Intraarticular corticosteroid injection of the knee joint is used to treat noninfective inflammatory joint disease secondary to rheumatoid arthritis, seronegative spondyloarthritides, or the chondrocalcinosis inflammatory phase of osteoarthritis.
After informed consent is obtained, the patient is placed in the sitting position with the knee flexed to 90 degrees. The patellar tendon is palpated and the middle of the patellar tendon is marked. 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 1½-in. (4-cm), 21-gauge needle is inserted horizontally and advanced to the intercondylar notch. Aspiration is attempted until the needle has entered the synovial space. If there is an effusion of the joint, the aspiration is completed. After negative aspiration or if the aspirated fluid is noninflammatory (clear and viscous), the joint is injected with a 2-mL mixture of 10 mg of triamcinolone acetonide (or equivalent) and local anesthetic (Fig. 67-52).
FIGURE 67-52. Knee joint injection. Approach for knee joint aspiration and injection. Anterior approach.
An alternate approach may be used to access the suprapatellar pouch, which is continuous with the synovial space of the knee. The patient is placed in the supine position with the leg fully extended. 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. Throughout the procedure, the patella should be grasped between the examiner’s thumb and forefinger and should be able to be moved from one side to another to ensure that the quadriceps muscle is relaxed. A 1½-in. (4-cm), 21-gauge needle is inserted horizontally into the suprapatellar pouch at a point lateral and posterior to the patella at the level of the cephalad edge. A small amount of pressure is placed on the patella, pushing it to the side of needle insertion. This improves the ability to direct the needle during advancement (Fig. 67-53). The patient should be advised to minimize walking activity for 24 hours after injection, to minimize dispersion of the corticosteroid from the joint. If fluid is exceptionally viscous, a 1½-in., 18-gauge needle may be required to aspirate the joint.
FIGURE 67-53. Knee joint injection. Medial approach to suprapatellar pouch for knee joint aspiration and injection. Note connection between suprapatellar pouch and main synovial cavity.
Corticosteroids should not be injected if there is any suspicion that the joint is infected. If the fluid appears infected, then it should be sent for culture and sensitivity and the patient treated appropriately for the infection. It is contraindicated to inject the joint in a person with hemophilia, unless the risk for intraarticular bleed has been minimized. Corticosteroid injection into the knee joint may impair epiphyseal growth in children, resulting in a significant leg-length discrepancy.