Safety Assessment of Femur

Femur is the longest and strongest bone in the human body. It is subjected to various loads created during different physiological activities. Stresses developed in the femur depend upon the material property, which depends upon the density of the femur and the load (body weight) acting on it. The femur density and body weight varies from person to person. Stochastic finite element analysis of the femur has taken care of all the uncertainties present in the material properties and forces acting on the femur head. Prediction of the stability of the femur depends upon the choice of the failure criteria, material properties, and loading condition. Thus, the focus of the present study is on three basic aspects. Firstly, the finite element model, determination of critical load on the femur as per the gait cycle, modeling of the load application, and boundary conditions. Secondly, stochastic finite element analysis of the femur as per the limit state derived from the maximum strain failure criteria, in which probabilistic material properties are employed. Third part deals with the computational efficiencies of the various methods employed to obtain the probabilities of failure and corresponding safety assessment of the femur for normal and osteoporotic patients. Further, the scope of the study covers the effect of a range of scatters (in terms of standard deviation) of random variables on probabilities of various cases.