transplantation of mesenchymal stem cells, recombinant human bmp-2, and their combination in accelerating the ::union:: after osteotomy and in-creasing, the mechanical strength of extracorporeally irradiated femoral autograft in rat models

background :delayed ::::union::::, non::::union::::, and mechanical failure is still problems encountered in limb salvage surgery (lss) using extracorporeal irradiation (eci). this study aimed to determine whether bone marrow mesenchymal stem cells (msc) and recombinant human bone morphogenetic protein-2 (rhbmp-2) improve host-graft ::::union:::: after osteotomy and also increase its mechanical strength.   methods : thirty sprague dawley rats were randomly divided into five groups. group i (control) underwent lss using eci method with 150 gy single doses. similar procedures were applied to other groups. group ii received hydroxyapatite (ha) scaffold. group iii received ha scaffold and msc. group iv received ha scaffold and rhbmp-2. group v received ha scaffolds, msc, and rhbmp-2. radiograph were taken at week-2, 4, 6, and 8 serum alkaline phosphatase and osteocalcin were measured at week-2 and 4. histopathological evaluation and biomechanical study was done at week-8.   results : the highest radiological score was found in group iv and v similar result was obtained in histological score and ultimate bending force. these results were found to be statistically significant. there was no significant difference among groups in serum alkaline phosphatase and osteocalcin level.   conclusion : combination of msc and rhbmp-2 was proven to accelerate ::::union:::: and improve mechanical strength of eci autograft.