The word fracture stands for interruption of the bone; this maybe due to a trauma, like a fall down. The healing of a fracture can be “primary” by creating directly new extra bone. In this case it is necessary to obtain: stability, compression and a good apposition of the fragments. For these reasons the patient needs a surgical approach involving plates and screws. Therefore, the healing can be “secondary” by leading to the formation of a callus. In this case an external fixator is worth to help the healing process in order to guarantee: stability, dynamization and, sometimes, compression or distraction.