The completely asymptomatic displaced femoral stress fracture: a case report and review of the literature.

Pain is protective in stress fractures. Its presence usually signals to the trainee to decrease or halt training. This prevents a microstress fracture from progressing into a macrofracture. A case is presented in which an infantry recruit sustained a displaced femoral diaphyseal stress fracture which was totally asymptomatic until the bone broke in the middle of a run.