If you think you are troubled by a plica in your knee you need to know following. Nearly all knees do have a plica and there are 5 types of plicae. The two most well-known plicae are first of all the mediopatellar (medial) plica placed on the inner site of the kneecap and the other is in the front of the knee named the infrapatellar plica (ligamentum mucosum). All the five plicae have no know function, but they are residuals from the fetal life.
Sometimes a knee impact or wrong use of the knee can cause a plica to get inflammed and the it gets swollen. The medial plica are known to catch between the kneecap and the femoral condyle and this typically causes symptoms of inner site pain and catching. The Infrapatellar plica is attached to the Hoffa Fad and moves significantly when the knee straightens and bends. Sometimes scar tissue in the infrapatellar plica can cause anterior knee pain based upon scar tissue in the plica.
First of all the treatment focus rest and antiinflammatory medicine (NSAID or steroids). When the plica has restored it self, a physiotherapist can help by restoring balance and correct movement patterns to prevent recurrence. Sometimes those treatments are not sufficient and one or more plicae have to be taken care of by arthroscopic surgery. Here it is very easy to remove. Some call Infrapaellar plica problems arthrofibrosis and call the procedure arthroscopic removal of the plica - anterior interval release. Personally I do not think this is arthrofibrosis, which is a more serious condition giving a stiff knee.
The three other plicae are the Suprapatellare plica that occasionally can give rise to pain above the patella in the Quadriceps tendon, the Laterale plica, that can cause outer site pain, and finally a plica that is localised in the rear of the knee and act as valve in front of a Baker cyst.