Plica Syndrome

The synovial plica is a thin, fibrous fold in the synovial membrane of the knee. Most people have four plicae, but the medial plica (located on the inner side of the knee) is the most commonly affected.

When irritated, the plica can thicken and cause pain, swelling, and mechanical symptoms such as clicking or locking of the knee.

Several factors can contribute to plica irritation and inflammation, including:

Overuse and Repetitive Movements

• Activities that involve frequent knee bending (e.g., running, cycling, squatting).
• Excessive stair climbing or prolonged kneeling.

Knee Trauma or Direct Injury

• Blows to the knee or falls can inflame the plica.
• Post-surgical irritation or scar tissue formation.

Muscle Imbalances and Poor Biomechanics

• Weak quadriceps and tight hamstrings can lead to excessive knee strain.
• Misalignment of the patella (kneecap) may increase friction on the plica.

Underlying Knee Conditions

• Patellar maltracking or meniscus injuries can lead to plica irritation.
• Arthritis or synovitis may contribute to inflammation.

Symptoms vary depending on the severity of plica irritation but commonly include:

• Pain on the inner side of the knee (medial aspect).
• Clicking, snapping, or popping sensation when bending the knee.
• Swelling and tenderness around the knee joint.
• Locking or catching sensation in the knee.
• Pain that worsens with prolonged activity (especially squatting or running).

Diagnosing plica syndrome requires a detailed medical history and clinical examination. Diagnostic methods include:

Physical Examination:

• Palpation of the medial plica to check for tenderness.
• Plica test (knee flexion and extension with pressure on the plica area).
• Assessment of knee biomechanics and muscle imbalances.

Imaging Studies:

• MRI (Magnetic Resonance Imaging): Helps rule out other knee conditions (e.g., meniscus tears, patellar issues).
• Ultrasound: Can detect plica thickening and inflammation.
• X-rays: Used to rule out fractures or arthritis.