Synovial plicae and chondromalacia patellae: correlation of results of CT arthrography with results of arthroscopy.

The purpose of this study was to compare computed tomographic (CT) arthrography with arthroscopy in the evaluation of patients with anterior knee pain. The authors studied 23 patients with patellar plicae at CT arthrography. Twenty of 21 patients presumed to have medial plicae at arthroscopy had similar findings at CT arthrography (sensitivity, 95%; specificity, 100%). However, 10 of 12 suprapatellar plicae and 11 of 11 lateral plicae seen at CT arthrography were not seen at arthroscopy. All 11 patients with a diagnosis of no or mild chondromalacia patellae at arthroscopy had similar CT arthrographic findings, whereas seven of 11 patients presumed to have moderate or severe chondromalacia patellae at arthroscopy had matching CT arthrographic results (sensitivity, 100%; specificity, 73%). CT arthrography was much more accurate in classifying plicae as thick (66%) as opposed to classifying plicae as thin (17%). The authors conclude that CT arthrography is an accurate and specific modality for distinguishing patients with anterior knee pain due to plicae from those with anterior knee pain due to differing causes.