This study aims to identify the efficiency of biomechanical and bioactive properties of the bovine cortical bone cage treated with conditionally surface demineralization.

The procured bovine femoral bones were got rid of lipid, protein, and blood materials by chemical process such as 3% hydrogen peroxide and 70% ethanol.

The long shaft bones were cut by band saw. Several bone cages were processed by milling machine. The cortical bone cages were demineralized by 0.6N HCl treatment with various conditions, which were the tendency of HCl treatment time, position, direction. After neutralization with pH 7.0, phosphate buffered saline washing and freeze drying process, the vial vacuum packed bone cages were sterilized by 25kGy gamma irradiation. The SEM and EDS system were proceeded for morphology and Ca content in various layers of bone cage. In vitro test for cell viability and differentiation, extracted supernatant from each bone cage by tissue culture was treated in MC3T3E1 cells. For indentifying releasing materials, the others were carried for quantitative analysis by ELISA. After each conditioned period, mRNA expression was compared by RT-PCR. The axial compression and bending strength were measured by universal testing machine (UTM) for biomechanical property.

Between the outer layer and inner layer of bone cage for 2 hour’s HCl, there was concentrated Ca extracted layer. The tendency of Ca content and direction of demineralised treatment had effects on the compression and elastic strength. In vitro test, initial Osteogenic transcription factor’s mRNA expression and quantitative result of releasing material had rewarding regulation by HCl-treatment time and treated direction. Conditionally surface demineralized bone cage had good osteoconduc-tivity and osteoinductivity for spinal interbody fusion.

Demineralized Bone Matrix (DBM) is currently used in various types of orthopaedic applications because of osteoconductive and osteoinductive properties. Fibrin glue is also used in cardiovascular and thoracic surgery due to its hemostatic, chemotactic and mitogenic properties. There is some possibility of being good biomaterial and biodegradable scaffold with DBM-fibrin glue mixture for bone void filler. After total hip replacement surgery, it takes long time to complete bone fusion. If patients have excess weight load after surgery, the artificial joint may not be adhered with patients’s bone.

That is why surgeons have to use any effective treatments for bone fusion for patient’s safety. In order to adapt to these surgical sites, DBMs are shaped in blocks or granules and preferable in porous forms. Combining these DBMs with fibrin glue provides a moldable and self-hardening composite biomaterial. This material will be applied to total hip replacement surgery for the effective fusion between bone and artificial joint. The aim of this work is to study the osteogenic properties of this composite material using in vivo and ex vivo. In radiological study, the DBM composite had been absorbed during one week since implantation surgery and after two weeks, some radio-opaque spots were observed in implantation sites. In histology study, Bone tissue had formed exotically in contact with the surface of the appeared well-mineralized, forming trabeculae between the granules, and had characteristics similar to those of cancellous bone. Bone growth in the tissue engineered filled with DBM and fibrin glue materials increased with implantation time.

In summary, these DBM and fibrin glue composites exhibited interesting biological and mechanical properties for filling large bone defect. These composites may be used in total hip replacement surgery for the effective filler between patient’s bone and artificial joint.