A novel coplanar X-ray guided method and device for insertion of distal locking screws in intramedullary bone nails. The device has coplanar holes, which allow insertion of protective sleeves. A drill and bone screws can be inserted through the protective sleeves. Radiopaque target markers in the aiming arm enable the easy positioning of an X-ray source such that an X-ray beam is coplanar with the aiming arm transverse holes. After the X-ray source is accurately oriented, a single X-ray snapshot is enough to assess the exact distortion of the implanted intramedullary nail. The X-ray beam need not be coaxial with the intramedullary nail holes. The aiming arm has a mobile portion and a fixed portion fastened to the nail, wherein said aiming arm can be adjusted, displacing the mobile portion over the fixed portion, to compensate for the distortion of the intramedullary nail after implantation. Once the aiming arm is precisely positioned, the aiming arm transverse holes and intramedullary nail holes are accurately aligned, protective sleeves are inserted through aiming arm holes, bone drills are drilled through the intramedullary nail holes and surrounding bone material, and bone screws are inserted, locking the intramedullary nail to the bone.