Effect of a carbonated HAP/β-glucan composite bone substitute on healing of drilled bone voids in the proximal tibial metaphysis of rabbits

• Highly porous carbonate HAP granules and β-1,3-glucan were used to fill bone voids.
• Critical size defects of rabbit tibiae were filled with the composite scaffolds.
• Biocompatibility, mineralization and osseointegration of implants were examined.
• Histological analysis indicated a high biocompatibility of composite grafts.
• We report penetration of bony tissue into implants and advanced osseointegration.

A novel elastic hydroxyapatite-based composite of high surgical handiness has been developed. Its potential application in orthopedics as a filler of bone defects has been studied. The biomaterial was composed of carbonated hydroxyapatite (CHAP) granules and polysaccharide polymer (β-1,3-glucan). Cylinders of 4 mm in diameter and 6 mm in length were implanted into bone cavities created in the proximal metaphysis of tibiae of 24 New Zealand white rabbits. 18 sham-operated animals were used as controls. After 1, 3 or 6 months, the rabbits were euthanized, the bones were harvested and subjected to analysis. Radiological images and histological sections revealed integration of implants with bone tissue with no signs of graft rejection. Peripheral quantitative computed tomography (pQCT) indicated the stimulating effect of the biomaterial on bone formation and mineralization. Densitometry (DXA) analysis suggested that biomineralization of bones was preceded by bioresorption and gradual disappearance of porous ceramic granules. The findings suggest that the CHAP–glucan composite material enables regeneration of bone tissue and could serve as a bone defect filler.