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Introduction
  • Injury patterns
    • isolated medial malleolus fracture
    • isolated lateral malleolus fracture
    • bimalleolar and bimalleolar-equivalent fractures
    • posterior malleolus fractures
    • Bosworth fracture-dislocations
    • open ankle fractures
    • associated syndesmotic injuries
      • isolated syndesmosis injury 
Anatomy
  • Biomechanics
    • deltoid ligament (deep portion)
      • primary restraint to anterolateral talar displacement
    • fibula
      • acts as buttress to prevent lateral displacement of talus
Imaging
  • Radiographs
    • external rotation stress radiograph
      • most appropriate stress radiograph to assess competency of deltoid ligament
        • a medial clear space of >5mm with external rotation stress applied to a dorsiflexed ankle is predictive of deep deltoid disruption
      • more sensitive to injury than medial tenderness, ecchymosis, or edema
      • gravity stress radiograph is equivalent to manual stress radiograph
      • syndesmosis
        • decreased tibiofibular overlap 
          • normal >6 mm on AP view
          • normal >1 mm on mortise view
        • increased medial clear space 
          • normal less than or equal to 4 mm
        • increased tibiofibular clear space 
          • normal <6 mm on both AP and mortise views
    • radiographic measurements 
      • talocrural angle     
        • measured by bisection of line through tibial anatomical axis and another line through the tips of the malleoli
        • shortening of lateral malleoli fractures can lead to increased talocrural angle 
        • talocrural angle is not 100% reliable for estimating restoration of fibular length
          • can also utilize the realignment of the medial fibular prominence with the tibiotalar joint
Classification
  • Lauge-Hansen
    • based on foot position and force of applied stress/force
    • has been shown to predict the observed (via MRI) ligamentous injury in less than 50% of operatively treated fractures
Lauge-Hansen Class
Sequence
Supination - Adduction (SA)

  1. Talofibular sprain or distal fibular avulsion
  2. Vertical medial malleolus and impaction of anteromedial distal tibia
Supination - External Rotation (SER)

  1. Anterior tibiofibular ligament sprain
  2. Lateral short oblique fibula fracture (anteroinferior to posterosuperior)
  3. Posterior tibiofibular ligament rupture or avulsion of posterior malleolus
  4. Medial malleolus transverse fracture or disruption of deltoid ligament 
Pronation - Abduction (PA)
  1. Medial malleolus transverse fracture or disruption of deltoid ligament
  2. Anterior tibiofibular ligament sprain
  3. Transverse comminuted fracture of the fibula above the level of the syndesmosis
Pronation - External Rotation (PER)
    
  1. Medial malleolus transverse fracture or disruption of deltoid ligament 
  2. Anterior tibiofibular ligament disruption
  3. Lateral short oblique or spiral fracture of fibula (anterosuperior to posteroinferior) above the level of the joint
  4. Posterior tibiofibular ligament rupture or avulsion of posterior malleolus 

