Fracture weakens ipsilateral long bones: mechanical and metabolic changes after femoral or tibial injury in rats.

We have studied the effect of tibial osteotomy on mechanical and metabolic properties of the femur, and the effects of femoral osteotomy or fracture on mechanical properties of the tibia in rats. In the bone ipsilateral to the trauma, there was a significant reduction of mechanical strength and stiffness, both in bending and torsion, compared with the contralateral side. The ipsilateral bone lost weight and the blood flow was increased. The mineral incorporation rate was not affected. This may be due in part to disuse of the traumatized limb, but the fracture itself may affect the other bones in the extremity.