What Is Arthrocentesis?/Arthrocentesis is a procedure performed to collect synovial fluid from joint spaces for the identification of a disease process or the relief of painful or bothersome symptoms. There are numerous indications for joint fluid aspiration, the most important of which includes the evaluation of synovial fluid for evidence of infection or inflammation. While the procedure specifics vary depending on the joint being aspirated, the general technique and steps remain consistent. The procedure tends to be very safe overall with few complications if performed correctly, and only a small number of contraindications exist.[rx][rx][rx][rx]
Anatomy and Physiology
Anatomy and relevant landmarks depend on which joint is being accessed. Please refer to specific articles of elbow arthrocentesis, knee arthrocentesis, and shoulder arthrocentesis for the relevant anatomy of the joints and surrounding structures.[rx][rx][rx]
Indications
Synovial fluid aspiration is indicated for the following:
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Evaluation for an intra-articular infectious process
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Diagnosis of inflammatory disease (e.g., crystalline arthropathy, spondyloarthropathies)
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Administration of medications for acute or chronic arthritis
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Symptom relief in a swollen, painful joint or inflammatory conditions (e.g., rheumatoid arthritis)
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Evacuation of possible hemarthrosis in a traumatic effusion
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Identifying communication between the joint space and a laceration
Many synovial fluid types are associated with specific diagnoses
Noninflammatory (Group I)
- Osteoarthritis, degenerative joint disease
- Trauma
- Rheumatic fever
- Chronic gout or pseudogout
- Scleroderma
- Polymyositis
- Systemic lupus erythematosus
- Erythema nodosum
- Neuropathic arthropathy (with possible hemorrhage)
- Sickle-cell disease
- Hemochromatosis
- Acromegaly
- Amyloidosis
Inflammatory (Group II)
- Rheumatoid arthritis
- Reactive arthritis
- Psoriatic arthritis
- Acute rheumatic fever
- Acute gout or pseudogout
- Scleroderma
- Polymyositis
- Systemic lupus erythematosus
- Ankylosing spondylitis
- Inflammatory bowel disease arthritis
- Infection (viral, fungal, bacterial) including Lyme disease
- Acute crystal synovitis (gout)
Septic (Group III)
- Pyogenic bacterial infection
- Septic arthritis
Hemorrhagic
- Trauma
- Tumors
- Hemophilia/coagulopathy
- Scurvy
- Ehlers-Danlos syndrome
- Neuropathic arthropathy
Contraindications
The only absolute contraindication to arthrocentesis is a peri-articular infection such as cellulitis, as this may introduce overlying bacteria into the joint space. There are a number of relative contraindications to this procedure. One is bacteremia, as it is theorized that the procedure can introduce bacteria into the joint space. Coagulopathy is a debated contraindication. The possibility of traumatic hemarthrosis is a concern, but a number of studies have shown little evidence of harm.[rx][rx]
Equipment
Skin Preparation
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Skin preparation solutions (e.g., chlorhexidine, betadine)
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Sterile gloves
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Sterile drapes
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Sterile gauze
Syringes
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3 cc to 5 cc syringe for instilling local anesthetic
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10 cc to 20 cc syringe for fluid aspiration
Needles
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25 gauge to 27 gauge for local anesthetic introduction
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18 gauge to 22 gauge for fluid aspiration
Medications
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Local anesthetic
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Medications being injected into the joint, if applicable
Other
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Three-way stopcock for draining large amounts of fluid
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Specimen collection tubes for laboratory analysis
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Hemostat (for stabilizing the needle when exchanging syringes if more than one is required for complete aspiration)
Personnel
This procedure can be performed without an assistant; however, having a nurse or other team member at the patient’s bedside may help with alleviating patient anxiety, unforeseen equipment failure, and documentation of the procedure.
Preparation
Appropriate preparation is essential to a successful procedure. Double-check to make sure all of the required equipment is at the bedside. Position the patient for the highest likelihood of success (depending on the joint being aspirated). Provide the patient with analgesia and anxiolytics if required.
Technique
This article will go over the general steps of arthrocentesis. The specific techniques of arthrocentesis of various joints are not to be discussed here. For those specifics, see the articles titled “Elbow Arthrocentesis,” “Knee Arthrocentesis,” and “Shoulder Arthrocentesis Technique.”[rx][rx][rx]
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Define the joint anatomy by palpating the surrounding bony landmarks. Ultrasound may be helpful in locating effusions.
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Select a puncture site and an approach to the joint based on the appropriate anatomy. Be sure to avoid tendons, major blood vessels, and major nerves.
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Apply the antiseptic solution to the area of needle insertion and surrounding skin. Allow the skin to dry and then put down the sterile drape surrounding the area of needle insertion.
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Using a 25 gauge to 27 gauge needle, first create a wheal of local anesthetic at the point of insertion. After the skin is anesthetized, infiltrate the skin down to the area of the joint capsule. For extremely painful joints, a regional nerve block can be used.
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Attach a larger needle of appropriate length to an appropriately sized syringe. Insert the needle into the joint space along the anesthetized track.
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For draining larger effusions, a three-way stopcock can be placed between the needle and the syringe.
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To change the syringe during the procedure, grasp the hub of the needle with a sterile hemostat and hold it tightly while removing the syringe.
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An attempt should be made to remove as much fluid or blood as possible. If fluid stops flowing, the joint is either drained completely, the needle tip is dislodged, or debris is obstructing the needle. Slightly advance or retract the tip, rotate the bevel, or aspirate less forcefully.
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Place fluid into appropriate tubes and send the synovial fluid for studies as indicated by the clinical scenario.
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Place a dressing or bandage over the puncture site, and apply pressure to achieve hemostasis.
Complications
Complications with arthrocentesis are rare.[rx][rx] They include the following:
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Infection – If the procedure is not done with a completely aseptic technique, or if there is an overlying infection, skin bacteria may be introduced into the joint space. This can be limited by maintaining a strict sterile technique and avoiding insertion through infected skin or subcutaneous tissue.
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Bleeding – Hemarthrosis after arthrocentesis is rare but more common in patients with a bleeding diathesis. When inserting the needle during the procedure, do so in a linear fashion without side-to-side movements to avoid shearing blood vessels and other structures.
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Allergic reaction – Patients with allergy to local anesthetic should not receive that class of medications.
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