  • Anatomic / Descriptive 
    • isolated medial malleolar
    • isolated lateral malleolar
    • bimalleolar
    • trimalleolar
    • Bosworth fracture-dislocation (posterior dislocation of the fibula behind incisura fibularis)
  • Danis-Weber (location of fibular fracture)
    • A - infrasyndesmotic (generally not associated with ankle instability)
    • B - transsyndesmotic
    • C - suprasyndesmotic
  • AO / ATA
    • 44A - infrasyndesmotic
    • 44B - transsyndesmotic
    • 44C - suprasyndesmotic
General Treatment
  • Nonoperative
    • short-leg walking cast/boot
      • indications
        • isolated nondisplaced medial malleolus fracture or tip avulsions
        • isolated lateral malleolus fracture with < 3mm displacement and no talar shift
        • posterior malleolar fracture with < 25% joint involvement or < 2mm step-off
  • Operative
    • open reduction internal fixation
      • indications
        • any talar displacement 
        • displaced isolated medial malleolar fracture
        • displaced isolated lateral malleolar fracture
        • bimalleolar fracture and bimalleolar-equivalent fracture
        • posterior malleolar fracture with > 25% or > 2mm step-off q
        • Bosworth fracture-dislocations
        • open fractures
      • technique
        • goal of treatment is stable anatomic reduction of talus in the ankle mortise
          • 1 mm shift of talus leads to 42% decrease in tibiotalar contact area
        • see fracture patterns below for specific treatment
      • outcomes
        • overall success rate of 90%
          • prolonged recovery expected (2 years to obtain final functional result)
        • significant functional impairment often noted
        • worse outcomes with: smoking, decreased education, alcohol use, increased age, presence of medial malleolar fracture
        • ORIF superior to closed treatment of bimalleolar fractures
        • in Lauge-Hansen supination-adduction fractures, restoration of marginal impaction of the anteromedial tibial plafond leads to optimal functional results after surgery 
      • postoperative rehabilitation
        • time for proper braking response time (driving) returns to baseline at nine weeks for operatively treated ankle fractures  
        • braking travel time is significantly increased until 6 weeks after initiation of weight bearing in both long bone and periarticular fractures of the lower extremity  q
Isolated Medial Malleolus Fracture
  • Nonoperative
    • short leg walking cast or cast boot
      • indications
        • nondisplaced fracture and tip avulsions
          • deep deltoid inserts on posterior colliculus
          • symptomatic treatment often appropriate
  • Operative
    • ORIF
      • indications
        • any displacement or talar shift
      • technique
        • lag screw fixation
          • lag screw fixation stronger if placed perpendicular to fracture line
        • antiglide plate with lag screw 
          • best for vertical shear fractures   
        • tension band fixation 
          • utilizing stainless steel wire
Isolated Lateral Malleolus Fracture
  • Nonoperative
    • short leg walking cast vs cast boot
      • indications 
        • if intact mortise, no talar shift, and < 3mm displacement
        • classically fractures with more than 4-5 mm of medial clear space widening on stress radiographs have been considered unstable and need to be treated surgically
          • recent studies have shown the deep deltoid may be intact with up to 8-10 mm of widening on stress radiographs
          • if the mortise is well reduced, results from operative and non-operative treatment are similar 
  • Operative
    • ORIF
      • indications
        • if talar shift or > 3 mm of displacement
        • can be treated operatively if also treating an ipsilateral syndesmosis injury
      • technique
        • open reduction and plating q
          • plate placement
            • lateral
              • lag screw fixation with neutralization plating
              • bridge plate technique
            • posterior
              • antiglide technique
              • lag screw fixation with neutralization plating
              • most common disadvantage of using posterior antiglide plating is peroneal irritation if the plate is placed too distally  
            • posterior antiglide plating is biomechanically superior to lateral plate placement
        • intramedullary retrograde screw placement
        • isolated lag screw fixation
          • possible if fibula is a spiral pattern and screws can be placed at least 1 cm apart
        • fixation of medial malleolus fracture
          • for transverse pattern, lag by technique using 3.5 fully-threaded screw is biomechanically superior to lag by design using 4.0 partially-threaded screws 
      • post-operative care
        • period of immobilization usually 4-6 weeks after ORIF
        • duration of immobilization should be doubled in Diabetic patients 
 Medial and Lateral (Bimalleolar) Fracture
  • Nonoperative
    • total contact casting
      • indications
        • elderly or unable to undergo surgical intervention
  • Operative
    • ORIF
      • indications
        • any lateral talar shift
      • technique
        • fibula
          • need to fix with one of the options listed in section above
        • medial malleolus
          • fixation options
            • cancellous lag screws
            • bicortical screws 
            • tension band wiring
            • antiglide plate to treat a vertical medial malleolus fracture q
          • orient screws parallel to joint for vertical medial malleolar fracture (Lauge-Hansen supination-adduction fracture pattern) q   
 Functional Bimalleolar Fracture (deltoid ligament tear with fibular fracture)
  • Operative
    • ORIF of lateral malleolus
      • indications
        • examination has been shown to be largely unreliable in predicting medial injury
        • can see significant lateral translation of the talus in this pattern
      • technique
        • not necessary to repair medial deltoid ligament
        • only need to explore medially if you are unable to reduce the mortise
        • see isolated fibular fracture techniques above
Posterior Malleolar Fracture
  • Nonoperative
    • short leg walking cast vs cast boot
      • indications
        • < 25% of articular surface involved
          • evaluation of percentage should be done with CT, as plain radiology is unreliable
