Effects of mechanical stress/strain and estrogen on cancellous bone structure predicted by fuzzy decision

A theoretical model was developed on the basis of fuzzy decision to predict cancellous bone structure following changes in mechanical stress/strain and estrogen. The model was validated experimentally by simulation of the normal structure of a rat distal femur, and further used to predict the structural alterations following ovarian hormone deficiency. The results show that net bone resorption after ovariectomy occurs in the metaphysis at locations where trabecula were subjected to the lowest mechanical stress/strain. These findings, consistent with experimental results, suggest that estrogen deficiency increase the mechanostat set point at which bone cells perceive mechanical stress/strain. Additionally, the results show that changes in bone architecture which are due to alterations in bone remodeling can be simulated by fuzzy decision without precise mathematical description, and multiple factors can also be readily incorporated into the model.