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This is procedure where a needle of appropriate length and calibre is placed in a specific joint under imaging guidance. This often uses ultrasound, but X-ray fluoroscopy or CT can also be used depending on the radiologist doing the procedure and the joint required.
A mixture of steroid and long-acting anaesthetic is injected once the radiologist is satisfied that the needle tip is correctly located in the joint cavity. A small amount of contrast medium may be used in X-ray or CT guidance to confirm needle tip placement.
Particulate injectable steroid medication (e.g. Kenacort or Celestone) is commonly used, except in joints around the spine where dexamethasone is recommended. Particulate steroids leaking into soft tissues around the spine have been associated with microvascular coagulation and spinal complications.
The injection is used for pain relief in both therapy and in the diagnostic assessment of a potential painful joint.
The following are generally accepted indications for therapeutic joint injections:
Generally, the patient will require at least a plain X-ray of the joint and often an ultrasound, CT scan or MRI. These imaging studies should be brought to the appointment.
Infection in or overlying the joint at the site of potential needle placement.
This is a very safe procedure with few risks.
There is a risk of infection, which is very small and probably lies between 1 in 20,000 and 1 in 75,000 injections carried out. The procedure should not be carried out if there is broken skin or infection overlying the joint at the site of needle placement or if the joint may already be infected.
There are possible complications of the steroid injection, which include aggravation of the pain due to a transient increase in synovitis from irritation of the joint lining by crystals in the steroid solution.
If the steroid is not injected solely into the joint, there is a risk of damage to the soft tissues at the injection site, including atrophy of the skin or subcutaneous fat and rupture or weakness of the tendons around the joint.
A localised area of skin depigmentation at the injection site can also occur.
Although the exact risk is not known, most doctors would advise against injection more than three or four times a year to avoid damage to the joint.
Occasionally, people are allergic to the injected medication. The exact risk of this is not known, but it seems to be very uncommon. The radiologist should be advised on the referral if there is a known iodine allergy and/or a prior contrast reaction. An ultrasound-guided injection does not use X-ray contrast, but this may be used if the injection is carried out using fluoroscopy or CT.
Steroid therapy can elevate blood sugars for a few days in patients with diabetes, but generally the dosage of steroid injected into a joint is relatively small and it has a minimal effect.
In patients with diabetes, more frequent monitoring of blood glucose for 48 hours is advised, particularly in patients using insulin or whose diabetes is unstable.
If joint pain and swelling increases over more than 48 hours (i.e. more than that expected from transient synovitis), then infection needs to be considered. Please contact the specialist who did the injection, the radiology clinic or, if clinically indicated, refer directly to the local emergency department for further assessment.
Page last modified on 31/8/2018.
RANZCR® is not aware that any person intends to act or rely upon the opinions, advices or information contained in this publication or of the manner in which it might be possible to do so. It issues no invitation to any person to act or rely upon such opinions, advices or information or any of them and it accepts no responsibility for any of them.
RANZCR® intends by this statement to exclude liability for any such opinions, advices or information. The content of this publication is not intended as a substitute for medical advice. It is designed to support, not replace, the relationship that exists between a patient and his/her doctor. Some of the tests and procedures included in this publication may not be available at all radiology providers.
RANZCR® recommends that any specific questions regarding any procedure be discussed with a person's family doctor or medical specialist. Whilst every effort is made to ensure the accuracy of the information contained in this publication, RANZCR®, its Board, officers and employees assume no responsibility for its content, use, or interpretation. Each person should rely on their own inquires before making decisions that touch their own interests.