(Fig 1-C.10) Peripheral Meniscal Instability

https://youtu.be/B9YVEff_c7E

https://youtu.be/VHbQLFiofuc

✅ Hypermobile Lateral Meniscus:

• It is thought to result from the congenital absence of posterior capsular attachments (similar to Wrisberg-type discoid meniscus, but without discoid morphology) or from tears in the posterior capsular attachment, especially the popliteomeniscal fascicles.

✅ Unstable Discoid Meniscus (DM):

• Symptoms: In unstable DM cases, including the Wrisberg type, symptoms typically include atraumatic snapping of insidious onset (snapping knee syndrome), presenting at a younger age (3–5 years). Older children and adolescents often present with tear-related symptoms.

✅ Early Signs of Instability:

• Indicators: Shape deformation in the discoid meniscus is an early sign of instability, which may include surface changes, meniscal shifts, and meniscal megahorns.
• Imaging Signs: "Pseudo–bucket-handle tear," "crimped meniscus sign," and parameniscal edema are key imaging signs of meniscal instability.

✅ MRI Signs of Peripheral Instability:

• Key Signs: MRI indicators include the absence of capsular insertions (observable as an absence of normal fascicles; T2 signal increase due to lack of coronal ligaments, simulating peripheral rupture) and anterior displacement of the posterior horn of the meniscus relative to the tibia (indicating meniscus subluxation).

 

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