胫骨远端后侧锁定接骨板固定Pilon后柱骨折的力学分析

Mechanical analysis of the distal tibia posterior locking plate fixation for posterior Pilon fracture

背景:Pilon后柱骨折行切开解剖复位内固定治疗已达成共识,但关于内固定方案的选择尚无统一标准。目的:探讨两种内固定方式修复Pilon后柱骨折的生物力学性能,为临床选择合适的内固定提供参考。方法:将20具右侧人工胫骨随机分成2组,根据Pilon后柱骨折特点及临床分型制造出Pilon后柱骨折模型。锁定接骨板组采用5孔胫骨远端后侧锁定接骨板系统固定,螺钉组采用2枚3.5 mm皮质骨螺钉由后向前双皮质固定。分别置于电子动静态万能材料试验系统中,垂直加载至内固定失效,记录出现不同台阶时的轴向加载负荷。结果与结论:(1)加载后2组标本均未发生螺钉弯曲或断裂;(2)出现0.5,1.0,1.5,2.0 mm台阶时,胫骨远端后侧锁定接骨板组的轴向加载负荷均大于螺钉组,随着后柱骨折块位移的增加,2组间的轴向加载力差值也越来越大,且组间比较差异均有显著性意义(P<0.05);(3)生物力学检测分析表明,在治疗Pilon后柱骨折中,胫骨远端后侧锁定接骨板的固定效果优于螺钉。

BACKGROUND： Open reduction and internal fixation has been confirmed to treat posterior Pilon fracture, but choosing which fixation scheme is still under discussion. OBJECTIVE： To explore the biomechanical properties of posterior Pilon fracture after repaired by two different fixation methods, thus providing reference for selecting an appropriate fixation scheme. METHODS： Twenty right artificial femurs were randomized into two groups A and B, and the models of posterior Pilon fracture were established based on its characters and classification. The group A received with 5 holes distal tibial posterior locking plate fixation, and the group B underwent two 3.5 mm of cortical screws from back to front bicortical fixation, followed by placed in the InstronElectroPulsE3000 universal electronic static and dynamic materials testing systems, vertical speed loaded until internal fixation failure, the loading was recorded when different steps appeared. RESULTS AND CONCLUSION： （1） After loading, none of groups presented with screw bent or broken. （2） The axial load when appeared with 0.5, 1.0, 1.5, and 2.0 mm steps in the group A was higher than that in the group B, and the axial load significantly increased with fracture fragment displacement increasing （P 〈 0.05）. （3） The biomechanical test shows that the distal tibial oosterior Iockina elate fixation is better than screws in the treatment of posterior Pilon fracture.