1.  (Optional) Use ultrasound to image the knee joint structures using an adjacent, but separate, acoustic window. This allows separate imaging from the injection site so that there is no contamination from the ultrasound gel. Alternatively, the entire site may be prepped in an aseptic manner and sterile ultrasound gel utilized.

2.  Create an aseptic insertion site by wiping with a single alcohol prep pad followed by two 10% povidone–iodine prep pads. Allow this site to completely dry by evaporation.

3.  Achieve good local anesthesia by using topical vapocoolant spray.

4.  (Optional) Using the no-touch technique, introduce the 25-gauge, 1 in. needle for local anesthesia at the insertion site. Inject 2 to 3 mL of 1% lidocaine with epinephrine to provide adequate local anesthesia. Deposit the anesthetic under the skin and in the soft tissue at the joint capsule.

5.  Have the patient relax the quadriceps muscles; then, have an assistant apply pressure to the medial aspect of the patella in order to displace it laterally.

6.  Position the 18-gauge, 1½ in. needle and syringe over the previously marked injection site in a medial direction and with the needle tip angled up underneath the patella and over the lateral femoral condyle.

7.  Using the aseptic, no-touch technique, quickly introduce that needle at the ­insertion site.

8.  Advance the needle medially underneath the patella and over the lateral femoral condyle until the needle tip is located in the joint capsule. Apply suction to the syringe while advancing the needle. The appearance of fluid in the syringe confirms that the joint capsule has been entered (Fig. 8.23). If fluid is aspirated, stop advancing the needle.

9.  Multiple syringes may be required in order to drain all of the synovial fluid if a large effusion is present.

10.  If injection following aspiration is elected, remove the large syringe from the 18-gauge needle and then attach the 5-mL syringe filled with the anesthetic/steroid solution or a proprietary glass syringe prefilled with viscosupplement.

11.  Inject the anesthetic/steroid solution as a bolus into the knee joint capsule. The injected solution should flow smoothly into the joint space. If increased resistance is encountered, advance or withdraw the needle slightly, and confirm aspiration of a small amount of joint fluid before attempting further injection.

12.  Following injection of the corticosteroid solution or viscosupplement, withdraw the needle.

13.  Apply a sterile adhesive bandage.

14.  Instruct the patient to move his or her knee through its full range of motion. This movement distributes the steroid solution throughout the knee joint.

15.  Reexamine the knee in 5 min to confirm pain relief.