Purpose <p>Intramedullary nailing is a standard method for osteosynthesis of diaphyseal humeral fractures. Distal locking, however, typically requires fluoroscopic guidance, which increases radiation exposure. This study aimed to compare standard fluoroscopy-guided distal locking with the Ezy-Aim system (Austofix, Australia) based on electromagnetic pulse detection from the perspectives of surgical times, radiation exposure, and complications.</p> Methods <p>A retrospective study included 58 patients treated for diaphyseal humeral fractures (AO/OTA 12A, 12B) between 2019 and 2023. Group A (<i>n</i> = 28) received osteosynthesis using the Ezy-Aim system; Group B (<i>n</i> = 30) underwent fluoroscopy-guided distal locking. Data on operative time, fluoroscopy time, radiation dose, and complications were analysed.</p> Results <p>In all, distal locking was not successful at the first attempt in 14.3% (4/28) of screws placed with Ezy-Aim and 20.0% (6/30) when fluoroscopy was used. Time and dose analyses were performed on the remaining 48 patients. The total surgical time was significantly longer with the Ezy-Aim system (median 58 min) compared to fluoroscopy (median 52 min, <i>p</i> = 0.034), primarily due to the time required for the device assembly. However, distal screw placement was faster with Ezy-Aim (median 12 min vs. 14 min, <i>p</i> = 0.019). Radiation exposure was significantly lower in the Ezy-Aim group (median total dose 418 cGy/cm² vs. 582 cGy/cm², <i>p</i> = 0.003). No complications were observed in either group.</p> Conclusions <p>The Ezy-Aim system reduces radiation exposure and speeds up distal screw placement, though it prolongs total operative time due to assembly requirements. This method offers a safe and effective alternative to fluoroscopic guidance for distal locking in humeral shaft fractures.</p>