The "floating" meniscus: MRI in knee trauma and implications for surgery.
OBJECTIVE
We describe 21 cases involving meniscal injury in which the meniscus appears free-floating on MRI of the knee. In these cases, the meniscus is completely surrounded by fluid. Correlation with surgical reports shows that the "floating" meniscus corresponds to a meniscal avulsion or detachment from the tibial plateau with an associated disruption of the meniscotibial coronary ligaments, which attach the meniscus to the tibia, allowing fluid to encompass the meniscus. A floating meniscus on MRI may represent a new specific finding for an uncommon form of meniscal injury known as meniscal avulsion.


CONCLUSIONS
The presence of a floating meniscus on MRI is a result of significant trauma to the knee leading to meniscal avulsion and is often associated with significant ligamentous injury. Alerting the surgeon to the presence of a meniscal avulsion facilitates appropriate surgical planning with meniscal reattachment to the tibial plateau.
Bikkina
Ravi S
RS
Department of Radiology, Duke University Medical Center, Erwin Rd., PO Box 3808, Durham, NC 27710, USA.
Tujo
Charles A
CA
Schraner
Albert B
AB
Major
Nancy M
NM
D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000175:diagnosis* / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008297:Male; D008592:Menisci, Tibial / Q000601:surgery; D008875:Middle Aged; D012189:Retrospective Studies; D000070600:Tibial Meniscus Injuries