Internal Fixation of Ankle Fractures

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Internal Fixation of Ankle Fractures
6-10
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Objectives

• Review ankle anatomy
• Identify the indications treatment goals for
  ORIF of ankle fractures
• Summarize the implant options

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AnatomyAnkle Bones

• Formed by medial malleolus of tibia, and lateral
  malleolus (fibula)
• Talus sits in mortise (as in
  mortise tenon)

Fibula
Tibia
Talus
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AnatomyAnkle Soft Tissues

• Ligaments connect ankle on medial lateral sides
• Important for stability

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AnatomyAnkle Soft Tissues

• Fibula connected to tibia by fibrous band of
  tissue called syndesmosis
• Also important for stability

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Ankle Fractures
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Ankle Fractures

• History
• Twisting injury
• Immediate pain lateral and/or medial
• Difficulty weight-bearing
• Physical examination
• Malleolar pain (posterior anterior)
• Difficulty weight-bearing
• Swelling
• Neurovascular involvement

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Ankle FracturesRadiographs

• Ankle Series AP, mortise, lateral
• Rule out other injuries
• Osteochondral injuries
• Lateral process fracture
• Anterior calcaneus fracture
• Base of 5th MT fracture

AP
Mortise
Lateral
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Ankle FracturesClassification

• Weber / AO Classification based on level of
  fibula fracture
• A Below syndesmosis
• B At syndesmosis
• C Above syndesmosis

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Simple Classification Stable
Unstable

• Stable fractures
• Most commonly involve medial or lateral side
  only
• Talus remains anatomic relative to tibia

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Simple ClassificationStable Unstable

• Unstable fractures
• Disruption of 2 or more aspects of the mortise --
  bone and/or ligament
• Talus may sublux or be dislocated from tibia

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Stable Examples
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Unstable Examples
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Indications for SurgeryAnkle Fractures

• Inability to obtain or maintain an anatomic
  mortise (unstable fracture pattern)
• Open fractures

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Basic Set-UpAnkle Fractures

• Supine position most common
• Occasionally prone for direct approach to
  posterior malleolus
• Bump beneath ipsilateral buttocks (allows easier
  approach to fibula)
• Tourniquet
• Prep / drape to above knee
• Pre-op antibiotics
• Fluoroscopy or X-ray

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General Considerations

• Small size of ankle bones dictates implant
  sizes
• Multiple complex 3-D articulations
• Weight bearing structure subject to high stresses
  (2 5x body weight)

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General Considerations

• Limited soft tissue coverage

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InstrumentationAnkle Fractures

• Small fragment set
• Cannulated screws
• K-wires
• Cerclage wire
• Power
• Have mini-frag available

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Ankle Fracture Surgical Tx

• Type
• One malleolus
• Bimalleolar
• Tri-malleolar

• Treatment
• Fix fibula with screw / TB wire / plate
• Plate fibula, lag screw tibia (medial malleolus)
• Plate fibula, lag screw tibia, fix posterior if
  gt20 - 25 articular surface involved

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Implant ConsiderationsLateral Malleolus

• One-third tubular plate 3.5 mm cortex screws
• Lateral
• Posterior
• 3.5mm compression plate for unstable fractures

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Implant ConsiderationsLateral Malleolus

• Locking plates -- lateral or posterolateral
• Osteoporotic bone
• Unstable fractures
• Distal fractures

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Implant ConsiderationsLateral Malleolus

• Hook Plate
• Used to obtain purchase in very
  distal fibula fractures

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Implant Considerations Posterior Malleolus

• Posterior to anterior Anterior to
  posterior

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Implant ConsiderationsMedial Malleolus

• Two partially threaded 4.0 mm cancellous screws
• K-wires
• Cerclage wire for tension band technique

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Syndesmosis FixationIndications

• Syndesmotic instability after fixation of
  malleolus
• Consider if fibula fracture gt 4 cm above
  joint line Maisonneuves fracture
• Have bone hook on back table to check stability
• Have large frag screws instruments available

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Implant ConsiderationsSyndesmosis

• Surgeons choice of large or small fragment fully
  threaded screws, one or two
• Not inserted as lag screw, but as a positioning
  screw (threads engage all cortices)
• Secures position of fibula next to tibia allowing
  torn syndesmotic tissues to heal
• May be removed in 6 - 12 weeks

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Implant ConsiderationsSyndesmosis

• Have pelvic forceps on back table
• May need longer plates than in small frag set
• 1/3 tubular, compression or specialty fibula
  plate
• Bioresorbable screws

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Case 1
Age 81 Gender Female Cause of Injury
Fall Fixation 3.5mm LCP Lateral Distal
Fibula Plate
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Case 2
Age 64 Gender Female Cause of Injury
Fall Fixation 3.5mm LCP Lateral Distal
Fibula Plate
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Summary

• Reviewed ankle anatomy
• Identified the indications treatment goals for
  ORIF of ankle fractures
• Summarized the implant options

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Thank You