What is an Arthrogram or Joint Injection?
The junction where two bones meet is a joint. Examples of joints include the hip, shoulder and the elbow.
The bones can be seen well with X-rays but other components of the joint such as ligaments and cartilage are not visible. Arthrography involves injecting contrast media or dye into the joint space so that the small inner parts of the joint can be seen by MRI or X-ray imaging. The information gained in this way can help determine the cause of joint pain and help plan further treatment or surgery.
Joint injections can also be used to deliver medicine directly into a joint as a treatment instead of a diagnostic study. The medications injected are usually an anti-inflammatory steroid mixed with a local anesthetic agent. Steroid injection may be combined with an arthrogram study, but frequently is done without any MRI or CT imaging.
How should I prepare?
No specific preparation is necessary. However, leave all unnecessary metal objects and electronic devices at home if you are having an MRI study. Please inform your doctor of all medications you are taking, and of any allergies, particularly to medications or latex.
MRI arthrography with gadolinium injected into the joint gives the most detailed information, but when patients cannot have MRI a different kind of iodine-containing contrast is injected into the joint and a CT scan is used.
Patients who have cochlear (ear) implants, certain kinds of metal clips for brain aneurysm surgery, most pacemakers and cardiac defibrillators, and certain kinds of cardiac valves cannot have MRI. Please inform your physician if you have any medical or electronic devices in your body, any shrapnel or bullets, or any metal fragment near your eyes. Please click here for link to information about MRI.
Women should always inform their physician if there is any chance they may be pregnant.
How is the procedure performed?
The patient is positioned on a fluoroscopy table, and the appropriate area of skin is cleaned with antiseptic and covered with a sterile drape. A local anesthetic is given and then a very thin needle is advanced into the joint using real-time X-ray imaging (fluoroscopy). The position is checked by injection of a small amount of contrast visible with X-ray, followed by a larger volume of contrast or MRI contrast. In the case of therapeutic injections, steroids and anesthetic are then injected. The needle is removed and a bandaid applied. The patient will be asked to move the joint to distribute the contrast or the medications to all parts of the joint.
For arthrography patients, the procedure is followed by imaging, usually in an MRI scanner. For patients who cannot go in the MRI scanner, a CT scan will be done.
What will I experience during and after the procedure?
You will feel a small pinprick and brief stinging when local anesthetic is injected in the skin. You will likely feel pressure and even a little pain as the needle enters the joint. Tell the radiologist so that more local anesthetic can be added. As the contrast or the steroid medications are infected, the joint may begin to feel tight. Occasionally, an immediate feeling of sweatiness and nausea may occur. Please inform the radiologist, as this may be the first symptom of fainting.
If your exam involves MRI: You may feel warm in the machine. You will hear loud tapping or thumping sounds during the times when images are being recorded, and you must maintain your position without moving during those times.
Allergic or other reactions to the contrast material are very rare. If you experience hives, itchy eyes or throat, or shortness of breath, inform the technologist immediately. After the exam you may feel fullness or discomfort in the joint. An over-the-counter pain medication may be helpful. If steroids are injected, they may rarely cause facial flushing a few days later.
Avoid vigorous exercise for at least 24 hours. If steroids and anesthetic are injected, you should keep track of your joint discomfort over the following days and weeks, and avoid vigorous exercise for about two weeks.
What are the benefits and risks?
Arthrography can give your physician important information about the cause of joint pain, and help in deciding how to proceed with treatment. Steroid injections can help reduce inflammation and may promote healing of joint structures. The main benefit may be to reduce pain enough to allow you to work or to sleep better.
Any needle puncture can carry a small risk of infection. Joint infection following arthrography or therapeutic injection is extremely rare. Allergies to contrast material are also rare.
Occasionally a nerve adjacent to the joint may be infiltrated with local anesthetic, causing temporary numbness. The amount of radiation from fluoroscopy is very small and limited to the area of the joint.
How will I get the results of this test?
The images will be studied and interpreted by a specially trained radiologist, who will send a signed report to your referring physician or primary care physician, who will discuss the results with you.
Radiologyinfo.org for Patients
The radiology information resource for patients. RadiologyInfo.org tells you how various X-ray, CT, MRI, ultrasound, radiation therapy and other procedures are performed. It also addresses what you may experience and how to prepare for the exams. The website contains over 200 procedure, exam and disease descriptions covering diagnostic and interventional radiology, nuclear medicine, radiation therap, and radiation safety and is updated frequently with new information. All material on the RadiologyInfo.org website is reviewed and approved by experts in the field of radiology from the ACR and RSNA, as well as other professional radiology organizations.