If you twist your ankle, it may swell up and hurt. This is usually a sign that the ankle is sprained. In other words, one or more ankle ligaments and the surrounding tissue are injured. Ankle sprains are among the most common injuries.
Ligaments are tough elastic bands of connective tissue that join bones in the joint to each other. Because the ankle joint is made up of many bones, there are also several ligaments that stabilize it.
When an ankle is twisted, the ligaments are overstretched. In the worst case, they might tear. Small blood vessels tear too, which is what causes the swelling around the ankle.
The following grades of severity are used to describe sprains:
- Mild sprain (grade I): This is the most common and least severe form. The ligaments are stretched but not torn. The ankle is still stable.
- Moderate sprain (grade II): This injury is more severe and more painful, and one or more ligaments are partially torn. The joint is somewhat unstable, movement is limited.
- Severe sprain (grade III): One or more ligaments are torn and the ankle is unstable. It's hardly possible to move the foot at all.
If you can put weight on your foot and walk immediately after having twisted your ankle, it's very unlikely that you have broken anything. If the ligaments have only been slightly stretched, you can usually move your foot normally again after a few days. But even minor ankle sprains can be painful.
Foot bones (outer side) with grade I, II and III sprains
Our ankle joints make it possible for us to move our feet upwards, downwards and sideways. Our feet tend to turn inwards rather than outwards, so your ankles are more likely to twist inwards if, for instance, you land awkwardly on your foot after jumping. That may injure the ligaments that run along the outside of the ankle (outer or “lateral” ligaments). The ligaments on the inside of the ankle (inner or “medial” ligaments) are less likely to be overstretched.
Some people have very weak ligaments and are therefore more likely to have sprains. The same is true of people with a high foot arch or muscle weakness. Athletes have a greater risk too: One quarter of all sports injuries are torn outer ankle ligaments. They often occur in people who play sports like volleyball, basketball or soccer.
Most ankle sprains without torn ligaments will have largely healed after two weeks: Even if you aren't able to put your full weight on the foot, it usually won't hurt much anymore.
If ligaments are torn or partially torn, it can take weeks for the ankle to return to normal. In some people who have more serious ligament injuries, it can even take two to three years for the ankle to become as strong and as mobile as before.
If you have already sprained your ankle once, you are at greater risk of spraining it again over the next few years. The risk is particularly high when a lot of strain is put on the joints – for instance, while playing soccer or basketball.
In about 1 to 2 out of 10 people who have a severe ankle sprain, the ankle remains permanently (chronically) unstable. This means that the joint still gives way too easily six months after the sprain has occurred. People who have a chronically unstable ankle are more likely to twist and sprain their ankle again.
Chronic ankle instability and frequent twisting and spraining can also increase wear and tear on the cartilage in the ankle joint. Cartilage is the smooth tissue that covers and protects joints. Too much damage to the cartilage may lead to osteoarthritis.
The doctor will first ask you about how the accident happened and any symptoms that you have. Then he or she will examine your foot and check how severe the injury is. The foot may also be x-rayed in order to rule out a possible fracture (break).
If the ankle sprain symptoms do not improve considerably after a few days, you might have a torn ligament. An MRI scan (magnetic resonance imaging scan) may be done too. This is because it is often easier to see ligaments and surrounding tissue better with MRI scans than with x-rays.
Some people wear bandages or ankle braces when they do sports, to try to stabilize their ankle and prevent further injuries.
Strength and coordination exercises are particularly suitable for preventing chronic ankle instability. To effectively stabilize the structures of the joint, these exercises typically need to be done for weeks or even months. Common exercises include training on a balance board (a board that easily tips sideways) – for example, while standing on one leg. You try to keep your balance while reacting to the tipping of the board. Your foot has to act against various strains and movements, which helps to strengthen the muscles and increase the stability of the ankle.
Sprained ankles swell up quickly, and start to hurt just as fast. The first things you can do to reduce pain and swelling include keeping your foot elevated, cooling the ankle, and wrapping it in a compression bandage to put gentle pressure on it. These measures are usually enough to relieve mild ankle injuries.
After a few days, the foot can be stabilized if necessary by bandaging it tightly or using a splint. If there is a lot of swelling, it may also be a good idea to wear a plaster cast for a short time.
There are good reasons to start doing gentle exercises early on, and not keep your foot still for too long. Surgery is rarely needed, even for ankle sprains with one or more torn ligaments.
When people are ill or need medical advice, they usually go to see their family doctor first. Read about how to find the right doctor, how best to prepare for the appointment, and what to remember.
De Vries JS, Krips R, Sierevelt IN, Blankevoort L, van Dijk CN. Interventions for treating chronic ankle instability. Cochrane Database Syst Rev 2011; (8): CD004124.
Kerkhoffs GM, Handoll HH, de Bie R, Rowe BH, Struijs PA. Surgical versus conservative treatment for acute injuries of the lateral ligament complex of the ankle in adults. Cochrane Database Syst Rev 2007; (2): CD000380.
MacAuley D, TM. B. Evidence-based sports medicine. London: 2007.
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