Meniscal root tear

Meniscal root tears are a type of meniscal tear in the knee where the tear extends to either the anterior or posterior meniscal root attachment to the central tibial plateau. They often tend to be radial tears extending into the meniscal root. 

Epidemiology

According to one source, they are thought to account for ~10% of all arthroscopic meniscectomies ⁵.

Pathology

While they can arise from a number of mechanisms, root tears are generally thought to be chronic ⁵. 

Associations

• ACL tears are associated with posterior horn root tears of the lateral meniscus 

Radiographic features

MRI

Best assessed on T2 weighted sequences. When it involves the posterior root, medial root tears are easier to diagnose than lateral root tears.

On medial posterior root tears there is often ²:

• shortening or absence of the root on sagittal images
• vertical fluid cleft on coronal fluid-sensitive (T2) images

On posterior root radial tears of the lateral meniscus, the appearance may be similar to radial tears in other locations.

For root tears in general, sagittal imaging may demonstrate a meniscal ghost sign.

Other features include:

• truncation sign on coronal images ⁴
• features meniscal extrusion on coronal plane ⁴

History and etymology

They were first described by M J Pagnani et al. in 1991 ⁶.