Rosen & Barkin's 5-Minute Emergency Medicine Consult (56 page)

See Also (Topic, Algorithm, Electronic Media Element)

• Anaphylaxis
  
• Urticaria
  

CODES

• 277.6 Other deficiencies of circulating enzymes
  
• 995.1 Angioneurotic edema, not elsewhere classified
  

BASICS

Common mechanisms and injury patterns of the ankle:

• Mechanism of injury:
  
  • Inversion injury: Lateral ankle distraction and medial ankle compression
    
    • Avulsion fracture of the lateral malleolus
      
    • Oblique fracture of the medial malleolus
      
  • Eversion injury: Medial ankle distraction and lateral ankle compression
    
    • Avulsion fracture of medial malleolus
      
    • Oblique fracture of the fibula
      
  • External rotation injury:
    
    • Disruption of the tibiofibular syndesmosis, or a fibular fracture above the plafond
      
    • Anterior or posterior tibial fracture with separation of the distal tibia and fibula (unstable fracture)
      
  • Inversion and external rotation (Maisonneuve fracture):
    
    • Medial malleolus avulsion fracture or deltoid ligament tear
      
    • Disruption of the tibiofibular syndesmosis
      
    • Oblique fracture of the proximal fibula
      
  • Inversion and dorsiflexion (snowboarders’ fracture):
    
    • Fracture of the lateral process of the talus
      
• Epidemiology
  
  • Most ankle fractures are malleolar
    
  • Common in young male and 50–70 yr old female
    
  • Associated with cigarette use and high BMI
    

• Ankle fractures in children often involve the physis (growth plate):
  
  • May result in angular deformity from growth plate injury
    
  • Associated with sports requiring sudden changes in direction and obese children
    
  • In children <10 yr old, growth plate is weaker than epiphysis
    
• Tillaux fracture:
  Salter–Harris type III injury of the anterolateral tibial epiphysis external rotation of the foot
  
• Triplane fracture:
  Uncommon fracture of distal tibia with fracture lines in 3 distinct planes (coronal, transverse, sagittal)
  

DIAGNOSIS

• History of trauma
  
• Local ankle pain, swelling, deformity
  
• Inability to bear weight
  
• Soft tissue injury, swelling, ecchymosis, skin tenting, skin blanching
  
• Neurovascular compromise:
  
  • Diminished capillary refill
    
  • Diminished posterior tibialis (PT) or dorsalis pedis (DP) pulses
    
• Limited range of motion
  

• Discover the position of the ankle at the time of injury and area of most significant pain
  
• Determine if patient was able to bear weight immediately or if he or she needed assistance to walk afterward
  
• Ask if the patient heard audible “pop” or “snap,” as this may indicate partial or full tendon rupture
  

• Ottawa Ankle Rules
  (OAR), 100% sensitive: Decision tool for ordering radiographs in patients with suspected injury to the ankle and midfoot:
  
  • Malleolar zone (if any finding is present, then
    ankle
    radiographs are indicated):
    
    • Bony tenderness at the posterior edge or distal 6 cm of either malleoli (points A and B)
      
    • Inability to bear weight for 4 consecutive steps both immediately after the injury and in ED
      
  • Midfoot zone (if either finding is present, then
    foot
    radiographs are indicated):
    
    • Bony tenderness at the base of the 5th metatarsal (point C)
      
    • Bony tenderness of the navicular (point D)
      
    • Inability to bear weight for 4 consecutive steps both immediately after the injury and in ED
      
  • Considered a reliable tool in children >5 yr
    
• Assess the skin for swelling, ecchymosis, skin tenting, disruption, or ischemia
  
• Careful evaluation of distal neurovascular status:
  
  • Capillary refill
    
  • Palpation or Doppler of DP and PT pulses
    
• Palpate proximal fibula for tenderness, especially when medial malleolus or deltoid ligament tenderness is present:
  
  • Peroneal nerve is at risk for injury with a Maisonneuve fracture:
    
    • Wraps around the fibular head
      
    • Test anterior tibialis and extensor hallucis longus
      
    • Assess sensation in the 1st web space
      

• Radiography:
  
  • Evaluate the mortise view for widening: Distance between talus to the medial and lateral malleoli should be uniform
    
• Unstable ankle fractures or dislocations require post reduction radiographs in all 3 planes after splinting
  
  • Anteroposterior (AP), lateral, and mortise (AP with a 20° lateral angle)
    
• AP and lateral radiographs of the tibia and fibula are indicated if a Maisonneuve fracture is suspected clinically
  
• Stress testing of the ligaments in a painful ankle is unnecessary in the ED if the patient will be re-examined in 3–7 days
  
• Stress radiographs of the ankle are usually unnecessary acutely
  
• CT scan or MRI:
  
  • Assess the degree of injury to the tibial plafond and associated ligamentous injury
    

N/A

• Ankle sprain
  
• Achilles tendon injury
  
• Os trigonum fracture
  
• 5th metatarsal fracture (Jones fracture)
  
• Peroneal tendon dislocation or injury
  
• Talar fractures
  
• Talar dome fracture/lesion
  
• Subtalar dislocations
  
• Calcaneal fractures
  
• Foot fractures
  
• Ankle diastasis
  
• Rattlesnake envenomation
  

• Injury to the growth plates may not be apparent on plain radiographs
  
• Consider splint immobilization, nonweight-bearing status, and orthopedic referral if clinical suspicion warrants, even in the setting of negative radiographs
  
• CT scan or MRI may be warranted to delineate the extent of the injury
  
• Inform parents of the possibility of growth abnormalities in patients with injury to the physis
  

TREATMENT

• Immobilize with soft splint to reduce pain, bleeding, and further injury
  
• Cautions:
  
  • Traction devices are usually unnecessary:
    
    • Contraindicated with open injuries
      
  • Protruding bone should not be reduced; the wound should be covered with a clean dressing
    

• Nonweight bearing
  
• Ice
  
• Compression
  
• Elevation
  

• Ankle fracture:
  
  • All ankle fractures or dislocations require orthopedic referral
    
  • Open ankle fractures:
    
    • Remove contaminants
      
    • Apply moist sterile dressing
      
    • Assess tetanus immunity
      
    • Antibiotics
      
    • Emergent orthopedic consultation
      
  • Closed ankle fractures:
    
    • Dislocations should be reduced promptly to prevent complications
      
    • Apply
      posterior splint
      to immobilize foot in 90° angle with the application of bulky dressings and covered by a volar posterior and coaptation (U-shaped stirrup) splint
      
    • Sugar tong (coaptation) can be added for mediolateral support
      
  • Stable injury
    : (one-sided nondisplaced malleolar fracture without ligamentous injury)
    
    • Isolated injury to the lateral malleolus without medial involvement is virtually always stable
      
    • Apply posterior splint
      
  • Unstable injury
    : (both sides of the ankle are injured i.e., bi- or trimalleolar fractures)
    
    • Urgent orthopedic consultation
      
    • Posterior splint as in stable injuries
      
    • May require open reduction and internal fixation (ORIF) emergently before significant swelling develops
      
  • Neurovascular injury
    requires emergent orthopedic consultation
    
• Ankle dislocations:
  
  • Closed reduction should be performed as rapidly as possible to minimize ischemia to the skin and reduce the risk of avascular necrosis of the talus
    
  • Skin tenting and evidence of neurovascular compromise are indications for immediate reduction, even prior to radiographs
    
  • Most ankle dislocations require ORIF
    
  • After reduction, place a posterior splint