Laboratory and Imaging Studies
Laboratory studies
Laboratory studies are not indicated in the workup of ligamentous injuries of the ankle.
Imaging studies
Indications for imaging studies in cases of suspected talofibular ligament injuries include the following:
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Bony tenderness or deformity
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Suspicion of a fracture or syndesmotic injury
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Severe pain or swelling that makes the physical examination unreliable
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Inability to walk
Initial radiologic studies of the ankle should include the following:
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An anteroposterior (AP) view with the ankle in slight adduction
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A true lateral view
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A mortise view (45° oblique view with the ankle in dorsiflexion)
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Consider stress views of the ankle.
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If a syndesmotic injury is suspected, then AP and lateral views of the tibia and fibula should also be obtained to rule out associated fibular fractures.
Magnetic resonance imaging (MRI) may be useful in evaluating the soft-tissue anatomy of the ankle, such as ligaments and tendons. [12, 13] This imaging modality is not typically an initial test performed, but MRI may be useful in the patient who is not healing, in whom a stress fracture is suspected, or in chronic ankle pain and instability.
A study by Xu et al showed that for diagnosis of partial tears of the anterior talofibular ligament, the sensitivity of three-dimensional MRI was 78%, and the specificity was 100%. For diagnosis of sprains, the sensitivity was 100%, and the specificity was 97%. [14]
A study with 25 participants reported that stress ultrasonography provides a safe, repeatable, and quantifiable method of measuring the talofibular interval and may augment manual stress examinations in acute ankle injuries. [15]
A systematic review and meta-analysis by Cao et al found that for acute anterior talofibular ligament injuries, the pooled sensitivity rates of MRI and ultrasonography were 82.1% and 88.6%, respectively. The pooled specificity rates of MRI and ultrasonography were 37.8% and 90.3%, respectively. [16]
