髋臼横行骨折经前入路不同内固定的生物力学研究

Biomechanical study on different internal fixations for acetabular transverse fracture through the anterior approach

目的比较髋臼横行骨折经前侧入路给予髋臼前柱3种内固定方式的稳定性。方法将制成髋臼横行骨折模型的18个新鲜标本,随机、平均分为3组。LS组:单纯拉力螺钉固定组;RP组:重建接骨板固定组;LP组:锁定重建接骨板固定组。本实验在美国BOSE-3500型生物力学试验机上进行,依据3枚克氏针所代表的三维坐标平面,将半骨盆标本调整至人体倒置单足站立位置固定于包埋盒中,实验进行连续性轴向加载直至三组内固定均达到失效。观察3组标本在同一载荷下的纵向移位、纵向位移均>2.00mm时的载荷及此时的内固定轴向刚度。结果 LS组骨折的纵向位移大于RP组、LP组,轴向刚度小于RP组、LP组,差异具有统计学意义(P<0.05),RP组与LP组的纵向位移及轴向刚度之间均无统计学差异(P>0.05)。结论经前侧入路给予前柱内固定治疗髋臼横行骨折时,锁定重建接骨板固定组与重建接骨板固定组稳定性相似,无统计学差异,单纯拉力螺钉固定组稳定性较弱。

Objective To compare the biomechanic stability of three different internal fixations for trans- vers acetabular fractures through the anterior approach. Methods Eighteen transverse acetabular fracture models were randomly divided into three groups （ n = 6 ）. The fractures were fixed with simple lag screws in group LS, with reconstruction plate in group RP, and with locking reconstruction plate in group LP. Continuous axial loading was imposed until the fixation failed. The longitudinal displacements, loading of failed internal fixation and axial stiffness were measured and compared by axial loading experiment between groups. Results Longitudinal displacements of group LS was longer than those of group RP and LP （ P 〈 0. 05 }. The maximum load and axial stiffness of group LS were smaller than those of group RP and LP（ P 〈 0. 05 ）. However, there was no significant difference in the longitudinal displacements,loading of failed internal fixation and axial stiffness between group RP and LP （ P 〉 0. 05 ）. Conclusion For the acetabular transverse fractures, locking reconstruction plate and reconstruction plate internal fixation can provide greater stability than simple lag screws. And the biomechanic stability of internal fixation with locking reconstruction plate is similar to reconstruction plate.