How To Do Metatarsophalangeal Joint Arthrocentesis

Diagnosis of the cause of a synovial effusion (eg, infection Acute Infectious Arthritis Acute infectious (septic) 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... 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 medications as part of treatment and for pain relief

Infection of skin or deeper tissues at the anticipated site of needle insertion

Severe bleeding diathesis, which may need to be corrected before arthrocentesis; routine therapeutic anticoagulation is not a contraindication, particularly if infection is suspected

Infection

Damage to tendon, nerve, or blood vessels (traumatic tap)

Antiseptic solution (eg, chlorhexidine, povidone iodine, isopropyl alcohol), sterile gauze, and gloves

Nonsterile underpads

Local anesthetic (eg, 1% lidocaine, 25- to 30-gauge needle, 3- to 5-mL syringe)

For joint aspiration, a 25-mm (1-inch) 22-gauge needle and a 5-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 10 mg or methylprednisolone acetate 20 mg) and/or a long-acting anesthetic (eg, 0.25% bupivacaine), a 22-gauge needle, and a hemostat to help switch syringes, if needed

Enlist an assistant to provide flexion and traction to the toe.

Sterile technique is necessary to prevent microbial contamination of both the joint space and the aspirated synovial fluid.

A digital nerve block can be used for anesthesia.

The aspirating needle is inserted along the dorsal portion of the joint, just medial or lateral to the extensor hallucis longus tendon.

Position the patient supine, with the knee flexed and the foot and toes flat on the stretcher.

Have the patient dorsiflex the great toe. Then, in this position, palpate the dorsal aspect of the metatarsophalangeal (MTP) joint and the prominent dorsiflexed extensor tendon.

Rest the foot 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.

Have an assistant manually plantarflex (about 20°) and apply axial traction to the toe to facilitate entry of the aspirating needle into the joint space.

Aspirate the joint using a 22-gauge needle. Enter the skin perpendicularly, at the level of the joint line, just medial or lateral to the extensor tendon. Direct the needle toward the center of the joint space. Gently pull back 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 the needle at a different angle.

Drain all fluid from the joint.

If intra-articular medications (eg, anesthetic, corticosteroid) are to be given, hold the hub of the needle motionless (using a hemostat if available) while removing the synovial fluid-containing syringe and replace it with the medication-containing syringe. If the needle has remained in place in the joint space, there will be no resistance to medication injection.

After injecting a corticosteroid, move the joint through full range of motion to distribute the medication 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 (NSAIDs) 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, the joint should be rested for about 24 to 48 hours.

If the patient has increased erythema, pain, and swelling > 12 hours after the procedure, the joint should be examined for possible infection.

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.

Joint effusion

Circumferential joint pain and capsule tenderness

Pain with both gentle, passive motion and with active joint motion

The hemarthrosis of a traumatic tap tends to be nonuniformly bloody and tends to clot.