Ankle and Foot 47 - Department of Radiology - University of ...

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47 Ankle and Foot 2259 47
Figure 47-65. CT scan of a 69-year-old patient
transferred to our emergency department after having
undergone nonsurgical reduction and casting of an
open ankle fracture-dislocation. The patient was sent
for CT to better visualize the fracture. A, In the axial
plane, we recognize the head of the talus (h-Ta) by its
articulation with the navicular (N), but the body of the
talus behind the head is missing. Small collections of
air, seen as black on CT, are scattered around the
fracture fragments, indicating that this was an open
fracture. B, The coronal plane shows no talus between
the tibia (Ti) and calcaneus (Ca). C, The sagittal plane
tells the whole story: the body of the talus (b-Ta) has
been sheered off the head and posteriorly displaced
behind the ankle mortise.
C
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Figure 47-66. Development of avascular necrosis
(AVN) of the talus after trauma in a 25-year-old who
was transferred to our emergency department with
the ankle already in a cast. A, Our initial casted lateral
radiograph revealed a vertical fracture (arrowhead)
through the body of the talus. Because of the risk of
AVN with talus fractures, the patient was immediately
taken to the operating room. B, Intraoperative
radiograph reveals anatomic reduction of the fracture
with two screws. No sclerosis is present in the talus.
C, On a lateral radiograph obtained 8 weeks later, the
body of the talus appears more sclerotic than the
surrounding bones. D, Midsagittal CT scan obtained 5
days after the CT scan in part C revealed a broad band
of sclerosis in the talar dome and body, characteristic
of AVN.
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9/9/2008 5:34:54 PM