Obturator Oblique and Pubic Ramus Inlet Views Can Better Guide the Insertion of an Anterior Column Acetabular Screw

Abstract

Objective The objective of the present paper was to investigate the value of obturator oblique and pubic ramus inlet views in guiding anterior column acetabular screw insertion. Methods We collected pelvic CT scans at the diagnostic imaging center of our hospital between 2017 and 2019. Virtual three‐dimensional (3D) models of the pelvis were created based on the CT scans. Then the transparency was adjusted to 30%. Two identical copies of the 3D model data were made. 3D model replications were divided into a control group and an experimental group. In the control group, the screw was inserted into the anterior acetabular column using obturator‐outlet and iliac‐inlet views. In the experimental group, the screw was guided under obturator oblique and pubic ramus inlet views. Based on whether the screw penetrated the hip joint and/or exited the pubic ramus, models were divided into three grades. Grade I: the screw travels completely within the anterior column bone corridor; Grade II: the screw exits the superior pubic ramus, but the length of the screw outside the channel does not exceed 1/2 of the anterior column; Grade III: the screw exits the superior pubic ramus and the length of the screw outside the corridor exceeds 1/2 of the anterior column. We compared the screw placement quality of the two groups and analyzed differences between genders. In addition, the distance between the screws and the acetabulum was recorded and compared among the two groups. Results A total of 110 hemipelves were selected, including those of 80 men and 30 women, with an average age of 46.76 ± 14.26 years. In the control group, the screw quality of 64 models (58.2%) was Grade I. In the experimental group, 94 models (85.5%) had Grade I screw placement quality. Grade II screw placement quality accounted for 18.2% of the control group and 7.3% of the experimental group. In the control and the experimental groups, there were 26 and 8 cases with Grade III screw placement quality, respectively. The quality of screw placement in the experimental group was significantly better than that in control group, and the difference between the two groups was statistically significant (P < 0.01). The distance between the screw and the acetabulum in the control group and experimental group was 0.92 ± 0.49 mm and 2.78 ± 1.15 mm, respectively. The difference between the two groups was statistically significant. Conclusion Anterior column acetabular screws can be inserted successfully and more accurately using the obturator oblique and pubic ramus inlet views.

Keywords

• Acetabulum
• Anatomy
• Cross‐sectional
• Fracture fixation
• Internal