Discoid meniscus does not require treatment as long as patients are asymptomatic or they have only minor symptoms 7,8.
However, this patient suffers pain and has clinical symptoms after a twisting injury.
MRI shows a discoid lateral meniscus with a horizontal cleavage tear and anterior displacement which is indicative of instability and a meniscocapsular tear and should be treated 9.
The condition has to be differentiated from the variant of an unstable Wrisberg type discoid lateral meniscus, where the meniscofemoral ligament of Wrisberg is the only stabilizing attachment 3,5.
Arthroscopy was recommended. Unfortunately, the patient did not follow up with her referring physician and we lost track of her.