An approach to ankle x-rays

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An approach to ankle x-rays

• Aric Storck PGY2
• (acknowledgement to Dr. Dave Dyck for several
  slides)
• September 11, 2003

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Objectives

• Review basic ankle fracture classification
• Review x-rays of common ankle fractures
• Discuss management of common ankle fractures

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Case 1

• 25 year old female
• Jumped off roof
• Right ankle pain
• Inability to weight bear on right foot
• What else do you want to know on history and
  physical examination?
• Does she need x-rays ?

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Ottawa Ankle Rules

• Order ankle x-rays if acute trauma to ankle and
  one or more of
• Age 55 or older
• Inability to weight bear both immediately and in
  ER (4 steps)
• Bony tenderness over posterior distal 6 cm of
  lateral or medial malleoli
• Sensitivity 100
• Specificity 40

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You have decided to order an ankle x-ray. The
nurse entering your orders asks which views you
want
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Ankle X-rays 3 views

• AP
• Identifies fractures of malleoli, distal
  tibia/fibula, plafond, talar dome, body and
  lateral process of talus, calcaneous
• Mortise
• Ankle 15-25 degrees internal rotation
• Evaluate articular surface between talar dome and
  mortise
• Lateral
• Identifies fractures of anterior/posterior tibial
  margins, talar neck, displacement of talus

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AP x-ray

• Identifies fractures of
• malleoli
• distal tibia/fibula
• plafond
• talar dome
• body and lateral process of talus
• calcaneous

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Tib/fib clear space
Tib/fib overlap
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AP xray
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Now apply what youve learned

• Lateral malleolar fracture
• Tib/fib clear space lt5mm
• Tib/fib overlap gt10 mm
• No evidence of syndesmotic injury

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Mortise X-Ray

• Taken with ankle in 15-25 degrees of internal
  rotation
• Useful in evaluation of articular surface between
  talar dome and mortise

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(No Transcript)
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Mortise x-ray

• Medial clear space
• Between lateral border of medial malleous and
  medial talus
• lt4mm is normal
• gt4mm suggests lateral shift of talus

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Mortise x-ray

• Talar tilt
• Normal -1.5 to 1.5 degrees (ie. Parallel)
• Can go up to 5 degrees in stress views
• lt2mm difference between medial and lateral
  talar/plafond distances

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Lateral x-ray

• Identifies fractures of
• Anterior/posterior tibial margins
• Talus
• Displacement of talus
• Os trigonum

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Stable vs Unstable

• The ankle is a ring
• Tibial plafond
• Medial malleolus
• Deltoid ligaments
• calcaneous
• Lateral collateral ligaments
• Lateral malleolus
• Syndesmosis
• Fracture of single part usually stable
• Fracture gt 1 part unstable

Source Rosen
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Walking the walk . Talking the talk
Ortho is on the phone. They ask you to describe
the fracture.
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Lauge-Hansen

• 15 basic types of injury in 5 major categories
• Described by two words
• Position of foot at time of injury
• Direction of talus within mortise causing
  fracture
• Eg supination-external rotation
• Further subdivided into worsening areas of injury
• Impossible to remember and clinically useless in
  the ED

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Danis-Weber

• Defines injury based on level of fibular fracture
• Abelow tibiotalar joint
• No disruption of syndesmosis
• Usually stable
• Bat level of tibiotalar joint
• Partial disruption of syndesmosis
• Cabove tibiotalar joint
• Disrupts syndesmosis to level of fracture
• unstable
• THE MORE PROXIMAL THE FIBULAR THE MORE SEVERE
  THE INJURY

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AO classification

• Similar to Danis-Weber scheme
• Takes into account damage to other structures
  (usually medial malleolous)
• 2 pages of classifications
• Remember them all for your exam!

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AO classification
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Potts classification

• Easy to remember
• First degree
• unimalleolar
• Second degree
• bimalleolar
• Third degree
• trimalleolar

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Case 2
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(No Transcript)
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Lateral Malleolar FractureDanis-Weber A

• Mechanism
• Suppination/adduction (inversion)
• Mortise intact
• Stable fracture
• Treatment
• Below knee cast

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Case 3
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Bimalleolar (lat post malleoli)

• Mechanism
• Inversion
• Avulsion of posterior malleolus (post
  tibiofibular ligament)
• Medial mortise wide
• Suggests instability
• Management
• Posterior slab
• Orthopedic consult

Source McRaes Practical Fracture Treatment
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Case 4
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(No Transcript)
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Trimalleolar Fractures

• Unstable
• Multiple ligamentous injuries
• Usually involves syndesmosis
• Treatment
• Posterior slab
• Urgent orthopedic consultation
• ORIF

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CASE 5
SourceRosen
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Pilon (tibial plafond) fractures

• Fracture of distal tibial metaphysis
• Often comminuted
• Often significant other injuries
• Mechanism
• Axial load
• Position of foot determines injury
• Treatment
• Unstable
• X-ray tib/fib ankle
• Orthopedic consultation

SourceRosen
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Case 6
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Tillaux Fracture

• Occurs in 12-14 year olds
• 18 month period when epiphysis is closing
• Salter-Harris 3 injury
• Runs through anterolateral physis until reaches
  fused part, then extends inferiorly through
  epiphysis into joint
• Visible if x-ray parallel to plane of fracture
  (may require oblique)
• Mechanism
• External rotation
• Strenth of tibiofibular ligament gt unfused
  epiphysis

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Tillaux Fracture

• Management
• Inadequate reduction of articular surface can
  lead to early OA
• Gap gt2mm in articular surface is unacceptable
• Advanced imaging techniques may be necessary
• Early orthopedic consultation
• Non-displaced
• NWB below knee cast
• Displaced
• surgery

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Case 7
Source Rosen
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(No Transcript)
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Maisonneuve Fracture

• Mechanism
• Eversion lateral rotation
• May cause medial malleolar fracture or deltoid
  ligament disruption
• Injury proceeds along syndesmosis and involves
  proximal fibula
• Always rule out Maisonneuve fracture in medial
  malleolar/ligamentous injury

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Maisonneuve Fracture

• Mechanism
• Eversion lateral rotation
• Causes medial malleolar fracture or deltoid
  ligament disruption

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• If injury proceeds along syndesmosis it involves
  proximal fibula Maisonneuve Fracture
• Always rule out Maisonneuve fracture in medial
  malleolar/ligamentous injury

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• As talus continues to rotate
• Posterior tib-fib ligament ruptures
• Interosseous membrane rips
• Gross diastasis
• Dupuytren fracture dislocation of the ankle

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Case 8
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the end