Forearm Fractures Workup

Updated: Oct 30, 2015
  • Author: Gopikrishna Kakarala, MBBS, MS, MRCSEd; Chief Editor: Harris Gellman, MD  more...
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Workup

Imaging Studies

The configuration of midshaft fractures of the radius and ulna varies depending on the mechanism of injury and the degree of violence involved. Low-energy fractures tend to be transverse or short oblique, whereas high-energy injuries are frequently extensively comminuted or segmented, often with extensive soft-tissue injuries.

Radiography

At least two radiographic projections (ie, anteroposterior and lateral) of the forearm must be obtained. These show the fracture, the extent of displacement, and the extent of comminution. Attention should be directed toward finding any foreign bodies in open fractures and gunshot injuries.

Also imperative is to include the elbow and wrist joint in the radiographs of forearm fractures to ensure that radial head and distal radioulnar joint injuries are not missed. A line through the center of the radial shaft, neck, and head should pass through the center of the capitellum in any view of the elbow.

A tuberosity view may help ascertain the rotational displacement of the fracture. This would help in planning how much supination or pronation is needed to achieve accurate anatomic reduction. The ulna is laid flat on the cassette with its subcutaneous border in contact with the cassette; the x-ray tube is tilted toward the olecranon by 20°. This radiograph is then compared with a standard set of diagrams that show the prominence of the radial tuberosity in various degrees of pronation and supination in order to determine the scope of the rotational deformity.

Computed tomography

Computed tomography (CT) is useful in distal radius fractures and radioulnar joint pathologies. One study examined whether the location of distal fractures of the radius correlate with the areas of attachment of the wrist ligaments. [15] Using data from CT scans of acute intra-articular distal radius fractures, the study noted that articular fractures of the distal radius were statistically more likely to occur at the intervals between the ligament attachments than at the ligament attachments. The most common fracture sites were the center of the sigmoid notch, between the short and long radiolunate ligaments, and the central and ulnar aspects of the scaphoid fossa dorsally.

These results suggest that CT may be used to identify the subsequent propagation of the fracture and the likely site of the impaction of the carpus on the distal radius articular surface.

Other modalities

Magnetic resonance imaging (MRI) is of limited utility in radioulnar injuries and is not indicated in uncomplicated forearm fractures. Angiography or vascular Doppler ultrasonography is useful to determine the level of vascular injury in selected cases in which vascular injury is suspected.