You are here

Ankle Sprains and Instability


An ankle sprain occurs as a result of injury to a ligament (or more than one) generally on the outside of the ankle. Ligaments are flexible lengths of fibrous tissue that connect the bones together in joints and create stability by limiting lateral movement. When an ankle is sprained, ligaments can either be stretched or can actually tear.


Ankle instability occurs when the ankle continually gives way resulting in multiple sprains.  It often starts after one particularly severe sprain injury. Instability results from ligaments that have stretched or partially or fully torn and the injury has failed to heal properly. Roughly 30 percent of sprains do not heal properly and the ligaments remain in a stretched condition. The ankle is then less able to support the body weight and makes it more prone to further injury.



A sprain is caused by any form of trauma which pushes the ankle joint from its usual position, for example, a fall, a blow to the ankle or sudden twisting. This often the result of…

  • A sports injury.
  • Not wearing the right shoes.
  • Walking or running on uneven surfaces.
  • An ankle weakened by previous injury.

Less frequently, weak ankles can be an inherited condition, making the person more prone to sprains and ankle injury.

Ankle instability, is the chronic result of prior ankle injury. Some conditions make people more susceptible to ankle instability, for example…

  • A tight Achilles tendon.
  • Muscle weakness issues.
  • Foot deformities.
  • Damage to the heel bone.
  • Natural laxity of the ligaments and tendons.
  • Arthritis present in the ankle.

Athletes and ballet dancers are particularly prone to ankle instability.


An ankle sprain will generally result in…

  • Bruising.
  • Difficulty walking / inability to put any weight on the ankle.
  • Discolouration of the skin.
  • Pain / soreness.
  • Stiffness in the ankle.
  • Swelling.

Tests / Diagnosis

The initial test is a physical examination, involving the ankle joint being moved to determine range of motion. Other tests which may be necessary include imaging tests, such as x-rays or an MRI scan. These will determine whether the injury is a sprain or whether any bones have been fractured.

Tests to evaluate potential ankle instability issues require the same imaging tests and may also include a CT scan or a social type of x-ray known as a ‘fluoroscopy’ and/or another ape of x-ray known as a ‘stress x-ray’.

Diagnosis of chronic ankle instability begins with imaging tests—e.g., x-rays, MRI, CT scans, and sometimes even fluoroscopy (in layman’s terms, a kind of x-ray movie).

In some cases, a stress x-ray may be ordered, which involves moving your ankle in certain directions while taking x-rays or fluoroscopic images in order to visualize the instability present.

Non-Operative treatment

Most acute sprains and some chronic instability can be managed without surgery.

Initial treatment of the acute injury is according to the “RICE” principle:

  • REST: avoid walking on the foot for a day or two, use crutches, cease sport.
  • ICE: keep cold packs on the joint.  20 mins on, 20 mins off.
  • COMPRESSION: an elasticated bandage to minimize swelling and support the joint.
  • ELEVATION: Keep the foot up, preferably above the level of the heart.

After the first couple of days, it is important to start active treatment.

A physiotherapist can help with regaining mobility, controlling swelling, returning to normal walking, and most importantly restoring Proprioception. This is your ability to sense the position of the ankle and actively respond to prevent it rolling or giving way. The later stages of therapy include muscle activation and strengthening exercises.

A protective brace can be useful for a short period.

Chronic instability may be manageable with a combination of therapy, exercises, and bracing.

Related Information

Anatomy of the Foot and Ankle
Ankle Ligament Reconstruction
Sprained Ankle