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What Is an Ankle Sprain?

An ankle sprain refers to tearing of the ligaments of the ankle. The most common ankle sprain occurs on the lateral (outside) part of the ankle. There's a good chance you may have sprained your ankle at some point while playing sports or stepping on an uneven surface — some 25,000 people sprain their ankle every day! It can happen in the setting of an ankle fracture (when the bones of the ankle also break). Most commonly, however, it occurs as a separate injury.


Patients report pain after having twisted an ankle. This usually occurs due to an inversion injury, which means the foot rolls inward and underneath the ankle or leg. It commonly occurs during sports but also happens frequently with day-to-day activities such as walking down the stairs.

After a sprain, you may feel pain on the outside of your ankle and experience various degrees of swelling and bruising. Depending on the severity of the sprain, you may or may not be able to put weight on the foot. While people often say, "if I can walk on my ankle, it isn't broken," this does not always hold true.


As noted above, ankle sprain injuries occur when the ankle is twisted underneath the leg, called inversion. Risk factors are activities, such as jumping/cutting sports like basketball and soccer, in which an athlete can come down on and turn the ankle or step on an opponent's foot. 

Some people are predisposed to ankle sprains. These injuries are more common in people with a high arched foot. This is because it is easier to turn on the ankle.

In those who have had a severe sprain in the past, it is also easier to turn the ankle and sustain a new sprain. Therefore, one of the risk factors of spraining the ankle is a history of a previous sprain or instability (looseness in the ankle). Those who have weak muscles, especially the peroneals that run along the outside of the ankle that provide muscular support to the ankle, may be more predisposed.


There are multiple ligaments in the ankle. Ligaments in general are the structures that connect bone to bone. Tendons, on the other hand, connect muscle to bone and allow the muscles to exert force on their associated bones. In the case of an ankle sprain, there are several commonly sprained ligaments. The two most important are the following:

  1. The anterior talofibular ligament (ATFL), which connects the talus to the fibula on the outside of the ankle.

  2. The calcaneal fibular ligament (CFL), which connects the fibula to the calcaneus.

There is a third ligament that is not torn as commonly. It runs more in the back of the ankle and is called the posterior talofibular ligament (PTFL). 

Ankle Ligaments

Injuries to the above ligaments must be differentiated from the high ankle sprain, which is a more severe type of ankle sprain involving ligaments that connect the tibia (long bone on the inside of the leg) to the fibula (bone on the outside of the leg).


Ankle sprains usually can be diagnosed with a physical exam and X-rays. Pain on the outside of the ankle, tenderness and swelling, and an ankle with an inversion-type injury may indicate a sprain. In these patients, normal X-rays also suggest that the bone has not been broken and instead the ankle ligaments have been torn or sprained. 

It is very important, however, not to simply regard any injury as an ankle sprain. Other injuries can occur as well. For example, the peroneal tendons can be torn. Achilles tendon tears are sometimes thought to be ankle sprains and go untreated. There also can be fractures in other bones around the ankle, including the fifth metatarsal or the calcaneus (heel bone). See a foot and ankle orthopaedic surgeon in your area for a thorough examination.

In very severe cases, an MRI may be useful to rule out other problems in the ankle such as damage to the cartilage. An MRI typically is not necessary to diagnose a sprain and is reserved for patients who are slow to recover and do not follow the normal progression of healing.


Surgery is not required in the vast majority of ankle sprains. Even in severe sprains, these ligaments will heal without surgery if treated appropriately. The grade of the sprain will dictate treatment. Sprains are traditionally classified into Grade 1 (mild), Grade 2 (moderate), and Grade 3 (severe) injuries. Perhaps more important, however, is the patient's ability to bear weight. Those that can bear weight even after the injury are likely to return very quickly to normal activities. Those who cannot walk may need to be immobilized. 

Treating your sprained ankle properly may prevent chronic pain and instability. For a Grade 1 sprain, follow the R.I.C.E. guidelines:

  • Rest your ankle by not walking on it until you can do it comfortably (this may require a boot brace or lace up brace).
  • Ice it to keep the swelling down. Don't put ice directly on the skin (use a thin piece of cloth between the ice bag and skin) and don't ice more than 20 minutes at a time to avoid frostbite.
  • Compressive bandages help to immobilize and support your injury.
  • Elevate your ankle above your heart level for 48 hours. The swelling usually goes down within a few days.

For a Grade 2 sprain, follow the R.I.C.E. guidelines and allow more time for healing. A doctor may immobilize or splint your ankle.

While a Grade 3 sprain takes longer to heal and may require a longer period of immobilization, they almost always heal. Surgery rarely is needed to repair the damage, but may be beneficial for patients who experience chronic ankle instability (a loose ankle that often gives out even when not participating in sports or high-impact activities). This surgery involves a ligament reconstruction. For severe ankle sprains, your doctor may consider treating you with a tall walking boot or cast for several weeks.

Severe ligament injuries often require rehabilitation. The goals of therapy are to allow for optimal healing of the ligaments, return to sport/work as quickly as possible, and prevent re-injury.


There are 3 phases of recovery:

  • Phase 1 includes resting, protecting, and reducing swelling of your injured ankle.
  • Phase 2 includes restoring your ankle's flexibility, range of motion, and strength.
  • Phase 3 includes gradually returning to straight-ahead activity and doing maintenance exercises, followed later by sport-specific exercises (e.g., sprinting and cutting).

Once you can stand on your ankle again, your doctor will prescribe exercise routines to strengthen your muscles and ligaments, and increase your flexibility, balance, and coordination. Later, you may walk, jog, and run figure-eights with your ankle taped or in a supportive ankle brace.

It's important to complete the rehabilitation program because it makes it less likely that you'll hurt the same ankle again. If you don't complete rehabilitation or if your ligament heals in a stretched-out position and cannot perform its normal function, you could suffer chronic pain, instability, and arthritis in your ankle. If your ankle still hurts, it could mean that the sprained ligament or ligaments have not healed right, or that some other injury occurred at the time of the ankle sprain (e.g., cartilage damage or tendon injury).

To prevent future ankle sprains, pay attention to your body's warning signs to slow down when you feel pain or fatigue, and stay in shape with good muscle balance, flexibility, and strength.

What is a high ankle sprain? Is that different from a regular ankle sprain?

A high ankle sprain refers to tearing of the ligaments that connect the tibia to the fibula (this connection is also called the syndesmosis). These are different and much less common, but often more debilitating, than the standard lateral ankle sprains, meaning those that occur on the side of the ankle. 

Do ankle sprains need to be treated with surgery?

Ankle sprains rarely, if ever, needed to be treated with surgery. The vast majority simply need to be treated with rest, ice, compression, and elevation followed by physical therapy and temporary bracing. 

I have sprained my ankle many times. Should I be concerned?

The more you sprain an ankle, the greater the chance that long-term problems will develop. For example, turning the ankle can lead to damage to the cartilage inside the ankle joint. You should see your foot and ankle orthopaedic surgeon if this is occurring.


Contributors/Reviewers: Jason Tartaglione, MD; Eric Tan, MD; Robert Leland, MD

The American Orthopaedic Foot & Ankle Society (AOFAS) offers information on this site as an educational service. The content of FootCareMD, including text, images, and graphics, is for informational purposes only. The content is not intended to substitute for professional medical advice, diagnoses or treatments. If you need medical advice, use the "Find a Surgeon" search to locate a foot and ankle orthopaedic surgeon in your area.