Should I Get an X-Ray for a Sprained Ankle?

A sprained ankle is a very common injury that can cause mild to severe ankle pain. If you have injured your ankle and are wondering, “should I get an X-ray for a sprained ankle?”, the answer will usually depend on how severe your symptoms are.

Here, we will explore signs that you may need an X ray of your ankle, how an X-ray works and the difference between a sprained ankle and an ankle fracture.

A sprained ankle: the basics

A sprained ankle refers to an injury to one of the ligaments in the ankle area. Ligaments are strong, fibrous tissues that connect one bone to another.

In the ankle, the ligaments that are most commonly injured are the ones on the outer side of the ankle. In roughly 9 out of every 10 ankle sprains, the foot turns inwards, causing the outer (lateral) ligaments to become overstretched. The result is a sprained ankle, which can cause severe pain.

This can happen during everyday activities, such as walking on uneven ground or during exercise. It can also be the result of a direct blow to the ankle e.g when falling, playing sports or if you are involved in an accident.

A sprained ankle can be graded according to how severe it is:

Grade 1 — a mild sprain; your ligament has been overstretched a little, but your joint is still stable
Grade 2 — a moderate sprain; your ligament has been overstretched to the point where it has torn (ruptured) a bit, but your joint is still stable
Grade 3 — a severe sprain; your ligament has been overstretched to the point where it has completely torn, and your joint is not stable

When to consider an X-ray for a sprained ankle

If you think you have badly sprained your ankle and are in pain, get medical advice and see your GP. They will determine whether or not you need an X ray based on your symptoms.

If you are in intense pain and cannot bear weight on your ankle, seek medical attention by visiting A&E (the emergency department).

Any of the symptoms below may suggest that you need an X ray:

A visible deformity in your ankle e.g if it is bent at an odd angle
An inability to bend or move your ankle
Intense pain when weight bearing
Severe or worsening bruising, pain or swelling

These painful symptoms suggest that you may have an ankle fracture – a broken bone in your ankle joint – instead of a sprained ankle. Ankle fractures need different treatment to ankle sprains in order to heal fully.

An ankle X ray can help detect an ankle fracture, although some very small fractures may not be visible on an X ray.

How do X-rays work?

An X ray uses low amounts of radiation to make images of the tissues in your body. They are a quick, cost-effective way to investigate bone fractures.

During an X ray, a beam of rays will be passed painlessly through your body. Some X-rays will be absorbed by your body. Those that pass through will be picked up by an X-ray detector. These signals are sent to a computer and processed to form a 2D digital image.

More dense tissues, such as bones, absorb more X-rays and so appear brighter and whiter on an X ray. Less dense tissues absorb fewer X-rays and appear in shades of grey. Areas filled by air appear black as they absorb very few X-rays.

To avoid unnecessary exposure to X-rays, your doctor will only recommend having an X ray if there is a clear need. An X ray of your ankle will expose you to about the same amount of radiation that you are exposed to from the environment in 3 hours or less.

After your X ray, you can immediately return to your usual activities.

Treatment for a sprained ankle: self care measures

You may recall being advised on the use of hot and cold treatments for muscle aches and sprains in the past. Latest research indicates that heat packs or hot baths should not be used as home treatments for new injuries. High temperature can increase swelling, which will slow down your recovery.

For 2-3 days after your sprain, make sure you wear an ankle support and/or shoes that support your ankle and provide good cushioning for the soles of your feet. To prevent further damage, rest when possible, avoid playing sports or taking part in activities that strain your ankle and refrain from putting weight on your injured ankle.

Every 2-3 hours, use a cold compress ie place an ice pack or a bag of frozen vegetables wrapped in a tea towel against your ankle for 20 minutes or less. You can also wrap a bandage around your ankle to support it – avoid wrapping the injured area too tightly as this can reduce blood supply to your ankle and interfere with healing.

Finally, whenever possible, raise your ankle above the level of your heart. This will help to reduce swelling or even prevent swelling from happening. If needed, take over-the-counter painkillers (eg paracetamol or ibuprofen tablets) and/or apply ibuprofen gel.

Alternatives to X-rays for ankle injuries

An X ray is usually the first imaging test considered if a healthcare professional suspects that you have fractured your ankle. However, if damage to the soft tissues is suspected, your doctor may recommend other imaging tests to assess the extent of the damage.

For example, ultrasound is often used as a quick, cost-effective test to investigate musculoskeletal conditions. This is because it creates live images of your muscles, ligaments and tendons.

Ultrasound can be particularly helpful for ankle injuries as your doctor can assess how your tissues respond when you move your foot. This is not possible with other imaging tests where you need to remain still.

An MRI scan or CT scan may be used if a bone fracture is suspected but was not detected by an ankle X ray. This is because both MRI and CT produce higher resolution images than an X ray. They also create 3D images rather than 2D images. This allows your doctor to examine the tissues in your ankle joint from multiple angles.

CT or MRI may be used if your ankle injury is not improving despite treatments such as rest, applying a cool compress, physiotherapy and gentle exercises. MRI can also help diagnose more complex ankle injuries, such as nerve damage or a high ankle sprain (syndesmosis).