[A new roentgen ray-free aiming technique for distal locking screw boring of the unreamed tibial nail].

A mechanical aiming device for the placement of distal locking screws of the unreamed tibial nail (UTN) has been developed. At the level of the distal nail end, a roughly placed "contact hole" is drilled (diameter, 6.0 mm). An asymmetric spacer is inserted through this contact hole, placed directly onto the nail and connected with the aiming arm. By this re-adjustment, the direction and the plane of both distal transverse holes are defined and can be drilled. A medial spacer re-adjusts the aiming arm for the aphole.