A sprained ankle is a very common injury and more than a million people attend A&E in the UK each year for this problem.
What are the ligaments of the ankle?
The ligaments of the ankle hold the ankle bones and joints in position. They protect the ankle joint from abnormal movements such as twisting, turning, and rolling of the foot. Ligaments are elastic meaning they have some give and usually allow some stretching like an elastic band and then go back to their normal shape. If stretched more than they can handle then fibres can tear, which is also known as a sprain.
There are several ligaments that stabilize the outside of the ankle which are demonstrated in the above illustration. The two most commonly injured ligaments are on the outside of the ankle, known as the ATFL (anterior talo-fibular ligament) and the CFL (calcaneofibular ligament). There is one broad ligament on the inside of the ankle called the deltoid ligament this may be injured in severe ankle sprains and in ankle fractures. There is also a ligament complex securing the tibia and fibula together called the syndesmosis and this may be injured during severe sprains (or fractures) sometimes we refer to this as a ‘high ankle sprain’. Injuries to the ligaments can be mild stretches (grade I), moderate tears (grade II) to completely torn (grade III).
How does a sprain occur?
Ligament sprains usually occur as a result of an inversion injury where the foot turns inwards, the exact position of the foot and the force involved determine which ligaments are injured and what proportion of each are torn. Ankle sprains present with variable degrees of pain and swelling, severe sprains can make it too painful for you to put weight through the foot.
As the ligaments are torn during a sprain the talus becomes briefly displaced from the joint and the surface may be damaged, the injury to the joint surface is called an osteochondral injury.
Sprained ankles present with pain and swelling but can have severe bruising, so that you think you may have broken it. In most cases you will be able to weight bear, and if you cannot then this usually indicates a more serious injury or possible a fracture and you should seek urgent medical advice. Either way it is sensible to get your sprained ankle checked out.
This should usually be made by a trained medical expert. If they are worried about a possible break, they may organise an X-ray. Even if the X-ray is normal, it doesn’t mean that this is not a serious injury, as a grade III ligament sprain is likely to have a normal X-Ray but should still be treated seriously.
A specialist may order an MRI (magnetic resonance imaging) scan if he or she suspects an injury to the joint surface, bone chips or other problems. Many specialists will wait for a few weeks before ordering an MRI if they are treating you with immobilisation anyway. This allows time for the swelling and bruising to settle.
How should my sprained ankle be treated?
The majority of simple sprains recover fully within a few days without more treatment than RICE – Rest, Ice, Compression and Elevation. Do not place ice directly on the skin but wrap crushed ice or a bag of peas within a towel and then place on the swollen area for 15 minutes 4 times a day.
It is recommended that all severe ankle sprains receive some form of support to allow the ligaments to heal in the right position. If they are allowed to heal lengthened or stretched then you will most likely be at risk of a further sprain in the future.
Early functional rehabilitation with the help of a physiotherapist can help maintain the flexibility, strength, co-ordination (proprioception) and stability of the ankle.
If you have severe swelling, an inability to weight bear on the foot or deformity you should seek urgent medical advice, an X-ray may be required to exclude a fracture. Even following rupture (grade III injuries) of one or more of the lateral ligaments the majority of patients return to active sports without the need for surgery. In grade III sprains your specialist may recommend either an ankle brace or a walking boot, and in some instances maybe even a plaster cast.
Treatment Guide for Severe Ankle Sprains
Week 1 – Week 4
Week 7 – Week 12
What happens if my ankle doesn’t settle?
A proportion of ankle sprains fail to settle and continue to cause pain, stiffness or giving way (instability). Those sprains that are not settling by 3 months, despite proper rehabilitation are called ‘chronic ankle sprains’
Chronic ankle sprains will need further investigation, to exclude scar tissue, localized damage to the joint surface or laxity of the ligaments that might respond to surgical treatment. Injury to joint surface or excessive scar tissue may benefit from an arthroscopy
If the ankle continues to give way, even after intensive physiotherapy, it might be necessary to repair or reconstruct the ligaments. Seek further medical advice from an orthopaedic foot & ankle specialist.