Ankle Sprains & Instability

An ankle sprain is a stretch or tear of the ligaments that hold the ankle joint together. It usually affects the ligaments on the outer side, after the foot rolls inwards. Most sprains heal with simple care and rehabilitation. Ankle instability is when the ligaments heal stretched or weak, so the ankle keeps giving way.

The outer (lateral) ankle ligament has three parts. The anterior talofibular ligament (ATFL) at the front is the one most often injured. In more severe sprains, the calcaneofibular ligament (CFL) below the ankle bone is also torn. Most ankle sprains affect these outer ligaments. Sprains are particularly common in running and jumping sports such as football, basketball and netball.

How bad is my sprain?

Sprains are usually graded by how much of the ligament is damaged:

• Grade I: the ligament is stretched but not torn
• Grade II: the ligament is partly torn
• Grade III: the ligament is completely torn

The NHS advises going to A&E if a crack was heard at the time of injury, the ankle has changed shape, or the foot is numb or tingling, or the skin around it has turned blue or grey or feels cold. Urgent advice is also needed if the pain is severe, the swelling is large, or it is impossible to put weight on the foot. A fracture or an Achilles tendon rupture can be mistaken for a sprain, so a severe injury needs proper assessment.

How is a sprain treated?

For the first two to three days, the NHS recommends:

• Rest: protect the ankle and limit walking
• Ice: a wrapped ice pack for up to 20 minutes every two to three hours
• Compression: a supportive bandage
• Elevation: keep the ankle raised on a pillow as much as possible

Paracetamol or ibuprofen gel can help with pain. Heat, alcohol and massage are best avoided in the first few days. Most people feel better within about two weeks. Running and other strenuous exercise may need to wait for up to eight weeks, and a severe sprain can take months.

For severe sprains, a UK trial of 584 people (Lamb and colleagues, The Lancet) found that a short period in a below-knee cast, or in one type of ankle brace, gave a faster recovery at three months than a simple tubular compression bandage. By nine months there were no significant differences between the treatments. After the early phase, rehabilitation focuses on restoring movement, strength and balance.

What is chronic ankle instability?

Some people with an acute ankle sprain go on to develop chronic ankle instability. This happens when a badly torn ATFL or CFL heals in a lengthened position, or when balance and muscle control around the ankle do not fully recover. The ankle then gives way more easily, which leads to further sprains. A high-arched foot with an inward-tilting heel can add to the problem.

Typical symptoms include:

• An ankle that feels weak or untrustworthy
• Difficulty walking on uneven ground
• Discomfort with sudden starting, stopping or changing direction
• Pain and swelling with increased activity
• Recurrent giving way

Repeated giving way can damage other structures in and around the ankle. Possible results include cartilage (osteochondral) damage, anterior or posterior ankle impingement, peroneal tendon tears or instability, and ankle arthritis. A study of 30 people with end-stage ankle arthritis caused by ligament injury (Valderrabano and colleagues, The American Journal of Sports Medicine) found that the arthritis developed on average about 34 years after the original injury.

Non-surgical management

Dedicated physiotherapy is the first treatment for instability:

• Active physiotherapy, including soft tissue work and range of motion exercises
• Strengthening of the peroneal muscles on the outer side of the leg
• Proprioceptive (balance and position sense) retraining
• An ankle brace for sport or uneven ground

Most people with ankle instability do not need surgery.

When is surgery recommended?

If instability persists after three to four months of physiotherapy, surgery is indicated. Mr Hester performs a lateral ligament reconstruction. The operation restores the normal length of the stretched ATFL and CFL through a small incision of about 2 cm, as a day case. A keyhole examination of the joint (arthroscopy) is often carried out at the same time to deal with any associated damage.

Most people report a good result after this type of repair, though some are not satisfied. Possible complications include stiffness, nerve problems and recurrent instability.

What is recovery like?

• 0–2 weeks: weight-bearing in a walker boot
• From 2 weeks: change to an ankle brace and start physiotherapy
• From 6 weeks: light jogging may begin

This allows a rapid return to function.

How Mr Hester can help

Mr Hester is a dual fellowship-trained foot and ankle surgeon (FRCS Tr&Orth), trained at Guy's and St Thomas' and in Toronto and Calgary, and a member of BOFAS and EFAS. He sees patients privately at The London Clinic, Cromwell Hospital, King Edward VII's Hospital and HCA The Shard. His NHS practice is at King's College Hospital.

Insured patients need a GP referral and an authorisation code from their insurer. Self-pay patients are welcome. To book, call 020 7046 8004.

Frequently Asked Questions

Sources

1. Sprains and strains. NHS. https://www.nhs.uk/conditions/sprains-and-strains/
2. Lamb SE, Marsh JL, Hutton JL, Nakash R, Cooke MW; Collaborative Ankle Support Trial (CAST Group). Mechanical supports for acute, severe ankle sprain: a pragmatic, multicentre, randomised controlled trial. Lancet. 2009;373(9663):575–581. PMID: 19217992. https://pubmed.ncbi.nlm.nih.gov/19217992/
3. Valderrabano V, Hintermann B, Horisberger M, Fung TS. Ligamentous posttraumatic ankle osteoarthritis. Am J Sports Med. 2006;34(4):612–620. PMID: 16303875. https://pubmed.ncbi.nlm.nih.gov/16303875/

Related: Lisfranc injury (often mistaken for a sprain) on anklefracturesurgeon.co.uk