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Usually, ankle sprains occur when people walk or run on uneven ground and the foot turns in, stretching the ligaments of the ankle beyond their limits and tearing them.
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Typically, the ankle is swollen, and walking is painful.
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Doctors can usually diagnose ankle sprains based on the physical examination and sometimes x-rays.
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Treatment usually includes PRICE (protection, rest, ice, compression with a bandage, and elevation of the leg) for mild sprains, immobilization and physical therapy for moderate and severe sprains, and sometimes surgery for very severe sprains.
In the United States, about 25,000 ankle sprains are reported each day.
The ankle joint consists of the shinbone (tibia), smaller leg bone (fibula), ankle bone (talus), and several ligaments, which hold the bones of the ankle in place (see figure Ligaments: Holding the Ankle Together).
The severity of the sprain depends on which ligaments are injured and how badly they are stretched or torn. Based on severity, doctors classify sprains as
Most ankle sprains are mild.
Sprains usually occur when the foot turns in, causing the sole of the foot to face the other foot (called inversion). This injury usually damages the ligaments on the outside of the ankle. Inversion can occur when people walk on uneven ground, especially when they step on a rock or off the edge of a curb.
Less commonly, the ankle is sprained when the foot turns out (called eversion).
When the foot turns out, several other injuries may occur:
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An avulsion fracture: The ligament that attaches the shinbone (tibia) to one of the foot bones on the inside of the ankle may pull a small piece of bone off the shinbone. Turning the foot out tends to cause an avulsion fracture rather than a sprain because this ligament is so strong.
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A high ankle sprain: The ligaments that hold the shinbone and the other lower leg bone (fibula) together at their lower ends may be torn.
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Fracture of the fibula: The fibula may be broken at the ankle or sometimes near the knee.
When the ankle is sprained, nerves may also be damaged.
Certain conditions tend to cause the foot to turn (or ankle to roll) out and thus increase the risk of a sprain:
Symptoms
In general, the area over the injured ligament is painful and swollen. Sometimes people with a sprained ankle have muscle spasms—unintended contraction of muscles around the ankle.
How severe symptoms are depend on the severity of the tear. If nerves are damaged, people may have problems sensing where their foot and ankle are without looking at them (a sense called proprioception).
Mild
Moderate to severe
Very severe
Ligaments tear completely. The whole ankle may be swollen and bruised. The ankle is unstable, and people cannot put any weight on it.
Healing usually takes 6 to 8 weeks. If people do not wait until their ankle is healed completely before they resume their usual activities, they increase their risk of future injuries, and the ankle may not heal well.
Nerves may also be damaged.
Very severe ankle sprains may fracture the cartilage at the ends of the bones in the ankle joint. This injury can result in long-term pain, swelling, and occasionally problems walking. The joint may catch (stick) or give way (involuntarily buckle). Sometimes arthritis develops in the ankle at a young age.
Diagnosis
Doctors ask how the injury occurred and do a physical examination.
Moving the ankle joint in various ways is necessary to determine how severe the sprain is. However, if a person has a lot of pain and swelling or muscle spasms, the examination is usually postponed until x-rays are done to check for fractures.
To evaluate the ankle, doctors gently touch the ankle to determine where the pain is most intense. If touching the skin over a ligament causes intense pain, the ligament is probably torn. If touching the skin over a bone causes pain, the bone may be fractured. Swelling and spasms make evaluating the ankle difficult. In such cases, doctors may immobilize the joint with a splint and examine the joint again several days later.
Doctors can usually diagnose sprains based on results of the examination. However, doctors sometimes take x-rays to check for a fracture when
Magnetic resonance imaging (MRI) may be done to check for other injuries, particularly if the ankle is still painful after 6 weeks of treatment with protection, rest, ice, compression, and elevation (PRICE).
Treatment
Treatment may include PRICE, as well as acetaminophen for pain control. Crutches are used for all sprains until people can walk normally.
Mild sprains
Most ankle sprains are mild, require no special treatment, and heal well.
PRICE is recommended. It involves the following:
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Protection: Support of the ankle with an elastic bandage, a splint, a specially designed boot, or a cast depending on how severe the sprain is
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Rest: Not walking on the injured ankle and using a crutch to walk when necessary
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Ice: Putting ice packs on the injured ankle
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Compression: Compressing the ankle by wrapping it and the foot with an elastic bandage or tape
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Elevation: Elevating the ankle as much as possible
Acetaminophen is usually used to relieve pain.
Most people can begin to walk and exercise immediately as long as they wear supportive footwear.
Moderate sprains
Moderate sprains may be treated with PRICE. If walking is extremely difficult, a splint or boot can be worn for support. Most people can begin to walk and exercise within a few days.
Physical therapy is needed to help minimize swelling, maintain the joint's range of motion, and gradually strengthen the muscles around the ankle (and thus prevent future sprains).
Severe sprains
Severe sprains require immediate medical attention. Without treatment, the ankle may remain unstable and painful.
The ankle is immobilized in removable cast or boot. Most people are referred to a specialist.
Whether surgery should be done is controversial. Most experts believe that surgically reconstructing torn ligaments is no better than treatment without surgery.
Physical therapy to restore movement, strengthen muscles, and improve balance is necessary before people resume strenuous activity. Physical therapy can also speed recovery.
