| Objective1. To establish different internal fixation pattens of finite element model andexperimental biomechanical model for1/2posterolateral tibial plateau fractures.2. To explore the biomechanical stability for1/2posterolateral tibial plateaufractures in two experimental models under different axial loads, and try to providescientific reference in the clinical application for posterolateral tibial plateaufractures.Methods1. The CT scanning was performed in the right tibia of a frozen male corpse, anda three-dimensional finite element model of the differerent internal fixation pattens for1/2posterolateral tibial plateau fracture was established. The maximum axialdisplacement of the fracture fragments and the Von Mises stress of the fracture surfaceand different internal fixation devices were analyzed under different axial load of thetibial plateau using the three-dimensional finite element software.2.12tibial specimens were choosed from6adult male antisepsis corpse and theage from53to76, average age of65.2years old.1/2posterolateral tibial plateaufracture models were randomly divided into three groups and each group of fourspecimens.5spots were tagged on same position in fractures of3fixation pattengroups, the three groups were divided into front and rear lag screw group, rear side ofplate and screw group, the lateral plate and screw group. To load different axialmechanical loadings in3fixation pattens by biomechanical loading device and to measured axial displacement of fracture block by using digital speckle correlationmethod.Result1.1/2posterolateral tibial plateau fracture models were esblished Successfullyestablished by using finite element method. The maximum axial displacement of thefracture fragments and the maximum stress on the different fixation devices were theminimum in the front and rear lag screw group (mean0.043944mm and59.351Mp),and the second in the rear side of plate and screw group (mean0.055221mm and188.373Mp), and the maximum in the lateral plate screw group (mean0.449152mmand249.230Mp) among the four axial loads. The stress distribution of fracture surfacewas uniform in the front and rear lag screw group, and concentrated in the lateral plateand screw group, and the most even in the rear plate and screw group, in which themaximum stress concentrated at the junction of the screw and bone.2.1/2posterolateral tibial plateau fracture models were esblished Successfullyestablished by using experimental biomechanical method. The point1displacement ismeasured in the group of front and rear lag screw group, the rear side of plate andscrew group, the lateral plate and screw group under axial load of250N,which were0.087±0.046mm,0.231±0.068mm,0.239±0.079mm. Point2displacement betweenthe three groups were0.176±0.067mm,0.516±0.113mm,0.540±0.126mm. Point3displacement between the three groups were0.111±0.027mm,0.281±0.059mm,0.287±0.062mm. Point4displacement between the three groups were0.094±0.011mm,0.265±0.049mm,0.275±0.052mm.Point5displacement between thethree groups were0.090±0.007mm,0.288±0.059mm,0.296±0.064mm. Q test isused in five points between two groups. Significant differences were found amonggroups the front and rear lag screw and the rear side of plate and screw, the front andrear lag screw and the lateral plate and screw（P<0.05）. There were no significant differences of the rear side of plate group and screw and the lateral plate and screwgroup（P>0.05）. The five points displacement trend in three group models under500N and1000N is similar with250N. With the increase of axial load force thedisplacement is also increased, the corresponding statistics of three groups of twocomparison between the results agree with250N. way,5point displacement is themaximum in five points of the three fixation pattens and distribution in posterolateralof fracture. All of the displacement is larger than the finite element method under thesame conditions, but the distribution of the maximum displacement on the fracturefragments in a similar distribution between the two groups.Conclusion1/2posterolateral tibial plateau fracture models were esblishedSuccessfully established by using method of finite element and experimentalbiomechanical. Two methods of research results show that the biomechanicalstability of1/2posterolateral tibial plateau fracture was the most advantageous in thefront and rear lag screw group, followed by the rear side of the plate and screwgroup,and the lateral plate and screw group was poor. For similar to the simulation ofthe posterolateral simple fracture of tibial plateau, front and rear lag screw fixed waycan be considered in clinic. It is very important to choose reasonable imagingexamination in preoperative for serious posterolateral tibial plateau fracture is causedby violence,which can avoid misdiagnosis on posterolateral tibial plateau fracturecombining with fibula neck fracture. It is important to fixed the fracture ofposterolateral tibial plateau and fibula neck at the same time for the stability of theknee joint for such patients. |
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