Meniscal flounce
Meniscal flounces refer to the "ruffled" appearance of the inner margin of knee menisci. They were initially thought to be only an arthroscopic finding, as a result of joint distension and anesthetic muscle relaxants but they are occasionally seen on MRI.
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Epidemiology
Meniscal flounces are uncommon with initial studies suggesting a frequency of around 0.2% on MRI scans, however more recently a frequency of up to 5% in relation to the medial meniscus has been reported.1,4 It is far more common to be seen with the medial meniscus than the lateral meniscus.
Pathology
They are not associated with an increased incidence of meniscal tears, but can be mistaken for one. They reflect a degree of redundancy in the medial meniscus and are typically seen in the flexed knee.
Radiographic features
MRI
In the sagittal plane the flounce is seen as a wave or kink in the inner margin of the meniscus. In the coronal plane, they may make the inner margin of the meniscus appear truncated or blurred and simulate a small radial tear.
Whenever a flounce is identified it is important to check that there are no ligamentous or capsular injuries that may be resulting in the laxity. This is particularly important if a lateral meniscal flounce is seen, as these are rare and may be a sign of popliteomeniscal fascicle injury/deficiency with hypermobile meniscus.
History and etymology
Out of interest, a flounce is a ruffle placed around a garment (often undergarment) as a decoration.
Differential diagnosis
- radial-type meniscal tear
Related Radiopaedia articles
Knee pathology
The knee is a complex synovial joint that can be affected by a range of pathologies:
- bone and cartilage
-
knee fractures
- distal femoral condyle fracture
- tibial plateau fracture (classification)
- patella fracture
-
avulsion fractures of the knee
- arcuate complex avulsion fracture (arcuate sign)
- anterior cruciate ligament avulsion fracture
- biceps femoris avulsion fracture
- iliotibial band avulsion fracture
- patella fracture
- posterior cruciate ligament avulsion fracture
- reverse Segond fracture
- Segond fracture
- semimembranosus tendon avulsion fracture
- Stieda fracturechronic avulsion injuries
- dislocation
- chondromalacia patellae
- osteoarthritis of the knee
- osteochondral defects
- osteochondritis dissecans of the knee
- patterns of bone bruise in knee injury
-
knee fractures
- ligaments
- anterior cruciate ligament tear
- anterior cruciate ligament ganglion cyst
- anterior cruciate ligament mucoid degeneration
- posterior cruciate ligament tear
- medial collateral ligament tear
- lateral collateral ligament tear
- medial patellofemoral ligament tear
- posterolateral corner injury
- posteromedial corner injury
- tendons
- meniscal lesions
- bursosynovial lesions
- fat pad
- popliteal fossa
- fascia
- alignment
- knee
- patellofemoral
- gamut