Pseudoband formation: Missed ATFL tears on MR imaging

Abstract

Background: The anterior talofibular ligament (ATFL) is the ligament most commonly injured during ankle sprains. Objective: The purpose of this investigation was to assess the sensitivity of Magnetic Resonance (MR) imaging for ATFL with open surgery, Bros-trom-Gould surgical interventional considered the gold standard. Methods: A retrospective chart review using Operating Room (OR) and MR reports from April 2008-November 2009 led to a review of 137 charts, with 15 cases meeting the inclusion criteria. Results: The sensitivity for ATFL tears irrespective of extent of the tear was 93%. For full thickness ATFL tears, 10 were found to be positive on MR but 13 on OR with a sensitivity of 77%. Of the three missed cases, 2 were described as sprain injuries and the other normal using MRI. Conclusion: The recommen-dations for MR assessment of ankle injury include use of dedicated sequences and understanding the " pseu-doband " concept. The two full thickness and two par-tial thickness tears on OR described as sprain injuries on MRI had a band of inflammatory granulation tis-sue. This tissue accounted for the appearance of the thick continuous band at MRI, the pseudoband. This study reaffirms the usefulness of MR in determining ATFL tears, aiding surgical decision making.