Three-dimensional Finite Element Analysis And Mechanical Study On The Osteolytic Metastases Of Proximal Femoral

Objective: This paper is written to achieve those three goals: first, to establish thethree-dimensional finite element model of different sizes of the osteolytic metastasestumor in proximal femoral; second, to analyze the stress changes in the local lesion duringslow walk mode, Third, to provide the basis for clinical preventive surgery by assessingthe fracture risks.Methods：The methods of this paper are designed as follow: First, Bothlower extremities of the volunteers underwent thin CT scan to obtain data related to thefemur. The image data were input into Mimics11.1image processing software for imageprocessing， then, the data were input into UG4.0software for modeling, Second, loadthe femur when single foot landing during slow walking mode. Finally, use the finiteelement software to analyze the femoral neck district, intertrochanteric area and change ofstress levels in subtrochanteric zone.Results:1.Defects of femoral neck level: When theintramedullary defect not involving inner cortex in diameter to90%, the local stressabruptly increased to135.98MPa. While intramedullary defects involving half of medialcortex to70%, the local stress abruptly increased to92.34MPa. When hemispheric lesionswith destruction of the cortex up to60%, the local stress was becoming greater than theyield stress, up to101.19Mpa.2.Intertrochanteric level: When the intramedullary defectnot involving inner cortex in diameter to80%, the local stress jumped to131.21MPa.While intramedullary defects involving half of medial cortex to80%, the local stressabruptly increased to105.19MPa. The hemispherical lesions with destruction of thecortex, defect of70%, the local stress was greater than the yield stress scale, up to92.21MPa.3. While intramedullary defects involving half of medial cortex to80%, thelocal stress jumped to92.42MPa. When hemispheric lesions with destruction of thecortex up to70%-80%, the local stress increased to89.97MPa~105.19Mpa, greater thanthe yield stress.Conclusion：In proximal femur, the intramedullary lesions which don’t penetrate the cortical bone have little effect on stress scales in the same place. For thelesions which destroy the unilateral cortical bone, the risks would occur on suchconditions as:1, In Femoral neck level, the destruction in diameter greater than60%;2, InIntertrochanteric level, the destruction in diameter greater than70%;3,In Subtrochantericlevel, the destruction in diameter greater than70%.