasibility and potential advantages of combining extracorporeal irradiation with vascularized bone grafting in the management of complex osteosarcomas, particularly in skeletally immature patients.