Lateral Ankle Sprain: A Calm, Practical Guide to Quick Response

A-Che is an athlete who loves to run. One day, while jogging in the park, he accidentally stepped on uneven ground and… “Ah!” His ankle rolled in an instant.

Did you know? A lateral ankle sprain is one of the most common sports injuries, and it doesn’t only happen to athletes; anyone can experience one.

Basic Overview

• Compared with the medial side of the ankle, which has the broad, strong deltoid ligament as a restraint, the lateral side of the ankle has several smaller ligaments acting as a static stabilizing system.

• The main ligaments on the lateral side of the ankle:

• Anterior talofibular ligament (ATFL): runs from the tip of the fibula across the lateral side of the talar neck; it becomes taut in plantarflexion and is injured most often.

• Calcaneofibular ligament (CFL): runs downward and backward from the tip of the fibula across the lateral side of the calcaneus; usually injured after the ATFL.

• Posterior talofibular ligament (PTFL): runs backward from the fibula across the talus; less often injured.

Epidemiology

• Lateral ankle sprains are the most common injury in athletes, accounting for about 14% of all sport-related injuries; more than 80% of sprains are caused by an inward-rolling (inversion) movement of the lateral ankle ligaments.

• These ligaments are injured in a sequential manner as extreme inversion and plantarflexion forces are applied to the ankle. The ATFL is injured first (an isolated ATFL injury occurs in about two-thirds of cases); after the ATFL is mildly injured, the CFL then takes on tension and is injured, followed by the PTFL, and the ankle joint capsule can also be sprained during an inversion injury.

• An isolated CFL injury is uncommon.

Risk Factors

• Athletes (especially those in sports involving jumping and rapid cutting movements, such as basketball, soccer, and rugby)
• Dancers
• Congenital tarsal coalition
• A previous history of ankle injury

Diagnosis

Ankle sprain grading:

• Grade 1: Ligament stretch without laxity; weight-bearing pain is minimal.
• Grade 2: Partial ligament tear, mild weight-bearing pain, swelling and bruising, increased ankle laxity, but a stable end-feel on range of motion.
• Grade 3: Complete ligament rupture, severe weight-bearing pain with swelling and bruising, and marked ankle laxity.

Physical Examination

• Palpation

  • Check for bruising and diffuse swelling around the ankle joint.
  • Ligament tenderness, to identify which ligaments are injured.
  • The anterior ankle joint and talar dome, with the foot fully plantarflexed, help diagnose other forms of injury, such as an osteochondral defect.
  • Palpate the medial and lateral malleoli and the base of the fifth metatarsal to check for a possible fracture.
  • In an ankle ligament injury, force can be transmitted to the distal tibiofibular syndesmosis, causing a syndesmotic injury, also known as a high ankle sprain.
  • Feel the distal pulses and manually test the appropriate muscle groups to assess neurovascular status.

• Anterior drawer test

  • Tests the stability of the ATFL; performed by holding the distal tibia and pulling the heel forward. Laxity relative to the opposite side indicates an ATFL tear.
  • The anterior drawer test of the ankle has relatively poor sensitivity and specificity.

• Inversion test

• Tests the stability of the CFL; performed by holding the distal tibia and moving the foot from neutral into inversion. Increased laxity compared with the opposite side (more than 15 degrees) suggests a possible CFL tear.

Diagnostic Tools

• X-ray: can be arranged based on the Ottawa ankle rules, including anteroposterior, lateral, and mortise views to rule out a fracture (weight-bearing if possible).

• Ottawa ankle rules: inability to bear weight, tenderness within six centimetres above the medial or lateral malleolus, tenderness over the fifth metatarsal, or tenderness over the ankle navicular; any one of these can prompt an X-ray, with a sensitivity of 96-99% for ruling out an ankle fracture.

• Other views such as the external rotation (ER) stress view and the varus stress (talar tilt) view are used to confirm instability.

• Ultrasound: the extent of lateral ligament injury can be confirmed by ultrasound, and its ability to diagnose ligament injury currently differs little from MRI.

