Lateral Ankle Ligament Sprains: Symptoms & Treatment

What are the Lateral Ligaments in the Ankle?

The Ankle-Joint Complex consists of a triform structure that includes the talocrural, distal tibiofibular, and subtalar joints. This complex is responsible for absorbing and distributing the shock forces that occur during any weight bearing task. [1]

The talocrural joint is responsible for plantarflexion and dorsiflexion– pointing and flexing motions of the foot– and is stabilized by the medial and lateral ligaments.

More specifically, the lateral ankle ligament complex is composed of the anterior talo-fibular ligament (ATFL), the posterior talo-fibular ligament (PTFL), and the calcaneo-fibular ligament (CFL). These three ligaments work together to prevent the ankle from inversion.

What is a Lateral Ankle Ligament Injury?

A lateral ligament injury of the ankle is one of the most common musculoskeletal injuries, with an estimated 23 000 ankle sprains occurring every day in the United States. [2]

This type of injury is also commonly referred to as an inversion sprain or lateral ankle ligamentous sprain (LAS). [3] 

The majority of ankle sprains involve the lateral ligament complex and result from forced internal rotation or inversion of the ankle during plantarflexion–the most unstable position of the ankle joint.

Since the ATFL is the weakest of the three ligaments, it is involved in almost every lateral ankle injury, whereas the CFL is only implicated in 50 to 75% of cases and the PTFL in 10%. [4]

While LAS are not particularly dangerous by themselves, they often go untreated and can lead to more serious residual symptoms, like chronic pain and weakened muscles.

Furthermore, individuals who have sustained a LAS are more likely to re-injure their ankle than those who have not. 

Typically, lateral ankle ligament injuries are graded based on the degree of damage to the ankle ligaments.

A Grade I sprain indicates a stretched ligament that may have very small tears; a Grade II sprain suggests a partially torn ligament; and a Grade III sprain designates a completely torn ligament. [5]


Depending on the severity of the ligament injury, patients will experience varying levels of pain, swelling, and discoloration on the outside of the ankle.

With a stretch injury, patients can expect minimal swelling and soreness on the outer ankle. Generally, they will only experience pain if full body weight is applied to the ankle.

When a lateral ankle ligament is partially torn, there will be even more inflammation, pain, and discoloration. The pain will be even more severe and individuals will likely struggle to bear any weight on the injured ankle.

In the case of a completely torn ligament, swelling and discoloration may develop on the inside of the ankle as well as the outside. Patients may not be able to put their foot down as any movement of the foot or ankle could be very painful. [5] By contrast, other patients with torn ligaments have reported minimal pain. [3]

Causes and Risk Factors

LAS often result from a forced or sudden inversion of the ankle, causing the lateral ankle ligaments to stretch or tear. These injuries are predominantly sports-related and result from either direct contact, indirect contact, or no contact at all.

In a direct-contact injury, contact from another person interferes with the foot during placement, causing the ankle to roll forward and outwards.

By contrast, the lateral ligaments can be damaged indirectly when an object hinders the way the foot comes into contact with the ground, creating uneven force distribution across the foot.

Alternatively, injuries can occur from functional activity and be entirely independent of outside obstacles. [1] 

While a lateral ankle ligament injury usually occurs haphazardly, there are several intrinsic factors that increase an individual’s risk of injury. These include high body mass index, limited range of motion in the ankle, decreased ankle muscle strength, poor static postural stability, and delayed muscle reaction time. [3]

Because these factors can also result from an ankle injury, individuals that have already injured their ankle have an increased likelihood of reinjury or chronic ankle instability. 

Furthermore, because the majority of LAS are sustained in recreational activities and competitive sports, athletes have a significantly higher risk than sedentary individuals.

More specifically, athletes who play sports requiring quick changes in direction, like basketball or tennis, are the cohort most likely to develop a LAS.

Diagnosis and Assessment

A lateral ankle injury is diagnosed based on patient medical history, patient input, a physical examination of the ankle and foot, and sometimes imaging tests.

Physicians often start with the patient’s medical history to determine if any previous injuries or medical conditions are relevant to the current injury. They will ask for an account of the injury to establish which joints and ligaments may have been involved.

Next, they will assess the ankle and foot, beginning with a general observation of inflammation, discoloration, bony protrusions, or obvious changes in muscle mass. The ankle will also be examined in non-weight bearing and weight-bearing positions to assess the grade of the sprain, ankle stability, and range of motion. [3]

Lastly, light palpation of the ankle is necessary to determine precisely where the injury and pain are located.

Other tests may be conducted to assess the integrity of the lateral ligaments and proprioception, including the Anterior Drawer Test and talar tilt.

If the injury appears more serious or if symptoms do not improve after 6 weeks, X-ray or MRI imaging tests may be used to scan for other serious injuries, such as ankle fractures, medial ligament injuries, ankle dislocations, and soft tissue damage.

Treatment and Home Remedies

Regardless of the severity of sprain, ankle lateral ligament injuries should be treated with the RICE method –Rest, Ice, Compression, and Elevation– within the first several days to reduce pain and swelling.

