New Diagnostic Tool for Detection of Subtle, Chronic Syndesmotic Insufficiency

The external torque device, which was developed at Balgrist University Hospital, is able to evaluate the syndesmotic ligaments as precisely as an intraoperative lateral hook test.

If tibiofibular syndesmotic injury is undetected, chronic instability may lead to persistent pain and osteoarthritis. Until now, no reliable diagnostic method has been available. The requirements for the ideal diagnostic tool for differentiating subtle syndesmotic insufficiency are 1) sensitive syndesmotic load, 2) three-dimensional evaluation, 3) comparison with the “healthy” contralateral side, 4) low invasiveness and 5) availability/costs. 

The external torque device with bilateral CT meets many of these requirements. In a biomechanical study on cadavers, we were able to demonstrate its reliability in detecting one, two, or three ligament injuries with greater sensitivity and similar specificity compared with the arthroscopic lateral hook test, which is considered today's gold standard. In a study on healthy volunteers we were able to show that the contralateral side can be used reliably as a comparative value. A reliable tool for assessing syndesmosis stability is also important to clarify the question of which syndesmotic injuries can be treated conservatively, and which should be better stabilized by surgery. In this regard, we are conducting a study comparing the stability of the syndesmosis on patients with syndesmotic injuries who were treated either conservatively or with surgery. And finally, we are planning new surgical methods to reliably restore the syndesmosis in the event of chronic insufficiency. We consider this scientific invention to be extremely helpful in better understanding the problem of syndesmosis injury.