Review article: Plica syndrome of the knee.

Plica syndrome is a pathological condition secondary to inflammation. Plicae around the knee are common and generally asymptomatic. They often are misdiagnosed. The morphology of knee plicae varies; mediopatellar plicae are the most common cause of the plicae syndrome. An intermittent dull pain is the most common symptom. Diagnosis is made by exclusion. Ultrasonography is useful; arthroscopy is the gold standard. Arthroscopic removal of the plica may be necessary when conservative treatment for up to 6 months fails.