The genetic basis for stress fractures

The exact cause of stress fractures is currently unknown. Strenuous exercise, especially repeated, cyclical, weight bearing activity (as in marching or running on hard surfaces) seems to be an essential prerequisite for development of stress fractures in the lower extremities. Most researchers agree that an inadequate adaptation of the bone to a change in its mechanical environment, involving an imbalance between bone microdamage and remodeling, is the mechanism that underlies stress fractures. However, the fact that only a fraction of soldiers undergoing similar vigorous training programs sustain stress fractures even though they are exposed to similar conditions of fatigue, diet, and weight load, has led to the notion of preexisting risk factors. Presumably, these risk factors predispose a susceptible individual to developing stress fractures which would become clinically apparent only under the appropriate conditions (i.e., vigorous physical training). Factors reported to be associated with a statistically significant increased risk of developing stress fractures are numerous.