The Anatomic Pattern of Injuries in Acute Inversion Ankle Sprains: A Magnetic Resonance Imaging Study.

Background: There are little data on the incidence and patterns of injuries seen on magnetic resonance imaging (MRI) in acute inversion ankle sprains. This study may help in the understanding of the pathomechanics, natural history, and outcomes of this common injury.

Study Design: Case series; Level of evidence, 4.

Methods: From June 2011 to June 2013, a total of 64 consecutive patients had MRI of the ankle performed for acute inversion injury to the ankle. All injuries/pathologies reported were recorded.

Results: Only 22% of patients had isolated lateral ligament complex injuries. Twenty-two percent of patients had other pathologies but no lateral ligament injury, and 53% had lateral ligament injuries in combination with other pathologies or injuries. The most common associated finding with lateral ligament injuries was bone bruising (76%) followed by deltoid ligament injury (50%). The overall incidence of bone bruising was 50%. Thirty percent of ankles had tendon pathology, 27% had deltoid ligament injury, and 22% had occult fractures.

Conclusion: Isolated lateral ligament ankle injury is not as common as is believed. The pattern of injury seems complex, and most patients appear to have more injuries than expected. MRI reveals additional information that may have significance in terms of diagnosis, treatment, and prognosis in this common injury.