Magnetic resonance imaging abnormalities after lateral ankle trauma in injured and contralateral ankles

To compare the prevalence of abnormal MRI findings associated with lateral ankle trauma in injured and contralateral ankles to identify lesions that may be pre-existent.

The study was approved by the institutional review board and informed consent was obtained from all subjects. 195 patients (mean age 37.5+14.7 years; 43% male) who visited their general practitioner 6-12 months earlier with an ankle sprain were selected. All patients completed a standardized questionnaire and underwent MRI (1.5T) of both ankles. Structural MRI abnormalities in the injured and contralateral ankle were compared using the McNemar test (for paired samples).

Bone marrow edema was frequently seen in the injured and contralateral ankle at the talocrural joint (25.1% versus 14.8%) and subtalar joint (24.6% versus 8.7%), but significantly more frequently in the injured ankle. Anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) lesions were frequently found in both ankles, in 55.9% and 37.4% of injured ankles respectively and in 17.9% and 5.6% of contralateral ankles respectively. Fractures, anterior and posterior tibiofibular ligament lesions, deltoid ligament lesions and signs of talonavicular osteoarthritis were almost exclusively found in injured ankles. Peroneal ligament lesions were not frequently found in both ankles.

The prevalence of structural MRI abnormalities in patients presenting with a previous ankle sprain in primary care is very high. However, especially bone marrow edema and lateral ligament lesions can also be found in a substantial percentage of contralateral ankles and may be either pre-existent or due to increased stress on the contralateral ankle after an ankle injury Correlation with clinical findings is essential.