A method for treating a fracture of a bone with a medullary canal. A first and a second group of three elongated monocortical pins are provided. Each pin has a stem with a first end portion having a conical shape with an external thread for insertion into a cortical portion of a bone. Each pin of the first and second group of three monocortical pins is inserted a predetermined distance from the bone fracture, and penetrates only into the cortical portion of the bone without reaching the medullary cavity, the pins of the first and second group being inserted such that they are not coplanar to each other. The stems of the pins of the first and groups are blocked to a first and a second common clamp element respectively. The first and second clamp elements are joined to a common rod to form a rigid external fixation system.
