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Chronic Ankle Instability

Kate Hosking, PT, DPT, OCS
Doctor of Physical Therapy

It is estimated that between 2 to 7 individuals per 1000 in the general population will sustain an ankle sprain each year, resulting in 1.2 million health care-related visits annually. 40% of ankle sprains are sports-related injuries and most commonly occur in sports that involve frequent running, jumping and cutting-type movements (ex. volleyball, basketball, and soccer).


Ankle sprains vary in location, severity, and can be acute or chronic. The most common type of sprain is a lateral ankle sprain (outer ankle) accounting for 85% of all ankle sprains. Less common are medial (inner ankle) and high ankle sprains.

When most of us think of ankle sprains, an acute injury comes to mind: pain, swelling, bruising, and difficulty walking immediately after the injury. In many cases, ankle sprains are managed with rest, ice, compression and elevation. Once feeling better, people often return to their activities without properly rehabbing the ankle. Without proper management of an ankle sprain, one can have residual deficits such as decreased ankle range of motion, decreased ankle strength, decreased hip strength, and altered neuromuscular control.

It has been well documented that the number one predictor of injury is a previous injury. Recurrent ankle sprains can lead to chronic ankle instability.

Chronic ankle instability is defined as:

History of at least 1 significant ankle sprain that resulted in inflammation and impaired physical activity.
Initial ankle sprain occurred 12+ months prior to testing and most recent sprain is at least 3 months old.
Two or more episodes of giving way and/or recurrent ankle sprain and/or feelings of instability at the ankle that does not result in a sprain.

Risk factors for chronic ankle instability can be broken down into non-modifiable and modifiable. Examples of non-modifiable risk factors include age, sex, height, foot/ankle anatomy, extremity alignment, and generalized joint laxity. Some things that can be modified are weight, BMI, bracing/taping, footwear, exposure to the sport, player position, playing surface, neuromuscular control, postural stability, and muscle strength.

Physical therapy can help address neuromuscular, postural stability, and ankle range of motion/muscle strength deficits. A physical therapist or athletic trainer are also knowledgeable in bracing, taping, and footwear. Addressing these risk factors can help improve quality of life and reduce the risk of future injury.

Do you think you have chronic ankle instability? A comprehensive evaluation is the key to developing an individualized program to meet your specific needs and goals. For more information, contact a sports rehab specialist at UP Health System Rehab Services for a free injury screen at 906-228-2595 or visit