Page 153 - ASOP ROT Study Guide

4.3 Computerized Axial Tomography

Using modern tomographic techniques, computers can be used to generate tomograms on a video
screen, and to print out the results on paper. This technique is known as Computer Aided
Tomography (or Computerized Axial Tomography), hence the term "CAT scanner".

4.4 Ultrasound

When investigating a fracture, ultrasound scanning can show the resulting accumulation of fluid
(especially blood).

4.5 Radioisotope Scanning

This technique involves injecting a very small quantity of a radioactive substance into the
bloodstream of the injured person. The radioactive substance attaches to phosphate molecules
which are actively taken up by bone. The radioactive substance therefore ends up in the bones. An
X-ray plate is then exposed under the affected part of the body and a radiograph of the bone is
obtained. The more metabolically active the bone is, the faster it takes up the radioactive substance.
The sites of unusual metabolic activity (i.e. at the site of the fracture) can be clearly seen on the
radiograph.

Where there is clinical doubt, radioisotope bone scanning can help in deterrnining whether a bone is
fractured or not. This is more useful in situations which are not acute, at about two weeks from the
time of injury. It is a highly sensitive test but does not tell us anything about the fracture except
that it is there. This technique is often used when a scaphoid (a bone in the wrist) fracture is
suspected, as this is not easily seen on a first X-ray.

5. DESCRIBING FRACTURES

It is important to describe the shape and degree of fragmentation of a fracture because these
features indicate the amount of energy which has caused the injury, and so help us to understand
it and how we may treat it.

5.1 Fracture Architecture

Once the fracture has been diagnosed, a description of the fracture must be noted.

It is useful to have a convention to describe injuries. A descriptive convention which is universal
and relevant to subsequent management may be achieved by obtaining the answers to the questions
below:

♦ Which bone is broken and on which side?

♦ Is the fracture open or closed?
Is the skin broken? - open fracture. Is the skin intact? - closed fracture
♦ Where on the bone is it broken?