• CT: to assess an occult fracture.

• MRI: rarely used for ankle sprains; it may help assess ligament integrity in chronic ankle instability, or evaluate an osteochondral defect that is not obvious on X-ray, and can be considered if pain persists for 6-8 weeks after a sprain without clear improvement.

Differential Diagnosis

• Tibia fracture (shaft, malleolus, etc.)
• Pilon fracture
• Fibula fracture (malleolus, Maisonneuve)
• Avulsion fracture
• Osteochondral defect in the talar dome / tibial plafond
• Anterior ankle impingement
• Os trigonum syndrome
• Talus fracture
• Calcaneal fracture
• Peroneal subluxation
• Bimalleolar / trimalleolar fracture

First-Line Treatment

• Short-term anti-inflammatory medication (NSAIDs) or local corticosteroid injection.
• Prolotherapy: for injured ligaments it may help ease pain and stimulate repair, though current evidence is limited; a recent study used a neurofascial prolotherapy injection approach to improve chronic ankle instability.
• PRP treatment: recent studies support that PRP injection was associated with faster improvement in pain and function, but it is not a cure-all; in practice, whether it is needed should be decided after an assessment.
• Stage 1 includes a RICE protocol to improve pain and swelling (usually weeks 1 to 2).
  • Initial treatment focuses on the PRICE protocol (Protection [support], Rest, Ice, Compression, Elevation) to reduce pain and swelling.
  • Crutches can be used until the patient can tolerate bearing weight.
  • Electrical stimulation and iontophoresis may play a role in controlling pain and swelling.
• Stage 2 includes progressive range-of-motion exercises, increasing activity and reducing swelling. Patients should continue using a protective brace when walking to prevent further injury. During this phase (weeks 2 to 4), patients should work toward full weight-bearing.
  • Crutches can be used until the patient can tolerate bearing weight. Depending on the situation, assistive devices, a compression device, or a walking boot can be used to provide protection and support while encouraging walking.
  • Patients should be advised to begin gentle exercise as soon as pain allows.
  • For severe sprains, short-term non-weight-bearing immobilization with a cast or walking boot for about 10-14 days can be considered.
• Stage 3 begins more active strengthening and rehabilitation exercises; specifically, patients should train proprioception and endurance (weeks 4 to 6).

Advanced treatment:

• Surgical considerations: severe laxity of the lateral ankle leading to repeated ankle injury may require ligament repair or ankle reconstruction to improve stability.

Possible Complications

• Joint stiffness from prolonged immobilization
• Recurrent joint instability
• Osteochondral injury
• CRPS (complex regional pain syndrome)
• Stretch neurapraxia

Return-to-Sport Assessment

The Ankle-GO Score

1. Scoring components: The Ankle-GO is a composite score made up of six parts, up to a maximum of 25 points, used to objectively assess the main deficits associated with an ankle sprain or chronic ankle instability. It helps guide decisions about when a patient can return to sport after a lateral ankle sprain. In one study, if a patient’s Ankle-GO score was below 8 at 2 months after injury, they were less likely to have returned to their pre-injury level of sport by 4 months; these are trial results and do not predict any individual’s outcome.

2. Functional tests: include the single-leg stance test (SLS), the modified Star Excursion Balance Test (mSEBT), the side hop test (SHT), and the figure-of-8 test (F8T).

3. Self-report questionnaires: include two subscales of the Foot and Ankle Ability Measure (FAAM), assessing activities of daily living (FAAMadl) and sport (FAAMsport), as well as the Ankle Ligament Reconstruction-Return to Sport after Injury (ALR-RSI) questionnaire.

Functional Tests

1. Single-leg stance test (SLS): standing on one leg on a firm surface, assessing static postural control. Scored according to the number of errors the participant makes.

2. Modified Star Excursion Balance Test (mSEBT): assesses dynamic postural control of the lower limb, including reach distance in three directions: anterior (ANT), posteromedial (PM), and posterolateral (PL).

