Frequently Asked Questions about ultrasound guided steroid (cortisone) injections

What is a musculoskeletal (MSK) ultrasound?

Ultrasound is high-frequency sound waves produced by a special machine. They can penetrate the skin providing very useful images of the deep tissues within the body. It is a harmless way of imaging and it is extremely useful in assessing various musculoskeletal conditions that can involve tendons, muscles, joints and the adjacent soft tissues. Unlike X-rays, ultrasound does not involve exposure to radiation or any harmful side effects.

What is a steroid/cortisone injection?

Steroids (also called cortisone) are anti-inflammatory medicines that can help relieve pain and inflammation in a specific body area. They can be injected into a joint to help relieve pain, usually in the context of arthritis. This is referred to as "an intra-articular steroid injection".

They also treat other inflammatory conditions like bursitis (inflammation of sac-like fluid collections present in different parts of the body) and tendonitis (tendon inflammation).

Steroid injections can’t treat the underlying cause of your condition, but they can treat the symptoms. They are potent anti-inflammatory medicines that should reduce inflammation and, in turn, the pain in that specific area. The Commonly used types of steroid injections are hydrocortisone, triamcinolone and methylprednisolone.

A steroid injection normally takes a few days to start working. The effect usually wears off after a few months. The injections usually also contain a local anaesthetic that provides immediate pain relief lasting a few hours.

What is the benefit of having an ultrasound guided steroid injection (vs a non-guided injection)?

Ultrasound is useful for assessing the joints, tendons and ligaments for any suspected injury or inflammation. In addition, it allows for direct visualisation of the needle to ensure the steroid medication is injected into the exact targeted site.

There is significant evidence that ultrasound guided injections provide better levels of pain relief and longer effects compared with injections done without imaging guidance. This is because ultrasound guidance allows for accurate placement of the needle and, thus delivery of the medicine to the exact site of pathology. Performing the injection under ultrasound guidance allows for the visualisation of the adjacent structures and reduces the risk of tissue injury at the injection site.

What are the possible side effects of a steroid injection?

Most people have intra-articular steroid injections without any significant side effects.

Possible side effects from an intra-articular steroid injection include:

Pain and discomfort for a few days. This is sometimes referred to as a steroid flare. Simple painkillers like paracetamol can help with this.
Temporary bruising due to small blood collection under the skin at the site of injection
Infection. This is very rare but important to be aware of. It is reported to happen in less than 1 in 10000 cases. The symptoms of infection are pain, swelling and redness at the injection site. Sometimes the patient may also have a fever. Get medical advice as soon as possible if you have these symptoms.
Injury to structures close to the injection site. This is rare with ultrasound guidance.
Local thinning of the fat at the injection site. This can cause dimples in the skin and can be permanent.
Local change in colour (usually lightening) of the skin at the injection site. This can be permanent.
if you have diabetes, your blood sugar level may temporarily increase.
If you have high blood pressure, your blood pressure may temporarily increase.
Temporary facial flushing.
Other side effects like mood changes, increased appetite, difficulty sleeping and menstrual disturbance are rare with intra-articular injections and more associated when the steroids are taken as tablets, injected into the muscle (intra-muscular) or the blood (intravenous).

What to expect on the day?

A specialist doctor (musculoskeletal radiologist) will ask you questions and perform the ultrasound examination. Then the doctor will explain the procedure to you.
You will need to expose the injected body part to allow it to be sterilised (cleaned). Wearing loose closing that allows for this would be useful.
Then the doctor will use the ultrasound machine to guide the needle into the exact preferred site and inject a mixture of steroids and local anaesthetic (numbing medication). A small plaster is usually applied to the injection site when the injection is done. You can remove this later during the same day.
You can eat and drink normally before and after a steroid injection. You can shower as usual but avoid very hot showers/steam rooms.
You can use simple painkillers like paracetamol if you experience pain at the injection site.
It’s advised not to drive immediately after the injection as it usually contains a small amount of local anaesthetic (numbing medication).
Rest the area for 48 hours after the injection. It is also advisable to avoid extraneous exercises for 48 hours after the injection.
You should be able to go home soon after the injection.

Who will perform my procedure/injection?

A specialist consultant musculoskeletal radiologist doctor with extensive experience in performing musculoskeletal ultrasound and ultrasound guided intervention will perform your scan and injection.

Can I have steroid injections in both shoulders or knees?

