Figure. Intraoperative arthroscopic image reveals a thickened band of tissue located between the patella and the medial femoral condyle (arrow).
A 14-year-old adolescent presents to the office with a 6-month history of left knee pain. She is very active with sports and describes feeling a catching and popping sensation when she runs. The patient notes that she is able to play through the pain and denies a history of trauma or known precipitating event. She completed 4 months of conservative treatment including activity modification and physical therapy with no improvement in pain. On physical examination she has no knee effusion. She has a popping sensation with range of motion with patellofemoral compression. Magnetic resonance imaging (MRI) is unremarkable for any soft tissue injury. However, an intraoperative arthroscopic image reveals a thickened band of tissue located between the patella and medial femoral condyle.
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Synovial plica is a thin cord-like band of tissue that is part of the synovial lining of the knee. There are 4 types of plicae (infrapatella, mediopatellar suprapatellar, and lateral). The most common type is suprapatellar plica, which arises from the posterior quadriceps tendon and passes to the medial side of the knee joint.1 The mediopatellar plica is the most often attributed to the development of plica syndrome.1
Synovial plica is normally found in the knee as a thin and flexible structure. Plica syndrome is caused by inflammation, usually related to overuse of the knee. A thick enlarged plica can impinge or become trapped at the patellofemoral joint during knee motion (running, biking, and bending). Medial plica syndrome refers to pain caused by plica impingement during knee motion. Symptoms include a sense of catching, locking, or giving way with knee motion.1,2
The diagnosis of medial plica syndrome requires physical examination and imaging studies. The use of MRI is often inconclusive. Therefore, the gold standard for diagnosis and management is knee arthroscopy.2 The initial treatment of choice should be conservative management (physiotherapy, corticosteroid injection) as medial plica syndrome often resolves over time. Arthroscopic removal of the symptomatic plica confirms the diagnosis and is successful at resolving pain.1,2
Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor in chief of the Journal of Orthopaedics for Physician Assistants.
1. Al-Hadithy N, Gikas P, Mahapatra AM, Dowd G. Review article: plica syndrome of the knee. J Orthop Surg (Hong Kong). 2011;19(3):354-358. doi:10.1177/230949901101900319
2. Bellary SS, Lynch G, Housman B, et al. Medial plica syndrome: a review of the literature. Clin Anat. 2012;25(4):423-428. doi:10.1002/ca.21278