Ankle sprains account for approximately 10% to 30% of all presenting injuries in an athletic cohort with most being lateral ankle sprains. Although historically the incidence of syndesmosis injury has been low with reports between 1% and 18% of all ankle sprains, the growing knowledge and understanding of syndesmosis injuries has come with an increase in incidence reported in the current literature with ranges from 17% to 74%. Injury to the syndesmosis is typically associated with high-speed collisions or rotational injuries that cause the foot to externally rotate while in a dorsiflexed position. The talus being wider anteriorly forces separation of the fibula from the tibia and additional external rotation force leads to abnormal stress on the syndesmosis ligaments. Owing to the mechanism of injury, other ankle ligaments also have the potential to be traumatized in the setting of a high-grade syndesmosis injury. Mait et al did a cadaveric study in which an external rotation force was applied to specimens in dorsiflexion, neutral, and plantar flexion. They found that syndesmotic injury occurred in 100% in dorsiflexion group, 50% in the neutral group, and 0% in the plantarflexion group. In addition, the deltoid ligaments superficial and deep were injured to varying degrees in all specimen with noted syndesmotic injury. Although the deltoid ligament also plays a role in syndesmosis stability, a cadaveric study by Clanton et al demonstrated that deltoid sectioning did not destabilize the syndesmosis until the AITFL and IOL were both released. Conversely, lateral ankle sprains have a 17% rate of concurrent low- to high-grade syndesmosis injury. With isolated injury, a stark contrast exists between that of lateral ankle sprains and syndesmosis injury. Injuries to the syndesmosis commonly occur in contact sports, over a 5-year span, National Football League (NFL) players had an average, per player, time loss of 2.5 weeks, 11.7 practices, and 1.4 games from syndesmotic injury compared with 1.25 weeks, 3.5 practices, and 0.3 games from lateral ankle sprains. Recovery time for syndesmosis injuries can exceed 31 days, which are often highly debilitating injuries in which athletes have trouble performing moves (eg, cutting and pushing off) and can result in chronic pain. Although this review covers isolated syndesmosis injuries, any ligamentous injury to the ankle requires a detailed examination and should be thought of as a spectrum possibly involving multiple structures.
J Am Acad Orthop Surg. 2020;28(13):517-527. © 2020 American Academy of Orthopaedic Surgeons