What is arthrocentesis?

Arthrocentesis is the removal of the synovial fluid that lubricates your joints. Doctors perform arthrocentesis using a needle and syringe. The fluid is removed and tested to diagnose the cause of a buildup of fluid. Causes include infection, arthritis, and joint injury. Doctors also use arthrocentesis to treat joint pain by removing excessive or infected fluid. Arthrocentesis is performed in many joints, including the elbow, knee, hip and jaw. 

Arthrocentesis is only one method used to diagnose or treat a variety of joint conditions, most often of the knee. Consider getting a second opinion about all of your treatment choices before having an arthrocentesis.

Other procedures that may be performed

Your doctor may perform other procedures in addition to arthrocentesis to diagnose or treat certain conditions. These include: 

  • 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 synovial fluid removed for infection and other disease

Why is arthrocentesis performed? 

Your doctor may recommend an arthrocentesis to diagnose and possibly treat the following diseases and conditions of the joints:

  • 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.

Ask your doctor about all of your treatment options and consider getting a second opinion before deciding on arthrocentesis.

Who performs arthrocentesis?

Orthopedic surgeons often perform arthrocentesis procedures. Orthopedic surgeons specialize in the medical and surgical treatment of conditions of the bones, joints, and connective tissues. 

Other specialists who perform arthrocentesis include:

  • Oral and maxillofacial surgeons are surgeons who diagnosis and treat diseases, injuries, and defects involving functional and aesthetic aspects of the mouth, teeth, jaws and face. Oral surgeons perform arthrocentesis of the jaw.
  • Sports medicine and pediatric sports medicine doctors are family practice, internal medicine, emergency medicine, or pediatric doctors who have additional training in sports medicine.

How is arthrocentesis performed?

Your arthrocentesis will be performed a doctor’s office, outpatient setting or hospital. The procedure takes less than 30 minutes and generally includes these steps:

  1. You remove clothing from the affected joint or you dress in a patient gown.
  2. You lie on the examination table to allow access to the joint. 
  3. You may have sedation to make you drowsy and relaxed, and possibly a pain medication. This is common for infants and children. You may have general anesthesia for arthrocentesis of the jaw. Your care team uses monitoring devices to watch your vital signs if you have sedation or general anesthesia.
  4. Your doctor cleans and numbs the joint and surrounding area with a local anesthetic.
  5. Your doctor inserts a needle into the joint space and withdraws a portion of synovial fluid into a syringe. The needle may be guided to the proper position using imaging technology if the joint is difficult to access, such as a hip joint.
  6. Your doctor detaches the syringe of synovial fluid from the needle and replaces it with a syringe of medication, if needed. The medication is injected into the joint. 
  7. Your doctor removes the needle and cleans and bandages the area.
  8. The synovial fluid is sent to the laboratory for testing. Your doctor will discuss the results with you at a later time.