en Orthopedic Orthopedic Original Research Original Research <p> <strong> Background </strong>: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. </p><p> <strong> Methods </strong>: 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. </p><p> <strong> Results </strong>: 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. </p><p> <strong> Conclusion </strong>: Combination of MSC and rhBMP-2 was proven to accelerate :::union::: and improve mechanical strength of ECI autograft. </p><p> <strong> </strong></p> Extracorporeal irradiation, Limb salvage surgery, Mesenchymal stem cell, Bone morphogenetic protein, Scaffold, Hydroxyapatite. 862 876 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-1569-10&slc_lang=en&sid=1 Achmad Fauzi Kamal fauzikamal@yahoo.com 200319475328460013927 200319475328460013927 Yes Department of Orthopaedic and Traumatology, CiptoMangunkusumo Hospital, Faculty of Medicine, Universitas Indonesia, Jakarta, Indonesia. Ismail Hadisoebroto Dilogo ismailorthofkui@yahoo.co.id 200319475328460013928 200319475328460013928 No Department of Orthopaedic and Traumatology, CiptoMangunkusumo Hospital, Faculty of Medicine, Universitas Indonesia, Jakarta, Indonesia. Errol Untung Hutagalung erroluhuta@yahoo.com 200319475328460013929 200319475328460013929 No Department of Orthopaedic and Traumatology, CiptoMangunkusumo Hospital, Faculty of Medicine, Universitas Indonesia, Jakarta, Indonesia. Diah Iskandriati atie@indo.net.id 200319475328460013930 200319475328460013930 No Primate Research Center, Bogor Agricultural University, Bogor, Indonesia. R. Susworo susworprof@gmail.com 200319475328460013931 200319475328460013931 No Department of Radiotherapy, CiptoMangunkusumo Hospital, Faculty of Medicine, Universitas Indonesia, Jakarta, Indonesia. Nurjati Chaerani Siregar anisiregar@gmail.com 200319475328460013932 200319475328460013932 No Department of Anatomical Pathology, CiptoMangunkusumo Hospital, Faculty of Medicine, Universitas Indonesia, Jakarta, Indonesia. Achmad Aulia Yusuf adang.kantaatmadja@yahoo.com 200319475328460013933 200319475328460013933 No Faculty of Public Health, Universitas Indonesia, Jakarta, Indonesia. Adang Bachtiar adang.kantaatmadja@yahoo.com 200319475328460013934 200319475328460013934 No Faculty of Public Health, Universitas Indonesia, Jakarta, Indonesia.