Ankle Fracture with a Complex Injury Mechanism and Misleading Hook Test Result: A Case Report

Ankle fractures and their mechanisms of injury can be complex. We report a case of a patient with an uncertain mechanism of injury and an uncommon combination of lower extremity fractures, which fit the criteria for a Lauge-Hansen classification pronation-external-rotation fracture, Maisonneuve fracture, Wagstaffe fracture, and posterior pilon fracture. Plain radiographs and computed tomography scan revealed Chaput tubercle avulsion fractures, an anterior distal fibular fracture fragment, multiple lateral malleolar fractures, a posterior malleolar fracture fragment with proximal displacement, a die-punch fragment between the posterior malleolar fragment and the tibia, a proximal fibular fracture, and possible ankle syndesmotic diastasis. Intraoperative hook test was negative after fixation of the fractures, so syndesmotic fixation was not performed. At 3-month follow-up, plain radiographs showed obvious syndesmotic diastasis. At 1-year follow-up, symptoms persisted and syndesmotic fusion was recommended but declined by the patient. This case demonstrates that both ankle fractures and their mechanisms of injury can be remarkably complex and confusing, posterior pilon fractures can occur along with pronation-external-rotation ankle fractures, syndesmotic fixation should be considered for all patients with Maisonneuve fractures, reliance on the hook test for surgical management decisions may not always be reliable, and there exists a need for a more accurate and reliable intraoperative test to determine the presence of ankle syndesmotic injury.