Risk factors for malalignment after intramedullary nail treatment of distal tibia fractures with associated fibula fractures

Purpose Malalignment of distal tibia fractures can lead to malunion/nonunion or alter the limb mechanical axis which may cause arthritis. Proposed methods to decrease malalignment include fibular fixation or multiplanar interlocking screws, however these remain controversial. This study aimed to identify factors associated with malalignment in distal tibial fractures with associated fibular shaft fractures. Methods A retrospective review was performed of distal tibia fractures with associated fibular shaft fractures treated with intramedullary nailing at two level one trauma centers between 2015 and 2019. Cases involving malalignment (> 5 degrees of deviation from anatomic axis on either coronal/sagittal axis) on final follow-up (minimum three months postoperatively) were compared to those without malalignment with regard to demographics, fracture characteristics, intraoperative characteristics, and complications. Results The rate of malalignment was 13%. On multivariate analysis, multiplanar distal interlocking screw fixation (odds ratio [OR], 0.18; 95% confidence interval [CI] 0.03-0.92) was associated with a decreased rate of final malalignment, while nail diameter > 10 mm was associated with a higher rate (OR, 4.05; 95% CI 1.25-13.11). Fibular fixation was not associated with malalignment. Conclusion Multiplanar distal interlocking screws may protect against malalignment. Fibula fixation does not appear associated with a decreased rate of malalignment in distal tibia fractures treated with intramedullary nails.