A Comparison of Screw Fixation and Suture-Button Fixation in a Syndesmosis Injury in an Ankle Fracture

Syndesmosis injuries are rare, but very debilitating and frequently misdiagnosed. The purpose of this clinical commentary is to review the mechanisms of syndesmotic injuries, clinical examination methods, diagnosis, and management of the injuries. Cadaveric studies of the syndesmosis and deltoid ligaments are also reviewed for further understanding of stress transmission and the roles of different structures in stabilizing the distal syndesmosis. External rotation and excessive dorsiflexion of the foot on the leg have been reported as the most common mechanisms of injury. The injury is most often incurred by individuals who participate in skiing, football, soccer, and other sport activities played on turf. The external rotation and squeeze tests are reliable tests to detect this injury. The ability of imaging studies to assist in an accurate diagnosis may depend on the severity of the injury. The results of cadaveric studies indicate the importance of the deltoid ligament in maintaining stability of the distal tibiofibular syndesmosis and the congruency of the ankle mortise. Intervention programs with early rigid immobilization and pain relief strategies, followed by strengthening and balance training are recommended. Heel lift and posterior splint intervention can be used to avoid separation of the distal syndesmosis induced by excessive dorsiflexion of the ankle joint. Application of a rigid external device should be used with caution to prevent medial-lateral compression of the leg superior to the ankle mortise, thereby inducing separation of the distal syndesmosis articulation. Surgical intervention is an option when a complete tear of the syndesmotic ligaments is present or when fractures are observed. Show more

Ankle syndesmotic injury does not necessarily lead to ankle instability; however, the coexistence of deltoid ligament injury critically destabilizes the ankle joint. Syndesmotic injury may occur in isolation or may be associated with ankle fracture. In the absence of fracture, physical examination findings suggestive of injury include ankle tenderness over the anterior aspect of the syndesmosis and a positive squeeze or external rotation test. Radiographic findings usually include increased tibiofibular clear space decreased tibiofibular overlap, and increased medial clear space. However, syndesmotic injury may not be apparent radiographically; thus, routine stress testing is necessary for detecting syndesmotic instability. The goals of management are to restore and maintain the normal tibiofibular relationship to allow for healing of the ligamentous structures of the syndesmosis. Fixation of the syndesmosis is indicated when evidence of a diastasis is present. This may be detected preoperatively, in the absence of fracture, or intraoperatively, after rigid fixation of the medial malleolus and fibula fractures. Failure to diagnose and stabilize syndesmotic disruption adversely affects outcome. Show more

The purpose of this study was to examine the mechanical necessity of using a syndesmosis screw to supplement rigid internal fixation of the fibula and medial malleolus in the treatment of pronation-external rotation fractures. The legs of thirty embalmed and five fresh cadavera were dissected and mounted through the tibia to a frame so that multiple radiographs could be made with a constant relationship between the specimen and the x-ray apparatus. A standardized pronation-external rotation load was applied to the foot, and widening of the syndesmosis was studied on mortise radiographs that were made after each experimental step. On the basis of previous investigations, we developed a model for pronation-external rotation injuries that included disruption of the syndesmosis and interosseous membrane up to the level of the fibular fracture. Accordingly, multiple repaired fibular fractures could be simulated at several levels in the same specimen by incremental proximal division of the interosseous membrane. Specimens were separated into two groups. Group I consisted of thirteen specimens in which the deltoid ligament, syndesmosis, and interosseous membrane were serially sectioned in 1.5-centimeter increments. Group II (ten sections) was subjected to the same protocol, except that the deltoid ligament was kept intact until the final step. The five fresh specimens were sectioned in the same way as those in Group I. In Group I, since the simulated pronation-external rotation injury included a deltoid tear, rigid medial fixation was not possible; accordingly, there was rigid fibular fixation only.(ABSTRACT TRUNCATED AT 250 WORDS) Show more