JB & JS open access
Three-Dimensional Computed Tomography-Based Mapping of the Intraosseous Safe Zone for Acetabular Cup Screw Fixation: A Retrospective, Single-Center Cohort Study
By Sato T, Hirasawa R, Hagiwara S and 5 others.
Abstract
Background
Conventional safe zones are defined by the proximity of acetabular cup screws to intrapelvic vessels; however, this relationship varies among individuals. This study aimed to define the intraosseous safe zone in which the screws remain entirely within bone without penetrating the medial wall.
Methods
Three-dimensional computed tomography data for 30 hips of female patients with normal acetabular morphology were analyzed. A hemispherical cup was positioned virtually, and screw trajectories were evaluated in 24 directions using a clock-face coordinate system referenced to the ipsilateral anterior superior iliac spine. Bone thickness was measured in each direction, and intraosseous safe zones were defined for screw lengths of 15, 20, 25, 30, 40, and 50 mm. Heatmaps were generated to visualize the distribution of safe regions, and the angular range in which screws remained intraosseous in all cases was determined.