第5掌骨颈骨折内固定方法的有限元模型比较

Comparison of finite element model of the fifth metacarpal neck fracture fixation methods

目的比较交叉克氏针、锁定钢板、单根顺行髓内针(髓内针)内固定方式对第5掌骨颈骨折的稳定性,寻找较理想的内固定方法。方法选择1例23岁健康男性志愿者,应用三维有限元软件模拟第5掌骨颈骨折内固定模型;其掌骨的形状和特性源于CT扫描图像,模型的正确性通过尸体模型验证。分别用交叉克氏针、锁定钢板、髓内针行内固定,其模型的掌骨头相同节点分别施加垂直载荷100 N,检测其骨折断面的最大相对位移。结果髓内针模型近端骨折块的最大位移为1.138 000 mm,远端骨折块最大位移为0.991 931 mm,髓内针模型远近端骨折块最大相对位移为0.146 069 mm;克氏针模型分别为0.737 305、0.598 466、0.138 839 mm;钢板模型分别为0.350124、0.289 484、0.060 640 mm。结论在骨折内固定稳定性方面,钢板模型明显优于克氏针、髓内针模型;因髓内针对关节周围组织无损伤,可降低关节炎和关节僵直的发生率,故可作为第5掌骨颈骨折的理想内固定方法。

Objective To analyse stability of cross Kirschner wires ,lock plate ang single line intramedullary needle to fix the fifth metacarpal neck fractures. Methods Choosing a healthy male volunteer, and using three dimensional finite el- ement software to simulate internal fixation models of fifth metacarpal neck fracture. The character of metacarpal and char- acteristics were showed by CT scan images, the validity of the models was definited through the body verification. Internal fixations were used cross kirschner wires, lock plate or the single line intramedullary needle, respectively. After being im- posed 100N force on the same nodes of the models, maximum relative displacement of fracture sections was observed. Re- suits The maximum displacement of proximal fracture piece of intramedullary needle model was 1. 138 000 mm. The maxi- mum displacement of remote fracture piece was 0. 991 931 mm, maximum relative displacement was 0. 146 069 mm. Kir- schner wires models were 0. 737 305, 0. 598 466, O. 138 839 mm, respectively. Lock plate model were 0. 350 124, 0.289 484, 0. 060 640 mm, respectively. Conclusions Lock plate model could get more significant stability than the oth- er two ways in the internal fixations. Intramedullary needle internal fixation is an ideal method for metacarpal neck fractures.