Sprained ankle
Synonyms and keywords: Ankle sprain; ankle injury; ankle ligament injury

# Overview
A sprained ankle is a common medical condition where one or more of the ligaments of the ankle is/are stretched, partially or completely torn. Ankle sprains are more common among physically active individuals. The anterior talofibular ligament is one of the most commonly involved ligaments. Sprains to the lateral aspect of the ankle account for 85% of ankle sprains. Females are more commonly affected with an ankle sprain than males. The diagnosis of most ankle sprains is made in the light of history of acute ankle trauma and examination findings.

# Classification
- Ankle sprain can be graded for functional loss of function:

# Pathophysiology
- The pathogenesis of ankle sprain is characterized by ankle movement beyond the elastic limits of its supporting structures causing acute ankle pathology.
- Lateral ankle sprain injury is usually caused by forefoot adduction, hindfoot inversion, and tibial external rotation with ankle in plantar flexion. Depending on the amount and direction of the force, one or more of the lateral ligaments can be involved.
- The ATFL is the most commonly injured structure with the lowest load to failure when compared to the other lateral ligaments. The anterior tallofibular ligament (ATFL) is the most commonly injured ligament and is most susceptible to injury during ankle plantarflexion with the ankle's bony anatomy providing less stability. In this position, ATFL acts as a collateral ligament to the ankle. The ATFL prevents talar internal rotation, anterior translation and is a restraint to plantarflexion. The most common mechanism of injury to the ATFL is inversion injury where a plantarflexed ankle undergoes supination and adduction.
- An ankle sprain can involve any of the following injuries:
Anterior (and/or posterior) talofibular ligament injury
Calcaneofibular ligament injury
Possible peroneal and flexor tendon injuries
Syndesmotic injury
- Anterior (and/or posterior) talofibular ligament injury
- Calcaneofibular ligament injury
- Possible peroneal and flexor tendon injuries
- Syndesmotic injury
- On microscopic histopathological analysis, microscopic failure of the collagen fibers characterize ankle sprain when the load and velocity applied to outweigh the mechanical strength of the ligament and speed of a corrective muscle reflex.

# Causes
A lateral ankle sprain occurs when the ankle is inverted beyond the elastic limits of its supporting structures causing acute ankle pathology.

# Differentiating ankle sprain from other Diseases
- Ankle sprain should be differentiated from (click on the disease name to read more):
Tendon pathologies: Tendon rupture, ITiFi ligament tear.
Joint pathologies: Joint effusion, and chronic osteoarthritis.
Fractures: of the low fibula, Diaphyseal fibula, medial malleolus, postmedial talar process, anterior calcaneal process, os peronei, fifth metatarsal,
Microfractures: of the cuboid, calcaneum, and tibia.
Stress fracture
Subluxation
Impingement syndrome, sinus tarsi syndrome, tarsal tunnel syndrome, Talar neck avulsion, peroneal groove pathology, peroneal tenosynovitis.
Muscle  pathologies: Split peroneus brevis, peroneus longus, tibialis anterior tear, tibialis posterior dislocation, and flexor digitorum brevis tear.
- Tendon pathologies: Tendon rupture, ITiFi ligament tear.
- Joint pathologies: Joint effusion, and chronic osteoarthritis.
- Fractures: of the low fibula, Diaphyseal fibula, medial malleolus, postmedial talar process, anterior calcaneal process, os peronei, fifth metatarsal,
- Microfractures: of the cuboid, calcaneum, and tibia.
- Stress fracture
- Subluxation
- Impingement syndrome, sinus tarsi syndrome, tarsal tunnel syndrome, Talar neck avulsion, peroneal groove pathology, peroneal tenosynovitis.
- Muscle  pathologies: Split peroneus brevis, peroneus longus, tibialis anterior tear, tibialis posterior dislocation, and flexor digitorum brevis tear.

# Epidemiology and Demographics
- The prevalence of ankle sprain is approximately  per 100,000 individuals worldwide. The most common injuries suffered from during athletic/recreational activities is lateral ankle sprains.
- The indoor/court sports has a "cumulative incidence rate of 7 per 1,000 exposures or 1.37 per 1,000 athlete exposures and 4.9 per 1,000 h".

## Age
- A systematic review and meta-analyses of prospective studies reported that children compared with adolescents and adults are more likely to sustain an ankle sprain.

## Gender
- A systematic review and meta-analyses of prospective studies reported that females are more commonly affected with ankle sprain than males.

