Abstract
This paper deals with relation between the stress of the finite element femur model and femoral morphological parameters. First of all, three-dimensional geometry of 42 human femurs (21 males and 21 females) was reconstructed numerically from photographic data in three different directions. These original data were used for finite element representation of the femur geometry, for determination of external load environment around the bone and also for calculation of characteristic morphological parameters of the whole bone shape. Finite element models of the femur were subjected to Integrated Structure Analysis System 2 (ISAS 2) under calculated load conditions with published material properties. Factor analysis was applied to calculated stress data, morphological parameters and load conditions. The following relations were found. (1) Equivalent stress on the diaphyseal surface is intensively influenced by bone thickness but it is never affected by a general size factor. (2) The direction of maximum equivalent stress on each cross section is related to neck torsion but the rotation of the maximum stress direction is not so closely related. (3) The inclination of the stress along the shaft on the medio-lateral margins is influenced by lateral leaning of the femur. (4) There is a sexual difference in the interaction between bone thickness and equivalent stress but the mechanism is not yet understood.
