The CT morphological characteristics and the clinical management strategy of posterior malleolar fractures with talar subluxation.

Background: The optimal clinical treatment and the computed tomography (CT) morphological characteristics of posterior malleolar fractures (PMF) with talar subluxation remain inconclusive. Clinically, both plate screws and lag screws are widely used to fix posterior malleolar fragments using a direct or indirect approach. We sought to summarize the morphological characteristics and modified classification on the basis of CT and the intraoperative strategy for posterior talar subluxation in PMF.

Methods: Retrospectively, 46 adult PMF patients with subluxations of the talus were recruited as the study cohort. According to its morphological features, PMF with subluxation of the talus can be divided mainly into two types using this modified classification: a complete fracture (the single-fragment type) and PMF with two-angled fracture fragments (the double-fragment type). The cohort's demographic information, classifications, fracture morphology, fixation methods, pain levels, and functional scores were recorded for both fracture types.

Results: The average values of the depths and heights of the posterior malleolar fragments were (29.1±7.3) mm for the single-fragment type and (17.9±4.2) mm for the double-fragment type. There was a significant difference in the mean values between the two types ( < 0.05). Posterior plate fixation was suitable for the single-fragment type, while antero-posterior and postero-anterior (AP-PA) lag screws fixations were made available for the double-fragment type. Both methods achieved good results. No significant differences were found in terms of sex, age, body mass index (BMI), side, Haraguchi classification, Bartoníček and Rammelt classification, Visual Analog Scale (VAS) scores, or American Orthopedic Foot & Ankle Society scores (AOFAS) when comparing the single-/double-fragment type groups after the mid-term follow-up ( > 0.05).

Conclusion: According to the injury mechanism and the morphological characteristics of the fractures, the proposed improved classification system for PMF with subluxation of the talus based on the injury mechanism and the fracture morphology can provide guidance for surgical management strategies and achieve optimal outcomes.