Stress analysis for osteoporosis head of femur: Finite element method for mechanical analysis of osteoporosis hip joint

Human hip joint diseases, such as osteoporosis, osteonecrosis, osteolysis, and osteoarthritis, induce pain and loss of mobility to millions of people around the world. Stress analysis is useful for identifying the effects of the abnormality on joint functions. Finite element analysis (FEA) is very powerful technique to the stress analysis of non-homogeneous and nonlinear biological systems. In this study osteoporosis was simulated using finite element analysis in Ansys 12.1 simulation environment. Osteoporosis cause loss of bone mineral density (BMD). Thus its effects are on bone physical and mechanical properties must be known since it can cause joint dysfunctions. In this study stresses, strains, and equivalent von-mises stresses were estimated in the head of femur during static stance for range of different bone mineral densities (1.32-0.4 g/cm3) to simulate the cases of normal healthy adult, aging, osteopenia and osteoporosis, from the results a curve for BMD vs. Strain has been sketched showing an increase up to four times in strains for the case of osteoporosis. The study assumed orthotropic behavior of bone, hence Young and Shear moduli decreased with decreasing BMD this case very large increase in strains and slight increase in tensile and compressive stress of the femur neck.