Direct versus indirect posterior malleolar fixation in the treatment of trimalleolar ankle fractures: Is there a difference in outcomes?

Purpose: The purpose of this study was to examine the differences in functional outcomes between direct and indirect surgical fixation methods of the posterior malleolus in the setting of trimalleolar fractures and identify any variables affecting patient outcomes.

Methods: Primary outcomes were evaluated by PROMIS scores for short-term outcomes regarding total pain (TP) and total function (TF) comparing 40 patients with direct fixation with 77 with indirect fixation. Continuous variables were analyzed using t tests for parametric variables and the Mann-Whitney U test for nonparametric variables. Categorical variables were analyzed using a χ² test. Univariate and multivariate linear regression models were performed to analyze factors that affect outcomes of TP and TF.

Results: There was no difference in TP or TF between groups (P = 0.65 vs. P = 0.19). On univariate linear regression for TP, BMI, incidence of complication, tobacco use, and open injury showed significance in increasing pain levels with open injuries providing the greatest effect (coef = 11.8). On multivariate analysis, BMI, incidence of complication, open injury, and tourniquet time all significantly increased pain. For TF, univariate analysis showed age, BMI, incidence of complication, and diabetes to decrease function, and use of external fixator and tourniquet time increased function. In the multivariate model, increased BMI, open injuries, and increasing tourniquet time all decreased TF while use of an external fixator increased TF.

Conclusion: This study showed no difference in TP and TF using the PROMIS outcome scores when comparing direct fixation versus indirect fixation under univariate and multivariate models.

Level of evidence: Therapeutic III.