Rare pattern of Maisonneuve fracture: A case report

BACKGROUND Maisonneuve fracture is a special type of ankle fracture that consists of proximal fibular fracture, a lesion of the inferior tibiofibular syndesmotic complex (interosseous ligament, anterior inferior tibiofibular ligament and posterior inferior tibiofibular ligament), and injury of the medial structure of the ankle (deltoid ligament tear or medial malleolar fracture). The accepted mechanism of Maisonneuve fracture is pronation external rotation according to the Lauge-Hansen classification. In this paper, we report a rare pattern of Maisonneuve fracture, which has the characteristics of both pronation external rotation ankle fracture and supination adduction ankle fracture. CASE SUMMARY A 31-year-old female patient accidentally sprained her right ankle while walking 5 d before hospitalization in our hospital. The patient was initially missed in other hospitals and later rediagnosed in our outpatient department. Full-length radiographs of the lower leg revealed proximal fibula fracture, inferior tibiofibular joint separation, and medial malleolar fracture involving the posterior malleolus, which was also revealed on computed tomography scans. Magnetic resonance imaging revealed rupture of the anterior inferior tibiofibular ligament and anterior talofibular ligament. We diagnosed a rare pattern of Maisonneuve fracture with proximal fibular fracture, inferior tibiofibular joint separation, medial malleolar fracture and ruptures of the anterior inferior tibiofibular ligament and anterior talofibular ligament. The patient underwent open reduction and internal fixation in our hospital. A 6-mo postoperative follow-up confirmed a good clinical outcome. CONCLUSION To our knowledge, this rare pattern of Maisonneuve fracture has not been previously described. The possible mechanism of injury is supination adduction combined with pronation external rotation. Careful analysis of the injury mechanism of Maisonneuve fracture is of great clinical significance and can better guide clinical treatment.