Purpose <p>Percutaneous fixation of pelvic fractures using sacroiliac (SI) screws is recognized as a less invasive alternative to open surgery. Despite advancements in this technique, complications still occur. This study aims to evaluate the accuracy of IS screw placement assisted by intraoperative 3D navigation. </p> Methods <p>A retrospective study was conducted on patients treated for sacral fractures or SI joint dislocations between 2016 and 2023 at a single institution. All procedures were performed using O-Arm 3D fluoroscopy and StealthStation S8 navigation platform (Medtronic). For each screw, all accuracy measurements—including length, angulation, and cortical perforation—were performed on the final 3D scans. </p> Results <p>Of the 241 screws implanted, 83.2% showed no perforation. Screw angulation was generally less accurate, with 26.5% of screws showing a minor deviation of 5° from the ideal trajectory. Accuracy was significantly lower in the axial plane compared to the coronal plane. On average, the implanted screws reached 78% of the maximum length the S1 corridor could accommodate. </p> Conclusion <p>This study represents the largest series to date of SI screw implantation using 3D navigation. Navigation proved to be safe for IS screw placement. Although overall accuracy in our series was slightly lower than that reported in other studies using the O-Arm, our sample included six times more patients, multiple surgeons, and a heterogeneous cohort. 3D navigation with O-Arm proved more helpful in avoiding cortical perforations than in improving screw angulation.</p>