Yes, you can, but these are usually staged (separated) by at least 2 weeks. The reason for this is if you have a steroid flare, which will be easier for you to manage if it only affects one side. Also, it is advisable to avoid extreme activities with the injected body part, particularly for 48 hours following the injection. Separating the two injections helps with this, as it will be easier for you to compensate by using the non-injected side (like your shoulder) to do some necessary activities.

How many steroid injections can I have?

You should discuss this with your doctor but repeated steroid injections can increase the risk of side effects. There is also some concern that repeated intra-articular steroid injection might cause damage to the cartilage. Therefore, steroid injections are usually not performed more than 3-4 times a year into the same body part.

What will happen after my appointment?

The doctor will explain the findings of the examination to you. You will be sent an electronic copy of the report by email shortly after your appointment. You are encouraged to share this with any relevant health care professionals (like your GP or other hospital specialists).

Can I drive immediately after a steroid injection?

It’s advised not to drive immediately after the injection as it usually contains a small amount of local anaesthetic (numbing medication). The duration of numbing medicine effect can last up to 12 hours.

Are cortisone injections safe?

These injections are generally very safe and routinely done in our practice. There is a very small risk of infection (about 1:10.000). The procedure will be explained to you in detail during your appointment, and all your questions will be addressed.

What are the commonly used steroid medicines in injections?

Triamcinolone (Kenalog) and methylprednisolone (Depo-medrone) are commonly used steroid injections for musculoskeletal conditions. These preparations are long-acting steroid injections that normally take a few days to start working.

How long will the effect of a cortisone injection last?

Current evidence suggests that cortisone can improve pain and function for up to 3 months, but in some cases, it can last longer. The injections usually also contain a local anaesthetic that provides immediate pain relief lasting a few hours.

How soon will a steroid injection start to work?

A steroid injection usually takes a few days (1-3) before you notice the effect, although sometimes the pain relief can start on the same day. The injected area will often feel sore for the first few days. This is referred to as (steroid flare) and can be seen after a steroid injection. Other injections like PRP and intra-articular Hyaluronic acid injections can take a few weeks (2-5 weeks) before noticing any results.

Do steroid injections just hide/mask the pain?

Steroid injections do not just mask or hide the pain but they act by reducing the inflammation in the targeted area, thus providing a strong and local anti-inflammatory effect to help control the symptoms and allow the patient to manage the condition, usually by undergoing effective rehabilitation.

How many steroid injections can I have?

If possible, we advise reducing the number of cortisone hip injections by combining any injection therapy with an effective physiotherapy programme to address the underlying cause. Repeated steroid injections into the same area should be avoided if the previous injection was less than 3-4 months ago.

Are cortisone injections painful?

Generally, steroid injections are well-tolerated and the majority of patients experience very little discomfort during the procedure. The corticosteroid is usually mixed with a local anaesthetic (numbing medicine) to enhance pain relief. We use ultrasound guidance to ensure the procedure is quick and efficient. Ultrasound ensures needle visualisation to choose the safest path for the injection and avoid any important or sensitive structures.

How long should I rest after a cortisone injection?

Usually, we advise patients to rest for 48-72 hours after having a cortisone injection. This can vary depending on the type of treatment and severity of the condition. Usually, patients who have a trochanteric bursa corticosteroid injection are usually advised to rest for 48 hours, while patients who had a more advanced procedure like PRP injection into the gluteal tendons may be advised to rest for 5-7 days.

Steroids injections and COVID 19

Steroid injections may reduce a person's immunity for 2-4 weeks following injection [Regan et al. Dec 2021]. The reduction in immunity for most people is likely to be small, and it is unclear if this impacts their risk of contracting COVID-19. The emerging data now suggests the risks are probably very low [McKean et al. Sept 2020].

The British Society of Rheumatology published its guidelines on 20th November 2020 regarding treating patients using corticosteroid injections to support clinicians and patients in clinical decision-making.

The aim of ultrasound guided intra articular injections is to deliver a small and effective dose of the medicine accurately and directly into the site of pain, thus minimising the side effects.

However, there remains a theoretical risk that a steroid injection could:

Increase the likelihood of contracting COVID-19 due to its immunosuppressant effect
Reduce the body’s ability to fight the COVID-19 virus
Potentially make the patients more contagious to people around them following a corticosteroid injection.

We screen our patients for any high-risk factors for COVID-19 (patients over 70, BMI>40, BAME, diabetes, ischaemic heart disease, chronic respiratory disease or hypertension).

Because the size of the risk is unknown, it is recommended that patients and clinicians reach a shared decision weighing the risks and benefits of proceeding with steroid injection treatment.