A plica is a ribbon-like fold of joint lining (synovium) which may be present in any knee as an embryological remnant.

ligamentum mucosus
The various plicae (plural) of the knee.


Plicae often mimic other conditions

Plicae are normal anatomical structures, so they are often ignored when the surgeon is investigating the problematic knee. They may cause clicking and catching and be mistaken for a meniscus problem, for example. But usually a careful arthroscopic examination will reveal thickening at areas that are being impinged or a bit of redness and some damage to underlying joint cartilage.

synovial plica
plical fold
An article about plica surgery in the knee based upon a forum discussion.

A list of references relating to the plica syndrome

What is the Plica Syndrome?

The plica syndrom is an often-missed cause of symptoms around the kneecap.

What are the common kneecap problems?

A quick overview of kneecap problems to help you with your research.

Medial plica

Plicae are often neglected as a cause of knee pain.

A case presentation by Mr Angus Strover.



Plica syndrome???

Medial Plica Syndrome - Cyclist.


Synovial Plica Syndrome of the Knee: A Commonly Overlooked Cause of Anterior Knee Pain. Lee PYF, Nixion A, Chandratreya A and Murray JM. Surg J (N Y). 2017 Jan; 3(1): e9–e16.

'The Sneaky Plica' revisited: morphology, pathophysiology and treatment of synovial plicae of the knee. Schindler OS. Knee Surg Sports Traumatol Arthrosc. 2014 Feb;22(2):247-62. doi: 10.1007/s00167-013-2368-4. Epub 2013 Feb 5.

See also -



eBook about plica problems in the knee

eBook - An overview of plica problems in the knee

An expert look at the various plical folds of the knee and the problems that can be caused by a troublesome plica.