Deficiencies of MRI in the diagnosis of chronic symptomatic lateral ankle ligament injuries

BackgroundStress radiography and more recently magnetic resonance imaging have been used to study the integrity of lateral ankle ligaments in chronic symptomatic instability after injury.AimOur aim was to see if magnetic resonance imaging was as good as examination under anaesthesia and stress radiography, for diagnosing injury to the lateral ankle ligaments.MethodologyFifty eight patients, 47 men and 11 women, who were athletes or military personnel, with symptomatic instability of their ankle were included in the study. This cohort of patients had MRI scans, stress radiography and arthroscopy of their ankle. Integrity of the calcaneo-fibular ligament (CFL) was recorded arthroscopically.The sensitivity, specificity, positive and negative predictive value of MRI and stress views, in assessing integrity of the CFL, were compared against arthroscopic findings.ResultsStress radiography under anaesthesia and MRI had sensitivity of 94% and 47% respectively and specificity of 98% and 83% respectively, for diagnosing injury to the CFL. Stress radiography has a higher accuracy in diagnosing CFL injuries as compared to MRI.ConclusionThe results of this study casts doubt on the efficacy of MRI in the diagnosis of serious ankle ligament injuries.