Modification of Distal Tibiofibular Relationship After a Mild Syndesmotic Injury.

BACKGROUND: The hypothesis of this study is that a sprain or tear of 1 or more of the 3 syndesmotic ligaments will result in a significant change in the osseous anatomy relationship when comparing injured to uninjured syndesmosis. Our secondary objective was to determine whether injuries to the syndesmosis as diagnosed on magnetic resonance imaging (MRI) could be found using static imaging.

METHODS: This is a descriptive radiological study of ankle MRI reports over a 12-year period, from 2 different institutions, and divided in two groups: normal and injured syndesmotic ligaments. A series of 6 lengths and 2 angles were measured on MRI axial views that describe the rotation, lateral, and anteroposterior translational relation between the distal tibia and fibula. Parameters from injured and uninjured ankles were compared using Student's t-test.

RESULTS: Fifty uninjured syndesmosis were compared to 64 injured syndesmoses. The majority of syndesmosis injuries concerned either an anterior inferior tibiofibular ligament sprain or tear. There was a significant difference in the anatomic position of the tibia and the fibula between injured and uninjured syndesmosis.

CONCLUSIONS: The anterior inferior tibiofibular ligament is the most commonly injured ligament in the syndesmosis in sports injury and results in subtle variations in the syndesmotic anatomy, which plain radiographs cannot assess. Because of the previously validated computed tomography scan measurement, this study demonstrates a potential to identify syndesmotic injury on other more accessible imaging modalities, such as computed tomography scan, by using a well-defined measurement system.

LEVELS OF EVIDENCE: Diagnostic, Level III : Retrospective, Radiologic Study.