musculoskeletal and connective tissue disorders
How To Do Metacarpophalangeal and Interphalangeal Joint Arthrocentesis
Step by Step Description of MCP and IP Joint Arthrocentesis
First, have the patient extend the finger. In this position, palpate the dorsal aspect of the joint and the extensor tendon. Then have the patient relax the finger. Apply traction to the relaxed finger, which expands the joint space slightly and makes the joint line visible as skin depressions—the areas for needle insertion—on either side of the extensor tendon. These landmarks are most apparent over the MCP joints. Rest the hand on an underpad. Prepare the area with a skin-cleansing agent, such aschlorhexidineor 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 the patient flex the fingers to the appropriate angle for the joint being punctured. Have an assistant apply gentle axial traction to the finger to facilitate entry of the aspirating needle into the joint space. Aspirate the joint using a 25-gauge needle. Enter the skin perpendicularly from above, at the level of the joint line, just medial or lateral to the extensor tendon or from the side at a 90° angle from above. Direct the needle toward the center of the joint space (see figureand figure). 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 at a different angle. Drain all fluid from the joint (usually ≤ 1 mL). If intra-articular medications (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 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. Injections into the MCP and IP joints should not exceed 0.5 mL in volume. 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 examination . Inspect the fluid for blood and fat. Apply an adhesive bandage or sterile dressing. For arthrocentesis of the metacarpophalangeal joint, insert a 25-gauge needle at either side of the extensor tendon from above or at a 90° angle from above, while gentle traction is applied to the finger. For arthrocentesis of the proximal interphalangeal, insert a 25-gauge needle at either side of the extensor tendon from above or at a 90° angle from above, while gentle traction is applied distal to the joint. 