

Early and accurate diagnosis of ankle syndesmosis injury is essential to facilitate timely effective and safe treatment, but they are difficult to diagnose. The incidence in ankle sprains ranges between 1 and 24%. The ankle syndesmosis includes the interosseous membrane and interosseous ligament together with the anterior inferior tibiofibular ligament, posterior inferior tibiofibular ligament, and the transverse ligament.
A recent systematic review showed that the external rotation stress test as used by Beumer et al. (2002) had very low of all diagnostic accuracy and lower sensitivity. However the test was performed without dorsiflexion. Dorsiflexion produces a slight widening of the ankle mortise, thereby stressing the syndesmosis and should therefore be integral to test performance.
The dorsiflexion external rotation stress test reproduces the mechanism of injury to the syndesmosis. According to a study by Sman et al. (2013) it has a sensitivity of 71%and a specificity of 63% and its clinical use as a stand-alone test is therefore rather weak.
To perform the test have your patient in sitting position with this knee hanging from the table at 90°. Then bring the patient’s talocrural joint into maximal dorsiflexion and apply external rotation stress to the injured foot and ankle.
This test is positive if the patient’s antererolateral pain over the syndesmosis is reproduced.
Other common orthopedic tests for syndesmosis injuries are: