What causes Ankle Instability?

The ankle joint is a box shaped bounded by the end of the tibia, the fibula and the talus bone. The talus is held to the tibia and fibula by strong bands of tissue called ligaments. These ligaments are extremely strong and designed to withstand huge forces.

The ligament on the inside of the ankle is called the ‘deltoid ligament’, which is mainly torn in association with ankle fractures. The ligament on the outside of the ankle (lateral ligament) is made up of three separate bands: one at the front (anterior talo-fibular ligament), one in the middle (calcaneo-fibular ligament) and one at the back (posterior talo-fibular ligament). The anterior talo-fibula ligament is most commonly injured in ankle sprains, seen in picture below, and accounts for the swelling usually seen in this area, following an ankle sprain.

Most ankle ligament injuries are caused by inversion injuries, where the foot rolls inwards. When this happens, the full force of the body’s movement is placed on the anterior talo-fibular ligament. This may stretch, with tearing of some of its fibres (sprain) or it may tear completely.

Why do I have pain as well?

In a few cases, a twisting force on the ankle may cause other damage. The bones around the ankle may be broken, a piece of the joint surface inside the ankle may be chipped off, ligaments connecting other bones in the foot may be sprained or torn, or the tendons around the ankle may be damaged. These are the common causes of ongoing pain after an ankle sprain.

How is an ankle sprain treated?

Most ankle sprains resolve with simple treatment, based on the principle of ‘RICE’:

• Rest take the weight off the injured joint as much as possible for a day or two
• Ice an ice pack (a small bag of frozen peas or corn is ideal) can be applied for 10-15 minutes 3-4 times a day to reduce swelling
• Compression a firm bandage or strapping will help to get swelling down
• Elevation resting with the ankle above the height of the body will allow swelling to drain away into the bloodstream

Although a couple of days rest is useful, it is best to start taking some weight on the injured ankle reasonably soon after injury, usually within 2-3 days. Also start to exercise and stretch the injured ankle as soon as possible after the injury.

Normally a sprained ankle will recover within 6-8 weeks, although the more severe injuries can cause swelling for a number of months.

Most simple sprains get better without any special treatment. However, if you have a severe injury or the initial injury does not recover normally, it is usually best to see a physiotherapist. I work closely with physiotherapists and can recommend a practice for you depending on your location.

My ankle keeps giving way, what should I do?

Most ankle injuries get better completely and cause no long-term problems. Ankle instability can occur and may be related to the ligaments healing back slack. More importantly, it can be related to damage to the small nerve endings that supply the ankle joint. These endings are very important, as they tell your brain where your ankle is and what position it is in (they are called “proprioceptive nerves”). Your brain relies on this information to control the muscles which move and protect your ankle. If these nerve endings are not working properly, your brain does not get reliable information and the muscles around your ankle may not work together properly. You would feel this as a tendency for your ankle to “give way”, often with minor stresses. This might make you prone to repeated ankle sprains.

As most people with ankle instability have proprioceptive nerves which are not working properly, the first treatment is a physiotherapy programme to re-train these nerves how to respond to movements of the ankle, by doing various exercises and activities. If your ankle or Achilles tendon are stiff, you will also be shown exercises to stretch these, and the strength of the muscles around the ankle will be increased by exercises. If your foot shape makes you prone to extra stress on the ankle ligaments, a moulded insole may be advised for your shoe to reduce these stresses.

Many people will find their ankle much more stable and comfortable after physiotherapy. However, in some people problems continue.

An MRI scan will be organised to assess the joint surface and to document the status of the ligaments and tendon that cross the ankle.

What are the surgical options?

Based on a diagnosis of ankle instability, the surgical options will include a Brostrum-Gould repair, which essentially tightens the ligaments on the outside of the ankle. Other techniques where we use polyester tape, to help support the reconstruction are now available and early results are encouraging. I tend to use this newer technique in very unstable ankles, and following failed initial surgery.