Skip to Main Content

We have a new app!

Take the Access library with you wherever you go—easy access to books, videos, images, podcasts, personalized features, and more.

Download the Access App here: iOS and Android. Learn more here!

  • Plica syndrome
  • Pathologic plica/plicae
  • Synovial plica/plicae syndrome

  • 727.83 Plica syndrome

  • M67.50 Plica syndrome, unspecified knee

  • 4E: Impaired Joint Mobility, Motor Function, Muscle Performance, and Range of Motion Associated With Localized Inflammation


  • Plica is a shelf, fold, or pleat in the synovial membrane in the knee.
  • It is the result of incomplete or partial reabsorb during fetal development.
  • Plica can be inferior, medial, or superior to the patella.
  • Can vary in size (length or thickness) and clinical relevance.
  • Plica can be thickened and inflamed, usually following acute or chronic trauma.
  • The medial plica is most implicated.
  • Medial plica extends from anteromedial aspect of patella to the suprapatellar pouch
  • Suprapatellar plica separates the suprapatellar pouch from the knee joint
  • Infrapatellar plica, also termed ligamentum mucosum, runs from the infrapatellar fat pad to the intercondylar notch

Essentials of Diagnosis

  • Diagnosed primarily through symptoms and exclusion of other knee pathologies
  • Mechanism of injury can be either from chronic or acute trauma
    • Chronic: friction or rubbing over the femoral condyle
    • Acute: pinching under the patella
  • Found in concurrence with range of pathologies, both chronic and acute
    • Chronic: chondromalacia or patellofemoral pain syndrome
    • Acute: ACL or meniscus pathologies or contusion
  • Differential diagnosis from other knee pathologies that may warrant a more immediate surgical intervention is essential (meniscus tear)
  • Combination of tests/cluster of findings has been reported to have the strongest diagnostic value in terms of sensitivity (1.0) for diagnosis of medial plica syndrome.

General Considerations

  • Plica are normal unless thickened or inelastic from acute or chronic inflammation
  • Plica syndrome signs and symptoms mimic other knee pathologies
  • Full history of symptoms, medical history screening, and differential knee orthopedic examination will ensure appropriate diagnosis
  • History of anterior knee pain, pain primarily over medial femoral condyle, visible or palpable plica, and exclusion of other anteromedial knee pain.


  • Plica syndrome most commonly involves the medial plica2
  • Presence of a plica has been reported to range from 10% to > 50% in normal knees.
  • Has been found with much greater frequency in patients who have anterior knee pain.2
  • No delineation in incidence noted based on gender or age
  • Individuals with Japanese have the highest prevalence of synovial plica in the knee.

Signs and Symptoms

  • Insidious onset of knee pain
  • Pain or mechanical symptoms (clicking, catching, giving away) located in the anterior knee
  • Symptoms elicited with flexed positions of the knee; transitioning between flexion to extension
  • Pain and mechanical symptoms with stairs; squatting
  • Tender to palpation over the plica; swelling in plica

Functional Implications

  • Pain/limitation with
    • Ascending or descending stairs
    • Sitting into or rising from chair
  • Catching or buckling of knee with
    • Rising from seated positions
    • Walking ...

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.