gms | German Medical Science

Objectives: Syndesmotic injuries are complex ankle injuries resulting in chronic pain and instability if not properly treated. Ogilvie-Harris et al evaluated the percentage of contribution of each ligament during 2 mm of lateral fibular displacement. The anterior inferior tibiofibular ligament provided 35%; the interosseous ligament, 22%; the transverse (deep posterior) ligament 33% and the superficial posterior inferior ligament, 9%. The superficial fibers from the posterior-inferior tibiofibular ligament (PITFL) originate widely on the posterior tubercle of the tibia and run obliquely, distally, and laterally to the posterior lateral malleolus. The deep PITFL passes from the posterior tibial margin to the osteochondral junction on the posterior and medial margins of the distal fibula. The location of the transverse ligament below the posterior tibial margin helps it to prevent posterior talar translation. We present a case of a PITFL injury with two posterior fragments of the fibula suggesting the hypothesis that the superficial and deep ligaments are of separate identities.

Methods: A case of 41-year-old male patient who suffered a bicycle accident associated with a complex ankle fracture (transverse medial malleolus, poster malleolus; and fibular tip as well as two additional posterior fibular fragments). After 14 days the medial malleolus was stabilized with two screws, the posterior malleolus with an antiglide plate, and the superficial posterior inferior ligament with an anchor. Due to persistence of pain and discomfort after 1 year, a comparative CT scan of both ankle showed instability of the fibula in the fibular notch associated with anterior translation. We therefore performed an osteotomy of the posterior fragment of the fibula, recentered the fibula in its notch and fixed it temporarily by two K wires. An intraoperative 3D imaging confirmed the correct reduction of the syndesmosis (Figure 1 [Fig. 1]). We then fixed the syndesmosis by TightRope^®. For stabilization of the PITFL, we utilized the InternalBrace^® ligament augmentation repair system. After confirming the stability of the syndesmosis, a cast was placed. No weight bearing was allowed for 8 weeks.

Results and conclusion: This report sustains the theory that the transverse tibiofibular ligament (or deep component of the posterior ligament) is a separate identity from the PITFL. The ankle injury mentioned above is considered a complex ankle injury requiring a high level of suspicion and a thorough knowledge of the anatomy and mechanics of ankle injuries for diagnosis and treatment. We believe that the technique described offers a stable construct for revision surgeries of the PITFL.