同种异体皮质骨移植的生物力学研究

目的探讨不同力学环境下同种异体皮质骨的生物力学性能变化。方法以４０只家兔前肢尺骨中段骨移植后造成不同受力状态的动物模型,左前肢承受正常生理载荷,右前肢承受低载荷,对植骨区标本进行三点弯曲破坏载荷、骨密度值、骨孔隙率的测试。结果同种异体皮质骨植入后,移植骨－宿主骨界面间的连接强度持续上升,而移植骨自身的生物力学性能呈较快下降再缓慢上升的趋势;从骨移植后第８周开始,正常载荷侧的移植骨－宿主骨界面间的连接强度明显高于低载荷侧,到第１６周时,正常载荷侧移植骨自身的生物力学强度改善也更为明显。结论同种异体皮质骨植入以后的生物力学性能呈较快下降再缓慢上升的趋势;生理载荷的刺激有利于同种异体皮质骨生物力学性能的恢复与改善

Incorporation of cortical allograft: a biomechanical study

Objective To explore the changes of biomechanmical properties of cortical allograft in different mechanical environments. Method Cortical allograft was transplanted to each side of the midshaft diaphyseal ulnar of 40 rabbits.The left transplanted allograft underwent normal physiological load,while the right underwent lower load. Animals were killed and specimens taken for examination of bone mineral density, bone porosity and maximal three point bend breaking load. Result The union strength of allograft host bone junction increased constantly,while the internal creeping substitution led to an initial greater weakening of the cortical allograft itself and the later recovery of its strength.In comparison, the union strength of the normally loaded graft host surface was significantly higher than that of the lower loaded side at eight and sixteen weeks after transplantation.At the sixteenth week,there was greater bone strength in normally loaded graft than that in less loaded graft. Conclusion The internal repair would lead to initial greater weakening of cortical allograft and the later gradual recovery of its strength.The effect of physiological load can accelerate the improvement of the biomechanical properties of allograft.