Factors Affecting the Clinical Outcomes of Surgically Treated Ankle Fractures Associated with the Posterior Malleolar Fragment.

BACKGROUND This study was performed to determine the factors that influence the clinical outcomes of surgically treated ankle fractures associated with the posterior malleolus (PM). METHODS We evaluated 42 fractures of 42 patients. Posterior malleolus fracture size was calculated using computed tomography. Posterior malleolar fractures with a size less than 10% were left nonfixated. The decision for larger fragments was performed using fluoroscopy following the fixation of other components. If the joint was found to be congruent, the PM was left nonfixated. Otherwise, the PM was reduced and fixated. Clinical outcomes were evaluated based on Weber, Freiburg, and American Orthopaedic Foot and Ankle Society scores. Ankle osteoarthritis was determined according to the Canadian Orthopaedic Foot and Ankle Society classification. The effect of PM fixation, age, PM fragment size, waiting period before surgery, presence of ankle dislocation, and number of injured malleoli on clinical outcomes were assessed. Statistical significance was set at a value of P < .05. RESULTS The mean patients age was 48.5 ± 14.9 years (range, 20-84 years) and the mean follow-up was 23.7 ± 8.6 months (range, 12-56 months). Fixation of the PM was performed solely in 12 patients. Postoperative displacement of the PM and articular step were less than 2 mm in all fractures. Statistically significant worse outcomes were demonstrated based on functional scores in the patients with a PM size greater than or equal to 25% (P = .042, P = .038, and P = .048, respectively) and in patients aged 60 years or older (P = .005, P = .007, and P = .018, respectively). However, there was no significant difference between functional scores and the other factors. Ankle osteoarthritis was observed at a higher rate in patients with PM size greater than or equal to 25% and in patients aged 60 years or older. CONCLUSIONS Clinical outcomes of the patients are mainly influenced by the patient's age and PM fragment size. However, if the tibiotalar joint is congruent, comparable results can be obtained in PM fixated or nonfixated patients.