What Is the Rate of Displacement of Occult Posterior Malleolus Fractures in Nailed Tibial Shaft Fractures?

Abstract

To describe the radiographic consequences of posterior malleolus fractures (PMF) present with tibial shaft fractures fixed with intramedullary nails. Retrospective cohort study. Level 1 trauma center. Seven hundred thirty-three patients with tibial shaft fractures. Intramedullary nail fixation and prophylactic articular fixation. Displacement of PMF with intramedullary nail insertion. Seven hundred thirty-three patients were identified with tibial shaft fractures treated with intramedullary nail fixation at a Level 1 trauma center without a uniform preoperative computed tomography protocol. One hundred thirty-three patients had an identifiable PMF appreciated on preoperative imaging. Of the 600 remaining patients without a known PMF, 29 had PMF identified after nail insertion: 24 patients with nondisplaced fractures that all healed radiographically at final follow-up, 3 patients had fractures <30% of the articular surface displaced 1-2 mm, and 2 patients had fractures >30% of the joint surface that displaced 1-2 mm. The incidence of radiographically observable PMF associated with tibial shaft fractures is high, even without a preoperative computed tomography screening protocol in place. In patients without an appreciable PMF on injury films, less than 1% (2/600) had displacement of a large, clinically significant PMF with nail placement. Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.