Ankle Sprain

Inversion (Lateral) Ankle Sprain

Sport Risk Factors

Running and jumping sports such as football, squash, tennis and basketball.

Vinette

Cristiano Ronaldo, the 4-time world football player of year, goes to change direction with the ball but rolls his right foot inwards. He immediately goes down with pain on the outside of his ankle. However, he is able to get up and walk over to the sidelines to be subbed off.

Pathophysiology

Sprain vs Strain

• Sprain = injury to ligaments
• Strain = injury to muscles (tendons)

TIP: sTrain has a ‘T‘, and Tendon starts with a ‘T‘.

The most common type of ankle sprain is an inversion (lateral) ankle sprain (85%), described in detail on this page:

 1. Inversion injury, involving twisting of weight-bearing plantar-flexed foot.

 2. Injures the anterior talofibular and calcaneofibular ligament of the lateral ligaments

• The lateral ligaments aim to resist over-inversion movement, however the anterior talofibular ligament is the weakest of these, hence it is more prone to injury from over-inversion.

Clinical Presentation

• Stiffness and tenderness over the lateral ligament
• Pain on inversion
• Swelling (inflammation) and bruising (immediate → 48 hours)
• Instability

Immediate Management

• Follow the Ottawa ankle rules to decide if an immediate x-ray is needed to rule out a # (fracture) of the ankle and mid-foot. 

Ottawa ankle rules:

• A decision aid to exclude fractures of the ankle in patients with an ankle sprain. Rule out an order to x-ray the patient for a suspected ankle fracture (as a differential) if 3 things are NOT present with pain in the malleolar zone:

 1. Bone tenderness in the posterior edge of the lateral malleolus

 2. Inability to weight bear immediately and in ED

 3. Bone tenderness in the posterior edge of medial malleolus

• TIP: * Mnemonic Alert * If it is an ankle fracture, then you are hanging off a LIMb

  L: Lateral malleolus (bone tenderness)

  I: Inability to weight bear

  M: Medial malleolus (bone tenderness)

Diagnosis

• Clinical diagnosis and examination
• Ottawa ankle rule to rule out an ankle fracture

Classification of an ankle sprain is by grades I-III:

• Grade I (mild): stretched ligament or small tears
• Grade II (moderate): incomplete tear
• Grade III (severe): complete tear, causing mechanical instability of the joint.

Management

Progression of management depends on the grade of the ankle sprain.

If Grade I:

 1.  PRICE +/- analgesia.

TIP: * Mnemonic Alert * PRICE

• P:  Protection from further injury
• R: Rest from activity 48-72hrs
• I: Ice applied to the affected area
• C: Compression of the ankle joint with an elasticated bandage
• E: Elevation of the ankle joint above the level of the heart

If Grade II/III:

 1. IMMOBILISATION. 

• Below knee immobilisation for 10 days

Click here for the NICE Guidance.

References

Baldwin A, Hjelde N, Goumalatsou C, Myers G. (2016). Oxford Handbook of Clinical Specialities. 10th ed. Oxford: Oxford University Press.

Moore K, Dalley A, Agur A. (2014). Clinically Oriented Anatomy. 7th ed. Philadelphia: Wolters Kluwer.

National Institute for Health and Care Excellence: Clinical Knowledge Summaries. (2016). Sprains and strains. [online]. Available at: https://cks.nice.org.uk/sprains-and-strains#!topicsummary [accessed 1 March 2017].

Teach Me Anatomy. (2017). The Ankle Joint. [online]. Available at: http://teachmeanatomy.info/upper-limb/joints/elbow-joint/ [accessed 1 March 2017].

Image References

Cristiano Ronaldo.   Pathophysiology.   Clinical Presentation.   Ottawa Ankle Rules.   Ankle Sprain Grades.   Ankle PRICE.   Ankle Immobilisation.