ACCURACY OF MRI SCAN IN THE DIAGNOSIS OF LIGAMENTOUS AND CHONDRAL PATHOLOGY IN THE ANKLE

Abstract

The aim of this study was to determine the accuracy of Magnetic Resonance Imaging (MRI) scanning compared to arthroscopic findings in patients presenting with chronic ankle pain and/or instability. We reviewed all patients who underwent arthroscopy of the ankle between December 2005 to July 2008 in our institution.

A total of 105 patients underwent arthroscopy for chronic ankle pain and/or instability. Twenty-four patients underwent MRI prior to the procedure. We compared the MRI findings with arthroscopic findings. We specifically examined for the anterior talofibular ligament (ATFL), calcaneofibular cigament (CFL) and osteochondral lesions(OCD). Arthroscopic findings were considered as a gold standard. There were 12 female and 12 male patients with an average age 39 years (11–65). The time interval between the MRI scan and arthroscopy was 7 months (2–18). In our study MRI had 100% specificity for the diagnosis of ATFL and CFL tears and osteochondral lesions. However sensitivity was low particularly for CFL tears. The accuracy of MRI in detecting ATFL tear was 91.7%, CFL tear was 87.5% and osteochondral lesion was 83.3%.

We conclude that MRI scanning has a very high specificity and positive predictive value in diagnosing tears of ATFT, CFL and osteochondral lesions. However sensitivity was low with MRI. In a symptomatic patient negative results on MRI must be viewed with caution and an arthroscopy is advisable for a definitive diagnosis and treatment.