有限元分析髋臼横行骨折不同植入物的内固定方式

Different fixation methods for transverse acetabular fracture: a finite element analysis

背景:髋臼横行骨折多累及髋臼前后柱。常用的前柱和后柱钢板固定需要采用前后联合入路,创伤大不利于患者术后恢复,而有限切开或经皮微创拉力螺钉置入虽能减少软组织损伤,但其固定强度缺乏生物力学验证。目的:对比横行骨折不同类型的内固定方式,并结合修复入路及软组织损伤情况探讨既能达到有效内固定,又能减少软组织损伤的内固定方式。方法:利用有限元分析方法,以第4代人工合成半骨盆sawbones为模板建立髋臼横行骨折模型,采用5种不同的内固定方式固定横行骨折。在模拟患者内固定后不完全负重站立下,对比髋臼前后方移位大小以评价不同内固定方式的稳定性。结果与结论:前柱锁定钢板+后柱螺钉固定骨折断端前方移位最小,前柱螺钉+后柱锁定钢板固定骨折后方移位最小,两种内固定方式移位均小于对应的重建钢板固定。采用前柱+后柱拉力螺钉固定骨折前后方移位均最大,固定效果最差。前柱锁定钢板+后柱螺钉可采用前单一入路即可完成内固定,减少手术创伤,具有较强的稳定性,且能直视下置入后柱拉力螺钉,减低螺钉置入的难度,是行之有效的内固定方法。

BACKGROUND： Transverse acetabular fracture often involves the damage of anterior and posterior columns of acetabulum. The most popular fixation of the anterior and posterior columns needs the combined anterior and posterior approach. Big trauma is not conducive to patient＇s recovery after surgery. Limited incision or percutaneous minimally invasive lag screw placement can reduce soft tissue injuries, but the strength of the fixation lacks of biomechanical verification.OBJECTIVE： To compare different types of fixations for transverse acetabular fracture, explore the appropriate fixation options that can achieve effective fixation and reduce tissue injury by combing with repair approach and the condition of soft tissue. METHODS： The fourth generation of synthetic semi-pelvic sawbones was set as a template to establish a model of acetabular transverse fracture using finite element analysis. Five different fixation options were used to fix the transverse acetabular fracture. The magnitudes of anterior and posterior displacement of transverse fracture were compared to assess the stability of different options under a simulated condition of incomplete weight bearing stand. RESULTS AND CONCLUSION： The motion at anterior column was minimal when fixed by anterior column locking plate ＋ posterior column screw and the minimum displacement at posterior column was the fixation of anterior column screw ＋ posterior column locking plate. Both of the motions of these two fixations were less than the reconstruction plate fixation respectively. The worst fixation was the anterior column and posterior column lag screw fixation with the largest displacement. The anterior column locking plate ＋ posterior column screw, accomplished by single approach, could not only reduce surgical trauma, but also has a stronger stability. Moreover, this fixation option is effective method to place posterior column lag screw under direct vision and reduce the difficulty of screw implantation.