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
What is an avulsion fracture?
An avulsion fracture occurs when a small chunk of bone attached to a tendon or ligament gets pulled away from the main part of the bone.
How does a calcaneal fracture present?
- Pain & tenderness around calcaneal area
- Inability to weight bear
- Swelling
- Bruising
- Heel may be shorted & widened
- May be varus deformity
What investigations are required for a calcaneal fracture?
- Initial imaging= plain film radiograph (AP, lateral & oblique views)
- Gold standard for calcaneal fractures= CT
What might you find on x-ray of a calcaneal fracture?
- Calcaneal shortening
- Varus tuberosity deformity
- Decreased Bohler’s angle
Discuss the management of calcaneal fractures
As a general rule:
- Extra-articular with minimal displacement: managed conservatively with cast immobilisatin & non-weight bearing for 10-12 weeks
- Majority of intra-articular calcaneal fractures: ORIF
State a potential complication of a calcaneal fracture
Subtalar arthritis
What is the second most common tarsal bone to fracture?
Talus
State the typical mechanism of injury of talar fractures
High energy trauma during which ankel is forced into dorsiflexion; taus presses against tibial plafond causing a fracture
What is the talus at high risk of following a fracture & why?
- Avascular necrosis
- Has extraosseous arterial supply which is highly susceptible to injury during fractures
What is Hawkin’s sign?
Subchondral lucency of talar dome visible 6-8 weeks following injury; indicative of adequete vascularity thefore low avascular necrosis risk
Describe the typical presentation of a talar fracture
- Pain
- Swelling
- Deformity
- Unable to dorsiflex or plantar flex the ankle
What investigations are required for a suspected talar fracture?
- Plain film radiographs (AP & lateral) **NOTE: lateral films should be taken in dorsi & plantar flexion to allow classification
- ?CT (if need more detail)
What classification is used to classify talar neck fractures?
Most talar fractures occur through the neck
Hawkin’s classification used to classify talar neck fractures
Briefly discuss the management of talar fractures
- Hawkins type I:
- non-weight bearing orthosis
- Hawkins type II-IV:
- Immediate reduction in A&E then subsequent surgical repair
- Repeat x-ray
- If reduction adequete, apply cast & wait for next available surgery list for ORIF
- If reduction not possible, ORIF required out of hours
- Period of non-weight bearing following surgery
State some potential complications of a talar fracture
- Avascular necrosis
- OA
State the typical mechanism of injury of tibial plafond/pilon fractures
High energy axial loads; talus punches up into tibial plafond
*Can occur in RTAs
Tibial plafond fractures are simple injuries; true or false?
FALSE; complex injuries which requrei sepcialist input
Describe the presentation of someone with a tibial plafond fracture
- Pain
- Inabilty to weight-bear
- Obvious ankle deformity
- Swelling
- Brusing
- Fracture blisters
What classification is used to classify severity of tibial plafond/pilon fractures?
Ruedi & Allgower
What investigations should be done for suspected tibial plafond/pilon fracture?
- Urgent bloods (coag & group and save)
- Plain film radiographs of ankle (AP, lateral & mortise. Full length views of tibial & knee also required)
- Subsequent CT imaging
Discuss the management of pilon fractures
Initial Management
- Reduction
- Below knee backslab
- Repeat neurovascular assessment & plain film radiographs
Preparation for surgery
- Elevate limb
- Monitor for compartment syndrome
- NBM
- IV fluids
Surgery
- Temporary spanning external fixator may be required for 7-14 days before ORIF to allow soft tissue swelling to subside
- *MAJORITY need ORIF; may do conservative for elderly or if operation very high risk*
State some potential complications of pilon fractures
Remember, most require surgery so a lot of complications can be from surgery too
- Non-union
- Post traumatic athritis
- Compartment syndroe
- Wound infection
