Medial patellar plica syndrome

Medial patellar plica syndrome is one of the conditions that can be associated with the presence of synovial plicae of the knee (in this instance a medial plica). It can be a common source of anterior knee pain.

Epidemiology

While it can affect those of any age, it typically involves the young patients involved in repetitive athletic activity.

Clinical presentation

Patients may present with pain over the anteromedial aspect of the knees (mostly above the joint line ⁸) and this may be accompanied by episodes of crepitation, catching, and pseudo-locking sensations. 

Pathology

Knee plicae are synovial invaginations which are thought to be remnants of embryological development. Plicae ≥1 mm may be present in over 70% of individuals and are mostly asymptomatic ^8,9. Under certain circumstances, they carry the potential to become inflamed and symptomatic. There can be fibrosis of a plica rendering it inflexible ⁸.

Radiographic features

Plain radiograph

Plicae are occult on plain radiograph.

MRI

Useful for identifying the presence of a plica and if it is thickened (typically appears like a shelf-like band). Signal characteristics of plicae are:

• T1: low signal
• T2/PD: low signal

In symptomatic patients, thickening of the medial plica and associated chondral defect of the medial patellar facet can be seen.

Treatment and prognosis

Management options range from the conservative end of rest - physiotherapy to corticosteroid injections to arthroscopic surgery.