Ankle 1 Flashcards
Remind yourself of the bones of the foot
Remind yourself of the anatomy of the ankle
- Talus bone articulates within mortise
- Mortise composed of tibial plafond & medial malleous and the lateral malleoulus
What is a syndesmosis?
- Joint in which the bones are united by fibrous connective tissue forming an interosseous membrane and/or ligament(s).
- Tibal and fibula joined by syndesmosis
- The syndesmosis is compromised of the anterior inferior tibiofibular ligament, posterior inferirior tibiofibular ligament and teh intra-osseous membrane
What do we mean by an ankle fracture?
Fracture of any malleolus (medial, lateral or posterior) with or without disruption to the syndesmosis.
NOTE: if tibiial articular surface (plafond) is involved this is a Pilon fracture and is considered a separate injury
What is a Piloon fracture?
Fracture of the tibial articular surface (the plafond). Pts often have other fractures too
We describe ankle fractures anatomically; state the 4 types
- Isolated lateral malleolus
- Isolated medial malleolus
- Bimalleolar fractures (medial & lateral malleolar fracture)
- Trimalleolar fractures (medial & lateral & posterior malleolar fracture)
The more proximal the injury, the lower the likelihood of ankle instability; true or false?
FALE; the more proximal the injury, the higher the likelihood of ankle instability
State 2 classifications we can use to classify ankle fractures and state where/when each is commonly used
- Weber classification: most common, used in settings like A&E
- Lauge-Hansen classification: used in orthopaedic practice
Describe the Weber classification of ankle fractures
- Type A= below the syndesmosis
- Type B= at the level of the syndesmosis
- Type C= above the level of the syndesmosis
The Lauge-Hansen classification is much more detailed than the Weber classification (therefore don’t need to know too many details). What is the classification based on?
Based on:
- Ankle position at time of injury
- Deforming force involved
A proximal fibula fracture is associated with what until proven otherwise?
Proximal fibula fracture is associated with an ankle fracture or dislocation until proven otherwise
State the clinical features of an ankle fracture
- Pain
- Inability to weight bear
- Tenderness over affeccted area
- Swelling
- History of traumatic injury
- +/- associated deformity
- Neuorvascular compromise (if very deformed ankle)
What are the Ottawa ankle rules?
Set of rules to help you determine whether or not pt should have ankle x-rays based on likelihood that there is a fracture
State some circumstances in which Ottawa ankle rules cannot be used?
- Pt intoxicated or uncooperative
- Pt has other distracting painful injuries
- Diminised sensation in legs
- Gross swelling
What must you do if a pt has dislocation aswell as fracture prior to sending a pt for an x-ray?
A displaced fracture dislocation requires immediate reduction therfore if there is dislocation then it should be immediately reduced (under sedation in A&E) and a below knee backslab should be applied prior to sending pt for an x-ray. After reduction must re-do neurovascular examination
**THEREFORE, you should never see an x-ray of a dislocated ankle!
What investigations are required for suspected ankle fractures?
- X-ray of ankle/mortise (AP & lateral)
- Complex ankle fractures, such as those with displaced posterior fragment, will need CT for surgical planning
What position must the foot be during ankle x-rays and why?
- Full dorsiflexion
- Talus can appear translated within the mortise when the ankle is plantar flexed because it is narrower posteriorly
What might you see on x-ray if there is an ankle fracture?
- Fracture
- Talar shift
Discuss how you would manage an ankle fracture (think about how management differs for different classes of fracture)
Following initial x-ray, you will know if it is Webber class A,B or C. Some fractures can be managed conservatively and some require surgery. For all fractures (unless open fracture/skin integrity compromised):
- Reduce fracture under sedation in A&E
- Place ankle in below knee backslab
- Repeat & document post-reduction neurovascualr examination
- Repeat x-ray to check if reduction adequete
Conservative Management (not displaced, Webber A & B with no talar shift, unfit for surgery)
- Return in 1 week for removal of backslab and replace with full plaster
Surgical management (any displacement, talar shift or open fracture)
- ORIF
Which ankle fractures can be managed conservatively?
Whcih ankle fractures need surgical management?
Conservative
- Non-displaced medial malleolus fractures
- Weber A and Weber B without talar shift
- Those unfit for surgical intervention
Surgical
- Displaced bimalleolar or trimalleolar fractures
- Weber C fractures
- Weber B fractures with talar shift
- Open fractures
What is the difference between a backslab and full cast?
A ‘back slab’ is a slab of plaster that does not completely encircle the limb and is used for injuries which have resulted in a large amount of swelling. A ‘full cast’ encircles the limb and does not need to be secured by a bandage.
State some potential complications of ankle fractures
- Post-traumatic arthritis
- Surgical risk if undergone surgery e.g. infection, PE, DVT, neurovascular injury, non-union, metal work prominence
Which tarsal bone is most commonly fractured?
Calcaneum; often fractured following fall from height resulting in excessive axial loading
Discuss how calacneal fractures can be classified
Classified as:
- Intra-articular (75%): involves articular surface of subtalar joint. Can be further classified by Sanders classification
- Extra-articular (25%): spar the articular surface of subtalar joint; are often avulsion fractures
