中文摘要：

目的通过有限元分析评价腰部斜形舟骨骨折螺钉位置居中性与垂直性对螺钉固定强度的影响。方法提取1例男性患者健侧腕关节CT的DICOM数据,通过MIMICS 10.0软件进行三维重建,于ANSYS 10.0软件中建立有限元模型,模拟舟骨腰部骨折及4种不同螺钉固定方式：①螺钉位于舟骨中央区且与骨折面垂直;②螺钉位于舟骨中央区但与骨折面不垂直;③螺钉位于舟骨中央区之外但与骨折面垂直;④螺钉位于舟骨中央区之外且与骨折面不垂直。分别模拟腕中立握拳及腕背伸桡偏2种体位,各施加载荷50N,评估螺钉固定的稳定性。结果实验结果显示当螺钉在舟骨内居中与骨折面垂直时,固定后承受最大负荷及最小负荷最低,其次为螺钉在舟骨居中但与骨折面不垂直时。而当螺钉在舟骨内不居中时,与骨折面垂直与否对应力影响不大。结论对于舟骨斜形不稳定骨折,将螺钉在舟骨内居中并垂直放置可以提供更高的固定强度。

英文摘要：

Objective To evaluate the influence of the central and perpendicular position of the screw to the fixation stability of the scaphoid fracture by finite element analysis. Methods One normal side wrist of a male patient was scanned by computed tomography（ CT）. The digital imaging and communications in medicine（ DICOM） CT images were then imported into Mimics 10. 0 for three-dimensional reconstruction. Scaphoid waist fracture was simulated based on the Herbert classification by finite element modeling with ANSYS 10. 0,and two types of virtual fixation were also achieved as follows： group 1： the screw was perpendicular to the fracture plane and also was central in the scaphoid; group 2 ： the screw was not perpendicular to the fracture plane but was ccentrally placed in the scaphoid; group 3： the screw was perpendicular to the fracture plane abut not central in the scaphoid; group 4： the screw was neither perpendicular to the fracture plane nor central in the scaphoid. The biomechanical stability was evaluated in wrist extension radial deviation and making a fist in neutral with load of 50 N respectively. Results Our study showed the fixation stability was much higher with the screw placed in the central zone of the scaphoid compared with eccentric placement of the screw. No difference was found if the screw was placed perpendicular to the fracture plane or not when the screw was not placed in the central area of the scaphoid. Conclusion In this finite analysis model of an unstable oblique scaphoid fracture,It was found that higher stability of fixation had been achieved with a screw placed centrally in the scaphoid and perpendicular to the fracture plane.