Internal Fixation
of
Ankle Fractures
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6-10
Objectives
 Review ankle anatomy
 Identify the indications & treatment
goals for ORIF of ankle fractures
 Summarize the implant options
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Anatomy
 Formed by medial malleolus of
tibia, and lateral malleolus (fibula)
 Talus sits in “mortise”
Fibula
Ankle Bones
Tibia
(as in “mortise & tenon”)
Talus
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Anatomy
Ankle Soft Tissues
 Ligaments connect ankle on medial & lateral sides
 Important for stability
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Anatomy
Ankle 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
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Malleolar pain (posterior & anterior)
Difficulty weight-bearing
Swelling
Neurovascular involvement
Ankle Fractures
Radiographs
 Ankle Series: AP, mortise,
lateral
 “Rule out” other injuries:
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AP
Mortise
Osteochondral injuries
Lateral process fracture
Anterior calcaneus fracture
Base of 5th MT fracture
Lateral
Ankle Fractures
Classification
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 Classification:
Stable & 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 Surgery
Ankle Fractures
 Inability to obtain or maintain an
anatomic mortise (unstable
fracture pattern)
 Open fractures
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Basic Set-Up
Ankle 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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Instrumentation
Ankle Fractures
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Small fragment set
Cannulated screws
K-wires
Cerclage wire
Power
Have mini-frag available
Ankle Fracture
Surgical Tx
Type
 One malleolus
Treatment
Fix fibula with screw /
TB wire / plate
 Bimalleolar
Plate fibula, lag screw tibia
(medial malleolus)
 Tri-malleolar
Plate fibula, lag screw tibia,
fix posterior if >20 - 25%
articular surface involved
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Implant Considerations
Lateral Malleolus
 One-third tubular plate &
3.5 mm cortex screws
 Lateral
 Posterior
 3.5mm compression plate for
unstable fractures
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Implant Considerations
Lateral Malleolus
 Locking plates -- lateral or posterolateral
 Osteoporotic bone
 Unstable fractures
 Distal fractures
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Implant Considerations
Lateral Malleolus
 Hook Plate
 Used to obtain purchase
in very distal fibula fractures
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Implant Considerations
Posterior Malleolus
Posterior to anterior
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Anterior to posterior
Implant Considerations
Medial Malleolus
 Two partially threaded 4.0 mm
cancellous screws
 K-wires
 Cerclage wire for tension band
technique
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Syndesmosis Fixation
Indications

Syndesmotic instability after
fixation of malleolus

Consider if fibula fracture
> 4 cm above joint line &
Maisonneuve’s fracture

Have bone hook on back table
to check stability
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Have large frag screws &
instruments available
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Implant Considerations
Syndesmosis

Surgeons choice of large or small fragment
fully threaded screws, one or two
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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
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May be removed in 6 - 12 weeks
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Implant Considerations
Syndesmosis
 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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Age: 64
Gender: Female
Cause of Injury: Fall
Fixation: 3.5mm LCP Lateral
Distal Fibula Plate
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Case #2
Summary
 Reviewed ankle anatomy
 Identified the indications & treatment
goals for ORIF of ankle fractures
 Summarized the implant options
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Thank You
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