累及方形区的髋臼骨折有限元建模及固定方法比较

Finite element modeling and comparison of fixation methods for acetabular fracture with involvement of the quadrilateral plate

目的建立累及方形区的髋臼骨折有限元模型，比较3种内固定方式的效果。方法利用有限元建模软件建立累及方形区的髋臼骨折模型，在Hypermesh V10．0中生成双柱钛板（A组）、前路特殊塑形钛板加方形区螺钉（B组）及前路特殊塑形钛板加方形区螺钉联合后柱螺钉（C组）3种内固定方式，分别对各组坐骨结节及股骨下端进行约束，依次模拟坐位、站位骨盆受力情况。于S，椎体上加载大小为600N的力，模拟坐位、站位时重力方向，测量各固定方式髋臼处的最大应力、最大位移和骨折线上各节点的位移并进行分析。结果分别在坐、站位下，在相同加载方式时3组髋臼处的最大应力分别为29．73，19．84，9．47MPa和13．28，12．18，9．62MPa，最大位移分别为1．14，1．11，1．08mm和1．13，1．10，1．09mm：C组〈B组〈A组。骨折线上节点位移均数比较：C组〈B组〈A组（P均〉0．05）。结论有限元模型能有效地反映骨盆的应力分布。前路特殊塑形钛板加方形区螺钉联合后柱螺钉内固定治疗累及方形区的髋臼骨折具有良好的生物力学稳定性。

Objective To compared different fixation methods for acetabular fractures involving the quadrilateral plate using a finite element model of the acetabulum. Methods A model of acetabular fractures with quadrilateral plate involved was developed in the finite element software and processed in Hypermesh VI0.0 to generate internal fixation with dual-column titanium plate （ Group A） , anterior special titanium moulding plate plus quadrilateral screws （Group B） , and anterior special titanium moulding plate plus quadrilateral screws combined with posterior column screws （ Croup C）. Pelvic stress in sitting and standing positions were simulated in sequence with constraint of tuber nodes and inferior femur. Maximum stress and displacement of the acetabulum and displacement of nodes on fracture lines were measured after a force of 600 N was applied to Sl verterbrae in line with the direction of gravity in sitting and stand- ing positions. Results In sitting position, the maximum stress and displacement of the aeetabulum ex- hibitedasequence of Group C （9.47, 1.08） 〈Group B （19.84, 1.11） 〈Croup A （29. 737 1.14）. Moreover, the same result was found in standing position with Group C （9.62, 1.09 ） 〈 Group B （ 12. 18, 1.10） 〈 Group A （13.28, 1.13）. Mean displacement of nodes on fracture lines ranked in order of Group C 〈 Croup B 〈 Croup A （ P 〉 0. 05 ）. Conclusions The finite element model can reflect the distribution of pelvic stress effectively. Anterior special titanium moulding plate plus quadrilateral screws combined with posterior column screws provide favorable biomechanical stability in treatment of acetabular fractures involving the quadrilateral area.