兔胫骨应力性骨折过程中的生物力学研究

目的 探讨兔应力性骨折发生过程中胫骨生物力学指标的变化与应力性骨折发生的关系.方法 将36只雄性大耳白兔随机分为6组,进行跑跳训练,根据制定的分组训练时间,于训练任务完成后的第7、14、21、28、35天分别处死动物.光镜下观察胫骨病理变化;生物力学机上行胫骨三点弯曲生物力学测试,描记载荷-变形曲线,并根据该曲线及相应参数分析胫骨生物力学性能.结果 实验组动物训练第2、3、4、5周后最大载荷与对照组动物相比之差异均有统计学意义(P＜0.05).实验组动物第1、2、3、4、5周后载荷与变形量之比与对照组动物相比之差异均有统计学意义(P＜0.05),最大应力和弹性模量与对照组动物相比之差异则均无统计学意义(P＞0.05).结论 应力性骨折的发生是一个由骨细胞直接参与的破骨细胞性重吸收大于成骨细胞性骨形成的生理过程;胫骨结构力学性能的改变是由胶原纤维紊乱、骨皮质厚度降低等所造成,从而导致应力性骨折的发生.

Research of biomechanics of rabbit''''s tibia during stress fracture

Objective To study the relationship between stress fracture and changes of tibia biomechanics indices during the stress fracture of rabbits. Methods Thirty-six male rabbits were divided into six groups for training. Controlling to the training schedule, the rabbits were put to death after finishing the training task on the 7th ,14th ,21st ,28th and 35th day. Pathological changes of tibias were observed by the optics microscope. Three point bending biomechanics test was made on the biomechanics machine and load-distortion curve was described, through which biomechanic's capability of tibias was analysed. Results After the model rabbits were trained at the 2nd ,3rd ,4th and 5th week, there is statistics significance (P<0. 05) of max-load between experiment group and control group. At the 1st ,2nd, 3rd , 4th and 5th week, there is statistics significance (P<0. 05) of load/stroke between experiment group and control group, no statistics significance (P>0. 05) of max-stress and elastic modulus between experiment group and control group. Conclusions Progression of stress fracture is a physiological process of osteoclast's absorbability in excess of osteoblast's osteogenesis. Change of tibia structural mechanics capability including turbulence of collagen fibre and decrease of cortex thickness induced the arising of stress fracture.