Anterior knee pain: do you know the synovial plica

What is synovial plica?

Its name comes from Greek and means fold. They are embryonic structures composed of synovial tissue, which are in the joints of animals in their embryonic phase and that with time disappear, leaving some remains in adulthood.

Specifically, in the knee of the human species, 70% of the population has some type of synovial plica. These can be of four types:

  • The suprapatellar plica
  • The medial plica
  • The infrapatellar plica or mucosal ligament
  • The lateral plica

Of all of them, the ones that present potential for pain or alteration of the knee are the medial plica and the mucosal ligament. The lateral plica can also generate discomfort and alterations, but it is much less frequent. The suprapatellar plica does not usually give any clinical symptoms.

What type of symptomatology causes medial plica?

They usually refer pain in the anterior region of the knee, which increases when going up and down stairs or ramps. Also when intense physical activity is performed, such as walking in the countryside, paddle tennis, tennis, gym exercises, etc. After such activity they usually complain of pain, a burning sensation in the anterior and medial area of the knee and a feeling of “functional instability” (as if the knee were going to fail on exertion). They also report that when they have been flexing their knee for a long time, they need to stretch it in order for the pain to diminish. Other times patients report that when they go to bed, they need to use a pillow between their knees to be able to fall asleep because the pain decreases.

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Are there diagnostic tests for this pathology?

The tests are clinical tests and diagnostic imaging tests: dynamic ultrasound and magnetic resonance imaging.

Clinical tests have been developed since 2004 by Dr. Sung Jae Kim, a renowned orthopedic surgeon and researcher from South Korea. The doctor described a test called “MPP TEST” (Medial Patellar Plica test) which in 2007 confirmed that it was a very reliable test with over 90% clinical reliability. Likewise, the American Orthopedic Surgeon Dr. Robert LaPrade described the “Plica snap test” which is a complementary test to Dr. Kim’s test and which also presents a significant reliability.

Dynamic ultrasound, developed by Dr. Lucas Paczesny (Radiology 2009) describes how the medial synovial plica slides over the medial femoral condyle and causes friction and its thickness can be measured with this technique.

Finally, magnetic resonance imaging. The work of Dr. Roberto Garcia-Valtuille (RadioGraphics 2002) has been very valuable, as he teaches very clearly how to look for these structures and presents examples with the corresponding arthroscopic image of the case.

Is there a treatment?

In principle, the treatment of anterior knee pain due to a medial synovial plica is conservative: analgesic and anti-inflammatory medication, rehabilitation treatment with muscle strengthening exercises and stretching of the quadriceps and flexor muscles of the knee.

If this treatment does not improve, I recommend subsynovial infiltration with autologous platelet-rich plasma, which is a very specific type of infiltration that can be performed with ultrasound monitoring. Usually three infiltrations are performed. The results of this treatment are good with an improvement of 70% of patients, although the improvement time ranges from one month to 6 months.

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If after 6 months, the pain continues, I recommend surgical treatment, which I perform by arthroscopic technique. In this treatment, the medial synovial plica, the hypertrophic tissue of the retropatellar fat of Hoffa and any synovial tissue that is enlarged or hypertrophied in the knee are resected. All this is done with a device called bipolar wave frequency that causes a phenomenon of sublimation (process that consists in the change from solid to gaseous state of a tissue without passing through the liquid state) and prevents bleeding of these structures very rich in vessels and nerves.

Does it heal completely?

In my experience of more than 20 years, I believe that this approach to anterior knee pain enriches the possibilities of healing it.

It is true that anterior knee pain is multifactorial and that we must be very thorough when looking for the true causes of the same, but it is also true that this pathology is more common than previously known.

To think that the synovial tissue is one of the main causes of anterior knee pain, is of obligatory appreciation and discard, to avoid committing a diagnostic failure.

My experience in this field is broad and enriching, in addition to having reported magnificent results with patients who were condemned to not perform physical activity because they had been told that they had cartilage lesions that prevented them from performing sports activities. In addition, in recent years, scientific articles have emerged that corroborate that we are on the right path towards a solution to the problem.

After the treatment of the synovial plica, the patients have recovered their sports activity in a natural and normal way, as if they had not had anything in the painful knee.

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In conclusion, I recommend that patients suffering from anterior knee pain be studied methodically and scientifically, ruling out the most important causes of anterior knee pain, including synovial pathology.

To learn more about synovial plica, contact a specialist in traumatology.