The Three-dimensional Finite Element Analysis Of Sacroiliac Joints Polyaxial Locking Anatomy-type Plate Screws System

Objectives1、To analyze sacroiliac joints polyaxial locking anatomy-type plate screwssystem’s mechanical properties by adopting finite element.2、To compare the stability by adopting two methods to fix sacroiliac joints:sacroiliac joints polyaxial locking anatomy-type plate screws system and sacroiliacjoint screws.MethodsBy CT axial scanning normal adult male’s pelvic to capture related materials toestablish three-dimensional finite element model, by using Mxliteview Vertion1.18、Mimics10.0、GeoMagic Studio9.0、, HyperMesh、Ansys11.0etc. to establishthree-dimensional finite element model of unilateral sacroiliac joint dislocation (right,similarly hereinafter), and according to the data of sacroiliac joints polyaxial lockinganatomy-type plate screws system and two sacroiliac joint screws to establishthree-dimensional finite element model, to import the unilateral sacroiliac jointdislocation model, to set boundary conditions and load conditions, and to analyze thebiomechanics of three-dimensional finite element and the distributing map of pelvicmodel’s stress, strain and shift changes, in this way to compare the stability betweenthe two different fixing methods.Results1、By establishing three-dimensional finite element model of unilateral sacroiliac joint dislocation, sacroiliac joints polyaxial locking anatomy-type plate screws systemand sacroiliac joint screws, and analyzing the three-dimensional finite element ofbiomechanics, the outcome demonstrates that under the psychological load conditionsthe sacroiliac joints polyaxial locking anatomy-type plate screws system is inconformity with the biomechanics, so when treating unilateral sacroiliac jointdislocation, the smaller the shift is, the stronger the stability of the pelvic is.Thestability of pelvic in the experimental group(sacroiliac joints polyaxial lockinganatomy-type plate screws system)better than the control group(sacroiliac joint screws),and it has a bit advantage under vertical loading conditions, but is not obvious.compared with the control group the maximum displacement of pelvic in theexperimental group were shortened approximately32.7℅whlie sacral32.0℅,underthe left twisting conditions, and under the right twisting conditions the maximumdisplacement of pelvic and sacral in the experimental group were shortenedapproximately30.3℅and21.7℅,respectively.2、The three-dimensional finite element of biomechanics of sacroiliac jointspolyaxial locking anatomy-type plate screws system manifests that under threephysiological loads conditions,the relative midpoint of the stress of screw locatesinside the bottom edge of the department of nail way of S1and plate.Three kinds ofphysiological load state,the maximum stress,in the experime group less than those inthe control group.Conclusions1、By establishing three-dimensional finite element model of sacroiliac jointspolyaxial locking anatomy-type plate screws system and sacroiliac joint screws,analyzing the three-dimensional finite element of biomechanics, the comparisonshows that sacroiliac joints polyaxial locking anatomy-type plate screws system has thesuperiority in treating unilateral sacroiliac joint dislocation.2、The analyzed outcome of three-dimensional finite element of sacroiliac jointspolyaxial locking anatomy-type plate screws system will be a feasible guide in improving medical equipments:increasing the thick of S1locking screw,changing theplate more thin and increasing S2nail way activities radian,appropriate,etc.