Meniscus incompetence after meniscotibial ligament avulsion
The condition is called a floating meniscus where the MRI scan shows a fluid gap between the bottom of the meniscus and the tibia bone, due to high-force traumatic detachment of the menisco-tibial (or coronary) ligaments that are a normal part of the anchorage system for the meniscus. 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.
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Avulsion of both posterior meniscal roots associated with acute rupture of the anterior cruciate ligament Mariani PP, Iannella G, Cerullo G and Giacobbe M. J Orthop Traumatol. 2015 Sep; 16(3): 259–262.
Biomechanical Consequences of Lateral Meniscal Posterior Root Avulsions. Geeslin AG, Civitarese DM, Turnbull TL, Dornan G, Fuso F and LaPrade RF. Orthop J Sports Med. 2015 Jul; 3(7 suppl2): 2325967115S00111.