Ultrasonographic examination of the deltoid ligament in bimalleolar equivalent fractures.

BACKGROUND: Lauge-Hansen supination-external rotation Stage IV ankle injuries may simulate a Stage II or Stage III injury radiographically if the medial disruption occurred through the deltoid ligament instead of the medial malleolus, making it difficult to determine whether an operation is indicated.

MATERIALS AND METHODS: Seventeen patients presented with radiographically isolated lateral malleolar fractures at the syndesmotic level. They were examined with ultrasonography for evaluation of the integrity of the deltoid ligament. Patients in whom ultrasonography showed complete rupture of the deltoid ligament received operative fixation of the ankle fracture, with exploration and repair of the deltoid ligament at the same time. Patients without complete rupture of the deltoid ligament were treated conservatively with a short leg cast for 6 weeks followed by an ankle brace for another 6 weeks. Nine male and six female patients completed the final clinical and radiographic evaluations.

RESULTS: Ultrasonography showed complete rupture of the deltoid ligament in six patients. Exploration of the deltoid ligaments confirmed the sonographic findings in all these patients. In the remaining nine patients, the deltoid ligaments were not completely ruptured on ultrasound. These fractures were treated conservatively, and all healed uneventfully. All the 15 patients had good or fair results on the final evaluation.

CONCLUSION: Ultrasonography is a convenient and accurate diagnostic tool to differentiate unstable bimalleolar-equivalent ankle fractures from an isolated lateral malleolar fracture. Thus, it can be helpful in the decision process for the treatment of choice for different fracture patterns.