Arthrocentesis (also called joint aspiration) is a procedure where
a doctor uses a needle to take fluid out of a joint. Joints are where two bones
meet. They allow our bodies to move. The hips, knees, ankles, elbows, shoulders, and
knuckles are all joints.
Why Is Arthrocentesis Done?
Arthrocentesis is done to:
understand why a joint is swollen or sore
relieve pain by taking fluid out of a joint
What Happens During Arthrocentesis?
First, doctors will make sure that your child is comfortable for the procedure.
This means doing some or all of the following:
Putting a numbing medicine on the skin.
Using a tiny needle to inject numbing medicine into the area around the joint.
Sedating your child by giving medicine through an IV (intravenously) to make your
child sleepy and relaxed.
If your child is sedated, his or her vital signs (heart rate, blood pressure, temperature,
and blood oxygen level) will be checked during the entire procedure.
When your child is comfortable, the doctor will start the procedure. During arthrocentesis:
The joint and surrounding area are cleaned with a special soap to sterilize the
The doctor carefully puts a needle into the joint. Sometimes, an ultrasound is
used to guide the needle into the right place.
When the needle is in place, the doctor uses it to pull some joint fluid into
The needle is taken out and the fluid is sent to a laboratory for testing.
A small bandage is put over the site where the needle went in.
How Do I Prepare My Child for Arthrocentesis?
If your child is old enough to understand, talk about the procedure:
Explain what is going to happen during the procedure.
Explain that it is important to lie still for the test and that a nurse or other
health care provider might help hold him or her in place.
If your child is getting sedation, explain that he or she will sleep through the
procedure and probably not remember it.
Give your child a chance to ask you and the doctor questions.
Ask your doctor if your child can eat or drink before the procedure. If your child
will get sedation, he or she may need to avoid eating or drinking for a few hours
before the arthrocentesis.
What Happens After Arthrocentesis?
If your child was awake during the procedure, the area where the arthrocentesis
was done may hurt a little bit. This should go away within a few hours. If your child
was sedated, he or she will need a few hours to rest after the procedure.
Follow your doctor's recommendations for activity after the procedure.
The lab results usually are back in a few days. The lab will look for germs (such
as bacteria), germ-fighting cells, signs of inflammation (irritation and swelling),
and other things in the joint fluid. Ask your doctor how you will get the test results.
Call your doctor if you have questions, or if your child:
Arthrocentesis is a safe procedure with very few risks. Very rarely, bleeding,
infection, or allergic reaction can happen. Your doctor will review all risks with
you before your child has the procedure.
How Can I Help My Child?
To make sure your child gets the best care:
Follow all instructions for caring for the joint where the arthrocentesis was
Be sure to get the test results of the arthrocentesis when they're ready.
Go to all follow-up visits as recommended by the doctor.