A study of the modified sacroiliac screw technique in Day type II crescent fracture dislocation of the pelvis
Authors: Li Renjie , Liu Leyu , Guan Jianzhong , Wang Xiaopan , Zhao Peishuai , Chen Xiaotian , Wu Min 
Published: September 2024

Background
When the traditional sacroiliac screw is used in the treatment of Day type II crescent fracture dislocation of the pelvis, the screw entry point may be located near the fracture line and lead to the failure of screw pressurization, and at the same time, the short channel of the iliac segment of the screw has defects such as insufficient holding power. This study proposes a modified sacroiliac screw technique and investigates the value of the modified sacroiliac screw in the treatment of Day type II crescentic fracture dislocations of the pelvis.
METHODS
We retrospectively analyzed 44 patients with pelvic Day type II crescent fracture dislocations who underwent surgical treatment from January 2019 to June 2023 in our hospital. They were divided into two groups according to the sacroiliac screws for comparative study. We compared the gender, age, cause of injury, fracture classification, time from injury to surgery, intraoperative bleeding, anterior ring fixation method, iliac fixation method, total length of sacroiliac screw, length of iliac and sacral segments of sacroiliac screw, shortest distance from the sacroiliac screw entry point to iliac fracture line, quality of reduction, postoperative complications, and clinical prognosis of the patients in the two groups.
RESULTS
Follow-up was obtained in all patients, and the differences between the two groups in terms of gender, age, cause of injury, fracture classification, time from injury to surgery, intraoperative bleeding, and fixation method of the anterior ring and ilium were not statistically significant (P > 0.05). The average length of the iliac segment of sacroiliac screws in group A was 3.71 ± 0.85 cm, which was significantly longer than that in the control group (2.12 ± 0.47 cm, P < 0.01).The shortest distance between the entry point of sacroiliac screws and the iliac fracture line in group A was 3.31 ± 0.88 cm, which was significantly longer than that in the control group (1.22 ± 0.64 cm, P < 0.01). The quality of fracture reduction was assessed according to the Matta score based on the pelvic X-ray results in the first week after surgery: group A: 12 cases with excellent results, 7 cases with good results, 2 cases with acceptable results, and no poor results; group B: 6 cases with excellent results, 12 cases with good results, 5 cases with acceptable results, and no poor results; the quality of reduction in group A was better than that in group B (P < 0.05). The VAS score of sacroiliac joint pain at the last follow-up was 0 in 10 patients, < 3 in 7 patients, and 4–6 in 4 patients in Group A. In Group B, there were 5 patients with a score of 0, 8 patients with a score of < 3, and 10 patients with a score of 4–6. The relief of sacroiliac joint pain in Group A was better than that in Group B. (p < 0.05)
Conclusion
When the modified sacroiliac screw is used to treat Day type II crescent fracture of the pelvis, the screw entry point can avoid the iliac fracture line, and at the same time, the screw channel is long and the holding force is stronger than that of the traditional sacroiliac screw, which is worthy of popularization and application in the clinic.