Radiology Teaching Files > Case 834754

Contributed by: Michael Richardson, Radiologist, University of Washington, Washington, USA.
History: Knee pain following trauma.

Fig. 1: AP Radiograph of the Right Knee

Fig. 2: A linear lucency (medial arrow) is noted on the lateral tibial plateau adjacent to the tibial spine. Also, there is increased sclerosis in the trabecular bone beneath the lateral plateau. If you are eagle-eyed, you also noted a step-off in the anterior rim of the tibial plateau (lateral arrow). This step-off tells us that we are dealing with a depressed fracture.

Fig. 3: Tomogram of the Right Knee

Fig. 4: Coronally Reformatted CT of the Right Knee - This particular reformatted CT image is at a plane somewhat posterior to that of the tomogram, and does not show the amount of depression as well as this particular tomographic slice. However, it does show the fracture and the impacted subchondral bone very well (arrow).

In the surgical planning of a patient with a tibial plateau fracture, an important question is whether the fracture is depressed, and if so, how much. Fractures that are non-displaced or only depressed less than 3 mm may do well without surgical reduction. Depression greater than 3 mm is usually an indication for open reduction and internal fixation. This may be hard to determine on plain radiographs alone. In the days of yore, such patients were worked up next with tomography. Nowadays, tomography units have mostly been phased out, with the tomo room usually converted to a CT suite or some other use. This patient had both examinations.

Last 2 images show that the depression is probably about 2 - 3 mm. Which method is best for depicting the depression? With state of the art CT and thin section cuts, we feel that CT is just as good as a tomogram for showing the amount of depression and far superior to a tomogram in showing the presence, number and orientation of all of the fracture planes and fragments.

References: Source: UW Radiology Main Online Teaching File: Case No. 20
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Additional Details:

Case Number: 834754Last Updated: 11-03-2004
Anatomy: Skeletal System   Pathology: Trauma
Exam Date: Access Level: Readable by all users

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