Dynamic high-resolution ultrasound in the diagnosis of calcaneofibular ligament injury in chronic lateral ankle injury: a comparison with three-dimensional magnetic resonance imaging.

PURPOSE: To date, no gold standard imaging method has been used to assess calcaneofibular ligament (CFL) injuries. Ultrasound (US) has become increasingly important in the assessment of ligaments around the ankle. However, very few reports in the literature have focused on detecting CFL injuries. The objective of this study was to determine the effectiveness of ultrasound in detecting CFL injuries in comparison with magnetic resonance imaging (MRI). METHODS: A retrospective study was conducted in 21 patients with chronic lateral ankle injury, 10 males and 11 females with a mean age of 27.6 ± 14.5 years (range 14-68 years). High-frequency US and three-dimensional (3D) MRI of the affected ankle were performed. Evaluations of the CFL were performed by two orthopedic surgeons experienced in US, while the MRI findings were interpreted by two musculoskeletal radiologists. The US findings were then compared with the MRI findings. RESULTS: US detected CFL injury in 9/21 patients, and these findings were confirmed by the MRI findings. However, one patient with a normal CFL on US was evaluated as laxity on MRI. In this study, US sensitivity and specificity in detecting CFL injuries was 90% (9/10) and 100% (10/10), respectively, with a positive predictive value (PPV) of 100% and a negative predictive value (NPV) of 91.7% in comparison with MRI. CONCLUSION: With the proper technique and knowledge of the ankle anatomy, high-frequency US proved to be an effective imaging modality in the diagnosis of CFL lesions in chronic lateral ankle injuries. US had a high sensitivity and specificity in the evaluation of the CFL when MRI findings were regarded as the reference standard.