Ankle Fracture Flashcards
Briefly describe the anatomy of the ankle joint
The ankle is comprised of the talus bone articulating within the mortise; the mortise is comprised of the tibial plafond and medial malleolus (the distal end of the tibia) and the lateral malleolus (the distal end of the fibula).
The tibia and fibula are joined at the syndesmosis.
What is the syndesmosis?
The tibia and fibula are joined at the syndesmosis, a very strong fibrous structure comprised of the anterior inferior tibiofibular ligament (AITFL), posterior inferior tibiofibular ligament (PITFL) and the intra-osseous membrane.
What is an ankle fracture?
An ankle fracture is a fracture of any malleolus (lateral, medial, or posterior), with or without disruption to the syndesmosis.
What are the different types of ankle fractures?
Ankle fractures can be described anatomically. Crudely, they can be described as:
- Isolated lateral malleolar fractures
- Isolated medial malleolar fractures
- Bimalleolar fractures ( = medial + lateral malleolar fracture)
- Trimalleolar fractures ( = medial + lateral + posterior malleolar fracture)
Briefly describe the Weber Classificaiton of ankle fractures
Weber classification, which classifies lateral malleolus fractures:
- Type A = below the syndesmosis
- Type B = at the level of the syndesmosis
- Type C = above the level of the syndesmosis
In addition to Weber Classification, what classification system is based on the ankle position at the time of injury and the deforming force involved?
Lauge-Hansen classification.
What are the clinical features of an ankle fracture?
Patients will often present with ankle pain following a traumatic injury. There may be associated deformity in cases of fracture dislocation (which require urgent reduction).
Very deformed ankles, which are common, may have neurovascular compromise and are often open fractures (typically over the medial side), so be sure to carefully check the skin integrity.
Briefly describe Ottawa Ankle Rules
Where there is diagnostic uncertainty, for example where the patient is able to mobilise and has no deformity, the ‘Ottawa rules’ can be employed.
These state that in the presence of any of the below features, plain radiographs must be undertaken:
- Bone tenderness at the posterior edge or tip of the lateral malleolus, OR
- Bone tenderness at the posterior edge or tip of the medial malleolus, OR
- An inability to bear weight both immediately and in the emergency department for four steps
Whilst useful, they cannot be used in cases if the patient is intoxicated or uncooperative, has other distracting painful injuries, has diminished sensation in their legs, or has gross swelling.
What investigations should be ordered for an ankle fracture?
A plain radiograph should be obtained in all suspected cases, with both AP and lateral views. Check the joint space for uniformity, ensuring no evidence of talar shift.
Complex ankle fractures, particularly where there is a displaced posterior malleolus fragment, will require a CT scan for surgical planning.
When plain radiographs are being taken why does the ankle need to be dorsiflexed?
It is essential that, when radiographs are taken, the ankle is in full dorsiflexion; this is because the talus, which is narrower posteriorly, can appear translated within the mortise when the ankle in plantarflexed.
What is shown in the image?
Ankle fracture (Weber C) show on plain film radiograph, in AP and lateral views.
Briefly describe the initial management of an ankle fracture
Initial management requires immediate fracture reduction, usually performed under sedation in the Emergency Department, to realign the fracture to anatomical alignment. Any patients that have with evidence of an open fracture should be managed accordingly.
Once reduced, the ankle should be placed in a below knee back slab. You must then repeat and document the post-reduction neurovascular examination. Request a repeat plain film radiography; if the reduction is not adequate, repeat reduction attempts are required.
Briefly describe consevative management of ankle fractures
Conservative management will often be opted for in:
- Non-displaced medial malleolus fractures
- Weber A fractures or Weber B fractures without talar shift
- Those unfit for surgical intervention
Briefly describe the surgical management of ankle fractures
Open reduction and internal fixation (ORIF) is often required in ankle fractures to achieve stable anatomical reduction of the talus within the ankle mortise. Ankle fractures that require an ORIF include:
- Displaced bimalleolar or trimalleolar fractures
- Weber C fractures
- Weber B fractures with talar shift
- Open fractures
The type of operative procedure performed depends on the specific type of ankle fracture sustained.
What are the complications of an ankle fracture?
The main complication following an ankle fracture is the risk of post-traumatic arthritis, however this is rare in cases with appropriate reduction and fixation.
Those who have undergone an ORIF have addition risk factors include surgical site infection, DVT or PE, neurovascular injury, non-union and metalwork prominence.
