Synovial Plica Syndrome: Symptoms & Treatment for Anterior Knee Pain

By Tom Sutton, DPT Student

Introduction and Anatomy

In a study by Lee et al, synovial plica syndrome (SPS) of the knee is said to be a cluster of symptoms and not one specific presentation or cause. Some of these problems may consist of pain in the anterior region of the knee, clicking, clunking and popping sounds that can occur during functional activities such as squatting or negotiating stairs.  SPS can affect males and females alike, most commonly between the ages of 10-30. Plica is actually the name of a structure in most peoples’ knees, many are non-symptomatic,”inward folds of the synovial lining,”(1) that can be impinged between the quadriceps tendon and femoral trochlea when the knee flexes between 70-100 degrees.   The plica is attached to the articularis genus muscle and runs into the synovial lining of the knee, located on the medial side of the retropatellar fat pad.  Figure 1 presents an image of the plica in the knee. The study performed by Lee et al investigated what synovial plica syndrome is, how it can affect people and how to properly treat this type of knee pain.

Presentation

Given the fact that SPS may bring about a number of complaints and symptoms from patients, it is important to understand exactly what problems are present and how to diagnose SPS in order to demystify this type of knee pain. Lee et al reports is that SPS is most commonly without a mechanism of injury.(1) Plica-related problems in the knee can come about during knee flexion over time such as kneeling and sitting or repetitive exercises like running or biking.(4) The patient is going to complain mostly about pain and a “snapping” sound  on the medial side of the knee joint during flexion.(4) For a complete list by Lee et al, see Table 1 for signs and symptoms of knee SPS.(1) SPS can also mimic other pathologies such as meniscal problems, osteoarthritis of the knee and patellar tendinopathy.(1) According to Schindler, anterior knee pain is the “cardinal symptom” of plica syndrome (5). Since SPS can be caused by a traumatic mechanism of injury, overuse or associated with co-morbidities such as diabetes, (1) obtaining past medical history becomes more pertinent. Additionally, if the patient were to be younger and around the age of 13, it would be prudent to find out if they have been experiencing growth spurts, as symptoms of SPS can occur during this time.(1)

For more specific information on SPS, here is a printable booklet that is courtesy of Houston Methodist. (4)

Application & Closing Thoughts

Furthermore, if there is a stability or strength problem elsewhere in the body such as the back, hip or ankle, it is possible that this may cause problems in the knee that could explain the idiopathic nature of plica syndrome.(1) There are special tests that can be performed including Hughston’s Plica Test and the Stutter Test.(1) Although special tests do not hold diagnostic value, they can be helpful in ruling in and ruling out pathologies. Applying the knowledge from several SPS studies and sources, there are a number of ways to address a patient with SPS. Finding the cause of the problem should be the priority of the physical therapist as they begin to formulate a program for the patient. Treatment may consist of a wide variety of techniques such as soft tissue manipulation, stretching, functional exercise and postural education. Functional exercise and training will be very important because the patient can learn more efficient movements for everyday lifestyle as well as gain the strength needed in both lower extremities in a closed-kinetic chain (CKC) fashion. Below are a few examples of helpful CKC exercises. 

SPS has been shown to respond well to conservative treatment, (6) and most patients have demonstrated improvement and decreased pain.(1) An important takeaway from this is to understand why the patient is experiencing SPS and address the cause. Otherwise, it is possible the plica problem will linger and surgical methods may be weighed as an option. Although some studies have shown that most patients with failed conservative treatment have had success with surgery,(1) avoiding a resection procedure altogether would be a much better alternative.

Blog Post written by Tom Sutton, DPT Student at the University of St. Augustine. Tom is currently in his final Clinical Rotation with me at Catz Physical Therapy Institute.

References

1. Nixion A, Chandratreya A, Murray J, Lee P. Synovial Plica syndrome of the knee: A commonly overlooked cause of anterior knee pain. The Surgery Journal. 2017;03(01):e9–e16. doi:10.1055/s-0037-1598047.

2. Griffith CJ, LaPrade RF. Medial plica irritation: diagnosis and treatment. Curr Rev Musculoskelet Med 2008;1(01):53–60

3. Dandy DJ. Anatomy of the medial suprapatellar plica and medial synovial shelf. Arthroscopy 1990;6(02):79–85

4. Houston Methodist. http://www.houstonmethodist.org/orthopedics/where-does-it-hurt/knee/plica-syndrome/. Accessed March 12, 2017.

5. Schindler OS. ‘The Sneaky Plica’ revisited: morphology, pathophy- siology and treatment of synovial plicae of the knee. Knee Surg Sports Traumatol Arthrosc 2014;22(02):247–262

6. Bellary SS, Lynch G, Housman B, et al. Medial plica syndrome: a review of the literature. Clin Anat 2012;25(04):423–428

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