Application of a modified rectangular locking device in the treatment of femoral shaft fractures with intramedullary nailing

• The modified rectangular locking device achieved a 98% success rate in distal locking screw placement with an average of only 1.1 fluoroscopic exposures per case. • The device reduced distal locking screw placement time to an average of 7.0 minutes, significantly improving surgical efficiency. • Postoperative functional outcomes were excellent, with an average American Knee Society Score of 185 after fracture healing. • The device offers advantages over existing techniques by eliminating the need for specialized equipment and extensive surgical experience, while ensuring accuracy and repeatability.