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  • 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


A 20-year-old man presents with anteromedial knee pain that has progressively worsened in the past 3 months. The patient complains of popping and clicking medial to the patella when he flexes and extends his knee. The patient has pain with popping, clicking, and giving away when he ascends and descends stairs or performs squatting activities. Upon palpation, the patient has pain and tenderness in the medial patellofemoral joint, with notable thickened band of soft tissue in this region. The patient has negative McMurray, Apley, Thessaly, and Ege tests for meniscus pathology, and negative patellar apprehension and medial/lateral glides for patellar instability. Patellar bowstring and medial plica shelf tests are positive.



  • Plica is a shelf, fold, or pleat in the synovial membrane in the knee

    • Result of incomplete or partial reabsorb during fetal development

    • Can be inferior, medial, or superior to the patella

    • Can vary in size (length or thickness) and clinical relevance

    • Can be thickened and inflamed, usually following acute or chronic trauma

  • Medial plica extends from anteromedial aspect of the patella to the suprapatellar pouch

    • Is most implicated

  • 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

FIGURE 199-1

Plica anatomy. (From Patel DR, Greydanus DE, Baker RJ. Pediatric Practice: Sports Medicine. Copyright © The McGraw-Hill Companies, Inc. All rights reserved.)

Essentials of Diagnosis

  • Diagnosed primarily through symptoms and exclusion of other knee pathologies

  • Mechanism of injury can be from either chronic trauma 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 ...

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