Suprapatellar plica synovialis: a common arthrographic finding.

The suprapatellar structures are often overlooked during double contrast knee arthrography. A plica synovialis suprapatellaris representing a remnant structure from the embryonic septum between knee joint and suprapatellar bursa was identified in 40 of 53 double contrast knee arthrograms. Symptoms including knee pain and clicking have been described in association with the presence of a plica synovialis. Only one of 40 patients in this series, however, was treated for the diagnosis of plica syndrome. Plica synovialis suprapatellaris is a common, usually incidental finding at knee arthrography and should not be mistaken for an adhesion or other capsular abnormality if the clinical findings of plica syndrome are absent.