The greater sciatic notch-based transcolumnar magic screw trajectory in the acetabulum: An anatomical guide

This study aims to define the greater sciatic notch (GSN)-based transcolumnar "magic screw" corridor in the acetabulum and to assess its morphometric characteristics and anatomical feasibility according to quadrilateral plate (QP) morphology.

Between November 2025 and January 2026, three-dimensional morphometric analysis was performed on pelvic CT reconstructions of 90 adults (180 acetabulae) with intact pelvic bones and no evidence of hip or pelvic pathology. Using Mimics, pelvic models were reconstructed and a virtual 6.5-mm cannulated screw was advanced from the midpoint of the GSN toward the anterior column along a transcolumnar intraosseous trajectory. Bilateral trajectory length, angulation, and QP thickness were recorded. Differences by sex and side, age associations, and anatomical feasibility ("easy" versus "hard") were analyzed based on anatomical corridor constraints.

Of the patients included in the study, 42 were male and 48 were female with a mean age of 49.88 ± 17.18 (range, 19 to 86) years. The defined GSN-based transcolumnar screw corridor was anatomically feasible in 94.44% of cases. Mean posterior acetabular screw length was 74.16 ± 7.49 mm right and 73.21 ± 6.90 mm left. Mean GSN entry segment length was 22.95 ± 4.14 mm right and 23.48 ± 4.34 mm left. Mean acetabular screw angles were 125.86° ± 6.05° right and 124.26° ± 5.24° left, with a small but significant right-left difference (p = 0.004). The QP morphology demonstrated substantial variability: mean maximum thickness was 14.87 ± 2.75 mm right and 14.77 ± 2.82 mm left, while minimum thickness was 3.46 ± 1.37 mm right and 3.48 ± 1.32 mm left. Men had significantly greater superior and posterior acetabular screw lengths and markedly thicker QP parameters compared with women (all p ≤ 0.027), with large effect sizes for QP thickness (d > 1.0).

A GSN-based transcolumnar magic screw corridor appears anatomically feasible in most adult pelves and provides a quantifiable intraosseous trajectory reaching both acetabular columns. Quadrilateral plate thickness emerges as the main anatomical limiting factor, particularly in female pelves and in cases categorized as corridor-constrained.