Arthrocentesis, commonly known as joint aspiration, is a minor surgical procedure during which excess synovial fluid (fluid from a joint) is drained with a sterile needle and syringe. Usually performed in the doctor's office, arthrocentesis is administered to provide relief to patients with swelling, inflammation and pain in any joint where there is an excess accumulation of fluid (effusion). Joints typically drained in this way include the shoulder, knee, hip, elbow, wrist or ankle.

Reasons for Arthrocentesis

Arthrocentesis, as a minimally invasive treatment, is frequently a good option for relieving pain and inflammation resulting from:

  • Rheumatoid arthritis
  • Tendonitis
  • Bursitis
  • Gout

The procedure is not only a treatment, but a diagnostic tool.

The Arthrocentesis Procedure

Arthrocentesis is performed under local anesthetic and involves inserting a needle with a syringe attached to it into the affected joint. In order to ensure greater precision and more effective results, arthrocentesis may be performed under ultrasound guidance. In many cases, if infection is not suspected, corticosteroid medication may be injected into the joint during this procedure in order to further reduce inflammation and alleviate pain. Fluid from the joint is aspirated and sent for laboratory testing.

This testing can sometimes determine the cause of the joint swelling in addition to helping patients achieve symptom relief. In the laboratory, synovial fluid is examined visually, microscopically and chemically to check for abnormalities. If the fluid appears cloudy or bloody, it may be a sign of infection or injury. If there are uric acid crystals present, the patient likely has gout. Other abnormalities of synovial fluid may include the presence of glucose or protein.

Risks of Arthrocentesis

Arthrocentesis is considered safe for most patients with only minimal risk of bleeding or bruising at the injection site. The procedure is brief and performed under local anesthesia, but some patients nonetheless find the experience painful.

The corticosteroid administered typically only affects the targeted area, but in rare cases may have a systemic effect, causing flushing, insomnia, or, in patients with mood disorders, instability. Most patients experiencing joint effusion can benefit from therapeutic drainage. Contraindications for arthrocentesis include the presence of a joint infection or an allergy to one of the medications used in the procedure.

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