Abstract:

Objective　To find and measure the safe lag screw placement channel (SLSC) in the anterior column of acetabulum by the digital simulation technique (DST).　Methods　To find and measure the safe lag screw placement channel in the anterior column of the acetabulum under the standard 3D coordinate system and the three-dimensional coordinate system of the pelvis by establishing 96 cases of 3D finite element female die of the anterior column of acetabulum through 3D reconstruction of 48 cases of normal adult pelvic spiral CT data by Mimics 15.0.　Results　The parameters of SLSC of the anterior column of acetabulum: The max radius is （4.65±0.54） mm in male, and （3.71±1.68）mm in female; The depth is （114.91±6.52） mm in male, and （102.97±6.24） mm in female; The narrowest screw placement site is in the anterior wall of the acetabulum, and the distance between the narrowest screw placement site and direct penetrating site :Male is（34.57±2.16）mm, and female is （29.82±1.94）mm; The distance between the narrowest screw placement site and retrograde penetrating site: Male is （73.32±3.27）mm, and female is（69.49±2.52）mm; The angle with the horizontal plane is（45.22±1.54）° in male ,and（43.59±3.24）° in female; The angle with the sagittal plane is （41.65±5.37）° in male, and（47.82±4.12）in female; The angle with the coronal plane is（18.71±2.36）° in male, and （19.23±2.49）° in female. The max radius, the depth of the screw, the angle with the longitudinal sectional plane showed sex-related statistical differences (P＜0.05).  Conclusions: DST can accurately measure the SLSC of the anterior column of acetabulum.

Key words: Digitization, Three dimensional reconstruction, Anterior column of the acetabulum, Screw, Safe screw