Missed isolated posterior malleolar fractures

Objective: The aim of this study was to evaluate the injury mechanism and clinical and radiologicalresults of the patients with isolated posterior malleolar fracture. Methods: Seven patients (5 male, 2 female; mean age: 32 years; range: 23-40) with a missed isolated posterior malleolar fracture were included in the study. All patients had initially been examined for an ankle sprain in the emergency room, where the initial plain radiographs did not show any abnormality. Due to the long lasting symptoms all patients underwent an MRI scan by the 3rd week which revealed a posterior malleolar fracture. Patients were treated with an ankle brace for 3 weeks. All patients were followed up for 1 year. Bone healing and degenerative changes were evaluated with plain Radiographs, including a 50° external rotation lateral. Clinical outcome was evaluated with American Orthopedic Foot and Ankle Society ankle hindfoot scale. Results: Fracture healing was seen in 6 of the 7 patients by the 6th week. There was no radiographic healing by 6th month in the remaining patient. Mean AOFAS ankle hindfoot scores at the beginning of the treatment and at 3rd month were 20 (11-31) and 86 (43-96), respectively. There was no instability or degenerative changes at one-year follow-up. Conclusion: Isolated posterior malleolar fracture should be kept in mind in patients who present with pain at the posterior part of the ankle following a forced plantar flexion and/or axial compression injury. A 50° external rotation lateral radiograph can be useful in detecting the fracture.