Biomechanical Study on Repairing Bone Defect with Composite of Bovine Bone Morphogenetic Protein and Hydroxyapatite

Abstract

To investigate the mechanical property (shear strength, bending strength and compressive strength) and the interface combinative ability of the composite of bovine bone morphogenetic protein (bBMP) and porous hydroxyapatite (HA) with different pore diameter. HA1 (Φ100-300μm) and HA2 (Φ130-500μm) were used as carriers of bBMP(5mg). The 4 types material (HA1, HA2, bBMP /HA1, bBMP /HA2) were implanted into the femur of 10 dogs (2 dogs each group) for the shear test and 15 dogs (3 dogs each group) for the bending test and compressive test. The shear strength of all kinds of materials were increased as time went on and the shear strength of bBMP/HA1 was highest in four materials. The bending strength of bBMP /HA1 was close to the normal femur in the 24th week. The compressive strength of all materials was lower than the cortex of the dog’s femur until 24th week. The compressive strength of bBMP /HA1 was the highest in four types. The compressive strength of HA2 and bBMP /HA2 was decreased after implantation. Implant of bBMP /HA with 100-300μm diameter had strong bonding with the host bone, and had better mechanical properties than that with 130-500μm diameter. So the porous bBMP /HA (Φ100-300 μm ) could be a useful graft material due to its strength.