Magnetic Resonance Imaging Characteristics of a Lateral Ligament Injury in Acute Ankle Sprains Among Athletes

BACKGROUND: It is important to identify the location and pattern of lateral ligament injuries that are related to the development and prognosis of chronic ankle instability in athletes with ankle sprains. PURPOSE: To describe the location and pattern of lateral ligament injuries on magnetic resonance imaging (MRI) in elite-level or amateur athletes with acute ankle sprains and to further assess the risk of associated concomitant injuries. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: The anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) of 110 athletes with an ankle lateral ligament injury (mean age, 24.7 years) were evaluated. MRI scans were evaluated for the location and pattern of ATFL and CFL tears such as sleeve avulsions as well as concomitant deltoid ligament injuries, bone contusions, and osteochondral lesions of the talus (OLTs). RESULTS: On MRI, 52 (47.3%) athletes had an isolated ATFL tear, 56 (50.9%) athletes had both ATFL and CFL tears, and 2 (1.8%) athletes had an isolated CFL tear. ATFL injuries occurred at the fibula, midsubstance, and talus in approximately equal numbers, whereas the majority of CFL injuries occurred at the calcaneal insertion. Concomitant deltoid ligament injuries were identified in 18 (16.4%) athletes. In addition, concomitant bone contusions and OLTs were identified in 38 (34.5%) and 6 (5.5%) athletes, respectively. Using linear-by-linear analysis, CFL injuries correlated with concomitant deltoid ligament and bone injuries (P = .023 and P = .001, respectively) and a sleeve injury pattern (P = .005). CONCLUSION: After an acute ankle ligament rupture, almost all athletes involved in this study had injured their ATFL, and approximately 50% had a concomitant injury to the CFL. The rate of sleeve-type CFL injuries at the calcaneal insertion was high, and concomitant deltoid ligament injuries and OLTs were associated with this pattern of injury.