Ankle sprains

David, 11, intends to play football in the Premier League when he is older.  Before then, he must serve his time with the school team.  During training, he ships a heavy tackle and rolls over his ankle. He limps over to the sideline and calls for help. Taking no risks with his future star, the coach insists mum takes him to ED. You are waiting with your game face on.

Having seen one or two sore ankles before, you are aware of the Ottawa ankle rules, but what are they? And are they applicable in kids?

Ottawa ankle rules

The Ottawa ankle rules are an evidence-based decision tool to advise indication for x-ray in an ankle injury.

An ankle x-ray series is required if:

There is any pain in the malleolar zones and…

• bony tenderness over the posterior aspect of distal 6cm of tibia (i.e. medial malleolus)

OR

• bony tenderness over the posterior aspect of distal 6cm of fibula (i.e lateral malleolus)

OR

• inability to weight bear (>4 steps) both immediately after the injury and in the ED

A foot x-ray series is required if:

There is any pain in the midfoot zone and…

• bone tenderness at the base of the 5^th metatarsal

OR

• bone tenderness at the navicular

OR

• inability to weight bear (>4 steps) both immediately after the injury and in the ED

Practice common sense – these rules are not applicable if your patient is: unable to give a reliable answer; has other distracting injuries; has diminished sensation in legs; is too swollen to establish bony tenderness; unable to walk prior to the injury.  Remember that a patient who walks with a limp is able to weight bear.

The rules were designed with adults in mind, however, they have been shown to be reliable in the assessment on children. They are sensitive but not specific for detecting fractures, therefore, they are most useful in ruling out fractures (and the need for imaging).  For every 1000 patients that exhibit negative Ottawa ankle rules, 14 will actually have fractures.

David does not meet the criteria for imaging.  He does have a swollen ankle with tenderness over the anterior aspect of his lateral malleolus.  You suspect an ankle sprain.

What is an ankle sprain?

A sprain occurs when you stretch or tear a ligament.

Symptoms include pain, swelling, bruising, tenderness, impaired function and joint instability (if severe).

Classification of a sprain:

• Grade 1 is stretching of the ligament, minimal swelling or bruising, no joint instability
• Grade 2 is a partial rupture of the ligament, moderate swelling or bruising, no joint instability
• Grade 3 is total rupture of the ligament, severe swelling or bruising, with joint instability

There are three main sets of ligaments in the ankle

• Lateral – Anterior Talo-Fibular Ligament (ATFL), Calcaneo-Fibular Ligament (CFL), Posterior Talo-Fibular Ligament (PTFL)
• Medial – Deltoid ligament
• Interosseous (tibiofibular) ligament

There are two tests for instability, which should be compared between the good and bad ankles:

1. Anterior drawer test – stabilize the leg with one hand, use the other hand to cup the heel and draw the foot anteriorly. If there is excessive movement then the test is positive.
2. Talar tilt test – stabilize the leg with one hand, use the other hand to cup the heel and rock the foot in an inversion movement. If there is excessive movement then the test is positive.

How should I manage an ankle sprain?

A simple PRICE approach, along with analgesia, is the first line of management:

Protection. For example, with a supportive boot.

Rest. Usually for 72 hours.

Ice. Cover ice in a tea-towel and apply to the ankle for 10-15minutes every 2-3 hours.

Compression. An elasticated bandage will help with swelling and provide some support (but should be removed at night).

Elevation. Elevate the ankle until the swelling goes down.

Early mobilization as tolerated will facilitate faster recovery, however more severe sprains may require a period of immobilization. (7-10 days).

Supervised physiotherapy has been shown to benefit in early follow-up but does not make a difference in the long term.

What is the prognosis?

The recovery period depends on the severity of the sprain. A grade 1 sprain may return to play in 1-2 weeks; whilst a more severe sprain may return to walking in 1-2 weeks, running in 6-8 weeks and return to regular sporting activity in 8-12 weeks.

David’s ankle was strapped up in a Tubigrip and he limped home, eager to get back on the pitch and continue his journey to stardom.