Describing Radiographs

When orthopedic consultation is indicated, proper management of the patient may rest on the emergency physician's accurate description of the x-ray. Often the narrative will influence the orthopedist's decision regarding the need for hospital admission and whether surgical versus nonsurgical management is warranted. In essence, the emergency physician should be able to transmit a virtual copy of the x-ray by means of verbal description.

There are various ways of classifying or categorizing fractures. The method presented here is intended to be the most practical from the standpoint of effective communication with a consultant who is not physically present.3

OPEN VERSUS CLOSED Although not a radiologic finding per se, this aspect of an injury is among the most important and should be conveyed to the orthopedist before any other. The implications of open fracture are of such significance that this factor alone may determine the patient's immediate care or ultimate disposition.

LOCATION OF THE FRACTURE Typical reference points used by orthopedists to describe the location of a fracture along the shaft of a long bone are the midshaft, the junction of the proximal and middle thirds, and the junction of the middle and distal thirds. Any fracture more proximal or distal than this may be localized in terms of its distance, in centimeters, from the bone end.

When a proximal or distal fracture extends into the adjacent joint, it is termed intraarticular. Intraarticular fractures have special significance because disruption of the joint surface may warrant surgery to restore the joint's contour and prevent subsequent traumatic arthritis. This feature of a fracture line, if present, constitutes important information.

Anatomic bony reference points should be cited when applicable. A fracture just above the condyles of the distal humerus or femur, for example, is most precisely called a supracondylar fracture. A fracture running from the greater to the lesser trochanter of the proximal femur is an intertrochanteric hip fracture, whereas a fracture just below the trochanters is subtrochanteric, and a fracture just above is said to involve the femoral neck. The area at or proximal to the coronoid process of the ulna is the olecranon and should be referred to as such, rather than simply the proximal ulna. Other bony landmarks include the radial head (proximal), radial styloid (distal), and greater tuberosity of the humerus. Numerous additional examples exist.

ORIENTATION OF THE FRACTURE LINE The most common orientations of fracture lines are illustrated in Fig 259-1. Torus and greenstick fractures are seen almost exclusively in young children, whose bones are more pliable than those of adults. Note the segmental fracture, which is commonly described incorrectly as a comminuted fracture. To an orthopedist, the term comminuted implies splintering or shattering. A single large free-floating segment of bone between two well-defined fracture lines is a segmental fracture.

DISPLACEMENT AND SEPARATION Displacement refers to the position of the fracture fragments as nonconcentric or offset from each other. It is expressed in terms of direct measurement (4-mm displacement) or in terms of the percent of the width of the bone (e.g., 50 percent displacement or complete displacement). The direction of displacement is based on the position of the distal fragment in relation to the proximal.

Displacement should not be confused with separation, which is the distance two fragments have been pulled apart. Figurei25.9.-2 illustrates principles of displacement and separation.

FIG. 259-2. Fracture displacement and separation. A. Nondisplaced, no separation. E. A 4-mm separation.

No displacement, slight separation. B. Fifty percent dorsal displacement. C. Complete dorsal displacement. D.

SHORTENING Shortening is the amount by which the bone's length has been reduced and is expressed in millimeters or centimeters. Shortening can occur by impaction (telescoping of the fragments into one another) or by the overlap of two completely displaced fragments ( Fig. 2.59:3). The latter is referred to by some orthopedists as overriding. Because an x-ray affords no depth perception, a fracture that appears impacted on one view must also be visualized at an angle 90° from the first to differentiate it from a fracture whose ends are completely displaced and overriding.


FIG. 259-3. Shortening at fracture site. A. Complete displacement with overriding. B. Impaction. In both cases, the width of the shaded area represents the amount of shortening.

Depending on the location of the fracture and the age of the patient, shortening may have long-range functional implications and may have to be corrected by closed manipulation or by surgery.

