交叉螺钉与钢板内固定治疗Sander III型跟骨骨折的有限元分析

目的 比较研究交叉螺钉与钢板固定治疗跟骨关节内骨折的术后即刻稳定性。方法 采集1名正常男性足部薄层CT数据集，据此建立交叉螺钉和钢板两种内植物固定跟骨Sander-III型骨折的三维有限元模型。分析两个模型在700 N垂直荷载下的应力分布和位移规律。结果 螺钉固定时应力集中于骨折端与螺钉接触的部位，不同部位螺钉的最大应力存在差别。钢板固定时应力集中于钢板与螺钉接触的位置，高应力区位于钢板中前部。钢板、螺钉与跟骨的最大应力均小于各自剪切强度。正常跟骨及骨折模型的位移集中于后距下关节，越向内侧位移越大。结论 交叉螺钉与钢板均可用于治疗跟骨骨折，固定具有良好的初始稳定性，建议术后早期进行功能锻炼和康复训练。

Finite element analysis on Sander III calcaneal fractures fixed by crossing screws or steel plate

Objective To make comparative study on the immediate stability of intra-articular calcaneal fractures fixed by crossing screws and by plate. Methods A set of foot CT images from a normal male were collected to construct 3D finite element models of Scander-III calcaneau fracture fixed by crossing screws and by steel plate, respectively. The regular pattern of stress and displacement distributions on these two fracture models under vertical load of 700 N was analyzed. Results For the screw-fixed model, the stress was concentrated at the connecting area between screws and fracture ends, and the maximum stresses were different for screws at different places. While for the plate-fixed model, the stress was concentrated at the connecting area between plate and screw. The highest stress was concentrated in anterior segment of the plate. The maximum stresses of plate, screw and calcaneus were all lower than their shear strength. The displacements of intact calcaneus and fractures were concentrated on the posterior subtalar joints, and a larger displacement appeared on the internal part of joint facet. Conclusions Both crossing screws and steel plate can be used to fix calcaneal fractures with a preferable initial stability. Functional exercise and rehabilitation are recommended at early time after operation.