Treatment Strategy for Posterior Malleolar Fractures: Different Operative Strategies are Needed for Each Morphological Type

CATEGORY: Trauma; Ankle INTRODUCTION/PURPOSE: The operative indication for posterior malleolar fracture (PMF) remains controversial. This study aimed to assess the midterm outcomes of PMF treatment for developing a treatment strategy for each morphological type. METHODS: In this retrospective analysis, 472 patients undergoing operative treatment for an unstable ankle fracture involving PMF were included after at least 3 years of follow-up. PMFs were classified by fracture morphology, according to the Haraguchi classification, and the outcomes of the groups wherein PMF was either fixed through a posterior approach or unfixed were compared (PMF fixation and nonfixation groups, respectively). The radiographic evaluation included the development of posttraumatic osteoarthritis. The clinical evaluation included the AOFAS score and postoperative complications. RESULTS: The mean patient age was 45.8 years, and the mean follow-up was 51 months. The intercalary fragment (ICF) was more frequently observed for type 1 PMFs preoperatively in the fixation group (P < .001). The postoperative outcomes of the two groups showed no significant differences. For type 2 PMFs, the radiological and clinical outcomes of the PMF fixation group were statistically superior to those of the nonfixation group (both P < .001). Overall, postoperative complications occurred more frequently in the fixation group (40.4% vs. 24.4%, P < .001). Compared with the patients with and without syndesmotic stabilization in type 3 PMF, no significant differences in the postoperative outcomes were observed. The radiological and clinical parameters showed no significant intergroup differences, including the postoperative complications when comparing PMF fixation using a plate and posterior screw. CONCLUSION: Different treatment strategies are required for each PMF morphological subtype. The operative treatment might not lead to favorable outcomes for all PMF subtypes: potential indicators for operation are the presence of an ICF preventing the reduction of the posterior malleolus in type 1 and all type 2 PMFs.