Not every ankle sprain needs an X-ray. A clear guide to the Ottawa ankle rules, what to do in the first few days, rehabilitation and the warning signs that mean you should see a doctor.
On this page 8 sections
- What is an ankle sprain and which ligaments are injured?
- What are the symptoms of an ankle sprain?
- When do you need an X-ray? The Ottawa ankle rules
- What can you do at home in the first few days?
- Rehabilitation and returning to sport
- Recurrent sprains and when surgery is considered
- When should you see a doctor?
- Key points
An ankle sprain is a stretch or tear of the ligaments on the outer side of the ankle, usually caused by the foot suddenly rolling inwards. Most sprains heal without surgery, with sensible loading and a structured exercise programme, and not every sprain needs an X-ray. Doctors decide using simple examination criteria such as the Ottawa ankle rules: an X-ray is advised if pressing on specific points of the ankle bones is painful, or if you were unable to take four steps both straight after the injury and when you were examined.
Below we explain how sprains are graded, which symptoms suggest a more serious injury, how to look after the ankle at home and what can be done when sprains keep recurring. Treatment is always planned individually after examination and, where needed, imaging.
What is an ankle sprain and which ligaments are injured?
The ankle joint is formed by the shinbone (tibia), the thinner outer leg bone (fibula) and the talus, held together by strong bands of tissue called ligaments. The most common sprain is an inversion injury, in which the foot twists inwards and downwards. The anterior talofibular ligament is usually injured first; in more forceful injuries the calcaneofibular ligament is also involved. Injuries to the inner (deltoid) ligament are less common.
A less familiar type is the "high ankle sprain", an injury to the syndesmosis, the ligaments binding the tibia and fibula together just above the joint. It typically follows an outward twist of the foot and usually takes longer to recover than a standard sprain.
How sprains are graded
Clinicians grade a sprain according to how badly the ligament is damaged. The table below is a general guide only; recovery time varies with age, activity level and any associated injuries.
| Grade | Ligament damage | Typical findings | Approximate recovery |
|---|---|---|---|
| Grade 1 (mild) | Stretching, microscopic tears | Mild swelling and tenderness; walking usually possible | A few days to 2-3 weeks |
| Grade 2 (moderate) | Partial tear | Obvious swelling and bruising; difficulty bearing weight | Around 3-6 weeks |
| Grade 3 (severe) | Complete tear | Widespread swelling and bruising; the ankle feels loose | May take several months |
What are the symptoms of an ankle sprain?
A tearing or popping sensation at the moment of injury, followed by pain and swelling on the outside of the ankle, is typical. Bruising often appears after a day or two and may track down towards the heel; on its own this does not mean the injury is serious. Common symptoms include:
- Pain and tenderness on the outer side of the ankle, in front of and below the bony bump
- Swelling and bruising
- Difficulty putting weight through the foot, going downstairs or walking on uneven ground
- A feeling that the ankle is giving way or cannot be trusted
- Reduced ankle movement
Pain directly over the bony bumps, rather than over the softer area where the ligaments run, raises the possibility of a fracture. This is where the Ottawa rules come in.
When do you need an X-ray? The Ottawa ankle rules
The Ottawa ankle rules are a well-validated examination guide developed to reduce unnecessary X-rays in emergency departments. In someone with pain around the ankle, a doctor will request an ankle X-ray if any of the following is present:
- Tenderness when pressing on the back edge or tip of the outer ankle bone (lateral malleolus), within its lowest 6 centimetres or so
- Tenderness at the back edge or tip of the inner ankle bone (medial malleolus)
- Inability to take four steps, even with a limp, both immediately after the injury and at the time of examination
If the pain extends into the middle of the foot, similar criteria are used to decide on a foot X-ray: tenderness at the base of the fifth metatarsal on the outer edge of the foot, tenderness over the navicular bone on the inner side, or inability to take four steps.
The rules are meant to guide the examining clinician, not for self-diagnosis. In young children, older adults, people with reduced sensation in the feet (for example from diabetic nerve damage) or several injuries, the doctor may request an X-ray regardless.
If the X-ray is normal, are other tests needed?
An X-ray shows fractures but not ligaments, cartilage or tendons. Most sprains need no further tests; more imaging is considered when pain does not settle as expected, or the ankle locks or catches.
| Test | What it shows | When it is considered |
|---|---|---|
| X-ray | Fractures, small bone fragments pulled off, joint alignment | When the Ottawa criteria are positive or the doctor feels it is needed |
| Ultrasound | Ligament and tendon tears, fluid in the joint | To assess the extent of ligament damage |
| MRI | Cartilage damage, bone marrow oedema, syndesmosis and tendon injuries | If pain is not easing after several weeks or an associated injury is suspected |
| CT scan | Detailed fracture anatomy | For planning treatment of complex fractures |
Injuries that can mimic or accompany a sprain include a fracture at the base of the fifth metatarsal, a cartilage injury of the talus (osteochondral lesion) and damage to the peroneal tendons behind the outer ankle bone. In growing children the ligaments are stronger than the growth plates, so an apparent sprain may also involve a growth plate.
What can you do at home in the first few days?
For mild and moderate sprains, the early aims are to control pain and swelling and protect the ligament without keeping the ankle still for too long. Unless your doctor advises otherwise:
- Protect: For the first day or two avoid movements that clearly increase the pain; use crutches for a short time if needed.
- Cool: Apply ice wrapped in a cloth, never directly on the skin, for 15-20 minutes at a time.
