Stress and strain patterns in normal and osteoarthritis femur using finite element analysis

Bone tissue stress and strain levels play a crucial role in bone remodeling. In fact, abnormal remodeling is documented in pathological conditions, such as in subject affected by osteoarthritis, even if this aspect seems to be poorly explored. We used FE analysis to investigate how the stress and strain distributions can be correlated with the loading conditions of the osteoarthritic femur and how a weird stimulation of trabecular tissue could lead to anomalous rearrangements of its pattern. For our analysis we developed, from X- ray images, 2D isotropic, homogeneous and linearly elastic models. The results show that stress and strain for the healthy femur are consistent with literature, whereas in osteoarthritic hips the physiological distribution of strain results altered and, consequently, anomalous remodeling processes take place: zones with very low (geodes) and/or very high (eburnation) bone density could appear, due to an unbalance in the activity of osteoblasts and osteoclasts.