First metacarpal joint injection is used to treat pain and inflammation secondary to osteoarthritis.
After informed consent is obtained, the patient is placed in a sitting position with the arm resting on the examination table. The forearm is placed on the ulnar side midway between supination and pronation, with the thumb adducted and held in flexion with the palm. The first metacarpal along the dorsal aspect to the groove at its proximal end is palpated. The patient is prepared in a standard aseptic fashion over an area large enough to allow palpation of landmarks, and sterile technique is used throughout the procedure. A 1-in. (2.5-cm) needle is inserted at the point of maximal tenderness. The needle is advanced into the joint space. Aspiration is attempted until the needle has entered the synovial space. After negative aspiration or if there is an effusion of the joint, the aspiration is completed. If negative aspiration or if the aspirated fluid is noninflammatory (clear and viscous), the joint is injected with a 1- to 3-mL mixture of triamcinolone acetonide (or equivalent) and local anesthetic (Fig. 67-45).
FIGURE 67-45. First metacarpal joint injection. Approach for first metacarpal joint aspiration and injection.
Piercing the radial artery and extensor pollicis tendon should be avoided.
Radial artery injury, extensor pollicis tendon injury, and increased pain for 1 to 3 days are uncommon, but may result from this injection. Hematoma and intravascular injection are possible due to the close proximity of the axillary vessels. If an arterial puncture occurs, prolonged direct pressure is usually adequate to prevent the development of a hematoma. Corticosteroids should not be injected if there is any suspicion that the joint is infected. If the fluid appears infected, it should be sent for culture and sensitivity and the patient treated appropriately for the infection.