- Compress and elevate: An elastic bandage helps to limit swelling; keep the foot above the level of your heart when resting. The bandage should never be tight enough to cause numbness or colour change in the toes.
- Load gradually: Starting to put weight through the foot early, as pain allows, generally helps recovery more than prolonged rest.
- Support: A lace-up or semi-rigid ankle brace, or taping, protects the joint while still allowing you to move, especially after a moderate sprain.
Heat, vigorous massage and alcohol are not advised in the first 48-72 hours because they can increase swelling. Ask your doctor or pharmacist about pain relief. After a severe sprain a short period in a walking boot or cast may be recommended, depending on the examination.
Rehabilitation and returning to sport
Once pain and swelling settle, rehabilitation becomes the priority. A common problem after a sprain is loss of the ankle's sense of balance and position (proprioception), so a programme should include balance work as well as strengthening:
- Stretching and mobility exercises to restore the ankle's range of movement
- Resistance-band work to strengthen the peroneal muscles, which turn the foot outwards
- Balance and coordination training, such as standing on one leg or using a wobble board
- Graded sport-specific drills such as running, hopping and changing direction
Return to sport depends on function rather than the calendar: full movement, hopping on the injured leg without pain, and strength and balance close to the other side. Taping or a brace during the first months back can help reduce the chance of another sprain. For more on how regular exercise supports the joints, see our article on exercises to protect joint health, and for other common sporting injuries, our guide to knee injuries in athletes.
Recurrent sprains and when surgery is considered
In some people the ankle keeps giving way months after the original injury and sprains again and again. This is known as chronic ankle instability. It may be caused by ligaments that healed in a lengthened position, incomplete recovery of balance, or both. Alignment differences, such as a high-arched foot with the heel tilted inwards, can also make repeated sprains more likely.
The first step is always a consistent rehabilitation programme of adequate length. If instability persists despite several months of appropriate rehabilitation, surgical options may be considered:
- Anatomical ligament repair: the stretched outer ligaments are shortened and reattached to the bone
- Ligament reconstruction: if the ligament tissue is poor, a new ligament is created using a tendon graft
- Arthroscopy: keyhole assessment and treatment of cartilage damage or tissue catching inside the joint
- Alignment correction: if a bony cause such as a marked heel tilt is present, it may be corrected with an osteotomy (a controlled cut in the bone)
The procedure is chosen according to the examination, imaging, activity level and expectations. You can read more about the management of sport-related ligament and cartilage injuries on our sports surgery page.
When should you see a doctor?
Most mild sprains improve noticeably within a few days of home care. An orthopaedic assessment is advisable if you notice any of the following:
- Being unable to take four steps straight after the injury and afterwards
- Marked tenderness when pressing on the ankle or foot bones
- A visible change in the shape of the ankle
- Numbness, tingling, coldness or colour change in the foot; in this case go to an emergency department without delay
- Swelling and pain that increase after 48-72 hours, or no clear improvement within a week
- Pain lasting longer than six weeks, or a feeling of locking or catching in the joint
- Repeated sprains and an ankle that still feels unreliable
- Any significant sprain in a growing child, or in someone with a condition such as diabetes that reduces sensation in the feet
At the examination, an orthopaedic surgeon assesses the ligaments, joint stability and any associated injuries, and decides on imaging and treatment on that basis.
Key points
- An ankle sprain is usually a stretch or tear of the outer ankle ligaments, and most are treated without surgery.
- The need for an X-ray is decided with examination criteria such as the Ottawa rules; bony tenderness and being unable to take four steps are key signs.
- In the first few days, protection, ice, compression, elevation and gradual loading as pain allows are recommended.
- Balance and strengthening exercises help reduce the risk of further sprains.
- Persistent pain or repeated sprains call for further assessment and an individual treatment plan.
Frequently Asked Questions
It is difficult to be certain at home, because both sprains and fractures can cause marked swelling and bruising. Sharp pain when pressing directly on the bony bumps of the ankle, and being unable to take even a few steps after the injury, make a fracture more likely. In that situation an assessment by a doctor, with an X-ray if indicated, is recommended.
For mild and moderate sprains, gradually putting weight on the foot as pain allows generally supports healing and helps prevent the stiffness that comes with prolonged rest. However, if you cannot take four steps, or weight-bearing is very painful, a fracture should be ruled out first. After a severe sprain your doctor may suggest crutches or a walking boot for a short period.
Swelling is usually most noticeable in the first 48-72 hours and then gradually goes down. After a mild sprain it may largely settle within one or two weeks, whereas after moderate or severe sprains some swelling can persist for several weeks, particularly at the end of the day. Swelling that increases over time, or pain that does not ease, should be checked by a doctor.
The length of time depends on the grade of sprain and your daily activities. After a moderate sprain a brace is often worn for everyday activities for a few weeks and then reduced as the exercise programme progresses. People returning to sport may be advised to use a brace or tape during training and matches for the first few months. A brace does not replace balance and strengthening exercises.
Repeated sprains are often linked to ligaments that healed in a lengthened position after an earlier injury, or to balance that has not fully recovered. Alignment differences such as a high arch with an inward-tilted heel, muscle weakness or cartilage damage inside the joint can also play a part. An examination is needed to identify the cause, and treatment usually begins with a structured rehabilitation programme.
This article is for general information only and does not replace a medical examination, diagnosis or treatment. Treatment options and outcomes vary from person to person.
Related treatment area Sports Surgery: Treating Knee, Shoulder and Ankle Injuries
