Stutter test

The jagged mark on the image is where examiner places the finger to feel for a stutter as the knee is actively bent and straightened.

What is a medial synovial plica?

A plica in the knee is an embryonic remnant of synovium - the thin tissue-like lining of the knee joint, and it is a normal anatomical structure.

The one that is present on the medial side of the knee, not in everyone, but quite commonly, is called the medial plica. It is also known as the medial synovial shelf, stretching along the side of the rounded condyles of the femur, where it can become nipped by the joint during movement.

Back to top

What is the plica syndrome?

Plica syndrome is simply pain in the front of the knee caused by the impingement between adjacent knee tissues of an inflamed or thickened synovial plica.

• Quote from peer-reviewed paper:

  "Plicae become pathological when its inherent qualities change due to an inflammatory process that alters the pliability of synovial tissue....[and it]....can become inelastic, tight, thickened, fibrotic, and sometimes hyalinized....[causing]....anterior knee pain, clicking, clunking, and a popping sensation on patellofemoral loading activity such as squatting"

  Citation: Lee PYF, Nixion A, Chandratreya A, Murray JM. Synovial Plica Syndrome of the Knee: A Commonly Overlooked Cause of Anterior Knee Pain. Surg J (N Y). 2017 Feb 15;3(1):e9-e16. doi: 10.1055/s-0037-1598047. PMID: 28825013; PMCID: PMC5553487.

Back to top

How to perform the stutter test for a medial plica

The patient sits on the edge of the examination couch with both legs hanging over the edge at 90 degrees. The examiner sits to the one side of the knee and places a finger over the medial side of the knee. The patient is asked to slowly straighten the knee and the examiner feels for a 'stutter' in the joint at about 45-60 degrees of flexion. This is the position where an enlarged plica might impinge between the femur and the patella.

• Quote from peer-reviewed paper:

  "Two physical exam techniques can suggest plica syndrome. These tests are the Stutter test and the Hughston test. When both tests are positive, the diagnosis of plica syndrome should be suspected. If only 1 of the 2 is positive, plica syndrome is less suspicious, but should still be considered."

  Citation: Casadei K, Kiel J. Plica Syndrome. [Updated 2023 Apr 10]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK535362/

Back to top

What causes the stutter?

An enlarged medial plica may get compressed between the femur and the contracting quadriceps muscle, with intermittent painful muscle spasm causing the stuttering of the quads.

Back to top