手舟骨腰部骨折3种内固定方式的有限元分析

目的　通过建立手舟骨腰部骨折三维模型来比较3种不同内固定方式的生物力学差异，为临床内固定方式的选择提供依据。 方法　选取健康志愿者的腕关节CT数据，应用软件建立舟骨腰部骨折的3种内固定方式模型：克氏针固定组、Herbert螺钉固定组、钉脚固定器组。分别在中立握拳位和腕背伸桡偏位施加载荷，并分析舟骨变形量、内固定器械的应力。 结果　在3种内固定装置下舟骨的变形量，克氏针最大，钉脚固定器最小。在两种工况下，舟骨变形量和固定装置的最大应力值不等，但趋势相同，均为钉脚固定器的舟骨变形量最小、所受的最大应力最小。钉脚固定器存在偏心效应，当载荷达到临界值时，易使舟骨愈合面出现开裂或不对称偏心现象。 结论　克氏针固定效果最差，钉脚固定器的固定效果最佳，钉脚固定器术后应适当限制手部负重。

Finite element analysis of three internal fixation methods for scaphoid waist fracture

Objective　To compare the biomechanical differences among three internal fixation methods by establishing a three-dimensional model of scaphoid waist fracture, so as to provide a method of selection of clinical internal fixation.　Methods　The wrist CT data of a healthy volunteer were selected. The application software was used to establish three internal fixation models of scaphoid waist fracture: a Kirschner wire fixation group, a Herbert screw fixation group, and a nail-feet-fixation device group. Load was applied to the neutral grip position and radial deviation-extension, and the deformation of the scaphoid, and the stress of the internal fixation device were analyzed.　Results　Among three internal fixation devices, the largest deformation of the scaphoid was under the action of the Kirschner wire, and the smallest was under the action of the nail holder. Under the two working conditions, the deformation of the scaphoid and the maximum stress of the fixture was different, but the trend was the same. Under the nail holder, both the scaphoid deformation and the maximum stress were the smallest. But the nail holder had an eccentric effect. When the load reached a critical value, the scaphoid healing surface was easily cracked or asymmetrically eccentric.　Conclusion　Kirschner wire fixation and nail-feet fixation is the worst and best in effect, respectively. The weight of the hand should be properly restricted after nail-feet fixation.