The most common site of injury is the anterior talofibular (FTA) ligament
Symptoms include pain, swelling and a haematoma at the site of injury.
X-rays should be taken in accordance with the Ottawa ankle rules.
Treatment is conservative (functional treatment: short period of immobilisation + exercises); in recurrent sprains surgery may be considered for selected patients.
Almost half of the patients are expected to have chronic problems, which should be taken into account when planning the initial treatment.
Prevalence
A sprain injury of the ankle is the most common musculoskeletal injury.
It accounts for 20-30% of all exercise-related injuries.
Almost half of all basket ball injuries, and one third of football injuries, are ankle sprains.
Predisposing factors
A past history of ankle sprain
Calf tightness
Weakness/paresis of the peroneal muscles
Mechanisms of injury and pathological anatomy
Plantar flexion and inversion
The most common site of injury is the anterior talofibular (FTA) ligament
The calcaneofibular (FC) ligament is injured in 10-20% of cases; always in conjunction with other ligament injuries.
The posterior talofibular (FTP) ligament is only injured in association with a dislocation of the ankle.
Clinical findings
Swelling and a haematoma in front of and below the lateral malleolus
In severe sprains, swelling is visible throughout the ankle, also medially.
Ankle sprains are not associated with deformity.
Pain and swelling will restrict movement.
Clinical tests
Deformities
Tenderness
Swelling
The drawer test
The inversion test
The examiner places one hand above the ankle whilst turning the heel inwards with the other hand.
Tests for syndesmosis injury
In the squeeze test, the lower parts of the tibia and fibula are manually squeezed together: pain in the region of the anterior tibiofibular (TFA) ligament is suggestive of injury to the distal syndesmosis.
External rotation test: the examiner holds the lower leg and, with his other hand, applies external rotation to the foot in order to verify whether the talus can be rotated outwards; instability and pain at the region of the anterior tibiofibular ligament are suggestive of syndesmosis injury.
Differential diagnosis
Syndesmosis injury
Peroneal retinaculum injury
The peroneal tendons subluxate over the lateral malleolus causing pain behind the lateral malleolus.
Injury to the calcaneal tendon (Achilles tendon)
Subtalar joint dislocation
Foot dislocation/fracture
Fracture of the lateral process of the talus (snowboarders)
Indications for ankle radiography
Ottawa ankle rules: ankle radiography is indicated if there is any pain in the malleolar zone and at least one of the following conditions is met:
bone tenderness at the distal 6 cm of the posterior edge of tibia, or at the tip of medial malleolus
bone tenderness at the distal 6 cm of the posterior edge of fibula, or at the tip of lateral malleolus
an inability to bear weight on the foot for four steps
Radiography of the foot should be performed if there is pain in the middle part of the foot and, additionally, there is tenderness at the base of the fifth metatarsal bone or at the navicular bone area.
At a later stage (6 weeks after the injury), a locking sensation or continuous swelling of the joint may be associated with cartilage damage of the talus. A CT or MRI scan may be indicated.
Treatment
The treatment of ankle sprains is conservative.
Application of cold, compression, elevation of the limb
Functional treatment
Severe sprains are immobilized with a plaster cast or an orthosis that supports the ankle in an 90° angle for a period of 10 days.
In ordinary sprains the ankle is immobilised for a short time, for 1-3 weeks, with the aid of a detachable orthosis in order to prevent sideways rotation.
A lengthy immobilisation in a plaster cast offers no benefits over the orthosis treatment
Orthosis treatment is superior to immobilisation in a plaster cast regarding time to return to work and sporting activities.
The use of adhesive strapping is associated with skin problems and it is not recommended.
Return of the range of movement and exercises
A sprained ankle will automatically pull itself into plantar flexion and inversion
Exercises should be commenced as soon as possible
Calf stretching and muscle strengthening exercises
Peroneal muscle exercises
Foot eversion exercises
Proprioceptive training
Started as soon as the patient is able to bear weight with no pain (1-3 weeks after the injury).
Balance board training
In athletes, co-ordination exercises according to the type of sport.
Prevention of ankle sprains
A history of an ankle sprain is the most common predisposing factor associated with a recurrent injury. Acute injuries should be treated thoroughly with functional treatment and short-term immobilisation. Tight calf muscles, in particular, should be prevented by frequent stretching exercises.
Patients with recurrent ankle sprains should consider wearing an ankle support in order to prevent sideways rotation during sporting activities.
Surgical outcome is usually good in selected cases. A surgeon should be consulted in cases where thorough, long (at least 6 months) conservative treatment does not produce the expected result: the patient has sustained dislocation tendency, subjective feeling that the ankle is giving way, repeated ankle sprain injuries.
References
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Hartsell HD, Spaulding SJ. Eccentric/concentric ratios at selected velocities for the invertor and evertor muscles of the chronically unstable ankle. Br J Sports Med 1999 Aug;33(4):255-8. [PubMed]
Stiell IG, McKnight RD, Greenberg GH, McDowell I, Nair RC, Wells GA, Johns C, Worthington JR. Implementation of the Ottawa ankle rules. JAMA 1994 Mar 16;271(11):827-32. [PubMed]
Karlsson J, Lundin O, Lind K, Styf J. Early mobilization versus immobilization after ankle ligament stabilization. Scand J Med Sci Sports 1999 Oct;9(5):299-303. [PubMed]
Mattacola CG, Lloyd JW. Effects of a 6-Week Strength and Proprioception Training Program on Measures of Dynamic Balance: A Single-Case Design. J Athl Train 1997 Apr;32(2):127-135. [PubMed]
Lamb SE, Marsh JL, Hutton JL ym. Mechanical supports for acute, severe ankle sprain: a pragmatic, multicentre, randomised controlled trial. Lancet 2009;373(9663):575-81. [PubMed]