The role of sclerotic changes in the starting mechanisms of collapse: A histomorphometric and FEM study on the femoral head of XXXX .

@entity135 @entity174 @entity6475 @entity3457 @entity2530
PURPOSE: To assess the distributions of stress, strain, and @entity174 areas using a finite element model (FEM), and examine the @entity3457 histopathologically in @entity2530 of the femoral head. METHODS: Three femoral heads were obtained during hip arthroplasty for femoral @entity135 . One sample with a normal area, two samples with a non-sclerotic boundary without collapse (Type 1), two samples with a non-collapsed sclerotic boundary (Type 2), and two samples with a collapsed sclerotic boundary (Type 3) were collected from each femoral head for the FEM and histopathological analyses. FEM was performed using CT data, and the distributions of von Mises equivalent stress, octahedral shear stress, @entity6475 , and simulated @entity174 area were evaluated. Furthermore, the osteoclast count at the boundary was compared for each type. RESULTS: In normal and Type 1 samples, the distributions of von Mises equivalent stress, octahedral shear stress, @entity6475 , and the @entity174 area were equally concentrated along the whole analytical range; however, in the Type 2 and 3 samples, they were concentrated along the thickened bone trabeculae at the boundary, which corresponded to the @entity174 area. Histopathologically, a significantly increased osteoclast number was observed only at the collapsed sclerotic boundary. CONCLUSION: These results demonstrated that both shear stress and @entity6475 tend to be concentrated on thickened bone trabeculae at the boundary. Fracture analyses revealed that the boundary of sclerotic changes, which results from the repair process, may be the starting point of the @entity174 . Additionally, the @entity3457 increases after collapse.
