(Joint Injection and Aspiration, Joint Aspiration and Analysis, Arthrocentesis)
What is joint aspiration?
Joint aspiration refers to removing fluid from the space around a joint using a needle and syringe. This is usually performed under a local anesthetic to either relieve swelling or to obtain fluid for analysis to diagnose a joint disorder and/or problem.
Joint aspiration is usually performed on the knee. However, fluid can also be removed from other joints, such as the hip, ankle, shoulder, elbow, or wrist.
Other related procedures that may be used to help diagnose joint problems include X-ray, bone scan, magnetic resonance imaging (MRI), computed tomography (CT scan), arthroscopy, and arthrography. Please see these procedures for additional information.
Anatomy of the joint
Joints are formed where bones meet. Most joints are mobile, allowing the bones to move. Joints consist of the following:
Cartilage. A type of tissue that covers the surface of a bone at a joint. Cartilage helps reduce the friction of movement within a joint.
Synovial membrane. A tissue that lines the joint and seals it into a joint capsule. The synovial membrane secretes synovial fluid (a clear, sticky fluid) around the joint to lubricate it.
Ligament. A type of tough, elastic connective tissue that surrounds the joint to give support and limits the joint's movement.
Tendon. A type of tough connective tissue that connects muscles to bones and helps to control movement of the joint.
Bursa. A fluid-filled sac located between bones, ligaments, or other adjacent structures that helps cushion joints.
Meniscus. A curved part of cartilage in the knees and other joints that acts as a shock absorber.
Reasons for the procedure
Joint aspiration may be performed to diagnose and assist in the treatment of joint disorders and/or problems. By analyzing the fluid obtained during the procedure, the following conditions may be determined:
Joint aspiration can also be performed to remove a large collection of fluid around a joint. Sometimes bursitis (inflammation of the bursa) causes fluid to collect in a joint. Removing the fluid will decrease the pressure, relieve pain, and improve movement of the joint. Sometimes, a medication is injected into the joint following removal of the fluid to help treat tendonitis or bursitis.
There may be other reasons for your doctor to recommend a joint aspiration.
Risks of the procedure
As with any surgical procedure, complications can occur. Some possible complications may include, but are not limited to, the following:
Discomfort at the aspiration site
Bruising at the aspiration site
Swelling at the aspiration site
Infection at the aspiration site
There may be other risks depending on your specific medical condition. Be sure to discuss any concerns with your doctor prior to the procedure.
Before the procedure
Your doctor will explain the procedure to you and offer you the opportunity to ask any questions that you might have about the procedure.
You will be asked to sign a consent form that gives your permission to do the procedure. Read the form carefully and ask questions if something is not clear.
Notify your doctor if you are sensitive to or are allergic to any medications, latex, tape, and anesthetic agents (local and general).
Notify your doctor of all medications (prescribed and over-the-counter) and herbal supplements that you are taking.
Notify your doctor if you have a history of bleeding disorders or if you are taking any anticoagulant (blood-thinning) medications, aspirin, or other medications that affect blood clotting. It may be necessary for you to stop these medications prior to the procedure.
If you are pregnant or suspect that you are pregnant, you should notify your health care provider.
Generally, no prior preparation, such as fasting or sedation is required. However, if fluid is taken from the joint to be tested in a lab, you may be asked to fast for a certain period of time before the procedure.
Based on your medical condition, your doctor may request other specific preparation.
During the procedure
A joint aspiration may be performed on an outpatient basis or as part of your stay in a hospital. Procedures may vary depending on your condition and your doctor’s practices.
Generally, a joint aspiration procedure follows this process:
You will be asked to remove clothing and will be given a gown to wear.
You will be positioned so that the doctor can easily reach the joint that is to be aspirated.
The skin over the joint aspiration site will be cleansed with an antiseptic solution.
If a local anesthetic is used, you will feel a needle stick when the anesthetic is injected. This may cause a brief stinging sensation.
The doctor will insert the needle through the skin into the joint. You may feel some discomfort or pressure.
The doctor will remove the fluid by drawing it into a syringe that is attached to the needle.
The needle will be removed and a sterile bandage or dressing will be applied.
The fluid sample will be sent to the lab for examination.
After the procedure
Once you are home, it is important for you to keep the joint aspiration site clean and dry. Leave the bandage in place for as long as instructed by your doctor.
The aspiration site may be tender or sore for a few days after the joint aspiration procedure. Take a pain reliever for soreness as recommended by your doctor. Aspirin or certain other pain medications may increase the chance of bleeding. Be sure to take only recommended medications.
Notify your doctor to report any of the following:
Redness, swelling, bleeding, or other drainage from the aspiration site
Increased pain around the aspiration site
Your doctor may give you additional or alternate instructions after the procedure, depending on your particular situation.