Ankle 1 Flashcards

1
Q

Remind yourself of the bones of the foot

A
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2
Q

Remind yourself of the anatomy of the ankle

A
  • Talus bone articulates within mortise
  • Mortise composed of tibial plafond & medial malleous and the lateral malleoulus
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3
Q

What is a syndesmosis?

A
  • 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
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4
Q

What do we mean by an ankle fracture?

A

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

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5
Q

What is a Piloon fracture?

A

Fracture of the tibial articular surface (the plafond). Pts often have other fractures too

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6
Q

We describe ankle fractures anatomically; state the 4 types

A
  • Isolated lateral malleolus
  • Isolated medial malleolus
  • Bimalleolar fractures (medial & lateral malleolar fracture)
  • Trimalleolar fractures (medial & lateral & posterior malleolar fracture)
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7
Q

The more proximal the injury, the lower the likelihood of ankle instability; true or false?

A

FALE; the more proximal the injury, the higher the likelihood of ankle instability

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8
Q

State 2 classifications we can use to classify ankle fractures and state where/when each is commonly used

A
  • Weber classification: most common, used in settings like A&E
  • Lauge-Hansen classification: used in orthopaedic practice
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9
Q

Describe the Weber classification of ankle fractures

A
  • Type A= below the syndesmosis
  • Type B= at the level of the syndesmosis
  • Type C= above the level of the syndesmosis
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10
Q

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?

A

Based on:

  • Ankle position at time of injury
  • Deforming force involved
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11
Q

A proximal fibula fracture is associated with what until proven otherwise?

A

Proximal fibula fracture is associated with an ankle fracture or dislocation until proven otherwise

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12
Q

State the clinical features of an ankle fracture

A
  • Pain
  • Inability to weight bear
  • Tenderness over affeccted area
  • Swelling
  • History of traumatic injury
  • +/- associated deformity
  • Neuorvascular compromise (if very deformed ankle)
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13
Q

What are the Ottawa ankle rules?

A

Set of rules to help you determine whether or not pt should have ankle x-rays based on likelihood that there is a fracture

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14
Q

State some circumstances in which Ottawa ankle rules cannot be used?

A
  • Pt intoxicated or uncooperative
  • Pt has other distracting painful injuries
  • Diminised sensation in legs
  • Gross swelling
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15
Q

What must you do if a pt has dislocation aswell as fracture prior to sending a pt for an x-ray?

A

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!

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16
Q

What investigations are required for suspected ankle fractures?

A
  • X-ray of ankle/mortise (AP & lateral)
  • Complex ankle fractures, such as those with displaced posterior fragment, will need CT for surgical planning
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17
Q

What position must the foot be during ankle x-rays and why?

A
  • Full dorsiflexion
  • Talus can appear translated within the mortise when the ankle is plantar flexed because it is narrower posteriorly
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18
Q

What might you see on x-ray if there is an ankle fracture?

A
  • Fracture
  • Talar shift
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19
Q

Discuss how you would manage an ankle fracture (think about how management differs for different classes of fracture)

A

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
20
Q

Which ankle fractures can be managed conservatively?

Whcih ankle fractures need surgical management?

A

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
21
Q

What is the difference between a backslab and full cast?

A

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.

22
Q

State some potential complications of ankle fractures

A
  • Post-traumatic arthritis
  • Surgical risk if undergone surgery e.g. infection, PE, DVT, neurovascular injury, non-union, metal work prominence
23
Q

Which tarsal bone is most commonly fractured?

A

Calcaneum; often fractured following fall from height resulting in excessive axial loading

24
Q

Discuss how calacneal fractures can be classified

A

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
25
Q

What is an avulsion fracture?

A

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.

26
Q

How does a calcaneal fracture present?

A
  • Pain & tenderness around calcaneal area
  • Inability to weight bear
  • Swelling
  • Bruising
  • Heel may be shorted & widened
  • May be varus deformity
27
Q

What investigations are required for a calcaneal fracture?

A
  • Initial imaging= plain film radiograph (AP, lateral & oblique views)
  • Gold standard for calcaneal fractures= CT
28
Q

What might you find on x-ray of a calcaneal fracture?

A
  • Calcaneal shortening
  • Varus tuberosity deformity
  • Decreased Bohler’s angle
29
Q

Discuss the management of calcaneal fractures

A

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
30
Q

State a potential complication of a calcaneal fracture

A

Subtalar arthritis

31
Q

What is the second most common tarsal bone to fracture?

A

Talus

32
Q

State the typical mechanism of injury of talar fractures

A

High energy trauma during which ankel is forced into dorsiflexion; taus presses against tibial plafond causing a fracture

33
Q

What is the talus at high risk of following a fracture & why?

A
  • Avascular necrosis
  • Has extraosseous arterial supply which is highly susceptible to injury during fractures
34
Q

What is Hawkin’s sign?

A

Subchondral lucency of talar dome visible 6-8 weeks following injury; indicative of adequete vascularity thefore low avascular necrosis risk

35
Q

Describe the typical presentation of a talar fracture

A
  • Pain
  • Swelling
  • Deformity
  • Unable to dorsiflex or plantar flex the ankle
36
Q

What investigations are required for a suspected talar fracture?

A
  • Plain film radiographs (AP & lateral) **NOTE: lateral films should be taken in dorsi & plantar flexion to allow classification
  • ?CT (if need more detail)
37
Q

What classification is used to classify talar neck fractures?

A

Most talar fractures occur through the neck

Hawkin’s classification used to classify talar neck fractures

38
Q

Briefly discuss the management of talar fractures

A
  • 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
39
Q

State some potential complications of a talar fracture

A
  • Avascular necrosis
  • OA
40
Q

State the typical mechanism of injury of tibial plafond/pilon fractures

A

High energy axial loads; talus punches up into tibial plafond

*Can occur in RTAs

41
Q

Tibial plafond fractures are simple injuries; true or false?

A

FALSE; complex injuries which requrei sepcialist input

42
Q

Describe the presentation of someone with a tibial plafond fracture

A
  • Pain
  • Inabilty to weight-bear
  • Obvious ankle deformity
  • Swelling
  • Brusing
  • Fracture blisters
43
Q

What classification is used to classify severity of tibial plafond/pilon fractures?

A

Ruedi & Allgower

44
Q

What investigations should be done for suspected tibial plafond/pilon fracture?

A
  • 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
45
Q

Discuss the management of pilon fractures

A

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*
46
Q

State some potential complications of pilon fractures

A

Remember, most require surgery so a lot of complications can be from surgery too

  • Non-union
  • Post traumatic athritis
  • Compartment syndroe
  • Wound infection