ANGULATION Angulation is expressed in terms of two parameters: direction and amount (Fig, 259-4). Quantifying the angulation is relatively simple. The physician need only estimate the amount of "unbending" (expressed in degrees) that would be required to make the fragments parallel.

Dorsal Apex Angulation

FIG. 259-4. Fracture angulation. All figures depict 30° dorsal angulation. A. and B. Direction is based on the apex of the angle drawn below the figures. C. Direction is based on the direction of the terminal fragment.

Describing the direction of angulation is more difficult because the terminology is less consistent among clinicians. Generally, when a fracture is near the midshaft of a long bone, the direction of angulation is the direction of the apex of the angle formed by the two fragments. Figure 259:4A and Figure 259:4B both represent 30° of dorsal angulation. When a fracture is located near the end of a bone, however, angulation is described in terms of the direction the terminal fragment is deviated. Figure259:.4.C. also represents 30° of dorsal angulation, even though the apex of the angle formed by the fragments is pointing in the opposite direction from that in the preceding figures. If there is a possibility of ambiguity in the description, specifying the direction of deviation of the distal fragment can usually resolve it.

Depending on the anatomic area involved, direction of angulation may be expressed as radial or ulnar, dorsal or volar, anterior or posterior, or lateral or medial.

ROTATIONAL DEFORMITY Rotational deformity—the extent to which the distal fracture fragment is twisted on its own axis relative to the proximal fragment—is generally not measurable on x-ray and sometimes not even radiologically apparent. This element of fracture description depends on physical examination. Its detection is particularly important in the phalanges of the fingers, where, if rotational deformity goes unrecognized and uncorrected, the affected finger will always be malaligned when the hand is closed.

FRACTURE COMBINED WITH DISLOCATION OR SUBLUXATION Injuries near a joint may involve dislocation or subluxation in combination with a proximate fracture. An example is fracture of one or more ankle malleoli, together with partial or complete displacement of the talus from beneath the tibia. Fracture-dislocations are significant injuries, often requiring surgical intervention. If, in describing the injury, the physician emphasizes the fracture component but expresses the dislocation or subluxation component as mere displacement, then the full severity may not be appreciated by the orthopedist. Such injuries should be described as fracture-dislocations or fracture-subluxations.

SALTER FRACTURES The physiology of Salter fractures—fractures involving the epiphyseal plate at the end of the long bone of a growing child—has already been discussed. Salter fractures are classified into five types, based on the pattern of the fracture line. Because the type generally correlates with the potential for future growth disturbance (and, consequently, with the aggressiveness of treatment required), the ability to classify such injuries based on their x-ray appearance is important.

Perhaps the easiest way to remember the Salter classification system is to think of these injuries not in terms of where the fracture line runs, but in terms of what has been broken off. Figure.i25.9.-.5. illustrates the anatomy involved. Table.25.9-2. describes the five types of Salter fractures, which are illustrated in Fig..i259:6. The potential for growth disturbance is least for type I and increases with the classification number, the worst prognosis being associated with type V injuries.

FIG. 259-5. Epiphyseal anatomy.

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TABLE 259-2 Description of Salter Fractures

FIG. 259-6. Epiphyseal fractures based on Salter-Harris classification.

Type I and type V Salter fractures may be radiologically undetectable. Type I injuries usually involve little or no separation of the epiphysis from the rest of the bone, and the lucent fracture line is not visible along the equally lucent epiphyseal plate. If the epiphysis and plate slip transversely along the end of the shaft, the abnormal position will be seen on x-ray, but slippage does not always occur. Diagnosis of acute Salter I fractures is usually clinical, based on the presence of swelling and tenderness in the region of the physis.

Type V injuries may be evident only retrospectively, when growth disturbance first begins to appear. At time of initial presentation, however, a history of a significant axial loading force, coupled with significant tenderness in the area of the epiphyseal plate, should suggest the possibility of a type V injury. Such children should be immobilized and referred for orthopedic follow-up.

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  • Anu
    How to describe arthritis in radiographs?
    2 months ago

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