In Vivo Degradation Study Of β-Tricalcium Phosphate/Poly-L-Lactide Composites In Cancellous Bone

Purpose:To investigate the in vivo degradation property ofβ-Tricalcium Phosphate/Poly-L-lactide Composites and Poly-L-lactide(PLLA) materials in cancellous bone comparatively.Method:Taking PLLA as the control group, compare the bioabsorption rate, light microscopic and scanning electron microscopic images ofβ-TCP/PLLA materials in 6w,12w and 24w after implanted into cancellous bone, subcutaneous and muscle tissues. Analyze the degradation rate, new bone tissues formation, rejection reaction of the tissues surrounding the composites and pathology of the kidney and liver.Result:β-TCP/PLLA composites contact more closely with surrounding bone tissues than PLLA. No foreign body reaction is observed. The bioabsorption rate ofβ-TCP/PLLA which is slower than PLLA in the first 6 weeks accelarates after this period, while more micropores and fine groove in the surfaces and inner part ofβ-TCP/PLLA composites are observed. No bony replacement is observed in 24w postoperatively.Conclusion:The degradation rate ofβ-TCP/PLLA composites that is slower than PLLA in the first 6 weeks speeds up after this period, which is propitious to stablize fixation of implants. Tissue compatibility ofβ-TCP/PLLA composites is better than PLLA. However, no osteoinductive property of both materials is observed during the study periods.