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Introduction
  • Epidemiology
    • incidence
      • most frequent tarsal fracture
      • 17% open fractures
  • Pathophysiology
    • mechanism
      • traumatic axial loading is the primary mechanism of injury
        • fall from height
        • motor-vehicle accidents
    • pathoanatomy
      • intra-articular fractures
        • primary fracture line results from oblique shear and leads to the following two primary fragments
          • superomedial fragment (constant fragment)
            • includes the sustentaculum tali and is stabilized by strong ligamentous and capsular attachments
          • superolateral fragment
            • includes an intra-articular aspect through the posterior facet
        • secondary fracture lines
          • dictate whether there is joint depression or tongue-type fracture
      • extra-articular fractures
        • strong contraction of gastrocnemius-soleus with concomitant avulsion at its insertion site on calcaneus
        • more common in osteopenic bone
      • anterior process fractures
        • inversion and plantar flexion of the foot cause avulsion of the bifurcate ligament
  • Associated injuries
    • orthopaedic
      • extension into the calcaneocuboid joint occurs in 63%
      • vertebral injuries in 10%
      • contralateral calcaneus in 10%
  • Prognosis
    • poor with 40% complication rate
      • increased due to mechanism (fall from height), smoking, and early surgery
      • lateral soft tissue trauma increases the rate of complication
Anatomy
  • Osteology
    • articular facets  
      • superolateral fragment contains the articular facets
      • superior articular surface contains three facets that articulate with the talus
      • posterior facet is the largest and is the major weight bearing surface
        • the flexor hallucis longus tendon runs just inferior to it and can be injured with errant drills/screws that are too long 
      • middle facet is anteromedial on sustentaculum tali
      • anterior facet is often confluent with middle facet
    • sinus tarsi
      • between the middle and posterior facets lies the interosseous sulcus (calcaneal groove) that together with the talar sulcus makes up the sinus tarsi
    • sustentaculum tali
      • projects medially and supports the neck of talus
      • FHL passes beneath it   
      • deltoid and talocalcaneal ligament connect it to the talus
      • contained in the anteromedial fragment, which remains "constant" due to medial talocalcaneal and interosseous ligaments 
    • bifurcate ligament
      • connects the dorsal aspect of the anterior process to the cuboid and navicular
Classification 
  • Extra-articular (25%) 
    • avulsion injury of
      • anterior process by bifurcate ligament   
      • sustentaculum tali
      • calcaneal tuberosity (Achilles tendon avulsion  
  • Intra-articular (75%)
    • Essex-Lopresti classification
      • the primary fracture line runs obliquely through the posterior facet forming two fragments
      • the secondary fracture line runs in one of two planes
        • the axial plane beneath the facet exiting posteriorly in tongue-type fractures  
          • when the superolateral fragment and posterior facet remain attached to the tuberosity posteriorly
        • behind the posterior facet in joint depression fractures 
    • Sanders classification
      • based on the number of articular fragments seen on the coronal CT image at the widest point of the posterior facet
Sanders Classification
Type I  • Nondisplaced posterior facet (regardless of number of fracture lines)
 
Type II  • One fracture line in the posterior facet (two fragments)
Type III  • Two fracture lines in the posterior facet (three fragments)
Type IV  • Comminuted with more than three fracture lines in the posterior facet (four or more fragments)
 
