Arthrocentesis is the aspiration of fluid from a joint cavity. A needle is inserted in the joint and fluid is removed for later examination. The usual purpose of arthrocentesis is the collection of synovial fluid for analysis and/or culture.

What Does Arthrocentesis Reveal?

Arthrocentesis helps a veterinarian diagnose cases of suspected inflammation or infection of a joint. Analyzing cells and microbes found in joint fluid can help determine the cause of an abnormal joint. It can also help confirm the presence of blood in a joint cavity following trauma or in association with clotting abnormalities. One or more joints may be aspirated, depending upon the clinical presentation and history.

Arthrocentesis is also performed for the purpose of inserting a contrast medium, used when an arthrography is performed. Occasionally arthrocentesis is used to administer therapeutic medications in the joint cavity.

How Is Arthrocentesis Performed?

The skin over the joint(s) is clipped and sterilized. A needle attached to a syringe is inserted and directed towards the center of the joint. When the correct area has been reached in the joint cavity, fluid is drawn into the syringe, and the needle and syringe is removed. The fluid is spread on a slide for examination.

Is Arthrocentesis Painful?

There is minimal discomfort involved with the insertion of the syringe. As with people, the pain experienced will vary among individual animals.

Is Sedation or Anesthesia Required?

Many animals require mild sedation for the procedure. Ill and debilitated animals may only require manual restraint.