meniscal ossicle

Meniscal
ossicle. MRI of the left knee, sagittal PD. A meniscal ossicle is visible on the posterior root of the medial meniscus (arrow).
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Meniscal
ossicle. a Coronal proton density weighted image of the knee showing a small lesion (arrow), isointense to marrow in the posterior horn of the medial meniscus, with a hypointense rim. b Coronal PDW fat suppressed image confirms the isointensity of the lesion to the marrow
jorthoptraumatol.springeropen.com • CC-by-2.0
Meniscal
ossicle. a Sagittal gradient echo images showing that the lesion (arrow) is isointense to the bone marrow and has a rim of hyaline cartilage. b Sagittal T1W image showing that the lesion is isointense to marrow with a hypointense rim
jorthoptraumatol.springeropen.com • CC-by-2.0
Meniscal
ossicle. Conventional radiograph of the left knee, frontal view. There is a calcium-density structure projected over the posteromedial femorotibial articular space.
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Meniscal
ossicle. Conventional radiograph of the left knee, lateral view. There is a calcium-density structure projected over the posteromedial articular space.
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Meniscal
ossicle. Coronal PD FS. The meniscal ossicle on the posterior root of the medial meniscus (arrow). There is bone marrow oedema on the posterior aspects of both tibial plateaux due to the trauma.
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Meniscal
ossicle. Axial PD FS. Posterior meniscal root tear (arrow) seen as a linear hyperintensity adjacent to the meniscal ossicle (asterisk).
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Meniscal ossicles are uncommon, often incidental, findings on radiography and cross-sectional imaging of the knee.

Epidemiology

Reported to have a prevalence of 0.15% in the general population .

Clinical presentation

Pathology

The etiology of a meniscal ossicle has not been definitively established, and congenital, traumatic, and degenerative origins have been suggested. Its association with the posterior horn of the medial meniscus may favor a traumatic origin .

It consists of cancellous bone with a cartilage interface. There is no fibroblast proliferation or neovascularization .

Radiographic findings

Plain radiography / CT
  • more often in the posterior horn of the medial meniscus
  • should have smooth margins, as opposed to a fracture fragment, and no donor site from the femur or tibia
MRI

The ossicle should follow bone marrow signal on all sequences:

  • T1: hyperintense
  • T2FS/STIR: hypointense

Treatment and prognosis

If symptomatic, conservative noninterventional therapy is tried first. If this fails, arthroscopic resection can be considered. Interventional therapy may also be considered if the ossicle is associated with other meniscal pathology.

Differential diagnosis

Siehe auch:
Assoziationen und Differentialdiagnosen zu Ossikel des Meniskus:
freier
Gelenkkörper
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