Arthrocentesis

What is arthrocentesis?

Arthrocentesis is the removal of the fluid (synovial fluid) that lubricates your joints using a needle and syringe. Doctors use this procedure to examine the fluid and diagnose the cause of an unexplained accumulation of fluid and joint swelling, such as arthritis. Arthrocentesis may also be used as a treatment to relieve joint pain by removing excessive or infected fluid from a joint.

Arthrocentesis is only one method used to diagnose or treat a variety of joint conditions, most often of the knee.You should discuss different testing and treatment options with your doctor or healthcare provider to best understand which option is right for you.

Other procedures that may be performed

In addition to arthrocentesis, your doctor may also recommend one or more additional procedures to diagnose or treat certain conditions. The following procedures may be performed during arthrocentesis:

• Medication injection, which involves injecting medication, such as an anesthetic or a steroid, into the joint. Medications are injected to help relieve pain, swelling and/or inflammation.
• Synovial fluid biopsy, which involves examining the removed synovial fluid for infection and other disease

Why is arthrocentesis performed?

Arthrocentesisis a procedure that may be recommended to diagnose and possibly treat a variety of diseases and conditions of the joints including:

• Arthritis, or inflammation of the joint. Both osteoarthritis and rheumatoid arthritis can lead to pain, swelling and destruction of the joint.
• Autoimmune disorders, such as lupus, which often leads to joint pain and swelling in some cases
• Bleeding into the joint (hemarthrosis), such as bleeding caused by a torn ligament or a bleeding disorder
• Crystal-induced arthritis such as gout
• Cysts filled with synovial fluid. Cysts can form as a complication of arthritis and breakdown of the joint.
• Injury to the joint, such as a fracture or a torn ligament or cartilage
• Joint infection, which is also called septic arthritis
• Unexplained joint effusion, which is a buildup of synovial fluid with swelling of the joint. Arthrocentesis is used to remove the excess fluid.

How is arthrocentesis performed?             

Your arthrocentesis will usually be performed in a doctor’s office or outpatient setting by a team led by a physician who is familiar with the anatomy of the joint and surrounding tissues. This is often an orthopedist, a doctor who specializes in conditions of the bones and connective tissue. In cases involving joints that are difficult to access, such as the hip, your arthrocentesis may be performed in a hospital setting using imaging technology to guide the process. Arthrocentesis of the jaw is usually performed by an oral surgeon and may require general anesthesia. The procedure usually takes less than 30 minutesand generally includes these steps:

1. You will remove clothing from the affected joint or you may be asked to dress in a patient gown.
2. You will lie on the examination table to allow access to the joint.
3. In some cases, your doctor will sedate you to make you drowsy and relaxed, and possibly a pain medication. This is common for infants and children. If sedation is used, your doctor will use certain devices to monitor your vital signs.
4. Your doctor will clean and numb the joint and surrounding area.
5. Your doctor will insert a needle into the joint space and withdraw a portion of synovial fluid into a syringe. If medication will be injected into the joint, your physician will detach the syringe full of synovial fluid from the needle and replace it with a syringe of medication. The medication can then be injected into the joint. The synovial fluid will be sent to the laboratory for evaluation.
6. Your doctor will remove the needle and clean and bandage the area.

Will I feel pain?

Your comfort and relaxation is very important to both you and your care team. You may feel a pinch, discomfort or stinging when the area is numbed andpressureduring the procedure. Your care team will give you pain and sedative medications as needed so that you stay comfortable. If you are uncomfortable in any way, tell a member of your care team.