Arthrocentesis takes joint fluid out of a joint using a sterile needle. This can be done in most of the joints in the body, but it is usually done on larger ones, such as the knee or shoulder.
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Reasons for Procedure
Arthrocentesis is done to:
- Find out why a joint is painful, swollen, or fluid-filled
- Drain fluid out of a swollen joint to decrease pain and increase your ability to move the joint
- Diagnose the specific type of arthritis occurring within a joint
- Confirm a diagnosis of infection in the joint
- Check for crystals in the joint fluid, which could be a sign of gout
In some cases, medication may be injected
into the joint space after the fluid has been taken out.
Problems from the procedure are rare, but all procedures have some risk. Your doctor will review potential problems, like:
- Infection of the joint
- Bleeding into the joint
- Increased pain
Some factors that may increase the risk of complications include:
- Infections on the skin
- Recent fever or infection
- Bleeding disorder
- Use of blood thinners
What to Expect
Prior to Procedure
You will be asked about your medical history. A physical exam will be done, including an examination of the joint.
Imaging tests to help view internal body structures may include:
You may be given local anesthesia. This numbs the area
where the needle will enter the joint.
Description of the Procedure
The area where the needle will be inserted will be cleaned. Next, a needle attached to a syringe will be inserted into the fluid-filled joint cavity. The fluid will be drawn into the syringe. After this, medication may be injected into the joint through the needle. After the needle is removed, pressure will be put on the spot over the joint. A bandage will be placed over the area.
How Long Will It Take?
About 5-10 minutes
How Much Will It Hurt?
You may feel stinging or burning if local anesthesia is injected into the area.
When you return home after the procedure, do the following to help ensure a smooth recovery:
- For the first 24 hours, use an ice pack for 15-20 minutes at a time every 3-4 hours. Place a towel between your skin and the ice pack.
- To reduce discomfort, take a pain reliever.
- Ask your doctor when you can resume normal activities.
- Be sure to follow your doctor’s instructions.
Call Your Doctor
After arriving home, contact your doctor if any of the following occurs:
- Signs of infection, including fever and chills
- Redness, swelling, increasing pain, excessive bleeding, or any discharge from the site
- Pain that is not relieved by the medication you have been given
If you think you have an emergency, call for emergency medical services right away.
National Institute of Arthritis and Musculoskeletal and Skin Diseases http://www.niams.nih.gov
Canadian Orthopaedic Association http://www.coa-aco.org
Updated October 2014. Accessed June 29, 2015.
Injections and procedures for knee pain. Arthritis Foundation website. Available at:
Accessed June 29, 2015.
Synovial fluid analysis. American Association for Clinical Chemistry Lab Tests Online website. Available at:
Updated October 8, 2014. Accessed June 29, 2015.
Zuber TJ. Knee joint aspiration and injection. Am Fam Physician. 2002;66(8):1497-1501.
Last Updated: 6/1/2013