What is an AC joint injection?

An AC joint injection is the injection of a steroid (synthetic cortisone) medication into the ac joint, which is located in the front portion of the shoulder.

What is the purpose of an AC joint injection?

The steroid medication is a powerful anti-inflammatory medication. Pathologic changes within the AC joint (i.e. arthritis) often lead to inflammation. This inflammation is a large cause of pain. An injection of steroid can substantially decrease this inflammation and thereby lead to a significant reduction in pain.

How is the procedure performed?

You will be placed on the procedure table. The injection site is sterilized with either iodine or chlorhexadine. The site to be injected is numbed with a local anesthetic, and a needle is directed to the target area. X-ray guidance is used to ensure proper placement and positioning of the needle. Contrast (x-ray dye) may be injected to be sure the needle is in the proper position. Once proper needle placement is confirmed, the steroid solution is slowly injected.

Will the procedure be painful?

The injection can be painful and we therefore provide the option of receiving IV sedation. IV sedation, combined with local anesthetic, can make the injection nearly pain free. It allows you to remain very still during the procedure, which can also make the injection easier, faster, and more successful. If you decide to have IV sedation, you must have a driver to get you home safely afterwards. In addition, you cannot have anything to eat or drink within 6 hours of your appointment (clear liquids are allowed until 2 hours before the procedure). If you take medications for diabetes, these medications may need to be adjusted the morning of the procedure. Your primary care physician can help you with this adjustment.

What are the discharge instructions?

If you received IV sedation do not drive or operate machinery for at least 24 hours after the procedure. You may return to work the next day following your procedure. You may resume your normal diet immediately. Do not engage in any strenuous activity for 24 hours. Do not take a bath, swim, or use a hot tub for 24 hours (you may take a shower). Call the office if you have any of the following: severe pain afterwards (different than your usual symptoms), redness/swelling/discharge at the injection site(s), or fevers/chills.

What are the risks and side effects?

The complication rate for this procedure is very low. Whenever a needle enters the skin, bleeding or infection can occur. Some other serious but extremely rare risks include paralysis and death.

You may have an allergic reaction to any of the medications used. If you have a known allergy to any medications, especially x-ray contrast dye or local anesthetics, notify our staff before the procedure takes place.

You may experience any of the following side effects up to 4 hours after the procedure:

  • Arm muscle weakness or numbness may occur due to the local anesthetic affecting the nerves that control your arm (this is a temporary affect and it is not paralysis). Your arm strength will return slowly and completely.
  • Dizziness may occur due to a decrease in your blood pressure. If this occurs, remain in a seated or lying position. Gradually sit up, and then stand after at least 10 minutes of sitting.
  • Mild headaches may occur. Drink fluids and take pain medications if needed. If the headaches persist or become severe, call the office.
  • Mild discomfort at the injection site can occur. This typically lasts for a few hours but can persist for a couple days. If this occurs, take anti-inflammatories or pain medications, apply ice to the area the day of the procedure. If it persists, apply moist heat in the day(s) following.

The side effects listed above can be normal. They are not dangerous and will resolve on their own. If, however, you experience any of the following, a complication may have occurred and you should either contact your doctor. If he is not readily available, then you should proceed to the closest urgent care center for evaluation:

  • Severe or progressive pain at the injection site(s)
  • Arm or leg weakness that progressively worsens or persists for longer than 8 hours
  • Severe or progressive redness, swelling, or discharge from the injections site(s)
  • Fevers, chills, nausea, or vomiting
  • Bowel or bladder dysfunction (i.e. inability to urinate or pass stool or difficulty controlling either)

How long does it take for the procedure to work?

The steroid medication begins to take effect in one to two days at which point you should start to see some benefit. The steroid effect continues to get stronger and stronger such that the peak effect occurs at about two weeks. Thereafter, the effect will stabilize and should last several weeks to months. Typically, the pain relief experienced from this procedure lasts 3-6 months, but there is significant variability from patient to patient and from one procedure to another. If and when the pain starts to return, this procedure can be repeated to try and attain some pain relief once again. Keep in mind that this injection may work very well for pain in certain areas but may not help with others. This is normal. Areas of pain that do not respond may need other treatments, which you can discuss with your doctor.