Can Syndesmosis Screws Displace the Distal Fibula?

Instability of the distal tibiofibular syndesmosis

The distal tibiofibular syndesmosis (DTFS) is more frequently injured than previously thought. Early diagnosis and appropriate treatment is essential to avoid long term complications like chronic instability, early osteoarthritis and residual pain. Management of these injuries require a complete understanding of the anatomy of DTFS, and the role played by the ligaments stabilizing the DTFS and ankle. High index of suspicion, appreciating the areas of focal tenderness and utilizing the provocative maneuvers help in early diagnosis. In pure ligamentous injuries radiographs with stress of weight bearing help to detect subtle instability. If these images are inconclusive, then further imaging with MRI, CT scan, stress examination under anesthesia, and arthroscopic examination facilitate diagnosis. An injury to syndesmosis frequently accompanies rotational fractures and all ankle fractures need to be stressed intra-operatively under fluoroscopy after fixation of the osseous components to detect syndesmotic instability. Non-operative treatment is appropriate for stable injuries. Unstable injuries should be treated operatively. Anatomic reduction of the syndesmosis is critical, and currently both trans-syndesmotic screws and suture button fixation are commonly used for syndesmotic stabilization. Chronic syndesmotic instability (CSI) requires debridement of syndesmosis, restoration of ankle mortise with or without syndesmotic stabilization. Arthrodesis of ankle is used a last resort in the presence of significant ankle arthritis. This article reviews anatomy and biomechanics of the syndesmosis, the mechanism of pure ligamentous injury and injury associated with ankle fractures, clinical, radiological and arthroscopic diagnosis and surgical treatment.

Biomechanical Sequelae of Syndesmosis Injury and Repair

This review characterizes fibula mechanics in the context of syndesmosis injury and repair. Through detailed understanding of fibula kinematics (the study of motion) and kinetics (the study of forces that cause motion), the full complexity of fibula motion can be appreciated. Although the magnitudes of fibula rotation and translation are inherently small, even slight alterations of fibula position or movement can substantially impact force propagation through the ankle and hindfoot joints. Accordingly, implications for clinical care are discussed.

Evidence-Based Surgical Treatment Algorithm for Unstable Syndesmotic Injuries

Background: Surgical treatment of unstable syndesmotic injuries is not trivial, and there are no generally accepted treatment guidelines. The most common controversies regarding surgical treatment are related to screw fixation versus dynamic fixation, the use of reduction clamps, open versus closed reduction, and the role of the posterior malleolus and of the anterior inferior tibiofibular ligament (AITFL). Our aim was to draw important conclusions from the pertinent literature concerning surgical treatment of unstable syndesmotic injuries, to transform these conclusions into surgical principles supported by the literature, and finally to fuse these principles into an evidence-based surgical treatment algorithm. Methods: PubMed, Embase, Google Scholar, The Cochrane Database of Systematic Reviews, and the reference lists of systematic reviews of relevant studies dealing with the surgical treatment of unstable syndesmotic injuries were searched independently by two reviewers using specific terms and limits. Surgical principles supported by the literature were fused into an evidence-based surgical treatment algorithm. Results: A total of 171 articles were included for further considerations. Among them, 47 articles concerned syndesmotic screw fixation and 41 flexible dynamic fixations of the syndesmosis. Twenty-five studies compared screw fixation with dynamic fixations, and seven out of these comparisons were randomized controlled trials. Nineteen articles addressed the posterior malleolus, 14 the role of the AITFL, and eight the use of reduction clamps. Anatomic reduction is crucial to prevent posttraumatic osteoarthritis. Therefore, flexible dynamic stabilization techniques should be preferred whenever possible. An unstable AITFL should be repaired and augmented, as it represents an important stabilizer of external rotation of the distal fibula. Conclusions: The current literature provides sufficient arguments for the development of an evidence-based surgical treatment algorithm for unstable syndesmotic injuries.