Senior Report 8.22

seniorreport

Case Discussion by Eric Malone, MD

Visual Stimulus Case:

A 26 year old male with a past medical history of schizophrenia presents after jumping out of a second story window in a possible suicide attempt. He was brought to the emergency department on petition and was originally taken to the crisis center, where, in addition to intramuscular haloperidol and lorazepam, he also received a foot X-ray, which is provided below.

He has no other injuries and complains only of right foot pain. Examination shows deformity of the dorsal aspect of the right foot with tenderness and soft tissue edema over the midfoot. Range of motion in the right ankle is intact, as are peripheral pulses and neurologic function.

8.2228.22

 

Questions:

  1. Based on the above X-ray, which of the following is the most appropriate course of management:

A. Order more haloperidol and lorazepam because the patient is clearly malingering and there is nothing wrong with his foot.

B. Posterior mold right leg splint (with stirrups), non-weight bearing on the right leg, crutches, adequate analgesia and rapid orthopedic outpatient follow up (following completion of psychiatric evaluation)

C. Pain control, preoperative laboratory studies, and emergency department orthopedic consultation

D. Post-op shoe, pain control, PRN orthopedic or podiatric follow up.

 

  1. In addition to the findings that you identified on the above x-ray, which of the following other injuries is also likely present:

A. Occult talar dome fracture

B. Disruption of the ligamentous structure of the midfoot at the tarsometatarsal joint

C. Disruption of the vascular supply of the fifth metatarsal head

D. Calcaneal tendon rupture

 

  1. Failure to diagnose and appropriately manage this injury pattern is most commonly associated with which of the following:

A. Midfoot instability and collapse, severe arthritis

B. Avascular necrosis of the fifth metatarsal head

C. Atrophic degeneration of musculature of the dorsal foot including extensor digitorum brevis

D. Fracture non-union

 

Answers:

  1. C
  2. B
  3. A

Discussion:

The radiographs demonstrate a fracture through the base of the second metatarsal. In addition, there is widening of the joint space between the base of the first and second metatarsals and inferolateral subluxation of the first and second metatarsals relative to their respective cuneiforms. As with seemingly all orthopedic injuries, this pattern has an eponymous description. This injury pattern is known as a Lisfranc injury.

Lisfranc injuries refer more generally to a pattern of injury that involves disruption of the Lisfranc joint. As shown below, the Lisfranc joint is described anatomically as the articulation between the bases of the metatarsals and cuneiform bones.

This joint extends across the midfoot. Any disruption with or without fracture can be described as a Lisfranc injury. Notably, not all such injuries involve obvious metatarsal fractures; some are subtle and involve only ligamentous injury. Note that in the normal anatomical relationships of the midfoot, the proximal metatarsal articulates with the tarsal bones such that the borders of each are aligned, as shown below. The medial border of the second metatarsal aligns with the medial border of the middle cuneiform on the AP view. Presence of an avulsion fragment within the joint space between the first and second metatarsals is known as a Fleck sign (because you can never have enough eponymous ortho descriptors).

Mechanistically, Lisfranc injuries occur as a result of either direct (i.e. blunt) or indirect trauma. With an indirect traumatic injury, the Lisfranc joint undergoes excessive pronation or supination in an already plantar flexed foot, resulting in ligamentous injury. Examination will show midfoot tenderness, soft tissue swelling, potential ecchymosis, and difficulty or inability to bear weight. Plantar ecchymosis is an exam finding specific for Lisfranc injury.

Radiographic evaluation for Lisfranc injuries should focus on the relationships of the midfoot structures described above. In reviewing the x-rays in this case, note the abnormal relationship of the base of the second metatarsal to the cuneiform (red), the widening of the space between the first and second metatarsals (yellow), and the Fleck sign (blue).

Some Lisfranc injuries can be subtle. If history and exam is suggestive of more severe injury than demonstrated by x-ray, weight bearing radiographs or CT should be considered. Failure to diagnose and obtain appropriate early fixation is associated with increased complication rates.

All suspected Lisfranc injuries warrant ermegency department orthopedic consultation, and most will undergo operative fixation and extensive casting as an outpatient. Even when appropriately diagnosed and managed, there is a high degree of post-operative complications, primarily residual pain.

References:

Ross G,Cronin R,Hauzenblas J,Juliano P. Plantar ecchymosis sign: a clinical aid to diagnosis of occult Lisfranc tarsometatarsal injuries. J Orthop Trauma 1996;10(2):119–22.

Rosen’s Emergency Medicine: Concepts And Clinical Practice. Marx J, Hockberger R, Walls RM, Adams J, Rosen P. Philadelphia. Mosby

M.J. Welck et al. / Injury, Int. J. Care Injured 46 (2015) 536–541

Hatem SF. Imaging of Lisfranc injury and midfoot sprain. Radiol Clin North Am 2008;46(6):1045–60.

DeOrio M, Erickson M, Usuelli FG, Easley M. Lisfranc injuries in sport. Foot Ankle Clin 2009;14(2):169–86.vier, 2010

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.