Abstract
Malignant lower-limb metaphyseal and diaphyseal bone tumours that have not yet invaded the epiphysis can usually be managed with limb-sparing surgery. Reconstructions using intercalary allografts, autoclaved autografts, extracorporeally irradiated autografts, vascularised autografts, and distraction osteogenesis have all achieved favourable results. In patients with metastatic disease and a short life expectancy, reconstruction with allografts or autografts should be carefully considered because a long recovery period is needed. An intercalary endoprosthesis provides immediate stability, a short recovery period and a low implant failure rate. Nonetheless, it may be expensive when there is inadequate space for stem insertion, necessitating a custom-made endoprosthesis. We present a 12-year-old boy with stage-III osteosarcoma of the metaphysis and diaphysis of the femur who underwent knee joint salvage and reconstruction with a retrograde, locked, intramedullary nail surrounded with methylmethacrylate. At the one-month follow-up, the patient could walk unassisted. At the 2-year follow-up, his Musculoskeletal Tumor Society score was 83%. The patient died from lung metastases at 31 months. He had not experienced any complications with the reconstruction.