Efficacy of 3T MRI vs Diagnostic Arthroscopy for the Diagnosis of Osteochondral Lesions of the Talus in Patients Undergoing Brostrom Repair for Lateral Ankle Instability

CATEGORY: Ankle; Arthroscopy INTRODUCTION/PURPOSE: Osteochondral lesions of the talus (OLT) are commonly seen in patients with lateral ankle instability. If left undiagnosed, OLTs can lead to significant ankle pain and progressive osteoarthritis. While arthroscopy has long been the gold standard for the diagnosis of OLTs, MRI is a useful imaging modality for pre-operative evaluation and surgical planning in patients undergoing surgery for lateral ankle instability. The purpose of this study was to evaluate the diagnostic accuracy of 3T MRI for the diagnoses of OLTs in patients undergoing a Broström Gould procedure for lateral ankle instability. METHODS: Following institutional review board approval, a database was obtained for all patients from 2/11/2015 to 1/21/2019 who underwent a Broström Gould procedure for lateral ankle instability in addition to diagnostic arthroscopy of the tibiotalar joint. Additionally, patients required a pre-operative 3T MRI for inclusion in the study. Patients who underwent the Broström Gould procedure but did not have a diagnostic arthroscopy or did not have a pre-operative MRI were excluded from the study. The average time from MRI to surgery was 3.5 months. Patient charts were then reviewed to determine the proportion of MRIs that correctly identified the presence or absence of OLTs compared to diagnostic arthroscopy. RESULTS: A total of 80 patients were included for analysis with an average age of 38.1 +- 14.3 years. 46 (57.5%) patients were female and 34 (42.5%) were male. A total of 39 patients (48.8%) were identified to have an OLT on arthroscopy. Of these 39 patients, 28 patients (71.8%) were correctly identified by the pre-operative 3T MRI as having an OLT and 11 patients (28.2%) had MRIs that failed to identify an OLT. 41 patients had an arthroscopy that was negative for OLTs. Of these 41 patients, MRI correctly diagnosed 40 patients (97.6%) as not having an OLT and misdiagnosed 1 patient as a false positive (2.4%). CONCLUSION: In patients undergoing Broström Gould procedures with diagnostic arthroscopy for osteochondral lesions of the talus, 3T MRI demonstrates a sensitivity of 71.8% and a specificity of 97.8%. Thus, pre-operative MRI can be a useful imaging modality to assess for OLTs prior to surgery and should prompt surgeons to perform an arthroscopy with subsequent treatment of the OLT. However, a negative MRI does not rule out the possibility of an OLT being present due to a relatively high false- negative rate.