What is a corticosteroid injection?
Corticosteroids are anti-inflammatories and should not be confused with anabolic steroids. Corticosteroid injections are often used to treat selected conditions affecting the joints, tendons, and ligaments. An injection can deliver medication directly to the affected area to provide short term relief of pain, inflammation and swelling.
How is the injection performed?
After identifying the specific site and using sterile technique to clean the skin, a small needle is carefully inserted. Your doctor may use an ultrasound scanner to guide the injection. A mixture of corticosteroid and local anaesthetic is usually delivered in the same syringe. This procedure takes less than 10 minutes and is done in the clinic.
What are the risks?
When indicated, a local corticosteroid injection is a safe and effective procedure. Potential side-effects include:
1) Crystal synovitis (steroid flare)
The injected corticosteroid may crystallise, causing pain. The reaction may occur within the first 2 days after the injection. Please call your doctor’s office or follow up if you are concerned you may have a steroid flare reaction. You can ice the area for 15 minutes 3–4 times daily. You may also take oral pain medications for temporary relief.
2) Allergic reaction
3) Skin discolouration (hypopigmentation)
Lightening of the skin over the injection site may occur and this can last for a few months after injection.
4) Fat Atrophy
If the injection site is close to the skin surface, you may notice a slight ‘depression’ or ‘dimpling’ of the skin which can persist for several months. This is due to atrophy of fat at the injection site. For injections at the heel, such as for planter fasciitis, atrophy of the heel fat pad can cause discomfort when walking or standing.
5) Temporary Increase in Blood Glucose Level
If you are a diabetic, you should monitor your blood glucose for the 3 days after the injection, and if you are taking insulin, you may need to adjust your insulin medication dose temporarily.
6) Weakening or rupture of tendons or ligaments
To minimize this risk, we inject the cortisone around and close to the tendon. For this reason, we avoid cortisone injections directly into tendons and ligaments. Ultrasound guidance helps to increase the accuracy of the injection. We also advise that you avoid vigorous physical activities for the first two weeks immediately following a corticosteroid injection.
If there is an increase in pain or redness in the days following an injection, there may be an infection. You should see your family doctor immediately, call the sports medicine clinic, or go to our Accident & Emergency Department, if you suspect that you have an infection following an injection.
In conclusion, a corticosteroid injection is recommended only if the benefits outweigh the risks. Your doctor will discuss the side-effects with you and will only proceed with the procedure with your informed consent.
What should I do after the injection?
1) Rest the affected joint for the first 24-48 hours from moderate to vigorous exercise. Daily activities are ok.
2) If there is pain during this period, ice the area and/or take pain medications.
3) Any bandage placed over the injected site can be removed after 24 hours.
4) Light exercise is allowed after the first 48 hours. However, you should avoid intense activities and exercise for the first 2 weeks.
The numbness from the anaesthetic may wear off after a few hours and pain may return until the anti-inflammatory effects of the corticosteroid starts working, which sometimes can take up to 3-4 days.