Does malreduction of the sacroiliac joint affect the clinical outcomes in unstable pelvic ring injuries after internal fixation? : a case control study

Abstract

Background: To evaluate the effects with malreduction of the sacroiliac joint on the clinical outcomes in unstable pelvic ring injuries after internal fixation. Methods: A retrospective analysis the data of patients with unstable pelvic ring injury after internal fixation from February 2016 to December 2019, all patients with disruption of the sacroiliac joint. All patients were grouped according to the maximum residual displacement of the sacroiliac joint（d）after operation. According to the post- operative CT, d≤5mm were classified as anatomical reduction group, and d＞5mm were classified as malreduction reduction group. The Majeed pelvic fracture scoring system was used to evaluate the postoperative functional outcomes, and the Visual Analog Scale was used to evaluate the postoperative pain. Re-displacement of the sacroiliac joint, or loosening and breakage of the internal plants, or re-displacement of the fracture were defined as the failure of internal fixation. Results: A total of 86 patients were included in this study, including 48 males and 38 females. According the measurement of postoperative CT, there were 36 cases with the sacroiliac joint anatomical reduction and 50 cases with the malreduction. The excellent and good rate of Majeed score, anatomical reduction group was more than malreduction group, the difference was statistically significant (χ2=13.242, P <0.05). VAS score with anatomical reduction group was less than malreduction group, the difference was statistically significant (χ2=13.285, P <0.05). The failure rate in the anatomical reduction group was lower than the malreduction group, and the difference was statistically significant (χ2=4.129, P＜0.05). Conclusion: Reduction and internal fixation of pelvic fractures with involving sacroiliac joint disruption, the functional outcomes with malreduction of sacroiliac joint is significantly worse than anatomical reduction. The malreduction group has a higher failure rate of internal fixation. Trial registration: The study was conducted according to the guidelines of the Declaration of Helsinki and retrospectively registered on Honghui Hospital, Xi'an Jiaotong University (identification number: 202306002).