Overview
An ankle sprain occurs when the ligaments supporting the ankle are overstretched or torn, usually when the foot rolls inward (inversion injury), straining the lateral ligaments. It is one of the most common musculoskeletal injuries. Most sprains heal fully with appropriate management, though inadequate rehabilitation leads to chronic instability.
How common is it?
Ankle sprains are extremely common — approximately 300,000 occur in the UK each year. They account for about 3 to 5% of all A&E attendances and are particularly prevalent in athletes.
Causes and risk factors
Sudden uncontrolled inversion or eversion of the foot stresses the ankle ligaments beyond their tensile capacity, causing fibres to stretch or tear.
Common risk factors
- Running on uneven terrain
- Landing awkwardly from a jump
- Contact sports: football, basketball, netball
- Previous ankle sprain (single biggest risk factor for recurrence)
- Wearing high heels
- Muscle weakness or fatigue
- Poor proprioception (joint position sense)
Symptoms
- Immediate pain and tenderness over the lateral (outer) or medial (inner) ankle
- Swelling and bruising developing over hours
- Difficulty bearing weight (in moderate to severe sprains)
- Feeling of instability or 'giving way'
- Stiffness and reduced ankle movement
When to see a doctor
Apply Ottawa Ankle Rules for X-ray: bone tenderness over the base of the 5th metatarsal or navicular, or inability to bear weight for 4 steps immediately after injury, warrants X-ray to exclude fracture.
Diagnosis
Clinical examination assessing tenderness location, stability (anterior drawer test), and range of movement. X-ray if Ottawa criteria met. MRI for suspected ligament rupture or osteochondral injury in complex cases.
Treatments
PRICE protocol (first 48 to 72 hours)
Protection, Rest, Ice (15 to 20 minutes every 2 hours), Compression (tubigrip or wrap), Elevation above heart level. Reduces swelling and pain in the acute phase.
Early mobilisation and physiotherapy
Once acute pain allows, early movement and weight-bearing as tolerated produce faster, more complete recovery than immobilisation. Physiotherapy with proprioceptive and strength exercises prevents re-injury.
Functional bracing
Semi-rigid ankle brace during rehabilitation and return to sport. More effective than cast immobilisation for grade II and III sprains in terms of return to sport time.
Surgery
Reserved for complete ligament rupture in athletes who fail 3 to 6 months of rehabilitation and have persistent instability. Brostrom-Gould ligament reconstruction has excellent outcomes.
Self-care and lifestyle
- Complete the full rehabilitation course before returning to sport
- Use a prophylactic ankle brace for high-risk sports for at least 6 months after an ankle sprain
- Balance and proprioception training (wobble board) specifically reduces re-sprain risk
- Replace worn-down sports footwear
Prevention
Proprioceptive training and ankle strengthening exercise programmes reduce ankle sprain incidence by 35 to 50% in athletes. Ankle bracing provides additional protection during the first year after a significant sprain.