Orthopedic surgeons often use injections to treat a variety of conditions. Commonly injected medications include cortisone, local anesthetics, and joint lubricants such as hyaluronic acid. In some cases, depending on the patient anatomy, delivering an injection is not as easy as it sounds.
Joint injections, for example, need to be administered within the joint space and not the surrounding soft tissue. Similarly, tendon injections should be administered in the tendon sheath, the structure covering the tendon, and not the tendon itself. Bursal injections are injections around the joint in areas that help lubricate and facilitate motion.
Traditionally, injections were given "blind," requiring an orthopedist to have a certain degree of experience, delicacy, and anatomical know-how. With the use of in office ultrasound, we are better able to localize and correctly place the injection where it needs to be.
How Ultrasound-Guided Injections Are Performed
Today, through advanced technology and hand-held devices we can use ultrasound to help diagnose certain soft tissue conditions as well as provide assistance to accurately place an injection.
Ultrasound-guided injections are performed much in the same way as traditional injections. The area to be injected will be cleaned with a disinfectant and a topical anesthetic will be applied to the injection site. To ensure the images come in clear, an ultrasound gel will be applied directly to the skin. The gel acts as a conductive medium that creates a tight bond between the skin and the ultrasound probe. This ensures the reflected sound waves have minimal interference.
The probe, also known as a transducer, is then placed near or adjacent to the targeted tendon or joint. Once the doctor has identified the anatomic landmarks on the monitor, the injection will be delivered using a standard needle and syringe.
The ultrasound also allows you to visualize fluids so that you can see if the medication is being distributed exactly where you need it to be.
What are common side effects after the test?
You may experience more soreness in the joint or area injected after the procedure but may also feel better initially as a result of the local anesthetic. The anesthetic will generally wear off after a few hours. This soreness may last for 2–3 days after the injection.
- Avoid strenuous activities (i.e. exercising, grocery shopping) after your injection for approximately 4-5 days.
- If the steroid part of the injection is going to reduce the pain and inflammation in the joint, this will usually start to occur between 3–5 days after the injection.
- If the pain becomes much worse in the days after the injection, this may indicate either an aggravation of the synovitis by the injection or very rarely an infection of the joint. If this occurs, contact your referring doctor or the emergency department of a hospital as soon as possible.