Tips and Pearls
Injury of the distal tibiofibular syndesmosis is commonly encountered in unstable ankle fractures. Although most surgeons agree that syndesmotic fixation is necessary in the presence of a concomitant deltoid ligament disruption, there is significant controversy including the size and number of screws, the amount of cortical purchase, the type of metal used, and whether to allow weight bearing before hardware removal.1,2 There is, however, a consensus in the current literature that the screws should be placed from posterolateral to anteromedial.3 Passage of a drill from the relatively small fibula into the larger tibia is undoubtedly easier than blindly attempting the almost impossible opposite direction, and although there are no supporting biomechanical studies, greater strength is likely with the screw head abutting the fibula. Nevertheless, there are rare occasions, such as a problematic open wound or a large screw that does not fit through a fibular plate, when an anteromedial-to-posterolateral syndesmotic screw may be helpful. We describe an easy new technique to ensure accurate placement of a medial-to-lateral syndesmotic screw.
After fixation of the fibula, a large bone clamp is used to reduce the syndesmosis. A path is drilled from posterolateral to anteromedial with an appropriately sized drill bit through both cortices of the fibula and tibia in a routine manner for a normal syndesmotic screw. After using a depth gauge to assess the proper length of screw, it is pushed past the medial tibial cortex until it can be palpated medially. A medial stab incision is made and the depth gauge is pushed out medially as far as possible. Using the protruding depth gauge as a guide for the angle and inclination of the path, a fully threaded screw is placed from anteromedial to posterolateral. Fluoroscopy can be used to continuously assess correct orientation and confirm accurate placement of screw.
CLINICAL CASE/ILLUSTRATION OF TECHNIQUE
A 74-year-old overweight female presented with an open fracture-dislocation of the ankle after a fall. Although having a generous soft tissue envelope, she had severe venous stasis and her surrounding skin was very friable. The wound began at the medial malleolus, extended anteriorly across the ankle joint, and ended just anterior to the fibula. She underwent irrigation and debridement, open reduction of the ankle, repair of the ruptured deltoid ligament, and minimally invasive submuscular plating of the fibula. Because of the nature of the soft tissue defect, the location of the fracture, and the constraints of the plate, the syndesmosis was fixed with two 3.5-mm cortical screws and one 2.7-mm locking screw (Fig. 1). The wound was closed primarily except for a small segment anteriorly, which was covered with a vacuum dressing and later skin grafted.
There are many factors to consider when fixing a syndesmosis. Anteromedial-to-posterolateral screws have never been considered before, at least in part, due to technical difficulty. Extenuating circumstances occasionally arise, however, in which this technique is a useful supplement to the orthopedic surgeon’s armamentarium.
1. Zalavras C, Thordarson D. Ankle
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2. Monga P, Kumar A, Simons A, et al. Management of distal tibio-fibular syndesmotic injuries: a snapshot of current practice. Acta Orthop Belg. 2008;74:365–369
3. Rammelt S, Zwipp H, Grass R. Injuries to the distal tibiofibular syndesmosis: an evidence-based approach to acute and chronic lesions. Foot Ankle
Clin N Am. 2008;13:611–633