1. Obtain oral or written informed consent. The potential risks of the injection include infection; bleeding; skin atrophy and depigmentation; allergic reaction to medication; or temporarily increased pain.

2. Assemble the necessary equipment. The injection requires a 21-or 22-gauge 1.5-inch needle, 8 mL of 1% lidocaine (Xylocaine), 1 mL of 8.4% sodium bicarbonate to decrease the sting of the injection, one 10-mL syringe, one 1- or 3-mL syringe, corticosteroid solution (Table 2), alcohol wipes, povidone-iodine wipes or swabs, some 2- × 2-inch pieces of gauze, a plastic bandage, gloves (sterile or nonsterile), and a marking pen.

3. Sterilize the injection area and use the thumb to palpate the point that is most painful over the bicipital groove. Confirm this is the biceps tendon by externally rotating the arm and placing the elbow in 90 degrees of flexion. Insert the 10-mL syringe of 1% lidocaine plus sodium bicarbonate with the 21- or 22-gauge 1.5-inch needle subcutaneously parallel to the bicipital groove. Inject approximately 5 mL of lidocaine plus sodium bicarbonate around the biceps tendon sheath in a fan-like distribution after aspirating and checking to avoid blood vessels. Ensure that the injection is not into the tendon itself because of the risk of rupture.

4. If a corticosteroid injection is required, use a hemostat between the needle and skin to hold the needle in place while changing to the 1- or 3-mL syringe containing the corticosteroid solution.

5. After the corticosteroid solution is injected, remove the syringe and reattach the 10-mL syringe with lidocaine and sodium bicarbonate. Slowly withdraw the needle while injecting the remaining lidocaine and sodium bicarbonate. This will flush any remaining corticosteroid solution out of the needle, lessening the chance that any remaining solution might cause skin atrophy or depigmentation. An alternative technique is to combine the lidocaine with sodium bicarbonate and corticosteroid solution in the same syringe to avoid changing syringes.

6. Apply the plastic bandage. Instruct the patient to keep it on for eight to 10 hours and watch for signs of infection, which may include erythema, increased pain, pus at the injection site, and a low-grade fever of 100.4°F (38°C) or higher.

7. Reexamine the patient after 15 to 20 minutes. Pain relief indicates a diagnosis of biceps tendinitis. Confirm the diagnosis by performing the Yergason test. It should be negative. A patient may also report pain relief if there is instability or subluxation of the biceps tendon. If the shoulder is still painful, consider problems with the rotator cuff, adhesive capsulitis, calcific tendinitis, or subacromial bursitis.