In short
Ankle instability means the ankle repeatedly gives way or feels wobbly, usually after one or more sprains have stretched the outer ankle ligaments. Balance and strengthening physiotherapy, and a brace for sport, help most people. If the ankle keeps giving way, a ligament repair (modified Broström-Gould) or reconstruction restores stability in around 9 out of 10 patients, and arthroscopy can treat problems inside the joint at the same time.
What is ankle instability?
Chronic ankle instability is when the ankle frequently “gives way”, rolls or feels unreliable, often on uneven ground, during sport, or even when walking. It usually affects the lateral (outer) ankle ligaments.
What causes it?
- Ligament injury. Repeated sprains stretch or tear the ligaments so they no longer hold the joint firmly. A single severe sprain that did not heal properly can do the same.
- Incomplete rehabilitation after an earlier sprain.
- Reduced proprioception. Ligament damage affects the joint’s position sense, so the muscles react too slowly.
- Weak peroneal muscles on the outside of the leg.
- Foot shape. A high-arched foot or heel that tilts inwards directs force to the outer ankle.
- Other problems inside the joint, such as loose fragments, scar tissue or cartilage damage, which can cause pain-related giving way (pseudo-instability).
What are the symptoms?
- Repeated sprains or rolling of the ankle
- The ankle giving way, especially on uneven surfaces
- Ongoing pain, swelling or tenderness on the outer side
- A feeling of wobbliness and lack of confidence in the ankle
- Difficulty with sports involving turning, jumping or running
Treatment without surgery
- Physiotherapy. Strengthening (especially the peroneal muscles), balance and proprioceptive training, and stretching.
- Bracing or taping for sport and uneven ground.
- Supportive footwear.
- Activity modification while rehabilitation progresses.
Surgery
If the ankle keeps giving way despite good rehabilitation, surgery can restore stability:
- Modified Broström-Gould repair. The stretched lateral ligaments are tightened and reattached to the bone, reinforced with nearby tissue.
- Ligament reconstruction. A tendon graft replaces ligaments that are too poor to repair.
- Ankle arthroscopy. Keyhole surgery to remove loose fragments, scar tissue or treat cartilage damage. This can be done at the same time.
- Osteotomy. Realigning the heel bone when foot shape is contributing.
Images from Prof Mason's practice
X-rays shown with patient identifiers removed. Results vary between patients.
Common questions
How successful is ankle stabilisation surgery?
Success rates are high. Most studies report significant improvement in stability in around 90 to 95% of patients, with good pain relief and return to normal activities and sport, sustained over the long term. Outcomes are better when the original damage is less severe and the rehabilitation programme is followed closely. Arthritis or other foot problems can affect the result.
What is the recovery after ankle instability surgery?
Usually a short period in a boot, then gradual weight-bearing and physiotherapy starting between two and six weeks after surgery. Return to sport and high-impact activities generally takes three to six months.
Can ankle instability lead to other problems?
Yes. Repeated sprains can damage the cartilage of the ankle (osteochondral injury), injure the peroneal tendons on the outside of the ankle, and over many years contribute to ankle arthritis. Treating instability helps protect the joint.
Do I need a scan?
Diagnosis is mainly clinical, from your history and examination. An MRI or ultrasound may be used to look at the ligaments, cartilage and tendons, especially before surgery.
Talk it through with a specialist
Consultations at Spire Liverpool, Salford and the Isle of Man. New patients £250.
Consultant Foot and Ankle Surgeon, MB BCh, PhD, FRCS (Tr&Orth), FRCS (Glasg), SFHEA, FFSTEd. GMC 6074953. Hunterian Professor, Royal College of Surgeons of England.
Page last reviewed 25 October 2026. This information is general and does not replace an assessment.
Prof Mason's published research on this topic
Peer-reviewed papers by Prof Mason and his colleagues. Links open the paper or its PubMed record.
- Usuelli FG, Mason LW, Maccario C, Grassi M, Ballal M, Molloy A. Lateral ankle and hindfoot instability: a new clinical based classification. Foot and Ankle Surgery, 2014.
- Tanaka H, Mason LW. Chronic ankle instability (review). Orthopaedics and Trauma, 2011.
- Gomaa A, Mason L. Chronic syndesmotic instability: current evidence on management. Journal of Clinical Orthopaedics and Trauma, 2024.
- Lambert L, Mangwani J, Davies M, Molloy A, Mason LW. Lateral transligamentous approach to the talar dome. Foot and Ankle Surgery, 2020.