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The Pelican Sign: Case Series Demonstrating A Unique Description of an Anteriorly Flipped Bucket-Handle Meniscal Tear of the KneeFunding None.
Introduction Bucket-handle tears (BHTs) of the menisci are not uncommon and can occur in isolation or in conjunction with other injuries. The torn fragment can be displaced within the intercondylar notch or flipped anteriorly. In case of anterior flipped fragment, appearances of such tears on magnetic resonance imaging (MRI) scan have been described as various signs in literature (for example double posterior cruciate ligament sign, double delta sign) but mostly in the sagittal or coronal planes.
Purpose The aim of this study was to describe a unique ancillary sign that helps to identify this injury on the axial MRI plane where the anterior flipped BHT figuratively resembles a “pelican bird.”
Materials and Methods A retrospective review of MRI sequences of 10 consecutive patients over a 3-month period referred following a traumatic knee injury with anterior flipped meniscal tears was performed. Demographic details, clinical indication, and other associated features on the MRI were correlated following the observation of characteristic MRI appearance of a BHT.
Results All 10 patients (M:F = 7:3) with a mean age of 24.7 (17–38 years) presented following a twisting injury. 6 out of 10 patients had associated soft-tissue injuries in the knee visualized on the MRI. All patients demonstrated the distinctive “pelican bird” sign on the axial sequences of anterior flipped BHT of either menisci. This was not present with BHTs with displaced fragment within the intercondylar notch.
Conclusion We conclude that the “pelican sign” on an axial sequence when present correlates well with a BHT and its anterior displaced/flipped meniscal fragment. This ancillary sign can complement other previously described signs on different MRI sequences used to confirm a displaced BHT.
Keywordsknee injuries - bucket-handle tear - double flipped meniscus sign - lateral meniscus - medial meniscus - magnetic resonance imaging
Informed consent (patient/guardian), mandatory only for case reports/clinical images—consent was obtained.
All the authors contributed to conceptualization, data curation, formal analysis, funding acquisition, investigation, methodology, project administration, resources, software, supervision, validation, visualization, writing and review and editing of the manuscript.
Article published online:
26 December 2022
© 2022. Indian Radiological Association. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/)
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