CHRONIC ANKLE INSTABILITY ASSESSMENT & MANAGEMENT

Chronic ankle instability is more than a “weak ankle”

Chronic ankle instability can develop after a lateral ankle sprain when symptoms and functional problems persist beyond the expected healing period. Around 20–40% of people who sustain a lateral ankle sprain may go on to develop chronic ankle instability, making appropriate rehabilitation after the first injury particularly important.

Importantly, chronic ankle instability is not simply a ligament that never healed. It usually involves two overlapping problems: mechanical instability and functional instability.

Mechanical instability refers to changes such as laxity of the lateral ankle ligaments, particularly the anterior talofibular ligament, altered joint mechanics and potentially degenerative changes.

Functional instability involves the sensorimotor system: impaired proprioception, delayed muscular reactions, reduced postural control and neuromuscular inhibition.

A patient can therefore have relatively normal ligament testing while still repeatedly describing the ankle as “giving way.” This is why assessment cannot stop with the anterior drawer or talar tilt test.

Assessment should include the whole system

A useful assessment starts with the history of the original sprain: how it occurred, its severity, how rehabilitation was managed and whether subsequent episodes of giving way or recurrent sprains have occurred.

Physical examination may include ligament testing, ankle and subtalar mobility, foot assessment and screening for possible syndesmotic involvement.

However, functional testing is equally important.

Strength assessment should consider dorsiflexion, plantarflexion, inversion and eversion, particularly the function of the peroneal muscles and tibialis posterior. Calf endurance and weight-bearing ankle dorsiflexion should also be assessed.

Restricted dorsiflexion is common in chronic ankle instability and may influence movement strategies during tasks such as squatting, landing and running.

Assessment should also extend beyond the ankle. Deficits in hip and trunk control can contribute to poor lower-limb stability, particularly during single-leg and multidirectional tasks.

The ankle may be where the symptoms are felt, but the movement problem can involve the entire kinetic chain.

Rule out more serious conditions first

Not every painful or unstable ankle should immediately be treated as chronic ankle instability.

In an acute or newly aggravated presentation, fracture should be considered using tools such as the Ottawa Ankle Rules. These help identify when radiography may be appropriate based on factors such as bone tenderness and inability to weight-bear.

Syndesmotic injuries also require attention. No single clinical test provides perfect diagnostic accuracy, so findings from tests such as the squeeze test and external rotation test should be considered together with the mechanism of injury and overall clinical presentation.

Other warning signs require additional investigation. Severe swelling, redness, warmth or calf tightness can raise concern for vascular pathology, while progressive numbness, weakness or neurological changes require further assessment.

Even a patient with an established history of chronic instability should be re-screened when new or unusual symptoms appear.

Early rehabilitation: restore movement and begin loading

During the acute stage, the first goals are to manage pain and swelling while gradually restoring movement and loading.

The PEACE & LOVE framework provides a useful approach: protect the injured area appropriately, educate the patient and progressively introduce loading, cardiovascular activity and exercise rather than relying on prolonged rest.

Where ankle dorsiflexion remains restricted, joint mobilisation may be considered alongside active mobility work.

The objective is to prevent the ankle from becoming unnecessarily deconditioned while respecting the irritability of the injury.

Strength alone is not enough

Strengthening is important, but chronic ankle instability has a major neuromuscular component.

Rehabilitation should progressively develop the peroneals, tibialis posterior, calf complex and intrinsic foot musculature. However, simply making these muscles stronger does not necessarily restore the rapid sensorimotor responses needed when the ankle encounters an unexpected perturbation.

Balance and neuromuscular training therefore form a central part of rehabilitation.

Progression might begin with controlled single-leg stance before moving toward more demanding tasks involving unstable surfaces, external perturbations and dynamic movement.

The aim is not simply to stand on one leg for longer. It is to improve the body's ability to detect changes in position and rapidly produce the appropriate muscular response.

This becomes particularly important in sports involving cutting, landing or unpredictable changes in direction.

Progress toward dynamic and sport-specific tasks

As strength, balance and tolerance improve, rehabilitation should become increasingly dynamic.

Plyometric exercises can gradually reintroduce rapid force production and absorption. Landing mechanics should also be evaluated rather than assuming that an athlete who can jump is automatically ready to return.

Sport-specific drills then progressively expose the athlete to acceleration, deceleration, cutting and the multidirectional demands of their activity.

This progression matters because pain and swelling often resolve before neuromuscular function has completely recovered.

An athlete may therefore feel ready while still having significant deficits in dynamic balance, strength or landing control.

Returning based solely on symptom resolution can leave the original mechanism for recurrent sprains largely unchanged.

Use objective criteria for return to sport

Return-to-sport decisions should combine patient-reported outcomes with physical performance testing.

Questionnaires such as the Foot and Ankle Ability Measure (FAAM) and Lower Extremity Functional Scale (LEFS) can track perceived function, while tools such as the Tampa Scale can identify fear of movement or reinjury.

Physical testing may include:

• single-leg hop testing

• repeated or timed hop tests

• Y-Balance testing

• landing-quality assessment

• strength testing

• sport-specific movement tasks

The Limb Symmetry Index (LSI) can compare the injured and uninjured sides:

LSI = injured-side performance ÷ uninjured-side performance × 100

A value of approximately 90% or greater is commonly used as one component of return-to-sport decision-making, although it should not be treated as a universal standalone threshold.

The important principle is that return should be based on a collection of criteria rather than simply the passage of time or the disappearance of pain.

Preventing the next sprain is part of rehabilitation

One of the most important opportunities in ankle rehabilitation occurs after the first lateral ankle sprain.

Delayed functional rehabilitation, recurrent sprains and persistent feelings of instability can increase the likelihood of developing chronic ankle instability.

Good rehabilitation should therefore go further than reducing swelling and restoring basic walking.

It should restore strength, ankle mobility, proprioception, balance, dynamic control and confidence, before progressively rebuilding the athlete's ability to tolerate the unpredictable demands of sport.

The ankle may feel better long before the entire system is ready. Successful rehabilitation means restoring that system — not simply waiting for the pain to disappear.