Ankle fractures are fractures that can involve the distal tibia, distal fibula, talus, and calcaneus.They are relatively common injuries.¹

Anatomy of the ankle joint

There are two joints that allow movement of the ankle:

• The true ankle joint (tibiotalar joint) - articulation is between the lower end of the tibia, the two malleoli and the body of the talus. This joint allows dorsiflexion and plantar flexion of the ankle.
• The subtalar joint - articulation is between the talus and calcaneus. This joint allows inversion and eversion of the ankle.

The distal tibia has a prominent medial malleolus and a less prominent posterior malleolus. The distal fibula is known as the lateral malleolus. The joint capsule and the surrounding ligaments stabilise the ankle. The distal fibula is joined to the distal tibia by the anterior and posterior inferior tibiofibular ligaments, an inferior transverse ligament, and a syndesmosis ligament.² The anterior and posterior talofibular ligaments join the fibula to the talus. The talus is joined to the calcaneus by the calcaneofibular ligament.² The deltoid ligament joins the medial malleolus to the talus, calcaneus, and navicular bones.²

Assessment of an ankle injury

History and examination of ankle injuries are discussed in detail in the Ankle Injuries article. Please refer to this article. However, some key points for suspected ankle fractures are detailed below.

Principles of care for ankle fractures¹

When assessing ankle fractures, consider:

• What was the mechanism of injury (inversion, eversion, plantar flexion, dorsiflexion)? This can help to determine the nature and severity of the injury.
• Are there associated injuries (ligamentous, capsular, vascular)?
• Does the ankle need immobilising?
• Is specialist orthopaedic referral needed?

Examination

• Ankle fractures and ankle sprains can present in a similar way.
• Features that may suggest a fracture include: obvious deformity, swelling, bruising, inability to weight-bear and bony tenderness.¹
• The patient should also be assessed and examined for co-existing injuries.

Investigations

• Not everyone with an ankle injury needs to have an X-ray.
• The Ottawa rules should be applied to see whether an X-ray is indicated.³
• Please refer to the 'Internet further reading link' below for diagrams and details explaining the Ottawa rules in relation to anatomy and tender points. The Ottawa rules are discussed further in the article dealing with ankle injuries.
• If an X-ray is performed, anteroposterior, lateral and mortice views can be taken.^1,2
• CT or MRI scans are sometimes needed for:
  • Identification of subtle fractures, e.g. talar fractures, which can be difficult to see on plain X-ray.
  • Assessment of ligamentous or intra-articular injuries.

Classification of ankle fractures⁴

There are various ways of classifying ankle fractures. The Danis-Weber classification is simple and is probably the most useful for primary care (see below). The Lauge-Hansen system is another classification in popular use: it links specific fracture patterns with the mechanism of injury.

The Danis-Weber classification is based on the fibular fracture in relation to the syndesmosis on radiography (this refers to the syndesmosis between tibia and fibula):

• Type A: fibular fracture below the syndesmosis, which is intact.
• Type B: fibular fracture at the level of the syndesmosis.
• Type C: fibular fracture above the syndesmosis, indicating rupture of the syndesmosis.

In addition, a simple classification based on the malleoli involved can be used, as this has implications for joint stability and further management options:

• Monomalleolar fracture
• Bimalleolar fracture:
  • Sometimes the deltoid ligament ruptures instead of the medial malleolus being fractured; this is equivalent to a bimalleolar fracture and is treated similarly.⁵
• Trimalleolar fracture (the third malleolus being the 'posterior malleolus', i.e. the posterior part of the distal tibia).

Some eponymous ankle fractures¹

• Pott's fracture: this is a term less used now. It loosely refers to fractures and fracture-dislocations of the distal tibia and fibula (bimalleolar fractures), involving at least two elements of the ankle ring. These fractures are unstable and require urgent treatment.
• Pilon fracture: a fracture of the distal tibial metaphysis and also disruption of the talar dome. The talus is 'driven' into the tibia as may happen in a fall from a height or a foot braced against the floor of a car in a collision. The fracture may be open. There may be associated injuries, e.g. spinal compression fractures or pelvic injury.
• Maisonneuve fracture: the combination of a proximal fibular fracture with a medial malleolar fracture or disruption of the deltoid ligament. There is partial or complete disruption of the syndesmosis.
• Snowboarder's fracture: this is a fracture of the lateral process of the talus produced by dorsiflexion and inversion of the ankle. The patient complains of lateral ankle pain. The fracture may not be evident on X-ray and may need CT scanning for diagnosis. Have a high index of suspicion for this fracture in snowboarders who complain of lateral ankle pain.

