Metacarpophalangeal Arthrocentesis Periprocedural Care

For metacarpophalangeal (MCP) arthrocentesis, as for any nonemergency procedure, informed consent should be obtained from the patient or the patient's representative. During the consenting process, possible complications must be discussed in detail, including bleeding into the joint, infection of the joint or surrounding skin, nerve injury, pain, bruising, and impaired mobility. It is important to emphasize that these complications can be minimized with sterile preparation and appropriate procedural technique.

Documentation in the medical record is required in the form of either a signed consent form or a written account of the interaction by the physician.

The patient evaluation should begin with a thorough history and physical examination. A focused examination of the MCP joint should include documentation of the overlying skin for signs of infection or previous surgical procedures. Joint size and mobility should also be assessed. The joint in question should be palpated for signs of warmth, crepitus, deformity, or ligamentous instability.

Equipment used in MCP arthrocentesis includes the following:

• Sterile gloves
• Sterile gauze
• Local anesthetic (eg, 1% lidocaine)
• Skin cleansing agent (eg, chlorhexidine or povidone-iodine)
• 3- to 5-mL syringe
• 25-gauge needle for anesthetic injection
• 22- to 25-gauge needle for joint aspiration
• Hemostat
• Specimen tubes
• Bandages

The patient may be positioned sitting or lying down with the hand resting on a bedside table in the prone position. Expose the joint of interest, and identify the joint line and the extensor tendon as it passes over the MCP joint. Swelling of the joint makes identification of the extensor tendon difficult; have the patient extend the ray against resistance to help identify the tendon. Using a marking pen, mark the needle entry site at the MCP joint, either medial or lateral to the extensor tendon. Alternatively, make a depression on the skin with a pen cap or needle sheath.

Next, anesthesia is applied to the skin and subcutaneous tissue. Special care should be taken to stay within the subcutaneous tissue, avoiding the joint space; anesthetic in the joint cavity may interfere with fluid analysis and delay diagnosis. Debate exists whether injecting anesthetic is just as uncomfortable as aspiration without local anesthesia. For this reason, the choice of whether or not to inject local anesthetics is practitioner-specific.