Abstract. Background. Extracorporeal radiation therapy (ECRT) has been reported as an oncologically safe and effective reconstruction technique for limb salvage in diaphyseal sarcomas with promising functional results. Factors affecting the ECRT graft-host bone incorporation have not been fully investigated. Methods. In our series of 51 patients of primary bone tumors treated with ECRT, we improvised this technique by using a modified V-shaped osteotomy, additional plates and intra-medullary fibula across the diaphyseal osteotomy in an attempt to increase the stability of fixation, augment graft strength and enhance union at the osteotomy sites. We analyzed our patients for various factors that affected union time and union rate at the osteotomy sites. Results. On univariate analysis, age <20 years, metaphyseal osteotomy site, V-shaped diaphyseal osteotomy, extramedullary plate fixation and use of additional plate at diaphyseal ostetomy had a significantly faster time to union while gender, tumor type, resection length, chemotherapy and use of intra-medullary fibula did not influence union time. In multivariate analysis, metaphyseal ostoeotomy, V-shaped diaphyseal osteotomy and use of additional plate at diaphyseal ostetomy were the independent factors with favourable time to union. Although the rate of union was higher with V-shaped diaphyseal osteotomy and use of additional plate and intra-medullary fibula at diaphyseal ostetomy, this difference could not be established statistically. None of the analyzed factors apparently affected the union rate in univariate analysis. Conclusion. Judicious choice of osteosynthesis and augmentation of ECRT graft can enhance incorporation with reduced complications and good functional outcome

Introduction. We analyzed the results of extracorporeal radiated (ECRT) autogenous tumour bone for reconstruction of diaphyseal defects after tumour resection at our institute. Methods. Sixteen diaphyseal bone tumours operated between March 2006 to March 2008 were reconstructed with ECRT bone after appropriate oncologic resection. These included 10 cases of Ewing's sarcoma, 5 of Osteosarcoma and 1 Adamantinoma. Nine involved femur, 5 tibia and 2 humerus. Suitable internal stabilisation (14 cases plate fixation, 2 intramedullary nails) was used after re-implanting ECRT bone. Average resection length was 18.9 cm (range, 11 to 30 cm). Results. There were 32 osteotomy sites in 16 patients. 4 cases with infection resulting in graft removal were excluded. Thus 23 osteotomy sites (one patient had a bipolar prosthesis inserted into re-implanted bone) were analysed for union. The average union time was 6.8 months. 12 metaphyseal sites united at average 6 months and 11 diaphyseal ends at average 7.8 months. 2 cases developed hypertrophic nonunion (both at diaphyseal sites) requiring revision and bone grafting. Reconstruction related complication were seen in 7(43%) out of 16 patients. Infection in 4 cases (25%), required multiple lavages, debridement and ultimately removal of the graft in all. The average follow up was 33 months (range, 27 to 45 months). There were 3 local recurrences (2 bony, 1 soft tissue), none of them in re-implanted bone. Four patients died of metastatic disease and 1 due to unrelated causes. At time of final review all survivors except one were capable of independent ambulation with an average MSTS Score of 26 (range, 18 – 29). Conclusion. Extracorporeal irradiation is an oncologically sound procedure with good functional outcomes. It is a convenient and inexpensive technique for limb salvage avoiding the logistic issues involved in allograft procurement and specialized expertise for microvascular anastomosis