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 that while playing sports as a child or stepping on an uneven surface as an adult you sprained your ankle—some 25,000 people do it every day. It can happen in the setting of an ankle fracture (i.e., when the bones of the ankle also break). Most commonly, however, it occurs in isolation.

Symptoms

Patients report pain after having twisted an ankle. This usually occurs due to an inversion injury, which means the foot rolls underneath the ankle or leg. It commonly occurs during sports. Patients will complain of pain on the outside of their ankle and various degrees of swelling and bruising. Depending on the severity of the sprain, a person may or may not be able to put weight on the foot.

Causes

As noted above, these 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. 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.

Anatomy

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:Ligaments in the ankle

  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). 

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).

Diagnosis

Ankle sprains can be diagnosed fairly easily given that they are common injuries. 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 because other injuries can occur as well. For example, the peroneal tendons can be torn. There also can be fractures in other bones around the ankle, including the fifth metatarsal or the calcaneus (heel bone). In very severe cases, an MRI may be warranted 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.

Treatments

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 I (stretched ligament), Grade II (partially torn ligament), and Grade III (completely torn) 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 I 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.
  • Compressive bandages 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 II sprain, follow the R.I.C.E. guidelines and allow more time for healing. A doctor may immobilize or splint your ankle.

A Grade III sprain puts you at risk for permanent ankle instability, especially if not treated appropriately. Surgery rarely is needed to repair the damage, but may be common in competitive athletes who want an expedited recovery and patients who experience chronic ankle instability (a loose ankle that often gives out even when not participating in sports or high-impact activities). 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.

Recovery

There are 3 phases of recovery:

  • Phase I includes resting, protecting and reducing swelling of your injured ankle.
  • Phase II includes restoring your ankle's flexibility, range of motion and strength.
  • Phase III 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 in your soft tissues.

FAQs

What is a high ankle sprain and 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 than the standard lateral ankle sprains, meaning those that occur on the side of the ankle. 

Do ankle sprains ever need to be repaired acutely?
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 problems will develop. For example, turning the ankle can lead to damage to the cartilage inside the ankle joint. You should see your doctor if this is occurring.

 

Last reviewed by Jason Tartaglione, MD, 2018

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