前路特殊塑形钛板加方形区螺钉治疗髋臼双柱骨折站位的有限元分析

Finite element analysis of standing position in both-column acetabular fractures fixed by anterior specially-shaped reconstruction plate combined with trans-plate quadrilateral screws

目的 探讨髋臼双柱骨折经前路内固定术后早期站位的安全性.方法 选择1例成年健康男性志愿者CT扫描,Mimics8.1重建半骨盆有限元模型,经网格划分及附值后构建前路特殊塑形钛板加方形区螺钉固定髋臼双柱骨折的半骨盆有限模型,模拟单足站位加载500 N轴向载荷,分析各部位应力及位移情况.结果 骨折经内固定后应力分布均匀,应力集中出现在钛板与螺钉结合处,最大应力为838 MPa,小于材料屈服强度；近端第1枚方形区螺钉承担应力较大,方形区螺钉跨方形骨折线处和前柱髂骨翼处短钛板近骨折线处出现了应力集中区域；后柱位移最大值为0.124 mm.结论 双柱骨折经前路特殊塑形钛板加方形区螺钉内固定后,早期生理负荷站位并不影响内固定的可靠性.

Objective To explore reliability of early standing postion after anterior fixation in both-column acetabular fracture.Methods One healthy adult male volunteer was chosen to take CT scanning.Hemipelvis three dimensional model was reconstructed by Mimics8.1.Fix fractures of both-column acetabular by anterior specially-shaped reconstruction plate combined with trans-plate quadrilateral screws after remeshing and parameters setting.The characteristics of the stress and displacement in model were analyzed under 500 N axial load imitating uniped standing position.Results The stress of fracture model fixed by the anterior internal fixation was well distributed,but the stress concentration happened at junction of screw and plate.The maximum stress value was 838 MPa,which was lower than yield strength of the titanium material.The first proximal trans-plate quadrilateral screw beared the larger stress than the others.One stress concentration zone appeared in trans-plate quadrilateral screws across square area of the fracture line,and the another one in short titanium plate across the anterior iliac wing fracture line.The maximum displacement of the posterior column was 0.124 mm.Conclusion Early standing postion could not influence the dependability of both-column acetabular fracture fixed by anterior specially-shaped reconstruction plate combined with trans-plate quadrilateral screws in physiological load.