Trends in Posterior Malleolus Fixation and Subsequent Syndesmotic Repair in Trimalleolar Ankle Fractures

Research Type: Level 3 - Retrospective cohort study, Case-control study, Meta-analysis of Level 3 studies Introduction/Purpose: Growing evidence suggests addressing posterior malleolus fractures in trimalleolar ankle fractures may enhance syndesmotic stability. However, syndesmosis open reduction internal fixation (ORIF) encounters various challenges, particularly malreduction, rendering it an imperfect procedure. This study aims to evaluate contemporary practices in the treatment of trimalleolar fractures, assessing whether there is a rising trend in posterior malleolus fixation alongside a decline in subsequent syndesmotic repair. Methods: A retrospective cohort analysis of the PearlDiver (Mariner dataset) database from 2010-2021 was performed for patients undergoing trimalleolar ORIF and stratified by posterior lip fixation status. Annual percentage incidence of syndesmotic repair within these cohorts was tabulated and compound annual growth rate (CAGR) and Mann Kendall analysis was performed to assess trends. Characteristics associated with posterior lip fixation were analyzed with χ2 analysis. Results: From 2010-2021, there was an increase in the incidence of concomitant posterior malleolus fixation in trimalleolar ORIF from 17.6% to 21.4% (CAGR: +6.2%, Mann Kendall p-value: 0.011). The incidence of trimalleolar ORIF without posterior fixation decreased from 82.4% to 78.6% (CAGR: -3.0%, Mann Kendall p-value: 0.04). The incidence of syndesmotic repair following trimalleolar fixation increased from 10.1% to 29.3% (CAGR for posterior fixation: +17.0%, Mann Kendall p-value: < 0.001; CAGR for no posterior fixation: +13.1%, Mann Kendall p-value: < 0.001). Trimalleolar ORIF with posterior fixation demonstrated similar rates of malunion, nonunion, and reoperation at two-years postoperative, with no significant differences on χ2 analysis, compared to those without posterior malleolus fixation. Conclusion: The incidence of trimalleolar ORIF with posterior lip fixation has increased over the past decade. Contrary to our hypothesis, the rate of subsequent syndesmotic repair following trimalleolar ORIF increased, potentially due to the heightened recognition of the importance of syndesmotic stability. Future randomized control studies may further evaluate the effect of posterior lip fixation on syndesmotic stability.