In young adults, nearly all complete femoral shaft fractures are displaced fractures. In a special situation of an adequate bending movement or an adequate direct force to break the femur, an incarceratable geometry of the fracture ends and balanced muscular forces of the thigh after a fracture, fracture ends will lock in varal alignment. In this situation, we can complete closed femoral nailing without the use of a fracture table and fluoroscope in lateral decubitus position after careful preparation. Therefore, we could avoid some radiation exposure.