Presentation
  • Symptoms
    • pain
  • Physical exam
    • inspection
      • diffuse tenderness to palpation
      • ecchymosis and swelling
      • shortened, widened, heel with a varus deformity
Imaging
  • Radiographs
    • recommended views
      • required
        • AP, lateral, and oblique foot
      • optional
        • Broden
          • allows visualization of posterior facet
          • useful for evaluation of intraoperative reduction of posterior facet
          • with ankle in neutral dorsiflexion take x-rays at 40, 30, 20, and 10 degrees of internal rotation 
        • Harris view 
          • visualizes tuberosity fragment widening, shortening, and varus positioning
          • place the foot in maximal dorsiflexion and angle the x-ray beam 45 degrees
        • AP ankle
          • demonstrates lateral wall extrusion causing fibular impingement
      • findings
        • reduced Bohler angle
        • increased angle of Gissane
        • calcaneal shortening
        • varus tuberosity deformity
    • measurement
      • Bohler angle (normal is 20-40 degrees) 
        • measured from lateral foot x-ray
        • flattening (decreased angle) represents collapse of the posterior facet
        • double-density highlights subtalar incongruity
      • angle of Gissane (normal is 120-145 degrees)   
        • an increase represents collapse of posterior facet
  • CT
    • indications
      • gold standard
    • views
      • 30-degree semicoronal
        • demonstrates posterior and middle facet displacement
      • axial
        • demonstrates calcaneocuboid joint involvement
      • sagittal
        • demonstrates tuberosity displacement
  • MRI
    • indications
      • used only to diagnose calcaneal stress fractures in the presence of normal radiographs and/or uncertain diagnosis  
Treatment
  • Nonoperative
    • cast immobilization with nonweightbearing for 6 weeks 
      • indications
        • calcaneal stress fractures
    • cast immobilization with nonweightbearing for 10 to 12 weeks
      • indications
        • small extra-articular fracture (<1 cm) with intact Achilles tendon and  <2 mm displacement
        • Sanders Type I (nondisplaced)
        • anterior process fracture involving <25% of calcaneocuboid joint
        • comorbidities that preclude good surgical outcome (smoker, diabetes, PVD)
      • techniques
        • begin early range of motion exercises once swelling allows
  • Operative
    • closed reduction with percutaneous pinning
      • indications
        • minimally displaced tongue-type fxs or those with mild shortening
        • large extra-articular fractures (>1 cm)
        • early reduction prevents skin sloughing and need for subsequent flap coverage
      • techniques
        • lag screws from posterior superior tuberosity directed inferior and distal
    • ORIF
      • indications
        • displaced tongue-type fractures  
        • large extra-articular fractures (>1 cm) with detachment of Achilles tendon and/or > 2 mm displacement
          • urgent if skin is compromised
        • Sanders Type II and III
          • posterior facet displacement >2 to 3 mm, flattening of Bohler angle, or varus malalignment of the tuberosity
        • anterior process fracture with >25% involvement of calcaneocuboid joint
        • displaced sustentaculum fractures
      • timing
        • wait 10-14 days until swelling and blisters resolve and wrinkle sign present 10-14 days
        • no benefit to early surgery due to significant soft tissue swelling 
      • outcomes
        • surgical outcome correlates with the number of intra-articular fragments and the quality of articular reduction
        • factors associated with a poor outcome    
          • age > 50
          • obesity
          • manual labor
          • workers comp
          • smokers
          • bilateral calcaneal fractures
          • multiple trauma
          • vasculopathies
          • men do worse with surgery than women 
        • factors associated with most likely need for a secondary subtalar fusion 
          • male worker's compensation patient who participates in heavy labor work with an initial Böhler angle less than 0 degrees
    • primary subtalar arthrodesis
      • indications
        • Sanders Type IV
      • techniques
        • combined with ORIF to restore height
Surgical Techniques
  • ORIF with extensile lateral or medial approach
    • goals
      • restore congruity of subtalar joint
      • restore Bohler angle and calcaneal height
      • restore width
      • correct varus malalignment
    • approach
      • extensile lateral L-shaped incision is most popular 
        • provides access to calcaneocuboid and subtalar joints
        • high rate of wound complications
      • medial approach can also be used 
        • full-thickness flap is created to maintain soft tissue integrity
    • technique
      • place a pin in the tuberosity to assist the reduction
      • provisional fixation with Kirschner wires
      • hold reduction with low profile implants
      • bone grafting provides no added benefit
    • postoperative care
      • bulky posterior U splint
      • early supervised subtalar range of motion exercises
      • nonweightbearing for 10 weeks
  • ORIF with sinus tarsi approach and Essex-Lopresti maneuver
    • technique
      • manipulate the heel to increase the calcaneal varus deformity
      • plantarflex the forefoot
      • manipulate the heel to correct the varus deformity with a valgus reduction
      • stabilize the reduction with percutaneous K-wires or open fixation as described above
Complications
  • Wound complications (10-25%)  
    • increased risk in smokers, diabetics, and open injuries
  • Subtalar arthritis 
    • increased with nonoperative management
  • Lateral impingement with peroneal irritation
  • Damaged FHL
    • at risk with placement of lateral to medial screws, especially at level of sustentaculum tali (constant fragment) 
  • Compartment syndrome (10%)
    • results in claw toes 
  • Malunion
    • introduction
      • loss of height, widening, and lateral impingement
    • physical exam
      • limited ankle dorsiflexion
      • due to dorsiflexed talus with talar declination angle <20
    • classification (see below) 
    • treatment
      • distraction bone block subtalar arthrodesis
        • indications  
          • chronic pain from subtalar joint
          • incongruous subtalar joint/post-traumatic DJD
          • loss of calcaneal height
          • mechanical block to ankle dorsiflexion
            • results from posterior talar collapse into the posterior calcaneus
      • technique
        • goal is to correct  
          • hindfoot height
          • ankle impingement 
          • subfibular impingement
          • subtalar arthritis
Malunion CT Classification & Treatment
Type I  • Lateral exostosis with no subtalar arthritis
 • Treat with lateral wall resection
Type II  • Lateral exostosis with subtalar arthritis
 • Treat with lateral wall resection and subtalar fusion
Type III  • Lateral exostosis, subtalar arthritis, and varus malunion
 • Treat with lateral wall resection, subtalar fusion, and +/- valgus osteotomy (controversial)
 

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