The Meniscal Comma Sign: Characterization and Treatment of a Displaced Fragment in the Meniscotibial Recess.

Displaced parrot beak flap tears in the meniscotibial recess are complex tears of the meniscus that begin as central radial tears and progressively extend toward the periphery, creating a detached fragment. These tears have not been described in the literature, but the authors have described them as the "meniscal comma sign" based on their appearance on magnetic resonance imaging. Displaced fragments are clinically significant because of the pain and mechanical symptoms they can cause as a result of tenting of the deep medial collateral ligament. Failure to distinguish these tears from meniscal extrusion and superimposed osteoarthritis on magnetic resonance imaging can cause them to be misinterpreted or missed, leading to a delay in treatment. [Orthopedics. 2018; 41(3):e442-e444.].