| Objective:The purpose of this article is to analyze the biomechanical mechanism and the therapy effect of L-model steel plate combining with the Injectable calcium sulfate in treating of lateral tibia plateau fracture,investigating the related clinical significance.Methods:1.Construction of 3-D finite element model(FEM) of human knee.Step 1. We obtained the CT images from a male adult volunteer(46-year-old) who received a computer tomography(CT,and 1mm between two CT slices).All the images were saved in CT machine and then copy into compact disc(CD),from which we attained every cross-section of the knee joint.Step 2.We processed the CT images,saving them in DICOM format and clean the parenchyma around the knee joint in scanning sequence.So we got every processed CT picture.Step 3.CT images were processed,selecting a series of key points in outer and inner surfaces,and obtained the inner and outer figure lines presenting the shape of knee when connecting the points.Finally we reconstruct them using 3-D FEM soft(Simpleware).We set stress rate as 0.01 in element property and the Poisson's rate was assumed to be 0.3 cortical bone,0.2 for cancellous bone.Young's modulus is divided into 256 class calculated according to CT value(Hounsfield).Finite element in the establishment of the unit will be corresponding CT value of the material properties of the bone,and as a result the surface of the knee can be more smooth,the internal stress closer physiological state,the experimental results more reliable.2.Step 1. Reverse Engineering Construction of the L-butress plate 3D solid model,finite element model,fracture fixation model.Step 2.Analysis with 3-D FEM:Analysis were carried out using the finite element analysis soft ANSYS 10.0,with 3 dimension 10-node tetrahedral entity mesh generation method.Results:1.After construction,we have got knee joint 3-D FEM in vivo,fracture knee joint 3-D FEM fixed by L-model steel plate;and we got the Von misese stress Value,the model was validited by literature knowledgement.2.The distribution of the knee stress post operation is in a relatively steady statement,we could got the lateral tibial plateau Von Mises Stress(VMS) distribution,displacement and stress of cancellous bone under the platform under diferent compressive stress.Then we can know how long patients can walk post operation.Conclusions:1.This finite element analysis model which based on CT scans can reflect the real geometry structures of human knee joint of femur,patella,and tibia vividly. The software(Simpleware) used in this research can establish a 3-D finite element model rapidly.2.Through software(Simpleware and UG) we establish a 3-D finite element model of fractured tibia plateau fixed by butress plate.3.The model can be exported into ANSYS,then anlysis.We could got the stress distribution state of Tibial plateau fracture post the L-butress plate fixation.Wheather Cancellous bone fill combined with the L-butress plate can increase anti-compressive strength more significantly than L-butress plate.How the mechanical properties of the fixed lateral tibial platform perform compared to the unfractured tibial plateau,these data could support the current clinical knowledgement, which prefer 10 to 12 weeks loading after operation.The treatment of depressed tibia plateau fractures with a calcium phosphate cement provides equivalent or better stability than conventional open reduction and internal fixation in pure depression tibial plateau fractures.Our result may suggest that non-weight-bearing postoperative period may be significantly reduced without clinically significant articular collapse.
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