Basics
Description
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
Signs and Symptoms
- 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
History
- 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
Physical Exam
- 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
Diagnosis Tests & Interpretation
Imaging
- 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
Diagnostic Procedures/Surgery
N/A
Differential Diagnosis
- 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
Pre-Hospital
- 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
Initial Stabilization/Therapy
- Nonweight bearing
- Ice
- Compression
- Elevation
Ed Treatment/Procedures
- 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
Medication
- Closed fractures:
- Primarily analgesics (opioids)
- Dislocations or displaced fractures requiring closed reduction consider:
- Short-acting benzodiazepine (midazolam 0.05-0.1 mg/kg IV) or barbiturate (methohexital 1-1.5 mg/kg IV) with opioid analgesic
- Open fractures:
- Cefazolin: 2 g loading dose (peds: 50 mg/kg) IV
- Gentamicin: 5-7 mg/kg q24h (peds: 2.5 mg/kg q8h) IV
- Vancomycin: 1 g loading dose (10 mg/kg in children) if penicillin allergic
- Tetanus toxoid if indicated
Follow-Up
Disposition
Admission Criteria
- Unstable ankle fractures require urgent orthopedic consultation and may require admission
- Open ankle fractures and dislocations should be admitted for debridement, irrigation, and IV antibiotics
- Ankle dislocations that are treated with either open or closed reduction
- Concern for compartment syndrome or neurovascular injury
Discharge Criteria
Simple nondisplaced stable ankle fractures without neurovascular compromise may be splinted for immobilization and discharged
Follow-Up Recommendations
- Splinting
- Elevation of affected lower extremity
- Fitted for crutches and shown how to use them
- Placed on nonweight-bearing status of affected joint, until seen by orthopedist
Pearls and Pitfalls
- To reduce a dislocated ankle, partial flexion of knee of affected limb will decrease tension on Achilles tendon and ankle
- Differentiate between ankle fracture and subtalar fracture on physical exam: While the latter is rare, it is also rarely reducible
- Remember to look for other injuries including lumbar spine, hip, tibia, fibula, especially the proximal fibular neck, and foot
Additional Reading
- Bachmann LM. Accuracy of Ottawa ankle rules to exclude fractures of the ankle and mid-foot: systematic review. Br Med J. 2003;326:417.
- Blackburn, EW, Aronsson DD, Rubright JH, et al. Ankle fractures in Children. J Bone Joint Surg Am. 2012;94(13):1234-1244.
- Dowling S, Spooner CH, Liang Y, et al. Accuracy of Ottawa Ankle Rules to exclude fractures of the ankle and midfoot in children: A meta-analysis. Acad Emerg Med. 2009;16:277-287.
- Koehler SM, Eiff P, et al. Overview of ankle fractures in adults. UpToDate.com. 2012 Oct.
- Slimmon D, Brukner P. Sports ankle injuries: Assessment and management. Aust Fam Physician. 2010;39(1-2):18-22.
See Also (Topic, Algorithm, Electronic Media Element)
Ottawa Ankle Rules Figure
Codes
ICD9
- 824.0 Fracture of medial malleolus, closed
- 824.8 Unspecified fracture of ankle, closed
- 824.9 Unspecified fracture of ankle, open
- 824.2 Fracture of lateral malleolus, closed
- 824.1 Fracture of medial malleolus, open
- 824.3 Fracture of lateral malleolus, open
- 824.5 Bimalleolar fracture, open
- 824.6 Trimalleolar fracture, closed
- 824.7 Trimalleolar fracture, open
- 824 Fracture of ankle
ICD10
- S82.56XA Nondisp fx of medial malleolus of unsp tibia, init
- S82.66XA Nondisp fx of lateral malleolus of unsp fibula, init
- S82.899A Oth fracture of unsp lower leg, init for clos fx
- S82.843A Displaced bimalleolar fracture of unsp lower leg, init
- S82.56XB Nondisp fx of med malleolus of unsp tibia, 7thB
- S82.66XB Nondisp fx of lateral malleolus of unsp fibula, 7thB
- S82.843B Displ bimalleol fx unsp lower leg, init for opn fx type I/2
- S82.899B Oth fracture of unsp lower leg, init for opn fx type I/2
SNOMED
- 263091001 Fracture dislocation of ankle joint (disorder)
- 16114001 Fracture of ankle (disorder)
- 209349006 Closed fracture dislocation, ankle joint (disorder)
- 209350006 Open fracture dislocation, ankle joint (disorder)
- 281531008 Fracture of medial malleolus (disorder)
- 281535004 Fracture of lateral malleolus (disorder)