Intra-Articular Injections of the Knee: A Step-by-Step Guide

Although some training is required, intra-articular injections are no longer considered an orthopedic subspecialty procedure, and there are a number of benefits to incorporating these injections into your practice. Many patients appreciate their primary care clinician making available services that traditionally required a referral to a specialist. Patients also avoid treatment delays.

Here is a step-by-step guide to familiarize you with the technique.

STEP 1: Selecting an injection approach

Common approaches for injecting the knee include the following¹ :

• Anterolateral (flexed knee)
• Anteromedial (flexed knee)
• Superolateral/lateral suprapatellar (straight knee)
• Superomedial/medial suprapatellar (straight knee)
• Lateral mid-patellar
• Medial mid-patellar.

One study found that the accuracy of the first attempt at needle placement was highest for lateral mid-patellar (93%) compared with anteromedial (75%) and anterolateral (71%) approaches (superolateral approach not done).

STEP 2: Identify and mark the injection site²

For superolateral approach:

• Palpate superolateral and lateral edges of patella with patient supine and leg straight
• Mark where lines intersect as in diagram.

If the patient cannot completely extend the knee, placement of a rolled towel to support the knee will help provide the patient comfort and minimize muscle spasm, improving the likelihood of a successful and comfortable injection.

STEP 3: Preparing the injection site²

• Aseptic technique

• – Swab area 3 times with a povidone iodine preparation (Beta-dine) and let dry.

• Local anesthetic options

• – Lidocaine
• – Vapocoolant spray

STEP 4: Aspiration (skip to Step 5 if no effusion is present)

If effusion is present, aspiration of the effusion can relieve patient discomfort, be of diagnostic benefit, and avoid dilution of a visco-supplement to be injected.²

• Insert 1 ½” 18-gauge needle for aspiration³
• If needle is accurately placed, the syringe should fill with fluid¹
• Compression of the opposite side of the joint or the patella may aid in arthrocentesis.³

STEP 5: Injection

If aspiration was required, the same needle can be used for aspiration and injection by changing the syringe.

• Insert needle (1 ½”, 21-gauge for corticosteroids; 1 ½”, 20- or 22-gauge for viscosupplementation) ¾” to 1 ¼” for injection
• Remove needle, wipe off povidone iodine solution, and apply bandage.

Post-injection care: Setting patient expectations and managing adverse effects

• Patient should avoid strenuous activity for 1 to 2 days after injection and apply ice to injection site
• Mild pain or swelling at the injection site can occur, but is rare

• – If mild pain or swelling occurs, recommend ice, nonsteroidal anti-inflammatory drug (NSAID), rest, and elevation
• – If significant pain or swelling occurs:

• Joint aspiration
• Send aspirate to lab to rule out joint infection
• Crystal analysis
• May provide intra-articular corticosteroid to decrease pain and inflammation after viscosupplementation if infection has been excluded.