[Injuries of the inferior tibiofibular syndesmosis]

The incidence of isolated distal tibiofibular syndesmotic ruptures in acute ankle sprains lies between 1% and 11%. These injuries are frequently overseen or misdiagnosed as anterolateral rotational instability of the ankle and often become apparent through protracted courses. Although the pathomechanics and extent of syndesmotic injuries have been systematically described by Lauge-Hansen and Weber, no generally accepted guidelines exist as to when these complex injuries are to be treated surgically to ensure sufficient and stable healing of the syndesmosis besides correct alignment of the distal fibula. So far, systematic follow-up regarding syndesmotic injuries in ankle fractures is missing, although it has long been recognized that tibiofibular diastasis secondary to chronic syndesmotic instability leads to external rotation of the talus. In combination with a valgus position of the talus, this instability leads to a decrease in the contact area which results in posttraumatic arthritic changes. This paper reviews the standard diagnostic and therapeutic procedures for acute syndesmotic ruptures in fracture dislocations of the ankle. Among the few corrective procedures advocated for chronic syndesmotic insufficiency are tibiofibular arthrodesis, synthetic ligament substitutes, and tenodesis with the peroneus brevis tendon. A sufficient reconstruction must restore the stability of the ankle mortise and alignment of the fibula in the tibiofibular incisura to ensure limitation of talar rotation. Therefore, a tenodesis was developed which substitutes the three important ligaments of the syndesmotic complex. The Casting procedure for chronic syndesmotic insufficiency was modified with reconstruction of the interosseous tibiofibular ligament in addition to the anterior and posterior tibiofibular ligaments. The resulting three-point fixation of the distal fibula appears more anatomically, physiologically, and biomechanically advantageous. The operative procedure is given in detail. Distal tibiofibular syndesmosis. Persistent instability of the distal syndesmosis. Ankle fractures. Syndesmotic screw.