The reconstruction of large bone defects caused by trauma, revision surgery, inflammation, tumor surgery, and developmental deformity remains a major challenge for the orthopaedic surgeon. To stimulate bone regeneration, the application of autologous bone grafts has advanced as the “gold standard” treatment but supplies are limited and harvesting entails significant donor site morbidity and risk of infection. Autologous bone grafts are also commonly used to repair orofacial bone defects, butoften result in unfavourable outcomes. This clinical observation, along with the fact that many bone abnormalities are limited to craniofacial bones, suggests that there are differences in bone metabolism between orofacial and axial bones. Different approaches in regenerative medicine include cell-based and scaffold-based strategies, delivery of osteoinductive growth factors, and genetic engineering. The most promising approach seems to be a combination of the different strategies. In the past, bone marrow-derived mesenchymal stem cells (MSCs), osteoblasts isolated from the axial skeleton (tOB) and osteoblasts isolated from orofacial bones (mOB) have been implicated in the enhancement of bone repair. However, in further experiments differences in osteogenic potential are evident between the different cell types. We therefore want to assess the osteogenic potential of MSCs, tOB and mOB in combination with a novel, medical grade composite scaffold, in a clinically relevant critical bone defect model. The cells will be attached to the scaffold using fibrin glue to encapsulate and immobilize them in situ.We hypothesize that this model of tissue engineered constructs (TEC) will be able to enhance bone healing in the defect and bony union at host-graft junctions and will provide valuable insight into cell-based bone regeneration and remodelling. The knowledge gained will serve as a baseline for the potential translation of TEC into a routine clinical application.
