BACKGROUND: With fewer traumas to the body, injectable artificial bone can be implanted into the body through the percutaneous injection. Meanwhile, the material can be any shape to fill bone defects. But now in clinic, there is no injectable artificial bone substitute product with the better ability of bone formation, which can be completely degraded and absorbed in vivo.
OBJECTIVE: To evaluate the degradation, absorption and osteogenesis in vivo ability of injectable and absorbable polyamine acid/calcium sulfate (PAA/CS) composites (containing 70% calcium sulfate), and to observe the ability to repair bone defects.
METHODS: A 5 mm×10 mm size bone defect model was made on the femoral condyle of 48 New Zealand white rabbits, which were randomly divided into experimental group (the defect was implanted with injectable and absorbable PAA/CS composites) and blank control group (without intervention).
RESULTS AND CONCLUSION: X-ray examination showed the defect of the experimental group was gradually filled by callus, at 16 weeks postoperation, the bone defects were recovered to normal cancellous bone density and the moulding was finished; the defects of the blank control group were inconspicuously repaired. Histological examination (hematoxylin-eosin staining and MASSON staining) showed that at 4 weeks postoperation, the material began to degrade and new original trabecular bone extended into the material; at 12 weeks postoperation, woven bone turned into shelf bone; at 16 weeks postoperation, the material was completely degraded and absorbed and the bone defects were repaired by new bone tissue completely. The injectable and absorbable PAA/CS composites can be completely degraded and absorbed in vivo, with a certain activity of bone formation, expected to be used as bone repair materials.