Comparison of anterograde versus retrograde percutaneous screw fixation of anterior column acetabular fractures

Percutaneous screw fixation is an effective technique in addressing minimally displaced anterior column acetabular fractures. The aim of this study is to evaluate the ease of percutaneous screw insertion for acetabular anterior column fracture, as it pertains to anterograde versus retrograde insertion techniques. From 2009 to 2013, CT imaging from 30 adult volunteers (15 males, 15 females) without history of pelvic disruption and/or morphologic abnormalities were evaluated. From these images, virtual 3D pelvic models were generated. The differences area of screw starting points, limitation position of anterior column screws, and range of screw directions were analyzed. We found in our analysis that anterograde and retrograde had not only variations in their starting points, but differences in areas of insertion. Typically, anterograde portals have a larger area for insertion. Additionally, given the limitations we noted in screw position and the severity of the acetabular fractures, this will allow the treating surgeon to determine the most optimal technique for percutaneous anterior column screw fixation. Results In our analysis, we found two areas for effective percutaneous anterograde insertion and one area for effective retrograde insertion. They both possess geometries with different shapes. Additionally, the area of anterograde insertion is larger than the retrograde area of insertion. The limitations in screw positions were shown in the AP, inlet, outlet, iliac oblique, obturator oblique, and lateral views. The direction range between superior and inferior and between medial and lateral were measured and recorded. In area of anterograde, the angle between the superior and inferior limits was 29.2. +/- 2.7., while the angle limit between medial and lateral was 18.5. +/- 1.8.. In area of retrograde, the angle between the superior and inferior limits was 8.32 degrees +/- 1.3 degrees, while the angle limit between medial and lateral was 7.5 degrees +/- 0.8 degrees.