Maisonneuve Fracture

Maisonneuve fracture refers to a combination of a fracture of the proximal fibula together with an unstable ankle injury (widening of the ankle mortise on x-ray), often comprising ligamentous injury (distal tibiofibular syndesmosis, deltoid ligament) and/or fracture of the medial malleolus. It is caused by pronation external-rotation mechanism.

This injury is highly unstable. Essentially all the ligaments and fascia holding the tibia and fibula together are disrupted i.e. nothing is holding your leg bones together!

The Maissonneuve injury is very easy to miss and can result in significant morbidity if not promptly diagnosed, immobilised, and referred to T & O surgical fixation.

This injury is very easily misdiagnosed as a bad sprain Consider obtaining views of the proximal leg to assess for a fibular fracture or weight bearing views of the ankle (to accentuate mortise widening) in any medial ankle injury!

History

The key here is mechanism, mechanism, mechanism.

  • What was the direction of force applied?
  • What was the height of the fall?
  • What was the direction the foot turned?
  • What happened afterward (i.e. weight bearing status)?

There are also certain red flags for serious injuries not to be missed:

  • The patient reports an external rotation mechanism – consider this the “thunderclap headache” or “chest pain radiating to the back” of the ankle.
  • The patient is not weight bearing at all.

Don’t forget the PMHx here.

  • Has the ankle been injured before?
  • What is the functional status of the unaffected limb?
  • Are there any sensory deficits from diabetes, recent back surgery or chronic alcoholism?

Examination

Do not limit your assessment to where the Ottawa Ankle rules guide you. Remember the ankle exam starts at the knee. Work your way down the entire fibula looking for tenderness. However, don’t be satisfied that the absence of tenderness there rules a Maisonneuve fracture.

  • Is there swelling?
  • Is the bruising?
  • Is there any gross deformity?
  • Any breaks to the skin?
  • Is the foot neurovascularly intact?
  • Is the pedal pulse present?
  • Is there bony tenderness to lateral & medial malleolus, navicular or base of 5th metatarsal?
  • Weight bearing status immediately after injury and now
  • Any movement of the ankle?

Your triage notes are just as important for injuries as they are for illness. Writing “Fell over, pain in ankle, partial weight bearing, bony tender” as triage notes doesn’t really tell the treating clinical anything. Be as detailed as possible regarding the mechanism and where the pain is that has justified the x-ray.

Don’t forget, if it’s busy, don’t worry about ordering an X-ray. An ankle assessment can take a while and your triage queue is more important the ordering an x-ray!

X-Ray

Ankle views may either show a fracture of the medial malleolus or widening of the ankle joint due to disruption of the distal tibiofibular syndesmosis (lateral talar shift) or deltoid ligament complex.

Widening between the talus and medial malleolus with an associated proximal fibula spiral fracture

When these ankle injury types are seen, further imaging of the entire fibula is recommended to assess for an accompanying proximal fibular shaft fracture.

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Management

  • Analgesia
  • Referral to T & O
  • Patient needs to be seen by T & O and not just referred to VFC
  • Usually an above knee cast will be required
  • If reduction required, consider Majors for adequate pain relief or Resus for sedation

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