Ultrasound Guided Joint Injections

What is an ultrasound scan?

Sound travels in waves. Ultrasound is sound which travels at a higher frequency than we can hear.  The ultrasound waves are sent to and from the body by moving a transducer (probe) over the surface of the skin of the area to be examined. Images (pictures) are taken for interpretation by doctors and sonographers trained in this speciality.  

Ultrasound scans can be used to diagnose a variety of conditions. They are also used to guide the position of needles for injections.

What is an ultrasound guided injection?

Interventional ultrasound refers to a wide range of invasive procedures performed percutaneously using ultrasound guidance. In practice, these procedures consist of aspiration of fluid collections and injection of steroids either into joint cavities and tendon sheaths or into the para-articular soft tissues. Your doctor will have already discussed with you why he/she recommends you should have an injection. The skin is cleaned with an antiseptic solution. The doctor may give you an injection of local anaesthetic to numb the area. This will cause a stinging sensation as it is injected but this quickly wears off. A needle is then used to inject the appropriate medication/product using the ultrasound imaging as guidance.

Anything I need to do before my appointment?

There is no preparation for this test. You can eat and drink as normal. You can take all your medications as usual. If you are on blood-thinning tablets, please continue taking them as usual provided they are being monitored appropriately. Please tell us if you are taking any anti-retroviral medications as these can affect treatment.  Please also let us know if you are allergic to steroids and any other medications or substances (e.g. latex) before your appointment.

If you are pregnant, think you may be pregnant or breastfeeding, you must notify the imaging staff.

What are the risks and benefits of having an injection?

An ultrasound guided injection is a common procedure. There are some complications or risks associated with the procedure: 

• Pain - sometimes the steroid injection can make the pain or discomfort temporarily worse.  We call this a Steroid Flare. This can be more painful for approximately two to three days after injection. You may take your regular pain killers to provide relief during this time

• Discolouration - very rarely a white dot or patch on the skin can appear after the injection, called ‘Depigmentation’. This is rarely permanent and may last for few months

• Fat atrophy – this is thinning of the fat, which may result in a dent in the skin

• Skin thinning or skin dimpling – occasionally the skin overlaying the injection becomes thinned over the course of some months. This is particularly noticeable when several injections are given close to the skin surface. This side effect does not occur in most people.

• Tendon rupture – this is rare but steroids may weaken the tendon so it is important to avoid any strenuous activity or exercises for three to four weeks and use splints or support.

• Infection – this is very rare. If there is redness or swelling over the injection site or you develop a fever, please see the GP or go to A&E immediately and explain that you have recently had an injection.  Allergic reaction is extremely uncommon  In patients with diabetes, blood sugar can elevate temporarily  

• No effect – the injection may not have any benefit

We have included some common side effects seen in our practice, but if you wish to know more, please discuss this with the doctor. If you would rather not have unknown risks, you may choose to not go ahead with a steroid injection. It is ok to change your mind anytime or even just before the injection.  

What happens on the day of my appointment?

Please note, no photography or electronic recording of any kind is permitted in the scanning room. There is no need to remove jewellery or hearing aids.Your scan will be performed either by a doctor specialising in imaging (a radiologist) or a sonographer who is a technician specialised in ultrasound imaging. We may ask you some questions about your health before the scan begins. A water-soluble gel is then applied to your skin. This allows the transducer to slide over the skin easily and helps to produce clearer pictures. Your doctor will discuss the procedure with you before the injection.The scan normally takes between 15 and 30 minutes to complete, depending upon which parts of the body are to be examined. Please feel free to ask questions during the test.

Will it hurt?

The ultrasound scan will not hurt. When you have the injection, you will feel a small needle prick, but it should not be too painful depending on your pain tolerance.

What happens afterwards?

The gel will be wiped off your skin and you will be able to get dressed. Rest the area injected for 24-48 hours. Remove the plaster after 24 hours. Antiseptic solution may discolour skin pink or orange but will be removed with cleaning. If you are a diabetic, you will need to keep an eye on your blood sugar levels as these can be raised slightly after a steroid injection. This usually settles after a few days. We recommend that you do not drive for at least 24 hours after the procedure.

When will the injection start working and how long will it last?

The symptoms usually improve about three days after the injection but this varies from patient to patient. The benefits of the injection may last for a few weeks or even months. You may need more than one injection to settle the symptoms. The result of the injection will enable your referring doctor to decide your ongoing treatment with you.

Is there anything I need to watch out for at home?

Please review the section above titled ‘What are the risks and benefits of having an injection’. You should contact your GP if you have a fever or notice redness or swelling around your injection site. This could indicate that you may have an infection. Your GP should be able to treat this with antibiotics.