A meniscal avulsion is a traumatic incident that results in the knee meniscus - or a portion of it - tearing away from its previously firm anchorage to the tibia bone.

menisco-tibial avulsion or floating meniscus
An avulsion of the menisco-tibial ligament results in an incompetent 'floating' meniscus. The injury is generally associated with other ligamentous damage in the knee, although the meniscus itself is usually intact. (left: intact, right: avulsed)


Floating meniscus

This may be due to a tear of the menisco-tibial (a.k.a. coronary) ligaments that are a normal part of the anchorage system for the meniscus, and may be the result of a high-force injury. The condition is also called a floating meniscus as the MRI scan shows a fluid gap between the bottom of the meniscus and the tibia bone. Generally, the meniscus itself remains intact, but without this anchorage the meniscus becomes incompetent as a shock absorber.


Meniscus incompetence after meniscal root avulsion

Avulsion of the meniscal root can lead to immediate incompetence, and the meniscus may extrude over the edge of the tibia.

Meniscus avulsion
Floating knee meniscus
Floating meniscus
Menisco-tibial ligament avulsion

An explanation of what it means to have a 'floating' knee meniscus on MRI imaging.



The “Floating” Meniscus: MRI in Knee Trauma and Implications for Surgery Bikkina RS, Tujo CA, Schraner AB and Nancy M. Major NM. American Journal of Roentgenology. 2005;184: 200-204.

Technique for Arthroscopically Assisted Superficial and Deep Medial Collateral Ligament–Meniscotibial Ligament Repair With Internal Brace Augmentation. Aaron K. Black AK, Schlepp C, Zapf M and Reid JB III. Arthrosc Tech. 2018 Nov; 7(11): e1215–e1219.

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Embedded courtesy of Christopher Adams, MD