History
The spectrum and diversity of symptoms can make plica syndrome difficult to pinpoint. Often, symptoms resemble or overlap with those of other pathologic conditions. [27, 28]
Reported symptoms include the following:
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Anterior or anteromedial knee pain
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Intermittent or episodic pain
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Clicking
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High-pitched snapping
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Occasional giving way
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Locking (really pseudolocking) and catching
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Aggravation of symptoms by activity, by stair climbing, or by prolonged standing, squatting, or sitting
Meniscal tears, patellar tendinitis, Osgood-Schlatter disease, Sinding-Larsen-Johansson disease, and patellar instability are the most commonly found concomitant conditions.
Physical Examination
On physical examination, the patient typically has tender points along the medial and inferior aspect of the patella (see the first image below); in some instances, a painful, hypertrophied membrane is palpable. The inferomedial quadrant (see the second image below) is the most consistently painful region. Occasionally, a medial apprehension test of the patella elicits a positive response, but careful evaluation reveals that it is due to direct tenderness to palpation in the region of the plica and is not true patellar instability.
Plica syndrome. The inferomedial quadrant is usually the most painful region by physical examination. This area is highlighted by several X's in this figure. A painful taut band of tissue that emanates from the central portion of the medial patella may often be palpated (3 o'clock position on the figure).
Rovere et al stated that a palpably tender plica in the absence of an intra-articular effusion conclusively establishes a diagnosis of plica syndrome, provided that other causes of knee pain are ruled out. [29] A taut articular band that reproduces the patient's pain upon palpation of the medial peripatellar region is virtually pathognomonic for plica syndrome. This may be referred to as a positive TARP sign, in which TARP stands for the following:
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T - Taut
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A - Articular band
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R - Reproduces
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P - Pain
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Plica syndrome. Typical appearance of a large beefy medial parapatellar plica.
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Plica syndrome. Patient pointing to the painful area of her knee.
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Plica syndrome. The inferomedial quadrant is usually the most painful region by physical examination. This area is highlighted by several X's in this figure. A painful taut band of tissue that emanates from the central portion of the medial patella may often be palpated (3 o'clock position on the figure).
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Plica syndrome. Axial MRI demonstrating abundant medial plical tissue.
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Plica syndrome. Preoperative appearance of medial parapatellar plica (a 4+ plica by the Jee classification, extending across more than two thirds of the medial facet of the patella).
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Plica syndrome. Postoperative appearance of the same patient as in Image 5 after plical resection.