3. Side hop test (SHT): involves 10 rapid lateral and medial hops, measuring the dynamic stability of the ankle.

4. Figure-of-8 test (F8T): involves rapidly hopping around two posts set 5 metres apart, assessing the ankle’s athletic ability and control.

Self-Report Questionnaires

1. Foot and Ankle Ability Measure (FAAM): divided into two subscales, activities of daily living (FAAMadl) and sport (FAAMsport), assessing patient-reported function.
2. Ankle Ligament Reconstruction-Return to Sport after Injury (ALR-RSI): measures the psychological readiness of patients with an injured ankle to return to sport.

Single-Leg Stance Test (SLS)

• 0 points: more than 3 errors
• 1 point: 1 to 3 errors
• 2 points: no errors
• Plus 1 point: no feeling of instability during the test

Modified Star Excursion Balance Test (mSEBT)

• Composite score (COMP):
• 0 points: if the composite score is below 90%
• 2 points: if the composite score is between 90% and 95%
• 4 points: if the composite score is above 95%
• Anterior (ANT):
• Plus 1 point: if the ANT direction measurement exceeds 60%
• Posteromedial (PM):
• Plus 1 point: if the PM direction measurement exceeds 90%
• Plus 1 point: no feeling of instability during the test

Side Hop Test (SHT)

• 0 points: completion time over 13 seconds
• 2 points: completion time between 10 and 13 seconds
• 4 points: completion time under 10 seconds
• Plus 1 point: no feeling of instability during the test

Figure-of-8 Test (F8T)

• 0 points: completion time over 18 seconds
• 1 point: completion time between 13 and 18 seconds
• 2 points: completion time under 13 seconds
• Plus 1 point: no feeling of instability during the test

Foot and Ankle Ability Measure (FAAM)

• Activities of daily living (FAAMadl) and sport (FAAMsport)
• 0 points: score below 90% (activities of daily living) or below 80% (sport)
• 1 point: score between 90% and 95% (activities of daily living) or between 80% and 95% (sport)
• 2 points: score above 95%

Ankle Ligament Reconstruction-Return to Sport after Injury (ALR-RSI)

• 0 points: score below 55%
• 1 point: score between 55% and 63%
• 2 points: score between 63% and 76%
• 3 points: score above 76%

Conclusion

Every sprain is a small reminder from your body. To avoid repeated sprains, recover promptly after an injury, learn stability training, and take good preventive measures. When your ankle is sprained, it is really telling you: “You need to pay more attention.”

Repeated sprains can make the joint increasingly unstable and raise the risk of future injury. That is why timely treatment and rehabilitation are so important. Stability training not only strengthens the muscles around the ankle but also improves the joint’s flexibility, making it less prone to injury. Beyond that, we should build good everyday habits, such as wearing well-fitting shoes and avoiding activity on very uneven ground. Only when we truly understand and care for our bodies can we avoid unnecessary injuries.

References

• Ankle Sprain - Foot & Ankle - Orthobullets
• Anesth Pain Med. 2022 Jan 23;12(1):e118317. doi: 10.5812/aapm.118317. eCollection 2022 Feb. Neurofascial Dextrose Prolotherapy for Managing Chronic Ankle Ligament Injury
• BMC Musculoskelet Disord. 2023 Jun 23;24(1):517. doi: 10.1186/s12891-023-06642-0. Use of a comprehensive systemic ultrasound evaluation in the diagnosis and analysis of acute lateral region ankle sprain
• Ankle and Foot Treatment with Prolotherapy - Journal of Prolotherapy
• Front Bioeng Biotechnol. 2022 Dec 22;10:1073063. doi: 10.3389/fbioe.2022.1073063. eCollection 2022. Platelet-rich plasma, a biomaterial, for the treatment of anterior talofibular ligament in lateral ankle sprain
• Sports Health. 2024 Jan-Feb;16(1):47-57. doi: 10.1177/19417381231183647. Epub 2023 Jul 11. Development and Validation of the Ankle-GO Score for Discriminating and Predicting Return-to-Sport Outcomes After Lateral Ankle Sprain