Finite element simulation of the hip joint during stumbling: a comparison between static and dynamic loading

Finite element stress analysis technique has been used to optimize both design and material selection in load-bearing components in artificial hip joints based on the static load analysis, by selecting the peak load during the patient activity. In this study, a component was subjected to a dynamic load due to stumbling and the peak static load of the same patient load activity. Two quantitative measures are calculated: peak stress and stressed volume. It has been shown that each measure may lead to differing conclusions. It is concluded that from a thorough analysis of the hip prosthesis components (prosthesis, cement mantle and bone) it is not the peak stress but rather the proportion of the stressed elements (or stressed volume) which should be the indicator if a precise analysis of the load transfer mechanism is required. In static analysis the material was assumed to be linear elastic continuum with isotropic properties, whereas in dynamic analysis it was assumed to be bi-linear elasto-plastic.