Three-dimensional Reconstruction And Finite Element Analysis Of Mechanical Properties In Spatial Structure Of Human Proximal Femur

Objective:(1) Reconstruct three-dimensional visualized model of spatial structure in human proximal femoral; (2) Establish finite element models of cancellous bone in proximal femoral; (3)To study the effect of different loading and off-axis angle on changes in spatial distribution and mechanical properties of cancellous bone from femoral head by using three-dimensional finite element method.Methods:(1) First we choose one side of the femur bone that the woman was died of heart disease.Then we use the PMMA and the rectangle to make the model.We intercept the proximal site of the femur in order to make a complet model;(2) Then we use the Grinder MH618 to deal with the model and get the photograph by the Scanners with some parameters;(3) The photograph was treated by some software just like MATLAB and MIMICS.Finally,We can get the three dimensional visualized model.We used some structural parameters to describe the cancellous bone in proximal femoral,such as Bone Volume Fraction (BVF,BV/TV),Bone surface/bone volume ratio (BS/BV), Trabecular thickness (Tb.Th), Trabecular number (Tb.N), Trabecular spacing (Tb.Sp);(4)Establish finite element models of cancellous bone in proximal femoral.The finite element analysis was used to simulate the uniaxial compression test, and the stress and strain distribution in different model was observed. The influences of different loading and off-axis angle on biomechanical properties of proximal femoral cancellous bone were investigated.Results:The authors obtained clear three-dimensional model of trabecular bone,reconstructed the real anatomic morphology of proximal femur,and established finite element model of trabecular bone in human proximal femur.The three-dimensional parameters of trabecular bone along the direction of principle compress are different with the depth below the top articular surface of the femoral head. There was significant difference among the maximum effective stress and the proportion of≥5000μstrain of the same cancellous bone specimen under the different loading or off-axis angle.The greater strain we preset,the larger the maximum effective stress value,and≥5000μstrain the proportion of cancellou bone.Conclusions:We utilized the data that obtained using the cross section grinding may establish a clear reliable three-dimensional model which reflects the spatial interior structure of proximal femur.This is a good method to research the interior structure of femur and provide the foundation for the three-dimensional finite element analysis. Because mechanical properties of cancellous bone depend on material and structure, does the dismatch between spatial structure and mechanical environment of cancellous bone would decrease biomechanical properties that may lead to the natural process of remodeling.