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为了解自身攻丝与非自身攻丝螺钉固定对骨结构的影响及拧钉和紧固过程中应力分布的变化,我们进行了两种皮质骨螺钉固定后骨结构的扫描电镜观察和两种螺钉拧入及紧固后的光弹模型观察。在扫描电镜观察中,先以两个临近打孔测试的最大扭矩(Mmax)的75～85％的扭矩于两测试孔间中点准备标本。结果显示自身攻丝钉孔Zimmer钉(3.5mm)组2孔4个标本均可见裂纹,其中一孔两个标本可见骨螺纹变形;Howmedica钉(3.6mm)/组(2.8mm钻孔)4孔8个标本均发现有骨裂;Howmedica钉2组
To understand the effect of self-tapping and non-self-tapping screws on the structure of bone and the changes of stress distribution during screwing and tightening, we conducted scanning electron microscopic observation of two bone structures after fixation with cortical screws and two screws Screw in and tighten the photoelastic model observation. In scanning electron microscopy, specimens were prepared at the midpoint between the two test wells with a torque of 75-85% of the maximum torque (Mmax) for the two near-perforation tests. The results showed that the cracks were found in 4 specimens of 2 holes of Zimmer nail (3.5mm) group, of which 4 holes were formed on two specimens of one hole, and 4 holes on Howmedica nail (3.6mm) / group (2.8mm hole) 8 specimens were found with osteofacies; Howmedica nail 2 groups