Arthrocentesis, or joint aspiration, is the procedure in which there is the removal of joint fluid through a surgical puncture. For the procedure, a sterile needle and a syringe are used to remove joint fluid. Joints have synovial fluid, which is a lubricant that helps with joint movement.
The reason to perform a joint aspiration is for the detection of conditions like joint inflammation, gout, infections and rheumatoid arthritis, according to MedicineNet. The joint fluid sample can be tested for different factors, like white blood cell count and glucose.
Although this procedure is useful for diagnosing different conditions, it may be also helpful to remove fluid that will relieve swelling in the knee joints. Likewise, cortisone can also be injected into the joint during the procedure to help minimize pain and inflammation in the affected area.
The procedure can take up to 10 minutes, and an anesthetic can be used prior to the procedure, states Kids Health.