What is chronic ankle instability?

Chronic ankle instability is an instability affecting the ankle joint and its surrounding structures. It usually develops after a severe ankle sprain. However some people are born with less stable ankles, who may be generally extra flexible throughout their entire bodies. Approximately 20% of ankle sprains lead to chronic ankle instability due to the resulting changes in ligament support, strength, postural control, muscle reaction time and sensation. 

What are the symptoms?

As well as being more susceptible to ankle sprains, people with chronic ankle instability may notice they are extra cautious during high-intensity activities, if walking or running on uneven surfaces or when changing directions quickly. They may experience a sense of weakness or "giving way" when weight-bearing.

What are the causes?

The primary causes of this condition are ligament laxity, decreased muscle strength of the muscles surrounding the ankle and reduced proprioception. 

Following an ankle sprain, ligaments can be stretched and slightly weaker. In more severe cases, they may have torn altogether, leaving the ankle structurally weaker. Without full rehabilitation, the surrounding muscles also become weaker, and studies have shown that balance and sensation of the ankle can also be reduced. This means that the ankle is more likely to be injured again, creating a vicious cycle leading to further instability.

How can physiotherapy help?

Physiotherapy treatment for chronic ankle instability focuses on improving strength, control and balance with a variety of techniques. This approach can significantly improve dynamic ankle stability and reduce the risk of future sprains. Physiotherapists can help patients to regain confidence and get back to their best performance. 

In some cases, taping or bracing for support can be used. However this can lead to dependence and further loss of strength and control if used unnecessarily. In cases of extreme ligament laxity or if physiotherapy fails, surgery to repair the damaged ligaments is considered. This is usually combined with a full post-operative physiotherapy rehabilitation program for greatest success.