Stable ankle fracture
A break in one of the ankle bones (most often the lateral malleolus - the bony bump on the outside of the ankle) where the joint remains in good alignment. Most stable ankle fractures heal well with a boot or cast rather than surgery.
📊 Ankle fractures account for around 9% of all fractures in adults, with stable patterns making up approximately 60-70% of cases. They are particularly common in older women due to bone density loss.
What is a stable ankle fracture?
The ankle joint is held together by the tibia (shin bone), fibula (outer leg bone), and talus (a foot bone). The lower ends of the tibia and fibula form the "mortise" - the socket that holds the talus in place. The bony prominences you can feel are the medial malleolus (inside) and lateral malleolus (outside). An ankle fracture is a break in any of these bones.
The crucial question is not just whether a bone is broken, but whether the joint remains stable. Stability depends on two things: the bone alignment, and the integrity of the ligaments. A stable fracture is one where the bones remain in good position and the talus sits correctly in the mortise. The most common stable pattern is an isolated, undisplaced or minimally displaced fracture of the lateral malleolus (Weber A or B without medial-sided injury).
Stable fractures heal well without surgery in most cases. Treatment is in a walking boot or below-knee cast, with progressive weight-bearing as the bone heals. Healing typically takes 6-8 weeks. The distinction between a stable and unstable fracture is critical and is made based on careful clinical examination and weight-bearing X-rays - it cannot reliably be made from a single non-weight-bearing X-ray.
Common mechanisms
- Twisting injury - foot rolls inwards or outwards while bearing weight (most common)
- Fall from standing height
- Sports injury - particularly football, netball, basketball
- Step off a kerb or down stairs
- Low-energy injuries in older adults with reduced bone density
Who is at risk? Risk factors include female sex, age over 50, post-menopausal status, osteoporosis, vitamin D deficiency, smoking, and previous ankle injury. Sport participation also contributes in younger patients.
Symptoms
Symptoms typically begin at the time of injury and can vary depending on the severity:
- Sudden pain at the time of injury, often after a twisting movement
- Inability to weight-bear immediately afterwards, though some patients can hobble
- Rapid swelling and bruising around the ankle
- Tenderness directly over the broken bone (rather than the ligaments)
- Visible deformity in displaced fractures
- Pain with attempts to move the ankle
When to seek help: Attend A&E on the day of injury if you suspect a fracture. The Ottawa Ankle Rules guide A&E doctors on whether X-rays are needed - bone tenderness over the malleoli or inability to weight-bear for 4 steps usually warrants X-rays.
How is it diagnosed?
Your foot and ankle specialist will take a detailed history and examine the foot. The following investigations may be arranged to confirm the diagnosis:
- X-rays - the standard imaging. Three views (AP, lateral, mortise) of the ankle
- Weight-bearing X-rays - essential to confirm stability when there is doubt. Subtle widening of the joint on standing indicates instability and changes management
- CT scan - sometimes needed to define complex fracture patterns
- MRI - rarely needed acutely, but useful for assessing associated ligament injuries
The Weber classification (A, B, C) describes the level of fibula fracture. Weber A and Weber B fractures without medial-sided injury are usually stable. Weber C fractures and any fracture with medial malleolar fracture or deltoid ligament injury are usually unstable and require surgery.
Treatment pathway
Treatment depends on the severity of the injury, your age, and your activity demands. Many injuries can be managed without surgery; others require surgical fixation.
Initial immobilisation
A backslab (half-cast) or removable walking boot for the first 1-2 weeks to allow swelling to settle. Strict elevation, ice, and rest. Crutches with non-weight-bearing or partial weight-bearing as advised.
Walking boot, progressive weight-bearing
Most stable fractures are managed in a removable walking boot rather than a cast. Modern evidence supports early weight-bearing, which reduces stiffness and accelerates rehabilitation without compromising healing.
Out of boot, transition to shoes
X-rays confirm union (bone healing). Out of the boot and back into supportive shoes. Physiotherapy begins for range of movement, strength, and balance.
