Ankle Fracture
Causes
Ankle fracture typically results from trauma: [Ref]
- Twisting injuries (e.g. falling, tripping, or participating in sports activities)
- Impact injuries (axial loading) (e.g. fall from height)
- Crush injuries (e.g. road traffic accidents, compressed by a heavy object)
Types and Classification
Anatomical Classification
Classified based on which malleolus is involved: [Ref]
- Isolated medial malleolus fracture
- Isolated lateral malleolus fracture
- Bimalleolar ankle fracture (most commonly medial + lateral)
- Trimalleolar ankle fracture (medial + lateral + posterior)
Danis-Weber Classification
Classified based on the distal fibular fracture location relative to the syndesmosis (fibrous joint connecting the tibia and fibula): [Ref]
- Weber type A: fibular fracture is below the syndesmosis (these fractures are typically stable)
- Weber type B: fibular fracture is at the same level as the syndesmosis
- Weber type C: fibular fracture is above the syndesmosis (these fractures are usually unstable)
Clinical Features
Typically present after a traumatic event with:
- Acute ankle pain
- Swelling around the ankle
- Brusing
- Tenderness over the malleoli
- Reduced range of movement
- Difficulty or inability to weight bear
- Visible deformity is possible
Maisonneuve injury = ankle fracture + proximal fibular fracture
Investigation and Diagnosis
Initial investigation: X-ray
The decision to perform an X-ray after an ankle injury should be guided by the Ottawa ankle rules, which help identify those who may have a bony fracture, rather than a soft tissue injury (e.g ankle sprain)
As per the Ottawa ankle rule, an ankle X-ray is indicated if there is pain in the malleolar zone PLUS any of the following:
- Bony tenderness at the posterior edge or tip of the lateral malleolus
- Bony tenderness at the posterior edge or tip of the medial malleolus
- Inability to weight bear (usually defined as inability to take 4 steps)
If an X-ray is not indicated, a clinically significant ankle fracture is less likely, and a soft tissue injury such as an ankle sprain is more likely.
Consider further imaging with CT in more complex fracture patterns (esp. when the posterior malleolus is involved)
Management
If the patient has a clinically deformed ankle → urgent X-ray → urgent reduction and splinting of the ankle
Exception: if waiting for X-ray will cause an unacceptable delay → urgent reduction
Indications for operative management (ORIF), ANY of the following: [Ref]
- Presence of neurovascular deficit
- Unstable ankle fractures, ANY of the following
- Weber type C ankle fracture
- Bimalleolar or trimalleolar fractures
- Fracture-dislocation
- X-ray showing talar shift or widened medial clear space (suggestive of deltoid ligament injury)
- Failed closed reduction
- Open fractures (also require IV empirical antibiotics and urgent orthopaedic assessment)
For stable fracture with no indications for surgery, treat conservatively with:
- Analgesia
- Immobilisation with splinting
- Weight-bearing as tolerated