What factors are associated with loss of alignment after open reduction and internal fixation for tibial plateau fractures? A retrospective multicenter (TRON group) study

Tibial plateau fractures (TPFs) are one of the most challenging intra-articular fractures to treat. Along with reconstruction of the articular surfaces, appropriate alignment of the knee joints must be obtained and maintained after open reduction and internal fixation (ORIF) for TPFs because loss of alignment (LA) is associated with worse clinical outcomes. We aimed to investigate and clarify the risk factors related to LA after ORIF for TPFs.This multicenter, retrospective cohort study used data of hospitals of the Trauma Research Group (TRON group) from January 1, 2011, to December 31, 2020. Among 293 TPFs extracted from the database, we evaluated the alignment of the articular surface to the anatomical axis of the tibia in the immediate postoperative and last follow-up radiographs. We defined a change of alignment from the immediate postoperative radiograph as LA. We evaluated the risk factors of LA using univariate and multiple logistic regression analyses.LA was observed in 27 fractures (9.2%). In multiple logistic regression analyses, preoperative articular step-off and postoperative condylar widening were statistically associated with LA (OR = 1.1, 95% CI: 1.02-1.19 and P = 0.012; OR = 1.04, 95% CI: 1.00-1.08, P = 0.045, respectively). We calculated the threshold by drawing a receiver operating characteristic curve using the final regression model. The threshold of postoperative widening was 8.2 mm. We divided the 293 TPFs into two groups according to this threshold and determined differences between the two groups using Fisher's exact test. The two groups were statistically significantly different (P = 0.00502).Preoperative articular step-off and postoperative condylar widening could be associated with LA after ORIF for TPFs. We suggest that intraoperative restoration of condylar widening is important for the prevention of malalignment following ORIF for TPF.