Answer radER vol. 1.5

radER Winners:

David Mishkin

Allison Loynd

Answer to Case 1.5

A 56-year-old man was brought to your ED after bring involved in a MVC.  He was a restrained driver in a car that was traveling at 40 MPH and slammed into a tree.  The patient denies loss of consciousness.

1.  When examining anyone with a complaint of ankle injury it is important to exam and document the 5 following areas:

  • Proximal fibula
  • Medial malleolus
  • Lateral malleolus
  • Proximal 5th metatarsal
  • Navicular (medial margin of the midfoot)

2.  The x-rays reveal the following findings: Proximal fibula spiral fracture, avulsion fracture off the medial malleolus and a non-displaced posterior malleolar fracture

3.  The patient should be splinted using a sugar-tong posterior mold technique, be placed on crutches, instructed to be non-wt. bearing, ice, elevation, provided pain medication and discharged with orthopedic follow-up within a week.  This is a potentially unstable ankle injury that may need surgical care.  This point should be emphasized to the patient who should be non-weight bearing until evaluated by the orthopedist.

special-comment-3

A proximal fibular shaft fracture that occurs in association with an ankle injury is termed a Maisonneuve fracture.  Its clinical significance is that, in most cases, it is indicative of disruption of the distal tibiofibular joint — an unstable ankle injury that usually requires surgical care – stabilization with a screw through the distal tibiofibular joint – a syndesmosis screw.  The mechanism of injury is external rotation of the foot relative to the lower leg.  Rotation of the talar dome within the ankle mortise splits apart the bones and ligaments of the ankle.  In most cases, the torsional force at the ankle produces a distal fibular (lateral malleolar) fracture.  In some cases, the lateral injury occurs proximally – the Maisonneuve fracture.

In this patient, there are both medial and posterior fractures, but no lateral injury at the ankle, which is suspicious for a Maisonneuve fracture.  This should prompt ordering radiographs of the entire tibia and fibula.  However, the distal tibiofibular joint space is not widened.  Therefore, prior to deciding on surgical care, the orthopedist will perform stress views of the ankle to ascertain whether or not the distal tibiofibular joint is intact.

A Maisonneuve fracture should be suspected when there is a medial ankle injury (medial malleolar fracture or deltoid ligament tear), or disruption of the distal tibiofibular joint (widening of the space between the distal tibia and fibula on the mortise view), or a “posterior malleolar” fracture (posterior lip of the distal tibia), and no lateral malleolar fracture.  The patient may complain only of pain at the ankle, not knee or lower leg, which is why the proximal fibula and fibular shaft should be palpated in all patients with ankle injuries.

When to Suspect a Maisonneuve Fracture

  1. Medial malleolar fracture or deltoid ligament tear (wide medial joint space) without a distal fibular fracture
  2. Widening of the distal tibiofibular joint without a distal fibular fracture.
  3. Tenderness over the proximal fibula in a patient who has sprained their ankle – ankle radiographs may be normal.
  4. Displaced fractures about the ankle, including distal fibular fractures, when there is tenderness over the proximal fibula. Some authors recommend radiography of the entire fibula in all patients with displaced fractures about the ankle.

image-11Figure:  External rotation of the foot relative to the leg splits apart the ankle mortise.  The force of injury on the lateral side is transmitted up to the proximal fibula.  The interosseous ligament (asterisk) usually remains intact.

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References

Lock TR, et al: Maisonneuve fracture: Case report of a missed diagnosis.  Ann Emerg Med 1987; 16:805-807. Del Castillo J, Geiderman JM: The Frenchman’s fibular fracture (Maisonneuve fracture). JACEP 1979;8:404-406. Schwartz DT: Emergency Radiology: Case Studies, McGraw-Hill, 2008, pp. 301-306.Pankovich AM:  Maisonneuve fracture of the fibula.  J Bone Joint Surg 1976;58A:337-342.  Duchesneau S, Fallat LM: The Maisonneuve fracture. J Foot Ankle Surg  1995 ;34:422-428.Hensel KS, Harpstrite JK: Maisonneuve fracture associated with a bimalleolar ankle fracture-dislocation. J Orthop Trauma 2002;16:525-528.Babis GC, Papagelopoulos PJ, Tsarouchas J, et al: Operative treatment for Maisonneuve fracture of the proximal fibula. Orthopedics 2000;23:687-690.

radER is a weekly contest, hosted by Dr. Kerin Jones’ “Fracture”,  consisting of a radiograph selected from various areas of emergency medicine that are central to the education of medical students and residents in training.  Special Comment is provided by Dr. David Schwartz, Associate Professor of Emergency Medicine at NYU/Bellevue Hospital Center and author of two emergency radiology textbooks.

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