## Race
- There is no racial predilection for ankle sprain.

# Risk Factors
- A study describing the common risk factors for development of ankle sprain among recreational basketball players reported having a previous history of ankle injury, wearing shoes with air cells in the heel, and not stretching before the game to be the common risk factors.

# Natural History, Complications and Prognosis
- The majority of patients with ankle sprain may remain asymptomatic.
- Early clinical features include tenderness, swelling, and ecchymosis over the anterior talofibuar and calcaneofibular ligaments. Although the patient may be asymptomatic depending upon the extent of injury.
- If left untreated patients with ankle sprain may progress to develop balance problems due to proprioception deficits.  .
- Common complications of ankle sprain include chronic pain, joint instability, arthritis.
- Prognosis is generally good but acute ankle sprains have been reported to have a high recurrence rate and may also lead to chronic ankle instability.

# Diagnosis

## Diagnostic Criteria
- The diagnosis of most ankle sprains is made in the light of history of acute ankle trauma and examination findings. Diagnostic imaging is unnecessary although ultrasound may help assess the extent of tendon injury.

## Symptoms
- Acute injuries may not demonstrate any signs and symptoms. Ask the patient to describe injury mechanism. Most sprains involve ankle inversion with some plantar flexion and suggest lateral ligament injury. Another mechanism, such as dorsiflexion, eversion suggest some other ligament involvement.

## Physical Examination
- Patients with ankle sprain usually appear fine. But, the patient may be in distress depending upon the intensity of pain.
- Physical examination of a typical lateral ankle sprain may be remarkable for:
- Tenderness, swelling, and ecchymosis over anterior talofibuar and calcaneofibular ligaments. Swelling and bruising of the whole foot and toe may be demonstrated if no proper treatment has been applied and the patient has been ambulating.
- The patient should be assessed for the degree of instability, site, pain intensity, and an evaluation of neurovascular status.

## Laboratory Findings
- There are no specific laboratory findings associated with ankle sprain.

## Electrocardiogram
- There are no ECG findings associated with ankle sprain.

## X-ray
- An x-ray may be helpful in the diagnosis of ankle sprain. The Ottawa criteria (100% sensitivity) helps indicate of the radiography is indicated. According to the criteria, in case of pain in the malleolar or midfoot region, or tenderness of the bone over the potential fracture region, or weight bearing inability for four steps right after the injury warrants radiography.
- Lateral, anteroposterior, and mortise views of the ankle help visualize the lesion.

## Ultrasound
- Ultrasound findings include thickening and hypoechogenicity of the affected ligament demonstrate a sprain.

## CT scan
- CT scan may be helpful in the diagnosis of ankle sprain. Findings on CT scan suggestive of sprain include thickening, thinning, irregularity, discontinuity, or an absent ligament. Sometimes bony avulsions can be visible.

## MRI
- An ankle MRI may be helpful for ankle injuries involving crepitus or locking, as these symptoms may indicate a displaced osteochondral fragment.
- An MRI may help identify syndesmosis sprains and peroneal tendon involvement.

# Treatment
- Although treatment decisions must be made on an individual basis, functional support for most ankle sprains is the first step. Brace, tape, elastic bandage, or soft cast are preferred over immobilization.  It gives the leg an exercise and yet keeps the damaged part from moving. Crutches and air-braces while conventionally used, are currently out of vogue.
- Immediately following the injury it is important the follow the PRICE protocol  Protection, Rest, Ice, Compression, and Elevation (also known as RICE: Rest, Ice, Compress, and Elevate).
- Cold therapy for 12 to 20 minutes together with compression until the swelling settles or 48 hours, is found to be helpful.
- Severe ankle sprains should be assessed by an orthopedic specialist, although physical therapy is extremely effective for most sprained ankles.
- The evidence of use of ultrasound, LASER, and manual therapy (such as anteroposterior glide of the talus, Mulligans mobilization with movement, chiropractic mortise adjustment technique) for reducing swelling and pain is at various levels.

## Medical Therapy
- NSAIDS are helpful for analgesia (both oral or topical are effective).

## Surgery
- Surgical repair can be performed for patients with ruptured ankle ligaments. Operative treatment has been shown to have a better long-term outcome for residual pain, recurrent sprains and stability in a randomised clinical trial.

## Prevention
- Effective measures for the primary prevention of the ankle sprain include warming up before the sports.

# Related Chapters
- Sprain