FRCSEd FRCS Trauma & Orth
Consultant Foot, Ankle & Knee Surgeon
Fairfield Independent Hospital, St Helens
Merseyside WA11 7RS
Spire Cheshire Hospital
Fir Tree Close
Warrington WA4 4LU
Ankle instability is a condition characterised by the ankle ‘giving way’ or feeling wobbly and unreliable, particularly on uneven surfaces.
Ankle ligament injuries are common:
About 10% of all A+E attendances
Incidence of about 5/1000/year
Estimated 302,000 attendances at UK emergency departments per year
Some of those patients who suffer a sprained ankle develop recurring complaints. 18% had pain and about 40% had recurrent sprains or feelings of instability.
Most patients can be managed non-surgically. For those who require surgery, much of this can be done arthroscopically.
Ankle Instability Symptoms
The “giving way” takes place on the lateral, or outer side and will often occur during sports and walking. However, it can also happen while standing and may be accompanied by swelling, discomfort, tenderness and pain.
Ankle Instability Causes
Chronic ankle instability usually develops following an ankle sprain that was not diagnosed properly or has not healed. An ankle sprain stretches and tears the connective tissues, known as the ligaments.
When this occurs, small nerve sensors inside the ligament are often damaged. These nerve sensors, called the proprioceptive nerves, give your brain information about the position of your joints, allowing you to move and protect these joints. For example, nerve sensors in the arm and hand allow you to touch your nose when your eyes are closed.
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. This causes your ankle to "give way", often with minor stresses.
Ankle instability makes you more prone to ankle sprains, which in turn exacerbate ankle instability. With each ankle sprain, the ligaments are increasingly weakened.
Ankle Instability Diagnosis
If your ankle feels unreliable and gives way repeatedly, or if you have recurring ankle sprains, it is recommended that you have a full assessment by a foot and ankle surgeon.
Your foot will be examined for signs of swelling and tenderness. By stretching your ankle in different directions, the surgeon will be able to see whether the ligaments are abnormally weak. This is known as a stress view.
The surgeon may take x-rays to check whether there is any damage to the ankle bones. An MRI scan may also be taken.
Ankle Instability Treatment
Treatment depends upon the severity of the ankle instability and the patient’s own activity levels.
Physiotherapy should be tried as the first treatment and is effective for many patients. Physiotherapy is based on retraining the damaged proprioceptive nerves, enabling them to respond to the movements of the ankle. The strength of muscles around the ankle will also be increased by exercises and activities. 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.
Surgery may be considered if ankle instability fails to improve following non-surgical treatment, and depending on the degree of weakness in the ligaments.
We offer an examination under anaesthesia, stress radiographs and arthroscopy to all patients with persisting functional instability after a functional rehabilitation programme. This allows us to treat intra-articular pathology and identify those with mechanical instability who can be offered a stabilisation procedure. Approximately 40% of our patients have had only an arthroscopic procedure. Patients with mechanically stable ankles and other intra-articular problems have generally had good results from arthroscopic surgery. Patients with unstable ankles will be offered a stabilisation procedure. We prefer to perform this about 6 weeks after the arthroscopy rather than at the same sitting because of the amount of swelling that tends to accompany an ankle arthroscopy.
There are two main types of operation for ankle instability
The damaged ligaments may be tightened and re-attached to the bone. Known as the Brostrom’s Procedure, this type of operation is highly successful and is appropriate for people with active lifestyles.
If all other options have been tried and are neither successful nor suitable, a tenodesis procedure may be carried out. This involves taking a strip of hamstring to recreate new ligaments. This approach should only be considered as a last resort, when the instability is severe and there is likely to be a great deal of stress on the ankle. This type of repair is a very durable treatment for ankle instability but frequently causes stiffness in the ankle.