Trigger finger injection

The hand is placed flat with the palm up and the fingers outstretched. The injection is directed towards the point of maximal tenderness of the A1 pulley, which arises from the palmar aspect of the metacarpal head and metacarpophalangeal (MCP) joint. The injection site is prepped with iodine or chlorhexidine. Ethyl chloride is sprayed on the skin for anesthesia. A 5/8-inch (1.5 cm), 25-gauge needle is inserted to a depth of 1/4 to 3/8 inch (6 to 10 mm) for trigger finger and 1/8 to 1/4 inch (3 to 6 mm) for trigger thumb. The needle is positioned at a 45-degree angle to the skin with the needle tip directed proximally, and is advanced down to the firm resistance of the flexor tendon, a rubbery sensation. The needle is backed up about 1 to 2 mm, and 1/4 mL of methylprednisolone (80 mg/mL) or 1 mL of triamcinolone (10 mg/mL) mixed with a local anesthetic (such as 1/2 mL of lidocaine) is injected around the tendon sheath. If resistance is encountered during the injection, the needle should be advanced or withdrawn slightly before attempting further injection.