Abstract
PURPOSE: This study aimed to design, develop, and validate a low-cost, 3D-printed external aiming device to facilitate accurate percutaneous screw fixation of minimally displaced posterior acetabular column fractures. It addresses the technical challenges of achieving optimal screw trajectories while minimizing fluoroscopic exposure, particularly in settings without access to navigation-guided systems. METHODS: In this Phase I study, CT scans of 40 adults (aged 18-75) were analyzed to identify morphometric parameters influencing posterior column screw trajectories, with attention to gender-specific anatomical variations. A modular external jig was designed using Autodesk Fusion 360 and fabricated via 3D printing. The jig was tested on six pelvic sawbone models (12 hemipelves) by eight orthopedic surgeons, resulting in 48 K-wire insertions. Key metrics included jig assembly time, entry point accuracy, and grading of K-wire exit points as Excellent, Good, or Failed. RESULTS: Significant gender-based differences were found in ASIS-PSIS distance (p < 0.001), sagittal posteroanterior angle (p = 0.007), and coronal mediolateral angle (p = 0.053), confirming the need for tailored jig design. Mean assembly time was 47.5 ± 2.0 s. Among 48 insertions, the central, medial, and anterior entry points achieved 100% accuracy, while the posterior and lateral approaches resulted in 50% and 64% failure rates, respectively-highlighting the critical importance of entry point selection. CONCLUSION: This study demonstrates the feasibility of a modular 3D-printed external aiming jig for accurate percutaneous fixation of minimally displaced posterior acetabular column fractures. As a pre-clinical benchtop validation on sawbone models (with cadaveric testing in progress), it offers a low-cost, rapidly manufacturable (1-2 days) alternative to navigation-based systems, particularly suited for resource-limited settings.