Plica syndrome , while being quite well known to physical therapists and physicians specializing in physical medicine and orthopedics, is not a common term people are aware of, unless perhaps they’ve been diagnosed as it being the possible source of their knee pain. Plica-syndrome, often characterized by anterior knee pain, is most commonly found along the superomedial aspect of the knee.
The “plica” is due to remnant embryological tissue that compartmentalizes the knee during fetal development. The plica is sometimes considered a “vestigial” structure, which means that it has lost its ability to function over time and does not functionally affect an individual whether it is present or absent. It has been likened to the appendix, which can be a source of pain but lacks significant important function.
I’ll make a case here for quick comparison that a similar flap, or cardiac remnant in the atrial septum of the heart from fetal development exists. In the case of this heart anomaly, this “vestigial” structure is often referred to as a patent foramen ovale or PFO. This left-over fetal tissue, sometimes takes the shape of a flap and in some hearts. Some PFOs have been even described as “tunnel-like”.
Patent foramen ovale has often been depicted as a defect or an incomplete closure in the walls of the chambers of the heart. A patent foramen ovale can vary in size but the location is usually the same. As described in the literature, the flap like opening or hole is in the dividing wall (septum) between the upper two chambers of the heart – the left atrium and the right atrium.
Identifying a PFO is important because a PFO is a potential pathway for a blood clot to escape from the heart and travel to the brain, causing a stroke. Similarly, the plica in the knee can get trapped and irritated to a point where it impairs normal joint ROM (range of motion) and can cause often less debilitating but still serious limitation to ADL’s (activities of daily living) when compared to the devastating effects of stroke.
How does this heart defect occur?
In the womb, all babies have a PFO. This is because a baby does not use its own lungs to filter and oxygenate its blood. Instead, it receives oxygen-rich blood from its mother via the umbilical cord. This blood has been filtered and oxygenated by the mother’s lungs. The PFO allows this blood to be sent directly to the brain, which has a high requirement for oxygen-rich blood during fetal development.
How common are PFO’s?
In most people, the two flap-like sections of septum which form the foramen ovale (or hole) fuse together after birth to form a solid dividing wall between the right and left atria. However, in an estimated 15-30% of the population, this area of the heart doesn’t fuse together and remains open or “patent”. This opening makes it possible for blood to cross from the right atrium to the left atrium—this is called a right-to-left shunt. The danger of blood shunting in this manner is that if it contains small debris or a clot it has bypassed the body’s natural filter (the lungs) and can pass directly up to the brain and cause a stroke . Worldwide, it is estimated that approximately 500,000 people may suffer this type of stroke each year.
My Conclusion and the current Medical Paradox
When symptoms arise this is where my comparison between PFO and Plica go down separate paths. Here’s how current treatment differs:
Accurate diagnosis of both symptomatic plica and “symptomatic” PFO remains the predominant challenge. The main difference is currently only with one syndrome the option of surgical treatment is widely accepted. Why is symptomatic PFO not being fairly treated as a true medical syndrome?