Surgery if displacement increases
Around 5-10% of fractures initially thought to be stable will displace during follow-up. If alignment is lost, surgery (open reduction and internal fixation with a plate and screws) may be needed.
Recovery
Recovery from a stable ankle fracture is generally smooth. Most patients are walking comfortably within 8-12 weeks. Some stiffness, swelling at the end of the day, and ache with weather changes can persist for many months and is normal. Full recovery, including return to sport, typically takes 3-6 months.
- Initial swelling and pain control: 1-2 weeks
- Walking in boot: 2-6 weeks
- Out of boot, into normal shoes: 6-8 weeks
- Walking comfortably: 8-12 weeks
- Return to sport: 3-6 months
What results can I expect?
The vast majority of stable ankle fractures heal well without surgery. Long-term outcomes are excellent for most patients, though a small minority develop ankle arthritis - particularly if there was associated cartilage damage at the time of injury. Recurrent injury risk is similar to the general population once recovery is complete.
In numbers
When can I…?
Typical activity timelines for this condition. These are approximate and vary considerably between patients. Always follow the specific guidance given by your surgeon and physiotherapist.
| Activity | Typical timeline | Notes |
|---|---|---|
| Bear weight in the boot | From the start, typically | Most stable patterns allow early weight-bearing in a removable boot, with crutches as needed for confidence.[1] |
| Drive | When out of the boot | When you can perform an emergency stop without the boot. Usually 6-8 weeks. Inform your insurer.[4] |
| Sedentary work | 1-2 weeks | Office work with the foot elevated is usually possible early. |
| Standing work | 6-10 weeks | Jobs requiring prolonged standing usually need 6-10 weeks off. |
| Return to walking | 6-10 weeks | Out of the boot once the fracture has united on X-ray, usually 6-8 weeks.[1] |
| Return to sport | 3-6 months | Gradual return guided by comfort, swelling, and strength. Stiffness can take many months to settle.[1] |
Is this normal?
Common concerns from patients with this condition or recovering from treatment, and whether they are expected or worth mentioning to your team.
Related injuries & conditions
Your questions, answered
Plain-English answers to the things people most often ask, grounded in published guidance. Tap a question to open it.
About thisWhat does a “stable” fracture mean?
A stable ankle fracture means one bone is broken but the joint is still well aligned and is not expected to shift. These often heal without an operation.
Your team confirms stability from the X-rays and how the ankle behaves.
Your choiceWill I need surgery?
Most stable ankle fractures are treated without surgery, in a supportive boot or cast while the bone heals.
Surgery is generally reserved for fractures that are or could become displaced.
Getting backHow long will I be in the boot?
Commonly around six weeks, with weight-bearing guided by your team. Swelling and stiffness can take longer to settle.
Follow-up X-rays check that healing is on track.
Getting backWhen can I drive or return to work?
Driving is reasonable once you are out of the boot and can safely and comfortably control the car, which depends on which foot and your job.
Desk work is possible sooner than jobs needing standing or lifting.
Pain & sleepHow do I manage the swelling and pain?
Keep the leg elevated as much as you can in the early weeks, use ice over the boot or cast as advised, and take regular simple pain relief.
Elevation is the single most effective thing for swelling.
UrgentWhat needs urgent review?
Increasing rather than easing pain, numbness, or cold or pale toes can mean the cast or swelling is too tight.
Calf swelling or breathlessness can signal a clot and needs urgent help.
References & further reading
- 1.NHS: Broken ankle
- 2.British Orthopaedic Foot & Ankle Society: Ankle sprain and instability patient information
- 3.British Orthopaedic Foot & Ankle Society: Ankle arthritis patient information
- 4.Royal College of Surgeons of England: Driving after surgery guidance
- 5.Ottawa Ankle Rules (decision tool for ankle injury imaging)
References are to UK clinical guidance and patient information from recognised organisations. This page is for general information and does not replace personalised advice from your own clinical team.