Suprapatellar Plica

plica synovialis suprapatellaris

The suprapatellar plica is a synovial fold at the superior pole of the patella forming the boundary between the suprapatellar pouch and the main knee joint cavity. It is a normal embryological remnant of the synovial membrane partition. When thickened or fibrotic, it can impinge between the patella and the femur during knee flexion.

Anatomical Data

Boundaries & Contents

Location	Front of the knee joint above the patella, at the junction of the suprapatellar pouch and the main joint cavity
Boundaries	Arises from the synovium beneath the quadriceps tendon Runs from the front of the femur toward the medial and lateral walls of the joint May form a complete septum, a partial shelf, or be absent

Biomechanics

Function & Actions

An embryological remnant of the synovial partition between the suprapatellar pouch and the knee joint. It usually has no mechanical role, but a complete septum can isolate the suprapatellar pouch, and a thickened plica can cause anterior knee pain.

Clinical Relevance

Clinical Notes

Pathological suprapatellar plica syndrome produces anterior knee pain above the patella, a palpable snap during flexion-extension, and a tender cord at the superior patellar border. Arthroscopy identifies the plica and allows resection. It is most symptomatic between 30-60 degrees of flexion when it is compressed between the patella and trochlea. MRI may show the thickened plica but arthroscopy remains the gold standard for diagnosis and treatment.

Pathology

Common Injuries & Conditions

Suprapatellar Plica Syndrome

Anterior knee pain from fibrotic thickening of the suprapatellar synovial fold impinging between the patella and trochlea during flexion, treated by arthroscopic plica resection.

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