Resting the foot will prevent further strain and tearing of the injured ligament; Ice will stimulate blood flow and help alleviate ankle pain; Compression will stabilize the ankle and allow the lateral ligaments to rest; and Elevation will reduce swelling, pain, and discomfort.

However, pain medication with anti-inflammatory properties is highly discouraged as some inflammation is necessary to heal the ankle ligament injury. [5] 

Orthotic devices are also frequently recommended to stabilize the ankle while enabling partial weight-bearing. The nature and duration of immobilization will differ based on the severity of LAS.

Stretch injuries can usually be treated conservatively with an ankle brace to partially immobilize the ankle and reduce stress on the ligaments. Braces should be worn for a few weeks or until the ankle regains full range of motion and strength.

For partial tears, the ankle may need to be immobilized for two to four weeks with a walking boot and night brace. The boot allows the patient to bear weight while immobilizing and protecting the ankle ligaments as they heal. Ankle braces may be worn at night to keep the foot at a 90º angle and limit strain on the ligaments. [5]

With a Grade III sprain, patients typically require four weeks of cast immobilization. Patients may begin weight-bearing activity with a cast or boot as soon as they can do so without pain. 

Following orthotic immobilization, patients are encouraged to begin a gentle massaging and stretching of the ankle, if pain allows. Physical Therapy exercises are intended to restore the ankle’s normal range of motion, mobility, strength and proprioception.

If necessary, patients may require continued use of orthotic devices to prevent chronic instability or excessive strain on the joints and ligaments. [5]

What exercises are recommended for the rehabilitation of lateral ankle ligament injuries?

As soon as pain and inflammation subside, patients should begin with range of motion or “ROM” exercises.

These can include various towel stretches, slow ankle circles, pointing and flexing of your toes, and lateral movements with a resistance band. Once the ankle has regained some mobility and stability, patients may include more balancing and proprioceptive exercises.

These exercises can be as simple as standing on one leg or can progress to balancing on unstable surfaces while performing an additional task. [6] Physical therapy exercises will be most effective if performed regularly. 

How long before normal physical activity can be resumed?

Recovery will depend on the severity of the injury and how well the body responds to rehabilitative treatment.

Before returning to regular physical activity, the ankle should have normal range of motion, strength, and proprioception. Twisting and hopping movements should be pain-free. [3]

On average, patients with Grade I sprains are able to resume functional activity after two to three weeks, whereas Grade II sprains will require three to four weeks of recovery, and Grade III sprains up to six weeks. [5]

If symptoms persist past six weeks, this may be an indication of more serious injury. 


While it may not be possible to prevent lateral ligament sprain, there are measures that can be taken to decrease the risks of injury and reinjury. Two of the most effective prevention techniques include prophylactic orthotic supports and physical therapy exercises.

Just as orthotic immobilization devices serve to stabilize the ankle ligaments as they heal, ankle taping and bracing are thought to provide mechanical support by preventing overextension and excessive stress on the joint stabilizers.

External supports are particularly effective in ensuring the ankle does not exceed its normal range of motion.

Preventative exercises are also valuable for improving range of motion and strengthening the stabilizing ligaments in the ankle. These exercises commonly include foot stretches, single-limb balancing exercises, muscle strengthening with resistance bands, and agility training. [6]

For athletes, it is highly recommended to warm up before starting sports activities as this increases blood flow to muscles, reducing the risk of muscle soreness and injuries.

Footwear is another factor that can reduce the risk of lateral ankle ligament injuries. Individuals should wear athletic shoes with good arch support and cushioning to ensure forces are distributed evenly across the foot.

This is especially important when physical activity is being performed on uneven surfaces. Additionally, patients should avoid high heels or other shoes that put unnecessary strain on the ankle ligaments. [5]


  1. McKeon, Jennifer M, and Matthew C Hoch. “The Ankle-Joint Complex: A Kinesiologic Approach to Lateral Ankle Sprains.” Journal of Athletic Training, National Athletic Trainers Association, June 2019,
  2. Kannus, P, and P Renström. “Treatment for Acute Tears of the Lateral Ligaments of the Ankle. Operation, Cast, or Early Controlled Mobilization.” The Journal of Bone and Joint Surgery, U.S. National Library of Medicine, Feb. 1991,
  3. Malkauskaite, Ilona, et al. “Lateral Ligament Injury of the Ankle.” Physiopedia,
  4. Ferran, Nicholas Antonio, and Nicola Maffulli. “Epidemiology of Sprains of the Lateral Ankle Ligament Complex.” Foot and Ankle Clinics, Elsevier, 10 Sept. 2006,
  5. Sheinberg, Robert H. “Ankle Ligament Injuries – Podiatry, Orthopedics, & Physical Therapy.” South Florida Institute of Sports Medicine – Podiatry, Orthopedics, & Physical Therapy,
  6. Kaminski, Thomas W, et al. “Prevention of Lateral Ankle Sprains.” Journal of Athletic Training, National Athletic Trainers Association, June 2019,

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