Safety, Efficacy, and Screw Accuracy of CT-Navigated INFIX for Unstable Pelvic Ring Fractures: A Retrospective Study

OBJECTIVES: To evaluate the clinical performance, screw placement accuracy, and complication profile of intraoperative computed tomography (CT)-guided anterior subcutaneous internal fixation (INFIX) for unstable anterior pelvic ring fractures. METHODS: . DESIGN: Retrospective study. SETTING: Single tertiary emergency medical center, equivalent to a Level I Trauma Center. PATIENT SELECTION CRITERIA: A retrospective review was performed of skeletally mature patients with unstable anterior pelvic ring injuries (Orthopaedic Trauma Association/AO type 61) treated with CT-navigated INFIX fixation between December 2020 and December 2024. Patients with incomplete imaging or follow-up were excluded. OUTCOME MEASURES AND COMPARISONS: Primary outcomes included operative time, intraoperative blood loss, screw placement accuracy (axial angle and skin-to-head distance), and functional outcomes using a modified Majeed score (excluding work and sexual activity domains). Complications were recorded and compared by fixation construct. RESULTS: A total of 41 patients were included, with a mean age of 50.7 ± 24.0 years. Mean operative time was 121.0 ± 61.8 minutes, and mean intraoperative blood loss was 86.8 ± 113.0 mL. Temporary external fixation was used in 48.8% of cases. The normalized modified Majeed score averaged 87.5 ± 12.7, and 65.9% of patients achieved "excellent" outcomes. The most frequent complication was lateral femoral cutaneous nerve injury (26.8%). No screw displacement occurred in cases with additional posterior fixation. Postoperative CT demonstrated consistent screw placement (mean axial angle, 27.0 degrees; mean skin-to-head distance, 15.3 mm), and no major neurovascular complications were observed. CONCLUSIONS: CT-guided INFIX allowed accurate screw placement with a low rate of major complications. Early functional outcomes were favorable when assessed with a modified score tailored to the study population. Combined anterior-posterior constructs enhanced fixation stability. Prospective comparative studies were warranted to clarify long-term outcomes. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.