What is plica syndrome?

There are many causes for anterior knee pain in the athlete.  One cause is plica syndrome. The plica is an extension of the synovial membrane in the knee. It can become inflamed or irritated following trauma or an increase in physical activity. Plica syndrome can cause anterior knee pain and a popping sensation in the knee that is due to a thick, fibrous plica snapping over the femoral condyle.

Plica syndrome is most often seen in runners and athletes. It can be confused with patellofemoral pain syndrome because of the location of the pain, its association with patellar dysfunction, and the population that it is found in. Having genu valgum (knock knees), weak/tight hip abductors, and ankle dysfunction can increase the risk of having plica syndrome.

Plica syndrome is diagnosed clinically but imaging is often used to confirm the presence of a thick plica and to exclude other causes of knee pain.The goal of treatment in plica syndrome is to reduce inflammation of the plica. This can be achieved using anti-inflammatory medication and injections. This method of treatment is most effective if the plica syndrome is not longstanding. Longstanding inflammation can lead to irreversible changes of the plica resulting in less than optimal results from conservative therapy. Surgical intervention can be utilized if conservative therapy fails.



Schindler, O. (2013). ‘The Sneaky Plica’ revisited: Morphology, pathophysiology and treatment of synovial plicae of the knee. Knee Surgery, Sports Traumatology, Arthroscopy Knee Surg Sports Traumatol Arthrosc, 247-262.