Repair of rabbit bone defect with composite of calcium phosphate bone cement and calcium phosphate cement mixed with different ratio of minimal morselized bone in vivo

Abstract

Objective To explore the effect of the calcium phosphate cement (CPC) /calcium polyphosphate fiber (CPPF) composites mixed with different proportion of minimal morselized bone on repair of bone defect in vivo. Methods A total of 36 New Zealand white rabbits were completely randomly designed into A, B, C, D groups and their bilateral radial bone defect model was prepared. The minimal morselized bone (300-500 μm in diameter) was made from the iliac of those rats. The CPPF and CPC were evenly mixed into CPC/CPPF composites which were divided into four groups in accordance with the CPPF weight O, 10％, 30％ and 50％ in CPC/CPPF composite. The CPC/CPPF composites of the four groups was mixed with the minimal morselized bone with ratio of 6:4 and then the mixture was implanted the bone defect of the rabbits in four groups. The gross, X-ray and histological observations were done at four and eight weeks. The biomechanical test was performed at eight weeks. Results When CPPF occupies 30％ of the CPC/CPPF composite, the maximum compressive load and bending loads were better than those in the other groups ( P ＜ 0.05 ), when the histological observation showed the most tight link between the artificial composite and the bone interface and the closest similarity between material degradation rate and the ossification rate, with the best osteogenesis and the optimal ratio.Conclusion The repair of bone defect can attain the optimal outcome through adding a certain ratio of minimal morselized bone into the CPC/CPPF to adjust the degradation rate of composites. Key words: Calcium phosphates; Bone transplantation; Bone substitutes; Calcium phosphate bone cement