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Medical Imaging

X-ray > Exams & Procedures > Joint Injection/Aspiration

The Joint Injection procedure is done so that under X-ray (fluoroscopic) control, a needle can be placed within a joint and medication can be injected. The joint aspiration also requires that a needle be placed within a joint though in this procedure fluid is drawn out of the joint to be examined by the lab for composition and/or infection.


There is no preparation required for this procedure. We suggest that you bring someone with you to help you home and make sure that you remain comfortable.


Contrast (X-ray dye) is usually not required for a joint aspiration but is used for the joint injection to ensure correct placement of the needle tip before the drug is injected.

The contrast is a clear fluid that will be absorbed and excreted by the body. It is tolerated extremely well by patients for this examination. The radiologist will ask a few questions about your allergic history to determine if it is right for you.


When you arrive the day of your examination you will be escorted to an area where you can change your clothes. You will then be taken into the examination room where the procedure will take place. During the examination there will be two other people present: a technologist and a radiologist. The technologist will ensure your comfort and safety throughout the procedure and make sure that the equipment functions properly. The radiologist carries out the fluoroscopy and will complete your procedure with the assistance of the technologist. Fluoroscopy uses radiation just like conventional X-rays, but it is similar to a movie rather than a snap shot.

St. Michael's Hospital is a teaching facility and there may be a student technologist or radiology resident present for your examination. These students are highly trained and closely supervised to provide you with the best care while maximizing their education.

You will be asked to lie on the X-ray table. The joint to be examined is then positioned for the exam. The radiologist will clean the area with a solution to sterilize the skin. A very small, fine needle will then be used to inject an anesthetic. The drug used is just like your dentist uses and although a small amount of burning or tingling may be felt with the injection it passes quickly, and most patients report feeling nothing.

The anesthetic is used to numb the path of the needle that will be used to enter the joint space. This drug is fast acting so the radiologist will then start to introduce the other needle. Using the fluoroscope, the radiologist will position the needle into the joint space. We ask that you remain as still as possible as this is the most difficult part of the procedure. You will feel little if anything during this time.

If you are having an aspiration, fluid will start coming back out of the needle once it is in the joint space. At this time, the radiologist will simply draw off a small amount of fluid to be examined by the lab. The needle will then be removed and the procedure will be over.

If you are having a joint injection, the radiologist will inject the contrast to ensure that the drug will be injected into the exact area needed. These drugs have been prescribed for you by your doctor, usually an orthopedic specialist. During the injection you may feel pressure within the joint, but nothing painful. The radiologist and technologist will assist you if you have any questions or concerns.

After the drug has been fully injected the needle will be removed. You will probably notice that the joint is a little stiff and weak immediately following the procedure. This is normal and a little extra care when using this limb is all that is necessary. After the joint aspiration procedure you will most likely not feel anything new or unusual.

At this point you can go home. You will return to your doctor who will discuss with you the effectiveness of this procedure.