Management^1,4

Initial management

1. As with any trauma patient, carry out a primary survey following the 'ABCDE' principles of trauma care.
2. Assess clinically for obvious deformity and for neurovascular status.
   • If there is neurovascular compromise or dislocation (obvious deformity) of the joint, the fracture should be reduced immediately - before X-ray - under analgesia or sedation.
   • Displaced fractures should be reduced as soon as possible after initial assessment - this reduces pain/swelling and may prevent skin necrosis.
   • Assessment of neurovascular status is by testing sensation over the dorsal and plantar surfaces of the foot, measuring capillary refill in all digits, and palpating the distal pulses (although the dorsalis pedis artery is absent in 2-3% of the population).
3. Open fractures should be covered with a wet, sterile dressing secured by loosely wrapped dry sterile gauze. Check tetanus immunisation; consider antibiotic prophylaxis.
4. Provide analgesia if required.
5. Full history, examination and X-rays (see separate Ankle Injuries article).
6. Once reduced, stabilise the fracture in a well fitted backslab cast.
7. Elevate the limb.
8. Re-assess neurovascular status to ensure there has been no compromise during the reduction.
9. Arrange post-reduction X-rays to confirm adequate fracture reduction.

Further management

Consider whether the fracture is stable or unstable. Unstable ankle fractures include:

• Fracture dislocation.
• Bimalleolar or trimalleolar fractures.
• Any lateral malleolar fracture with substantial talar shift.

As with all fractures, aim to reduce the fracture, maintain reduction, promote healing and restore function. This can be achieved both conservatively and operatively.

Conservative treatment

Conservative treatment (in a cast) can can be considered for:

• Non-displaced fractures or anatomically reduced fractures - although functional outcome may be better if treated operatively.
• Patients with serious comorbidities who are not fit for surgery.

Conservative treatment comprises:

• A well moulded cast for 4-6 weeks - following this, weight-bearing can be resumed.
• Serial radiographs to ensure the reduction, joint congruity and healing are maintained (e.g. repeat radiographs immediately after reduction, at 48 hours, at 7 days, and then at two-weekly intervals).
• Consider operative treatment if the fracture fails to heal or displaces.
• One audit found that some stable fractures may be more effectively treated in a functional brace than a cast, and do not need further X-rays.⁶

Operative treatment

Operative treatment involving open reduction and internal fixation is considered for:

• Displaced unstable fractures.
• Talar subluxation.
• Joint incongruity.
• Bimalleolar or trimalleolar fractures - >25-30% involvement of the plafond or >2 mm step off.
• Syndesmotic disruption:
  • Weber C fractures; some Weber B fractures.
  • Tibiofibular clear space of ≥6 mm on anteroposterior radiography.

Complications¹

• Infection.
• Compartment syndrome.
• Vascular compromise and foot ischaemia.
• Deep vein thrombosis (secondary to immobilisation).
• Fracture non-union and malunion.
• Poor wound healing.⁷
• Osteoarthritis (especially talus fractures).
• Reduced movement at the ankle (calcaneal fractures can compromise inversion and eversion).
• Ankle fractures involving the growth plate in children can lead to deformity and growth disturbance.

Document references

1. Iskyan K et al, Ankle Fracture in Emergency Medicine, Medscape, Feb 2010
2. Mulligan ME, Imaging in Ankle Fractures, Medscape, May 2011
3. Ottawa Ankle Rules; Ankle Injury - X-ray for acute injury of the ankle and foot. Guidelines and Protocols Advisory Committee, British Columbia, January 2009.
4. Mordecai S, Al-Hadithy N; Management of ankle fractures. BMJ. 2011 Oct 28;343:d5204. doi: 10.1136/bmj.d5204.
5. Small K; Ankle sprains and fractures in adults. Orthop Nurs. 2009 Nov-Dec;28(6):314-20. [abstract]
6. Jain N, Symes T, Doorgakant A, et al; Clinical audit of the management of stable ankle fractures. Ann R Coll Surg Engl. 2008 Sep;90(6):483-7. [abstract]
7. Srinivasan CM, Moran CG; Internal fixation of ankle fractures in the very elderly. Injury. 2001 Sep;32(7):559-63. [abstract]

Internet and further reading

• O'Keeffe D, Nicholson DA, Driscoll PA, et al; ABC of emergency radiology. The ankle. BMJ. 1994 Jan 29;308(6924):331-6. [abstract]
• Ankle Joint Menu, Wheeless' Textbook of Orthopaedics
• Paediatric ankle fractures, Wheeless' Textbook of Orthopaedics
• Shariff SS, Nathwani DK; Lauge-Hansen classification--a literature review. Injury. 2006 Sep;37(9):888-90. Epub 2006 Aug 8. [abstract]