Chronic ankle instability and repeated sprains

What is chronic ankle instability?

A group of ligaments holds the outer (lateral) side of the ankle together. The main two are the anterior talofibular ligament (ATFL) and the calcaneofibular ligament (CFL). When the foot rolls inward, these ligaments can stretch or tear — an ankle sprain. Sprains are graded from mild stretching to a complete tear.^[2]

Most people recover. In some, though, complaints of instability continue, and this is called chronic ankle instability.^[3] A common cause is a sprain that did not have complete rehabilitation, and repeated sprains can progressively weaken the ligaments.^[2,1] An international consensus of ankle specialists notes that lateral ankle sprains and chronic instability carry a broad health burden. This includes reduced physical activity and earlier arthritis in the ankle after injury.^[4]

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Symptoms

• the ankle repeatedly “gives way” or rolls, especially on uneven ground or during sport
• persistent discomfort, swelling or stiffness on the outer side of the ankle
• a feeling that the ankle is weak or can’t be trusted
• repeated sprains from minor missteps^[1]

How it’s evaluated

The history tells us a lot. We ask how the ankle was first injured, how it was treated, how often it gives way and what activities trigger it. The examination checks for tenderness, swelling, and how loose the ankle is when it is stressed. It also looks at alignment, calf tightness, and strength and balance. X-rays are used to check the bones and joint.^[1,2]

Ongoing ankle pain has causes other than loose ligaments, and they can occur together with instability. Examples are arthritis and impingement of soft tissue in the joint. Others are a cartilage injury (see osteochondral lesions of the talus), a tendon injury (see peroneal tendon injuries), a high-arched foot that tilts the heel inward (see cavus foot), and a bony connection between foot bones (tarsal coalition).^[7] When symptoms don’t match the examination, or the ankle is still painful despite rehabilitation, an MRI may be recommended to look for these. See foot and ankle imaging.

If you have just sprained your ankle, X-rays are needed only if certain findings are present. The Ottawa ankle rules are a checklist that is very sensitive for ruling out a fracture. They are not very specific, which means some normal X-rays are taken to be safe.^[8]

Non-surgical care

Treatment starts with rehabilitation, and it is supervised whenever possible. Clinical guidelines prefer supervised exercise programs to passive treatments. After an acute ligament injury, they recommend a brace or tape combined with exercise.^[9] An overview of systematic reviews found strong evidence for bracing and moderate evidence for neuromuscular (balance and coordination) training in preventing another sprain.^[5] Exercise-based rehabilitation after a first sprain reduced the chance of re-injury at 12 months (odds ratio 0.60).^[6]

• Physical therapy: strength, balance and coordination training, and sport-specific work.^[1]
• Bracing: a brace supports the ankle and can help prevent another sprain.^[1,5]
• Medicine: anti-inflammatory medicines can reduce pain and swelling. They are not free of side effects and may not be right for everyone.^[9]

A Cochrane review found that neuromuscular training improved ankle function compared with no training, though the trials were small and follow-up was short.^[10]

When surgery is considered

Surgery is generally considered when the ankle keeps giving way despite months of rehabilitation. It is also considered when instability is severe or imaging shows a problem that needs to be treated.^[2,1] The most common approach is an anatomic repair of the ligaments (the Broström procedure and its modifications).^[11,12] When the ligaments are too damaged to repair, they can be reconstructed with a tendon graft.

Anatomic repair has good long-term results. In a systematic review of 669 procedures, the revision rate was 1.2% after an average follow-up of 8.4 years.^[11] Reviews with at least ten years of follow-up found better function and less later arthritis after anatomic repair than after older, non-anatomic operations.^[12] Randomized trials are few and small, so conclusions about which technique is best are limited.^[13,10]

For the operation itself, including arthroscopic techniques, and recovery, see ankle ligament reconstruction and ankle arthroscopy.

When to seek care

Consider an evaluation if your ankle has given way more than once or you avoid activities because you don’t trust it. The same goes for pain and swelling that persist for weeks after a sprain.