Method to attach two sections of bone together in which a telescoping screw system is positioned through a hole of a fixation device attached to a first section of bone while the screw system is in a closed configuration in which the screw body is telescoped inside the screw barrel. The screw body is then advanced relative to the screw barrel to cause penetration of the forward, threaded end of the screw body into a second section of bone, and thereby bring the screw system toward an open configuration in which the screw body is telescoped outside the screw barrel. The screw barrel is also engaged to the fixation device via a cooperating engagement mechanism.