(See also Evaluation of the Patient with Joint Symptoms Evaluation of the Patient With Joint Symptoms Some musculoskeletal disorders affect primarily the joints, causing arthritis. Others affect primarily the bones (eg, fractures, Paget disease of bone, tumors), muscles or other extra-articular... read more and Evaluation of the Wrist Evaluation of the Wrist An evaluation of the wrist includes a physical examination and sometimes arthrocentesis. (See also Evaluation of the Patient With Joint Symptoms.) In this view, the triquetrum overlaps (dorsal... read more .)
Diagnosis of the cause of a synovial effusion (eg, infection Acute Infectious Arthritis Acute infectious arthritis is a joint infection that evolves over hours or days. The infection resides in synovial or periarticular tissues and is usually bacterial—in younger adults, frequently... read more , crystal-induced arthritis Overview of Crystal-Induced Arthritides Arthritis can result from intra-articular deposition of crystals: Monosodium urate Calcium pyrophosphate dihydrate Basic calcium phosphate (apatite) Rarely, others such as calcium oxalate crystals read more )
Removal of a synovial effusion and/or injection of drugs as part of treatment and for pain relief
Infection of skin or deeper tissues at the anticipated site of needle insertion
If possible, an alternate, uninfected site should be used. However, acutely inflamed joints may be generally warm, tender, and red, thus mimicking extra-articular infection and making it hard to find an uninvolved insertion site. Ultrasonography can be done; visualization of a joint effusion can reinforce the decision to do arthrocentesis despite surrounding erythema. NOTE: If infectious arthritis is strongly suspected, arthrocentesis should be done regardless of erythema or negative ultrasonographic results because joint infection must not be missed.
Severe bleeding diathesis, which may need to be corrected before arthrocentesis; routine therapeutic anticoagulation is not a contraindication, particularly if infection is suspected
Complications are uncommon and include
Damage to tendon, nerve, or blood vessels (traumatic tap)
Antiseptic solution (eg, chlorhexidine, povidone iodine, isopropyl alcohol), sterile gauze, sterile bandage, and sterile gloves
Local anesthetic (eg, 1% lidocaine, 25- to 30-gauge needle, 3- to 5-mL syringe)
For joint aspiration, a 25-mm (1-inch) 22- to 20-gauge needle and 10-mL syringe
Appropriate containers for collection of fluid for laboratory tests (eg, cell count, crystals, cultures)
For intra-articular therapeutic injection, a syringe containing a corticosteroid (eg, triamcinolone acetonide 40 mg or methylprednisolone acetate 40 mg) and/or a long-acting anesthetic (eg, 0.25% bupivacaine), and a hemostat to help switch syringes
Sterile technique is necessary to prevent microbial contamination of both the joint space and the aspirated synovial fluid.
Needle insertion is just distal to the Lister tubercle (dorsal radial tubercle) and ulnar to the extensor pollicis longus tendon.
Neurovascular injury may occur if needle entry is on the radial side of the extensor pollicis longus tendon (ie, in the anatomic snuffbox).
Arthrocentesis of the wrist
Synovial fluid is withdrawn from the radiocarpal joint. To help identify the extensor pollicis longus tendon, the patient should actively extend the wrist and thumb. To puncture the joint, the wrist is flexed and ulnar-deviated about 20 to 30°. Traction is applied to the hand. Needle entry occurs just distal to the Lister tubercle, ulnar to the extensor pollicis longus tendon.
Position the patient sitting or supine with the wrist on a bedside table.
Step-by-Step Description of Procedure
Palpate the dorsal aspect of the wrist to identify the Lister tubercle, which is the bony prominence palpable on the distal dorsal radius. Isolate and identify the extensor pollicis longus tendon by directing the patient to extend the thumb. Needle entry occurs distal to the tubercle and ulnar to the tendon. If desired, mark the insertion site with a skin-marking pen.
Rest the forearm and hand on an underpad. Prepare the area with a skin-cleansing agent, such as chlorhexidine or povidone iodine, then use an alcohol wipe to remove the agent.
Place a wheal of local anesthetic over the needle entry site using a 25- to 30-gauge needle. Then inject more anesthetic along the anticipated trajectory of the arthrocentesis needle (about 0.5 to 1 cm), but do not enter the joint space.
Aspirate the joint suing a 22- or 20-gauge needle on a 10-mL syringe.
Have an assistant apply axial traction, slight flexion (20 to 30°), and ulnar deviation to the hand to facilitate needle entry into the joint space.
Insert the needle perpendicular to the skin, just distal to the Lister tubercle and on the ulnar side of the extensor pollicis longus tendon. Direct the needle volarly toward the joint space, and pull back gently on the plunger as you advance. Synovial fluid will enter the syringe when the joint is entered.
If the needle hits bone, retract almost to skin surface and then redirect at a different angle.
Drain all fluid from the joint.
If intra-articular drugs (eg, anesthetic, corticosteroid) are to be given, use a hemostat to hold the hub of the needle motionless while removing the synovial fluid-containing syringe and attaching the drug-containing syringe. If the needle has remained in place in the joint space, there will be no resistance to drug injection. Injections into the radiocarpal joint should not exceed 40 mg of corticosteroid or 1 mL in volume.
After injecting a corticosteroid, move the joint through full range of motion to distribute the drug throughout the joint.
Transfer synovial fluid to tubes and other transport media for synovial fluid analysis Synovial fluid examination Some musculoskeletal disorders affect primarily the joints, causing arthritis. Others affect primarily the bones (eg, fractures, Paget disease of bone, tumors), muscles or other extra-articular... read more . Inspect the fluid for blood and fat.
Apply an adhesive bandage or sterile dressing.
Ice, elevation, and oral nonsteroidal anti-inflammatory drugs may help relieve pain.
If an intra-articular anesthetic has been given, limited joint activity should be prescribed for 4 to 8 hours.
If an intra-articular corticosteroid has been given, a period of immobilization lasting about 24 to 48 hours may be needed.
If the patient has increased redness, pain, and/or swelling > 12 hours after the procedure, the joint should be examined for possible infection.
Warnings and Common Errors
Carefully ensure optimal positioning before joint puncture.
Allow adequate time for local anesthesia to take effect before proceeding.
To avoid damaging the synovium and articular cartilage, do not advance the needle against resistance and do not move the needle once it has begun draining synovial fluid.
If the needle tip must be relocated, first withdraw it almost to the skin surface and then redirect; do not try to change the angle of insertion while a needle is embedded in tissue.
Tips and Tricks
Consider doing ultrasonography if there is no obvious large effusion.
Note also that warmth, tenderness, and redness may overlie an acutely inflamed arthritic joint, mimicking extra-articular infection.
When trying to differentiate infectious arthritis from infection of the overlying structures (a contraindication to arthrocentesis Contraindications Arthrocentesis of the wrist is the process of puncturing the radiocarpal joint with a needle to withdraw synovial fluid. (See also Evaluation of the Patient with Joint Symptoms and Evaluation... read more ), infectious arthritis is more likely with the following:
Circumferential joint pain
Severe pain with passive joint motion
When inspecting fluid, consider the following:
The hemarthrosis of a traumatic tap tends to be nonuniformly bloody and tends to clot.