This trial aims to evaluate whether any of several different approaches using mesenchymal stem cells can assist in bone repair. The trial is being conducted by the University of Indonesia in conjunction with the National University of Singapore and aims to enrol five participants between November 2012 and December 2014. The trial will compare treatment involving mesenchymal stem cells, the factor HA-CaSO4, the factor BMP-2, and an implant in treating critical-sized (> 2.5 cm) bone defects. Participants will be monitored for complications and changes in clinical condition.