plica syndrome; synovial plica syndrome
A tightening of the synovial plica (bands or folds of tissue) that may form in the knee joint. Many people have plicae in three or four places in the knee, with no adverse symptoms. However, when the plicae tighten (for example, as a result of an athletically related knee trauma) they can become hard and damage the knee. A tightened mediopatellar plica (the plica most likely to tighten) behaves like a bowstring, eroding the medial facet of the patella and the medial femoral condyle, causing anteromedial knee pain and a clicking noise as the plica snaps over the end of the femur. The symptoms mimic other knee disorders, so that knee plica is notoriously difficult to diagnose. Rest and ice are the most useful forms of treatment, but sometimes localized steroid injections are used. In cases that do not respond to conservative treatment, the plicae may be removed arthroscopically.
