From the Guidelines
Knee drainage, or arthrocentesis, should be performed under sterile conditions with a 18-22 gauge needle attached to a syringe, typically from the lateral approach with the knee flexed at 15-20 degrees, and fluid analysis should include a total cell count and differential leukocyte count, as well as culture for aerobic and anaerobic organisms 1.
Procedure Details
The procedure involves inserting a needle into the knee joint to remove excess fluid for diagnostic or therapeutic purposes.
- First, the skin over the knee is cleaned with an antiseptic solution like chlorhexidine or povidone-iodine.
- Local anesthesia (typically 1-2% lidocaine) is injected into the skin and subcutaneous tissues.
- Using sterile technique, a needle attached to a syringe is inserted into the joint space.
- The fluid is aspirated slowly and collected for analysis if needed.
- After removing the needle, pressure is applied to the site, and a sterile bandage is placed.
Post-Procedure Care
Post-procedure, patients should rest the knee for 12-24 hours and watch for signs of infection like increased pain, redness, or fever.
- This procedure relieves pressure from accumulated fluid, reduces pain, and allows for diagnostic testing of the fluid to identify conditions like infection, gout, or inflammatory arthritis.
- Complications may include infection, bleeding, or pain, which is why proper sterile technique is essential, as supported by the Infectious Diseases Society of America guidelines 1.
Diagnostic Considerations
The synovial fluid analysis should include a total cell count and differential leukocyte count, as well as culture for aerobic and anaerobic organisms, and a crystal analysis can also be performed if clinically indicated 1.
- The American College of Radiology suggests that knee joint aspiration, often with fluoroscopy or ultrasound guidance, is extremely useful in diagnosing joint infection after total knee arthroplasty 1.
From the Research
Knee Drainage Procedure
To perform a knee drainage, also known as arthrocentesis, the following steps can be considered:
- The procedure is typically performed to collect fluid from the joint for analysis or to inject medication for pain relief 2, 3
- It is essential to follow proper technique and precautions to minimize the risk of complications, such as bleeding or infection 4, 5
- The safety of the procedure has been established in patients receiving anticoagulation therapy, including those on direct oral anticoagulants (DOACs) 4 and warfarin 5
Precautions and Considerations
- Patients on anticoagulation therapy can undergo arthrocentesis and joint injection without discontinuing their medication, as the risk of bleeding is low 4, 5
- The procedure can be performed in an outpatient setting, and patients can be monitored for any potential complications 4
- Exercise and physical therapy may be recommended after the procedure to improve range of motion and reduce pain, although the evidence is limited to temporomandibular joint arthrocentesis 6