A painful swollen joint or a tender area around a tendon is usually caused by inflammation. In a joint this may be due to arthritis and in a tendon is called tenosynovitis.
Inflammation is usually treated by rest and then if appropriate, by non-steroidal medication, such as ibuprofen. Physiotherapy may be appropriate for some conditions.
If the pain and inflammation continues, a cortisone injection may be recommended.
Joint injections are done for people with rheumatoid arthritis, osteoarthritis and many other conditions.
Sometimes cortisone is injected into the tissues around joints as well because this can help with conditions such as tennis elbow.
What is injected into the joints?
A small amount of steroid which is often mixed with local anaesthetic.
What are the advantages of cortisone injections?
A single injection can avoid certain side effects that can accompany many oral anti-inflammatory medications, notably irritation of the stomach.
In about 70% of cases, the steroid reduces the swelling and pain a patient has.
How long will it be before my joints feel better?
The local anaesthetic will start to reduce the pain within a few minutes of the injection.
This pain relief will last for 1-2 hours. The steroid will take longer to start working; sometimes it can be 1-2 days after the injection, before the pain starts reducing. It is important to rest the joint for the first 48 hours.
In the first 48 hours the pain may get slightly worse before it starts getting better. During this period to take painkillers such as paracetamol, or use a cold pack.
The joint that has been injected will hopefully feel better for up to 3 months and sometimes longer, but everybody is different so it may not last this long.
What are the disadvantages and side effects of cortisone injections?
Disadvantages of cortisone injections are the necessity of piercing the skin with a needle as well as potential side effects.
Facial flushing may occur in up to 40% of cases but lasts only briefly. Sweating and insomnia are also uncommon. It should be emphasised that though each of these side effects is possible, they usually do not occur.
Complications are uncommon but include:
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Shrinkage (atrophy) around the site of the injection (up to one in 20)
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Lightening of the colour (depigmentation) of the skin at the injection site (about 1 in 50)
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Introduction of bacterial infection into the body (about 1 in 10,000),
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Local bleeding from broken blood vessels in the skin or muscle,
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Soreness at the injection site, and aggravation of inflammation in the area injected because of reactions to the corticosteroid medication (post injection flare).
Increased pain after the injection is typically due to a post injection flare. A true allergic reaction to cortisone is very rare. Tendons can be weakened by corticosteroid injections in or near tendons. Tendon ruptures as a result are very uncommon.