锁定接骨板外置治疗42A3型骨折的生物力学分析

Biomechanical analysis of external locking plate in the treatment of type 42A3 fracture

目的:构建锁定接骨板外置治疗胫骨干横形骨折(AO-OTA分型:42A3型)的模型,运用有限元分析的方法,分析不同骨折断端分离间隙时,接骨板、螺钉及胫骨的应力及分布情况,并为该治疗方案提供理论依据。方法:获得1名健康志愿者左侧胫骨的CT扫描DICOM图像,使用Mimics 21.0软件、Geomagic Studio 2014软件、SolidWorks软件、Hypermesh14.0软件、MSC.Patran 2019软件和MSC.Nastran 2019软件建立接骨板外置治疗不同骨折分离间隙的42A3型骨折有限元模型,并通过有限元分析胫骨、接骨板及螺钉的最大应力值及分布情况。结果:在0.2~2.0 mm分离间隙下,随着骨折断端分离间隙增大,力加载终止时刻及力加载全程胫骨、接骨板、螺钉最大应力值均呈上升趋势;且接骨板最大应力值>螺钉最大应力值>胫骨最大应力值;接骨板最大应力值在接骨板第3、4、5板孔附近;螺钉最大应力值在第3螺钉尾部;胫骨最大应力值出现在骨折断面处;胫骨、接骨板、螺钉力加载全程最大应力值均大于其自身力加载终止时刻最大应力值。结论:当42A3型骨折断端分离间隙小于2.0 mm时,锁定接骨板外置治疗42A3型骨折的生物力学可达到固定强度,该治疗方式可供选择。

Objective To establish a finite element model of external locking plate for the treatment of tibial transverse fractures(AO-OTA:42A3),and to analyze the stress distribution of the plate,screw and tibia in different fracture gaps,thereby providing a preliminary theoretical basis for the therapeutic scheme.Methods The DICOM file of CT scanning data of the left tibia in a healthy volunteer was obtained.Mimics 21.0 software,GeomagicStudio2014 software,SolidWorks software,Hypermesh 14.0 software,MSC.Patran 2019 software and MSC.Nastran 2019 software were used to establish the finite element models of type 42A3 fractures with different fracture gaps treated with external locking plate.The maximum stress values and distributions of tibia,plate and screw were analyzed with finite element method.Results When the fracture gaps was 0.2-2.0 mm,with the fracture gaps increasing,the maximum stress values of tibia,plate and screw were upward at the end of force loading and during the loading.The bone plate had the maximum stress value,followed by screw and tibia.The maximum stress of the locking plate was near the third,fourth,and fifth holes of the plate;the maximum stress value of the screw occurred at the tail of the third screw;and the maximum stress value of the tibia appeared at the fracture section.The maximum stress values of tibia,plate and screw during the loading were all greater than the maximum stress values at the end of the loading.Conclusion When the fracture gap is less than 2.0 mm,the external locking plate for the treatment of type 42A3 fractures can achieve sufficient biomechanical strength,which makes it be an alternative therapeutic option.