Influence of posterior malleolar fragment morphology on the outcomes of trimalleolar fractures: A systematic review and meta-analysis

Trimalleolar fractures are generally considered to have inferior outcomes among ankle injuries. Historically, emphasis was placed on the size of the posterior malleolar fracture (PMF) to guide surgical decision-making and predict outcomes. Recent studies have suggested that the morphology of the PMF fragment is more important than its size. The aim of this systematic review was to determine if the outcomes of trimalleolar fractures depend on the morphology of the PMF as per the Haraguchi classification system after surgical fixation.A systematic literature search was conducted in the electronic databases of PubMed, Embase, Scopus, and Ovid. Title and abstracts were screened, and data from eligible studies were extracted. Meta-regression and pooled analysis was performed using appropriate computer software.11 studies with 597 patients were included in the final analysis. Pooled mean AOFAS score was 87.43 (95% CI 84.24-90.62) after a mean follow-up of 31.6 months. Univariate and multivariate meta-regression analysis demonstrated that as the percentage of Haraguchi type 1 patients increased, there was a statistically significant improvement in outcome scores. A similar trend was noted for Haraguchi type 3 fractures, and a reverse trend was observed for Haraguchi type 2 injuries, although neither were statistically significant.Our review suggests that the outcomes of trimalleolar fractures after surgical fixation may depend on the morphology of the PMF, with Haraguchi type 1 fractures having overall superior functional outcomes than Haraguchi type 2 and 3 injuries. Future studies need to done to conclusively prove or refute these findings.