Ankle syndesmosis injuries: anatomy, biomechanics, mechanism of injury, and clinical guidelines for diagnosis and intervention.

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.