        • < 2 mm articular stepoff
        • syndesmotic stability
  • Operative
    • ORIF
      • indications
        • > 25% of articular surface involved
        • > 2 mm articular stepoff
        • syndesmosis injury
      • technique
        • approach
          • posterolateral approach  
          • posteromedial approach 
          • decision of approach will depend on fracture lines and need for fibular fixation
        • fixation
          • anterior to posterior lag screws to capture fragment (if nondisplaced)
          • posterior to anterior lag screw and buttress plate
          • antiglide plate
        • syndesmosis injury
          • stiffness of syndesmosis restored to 70% normal with isolated fixation of posterior malleolus (versus 40% with isolated syndesmosis fixation)
          • stress examination of syndesmosis still required after posterior malleolar fixation
          • posteroinferior tibiofibular ligament may remain attached to posterior malleolus and syndesmotic stability may be restored with isolated posterior malleolar fixation 
Bosworth Fracture-Dislocation
  • Overview
    • rare fracture-dislocation of the ankle where the fibula becomes entrapped behind the tibia and becomes irreducible
    • posterolateral ridge of the distal tibia hinders reduction of the fibula 
  • Operative
    • open reduction and fixation of the fibula in the incisura fibularis
      • indicated in most cases
Hyperplantarflexion Variant                                                                                                                                                    
  • Overview
    • fracture-dislocation of the ankle due to hyperplantarflexion 
    • main feature is a vertical shear fracture of the posteromedial tibial rim
    • "spur sign" is a double cortical density at the inferomedial tibial metaphysis 
  • Operative
    • fixation of posteromedial and posterior fragments with antiglide plating
Open Ankle Fracture
  • Operative
    • emergent operative debridement and ORIF
      • indicated if soft tissue conditions allow
      • primary closure at the index procedure can be performed in appropriately-selected Gustilo-Anderson grade I, II, and IIIA open fractures in otherwise healthy patients sustaining low-energy injuries without gross contamination 
    • external fixation 
      • indications
        • soft tissue conditions and overall patient characteristics 
Associated Syndesmotic Injury
  • Overview
    • suspect injury in all ankle fractures 
      • most common in Weber C fracture patterns
      • fixation usually not required when fibula fracture within 4.5 cm of plafond
      • up to 25% of tibial shaft fractures will have ankle injury
  • Evaluation 
    • measure clear space 1 cm above joint 
      • it has also been reported that there is no actual correlation between syndesmotic injury and tibiofibular clear space or overlap measurements
      • lateral stress radiograph has more interobserver reliability than an AP/mortise stress film
    • best option is to assess stability intraoperatively with abduction/external rotation stress of dorsiflexed foot
    • instability of the syndesmosis is greatest in the anterior-posterior direction
  • Treatment
    • operative
      • syndesmotic screw fixation
        • indications
          • widening of medial clear space  
          • tibiofibular clear space (AP) greater than 5 mm 
          • tibiofibular overlap (mortise) narrowed
          • any postoperative malalignment or widening should be treated with open debridement, reduction, and fixation  
        • technique
          • length and rotation of fibula must be accurately restored  
          • outcomes are strongly correlated with anatomic reduction 
            • placing reduction clamp on midmedial ridge and the fibular ridge at the level of the syndesmosis willa chieve most reliable anatomic reduction 
          • "Dime sign"/Shentons line to determine length of fibula   
          • open reduction required if closed reduction unsuccessful or questionable 
          • one or two cortical screw(s) 2-4 cm above joint, angled posterior to anterior 20-30 degrees
          • lag technique not desired
          • maximum dorsiflexion of ankle not required during screw placement (can't overtighten a properly reduced syndesmosis)
        • postoperative
          • screws should be maintained in place for at least 8-12 weeks
          • must remain non-weight bearing, as screws are not biomechanically strong enough to withstand forces of ambulation
        • controversies
          • number of screws
            • 1 or 2 most commonly reported
          • number of cortices
            • 3 or 4 most commonly reported
          • size of screws
            • 3.5 mm or 4.5 mm screws
          • implant material (stainless steel screws, titanium screws, suture, bioabsorbable materials)
          • need for hardware removal
            • no difference in outcomes seen with hardware maintenance (breakage or loosening) or removal at 1 year
            • outcome may be worse with maintenance of intact screws
Diabetic Ankle Fractures (with or without Neuropathy)
  • Risks
    • prolonged healing
    • high risk of hardware failure
    • high risk of infection
  • Enhanced fixation   
    • multiple quadricortical syndesmotic screws (even in the absence of syndesmotic injury)
    • tibiotalar Steinmann pins or hindfoot nailing
    • ankle spanning external fixation
    • augment with intramedullary fibula K-wires
    • stiffer, more rigid fibular plates (instead of 1/3 tubular plates)
      • compression plates
      • small fragment locking plates
  • Delay weightbearing   
    • maintain non-weightbearing postop for 8-12 weeks (instead of 4-8 weeks in normal patients
Complications 
  • Wound problems (4-5%)
  • Deep infections (1-2%)
    • up to 20% in diabetic patients
      • largest risk factor for diabetic patients is presence of peripheral neuropathy  
  • Post-traumatic arthritis 
    • rare with anatomic reduction and fixation
    • corrective osteotomy requires anatomic fibular and mortise correction for optimal outcomes   
      • isolated syndesmosis injury 
Anatomy
  • Biomechanics
    • deltoid ligament (deep portion)
      • primary restraint to anterolateral talar displacement
    • fibula
      • acts as buttress to prevent lateral displacement of talus
 

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