David A. Feaker JR*
Matthew J. Wilson*
Christopher S. Smith*
Michael J. Gardner

*The views expressed in this chapter are those of the author(s) and do not necessarily reflect the official policy or position of the Department of the Navy, Department of Defense or the United States Government. David A. Feaker, Matthew J. Wilson, and Christopher S. Smith are military service members and this work was prepared as part of their official duties. Title 17 U.S.C. 105 provides that ‘Copyright protection under this title is not available for any work of the United States Government.’ Title 17 U.S.C. 101 defines a United States Government work as a work prepared by a military service member or employee of the United States Government as part of that person’s official duties.

Bony Anatomy¹^–⁶

The forearm is composed of the radius and ulna. Proximally, the radius articulates with the capitellum as well as the ulna at the lesser sigmoid notch while the ulna articulates with the trochlea via the trochlear notch, which is formed by the olecranon and coronoid.
Distally, the radius articulates with the scaphoid and lunate at the scaphoid fossa and lunate fossa. The radius and ulna articulate distally at the sigmoid notch.
The radius rotates about the axis of the ulna. The bow of the radius allows for supination and pronation about the ulna and must be restored with ORIF of the radius. The radius also has a minor anterior bow.
The ulna is rather straight in comparison to the radius with a minimal anterior bow. The ulna is subcutaneous in its position along the medial forearm.
Important bony landmarks of the radius proximally are the radial head, which is palpable on the lateral aspect of the elbow as well as the radial tuberosity, which is oriented on the lateral aspect of the radius in supination and the dorsal aspect in pronation. The radial shaft is distal to the radial tuberosity.

Radiographic Anatomy

On an AP of the forearm (Fig. 10-1), the wrist should be positioned in supination and the elbow should be extended against the table. Distally, the radial styloid should appear in profile, and there should be minimal overlap of the radius and ulna. Proximally, the radial tuberosity should slightly overlap the ulna and should be 180 degrees from the radial styloid. The radiocapitellar joint should be well visualized with minimal overlap of the proximal ulna. If the elbow is unable to be fully extended, then two AP views should be taken. One AP is taken with the humerus parallel with the tabletop and the second radiograph is taken with the forearm parallel with the tabletop.⁷^–⁹
A good lateral of the forearm (Fig. 10-2) is evident when there is a good lateral of the elbow as well as a good lateral of the wrist. Elbow is placed in 90-degree flexion, and humeral epicondyles are superimposed and perpendicular to the image receptor. The humerus and the forearm are positioned in the same plane, which may require the distal forearm to be slightly elevated using a radiolucent sponge or towel. The wrist is placed in a true lateral position with elbow in 90-degree flexion, ulnar side down, and radius and ulna superimposed. The wrist is positioned neutral (without flexion or extension) and the radius and ulna superimposed by aligning the second and third metacarpals with the radius.⁷^–⁹
Intraoperatively, it is difficult to view both the forearm and wrist within the same radiograph due to a limited viewing field provided by fluoroscopy (Figs. 10-3 and 10-4). We recommend obtaining a perfect lateral of the wrist and then repositioning the fluoroscopy without changing the position of the upper extremity to assess the placement of the hardware. When working proximally, obtain a perfect lateral of the elbow and then move the beam distally.

Gardner1e-ch010-image001 — Figure 10-1 The AP view of the forearm shows the radial styloid in profile with minimal overlap of the radius and ulna. Note that the radial tuberosity slightly overlaps the ulna and the radial styloid and radial tuberosity are separated by 180 degrees.

Gardner1e-ch010-image002 — Figure 10-2 A perfect lateral of the forearm is defined by obtaining a good lateral of the wrist combined with a good lateral of the elbow.

Gardner1e-ch010-image003a — Figure 10-3 **A and B:** Intraoperative imaging does not allow for simultaneous visualization of wrist and forearm on a lateral view. Obtain a perfect lateral of the wrist prior to imaging the forearm.

Gardner1e-ch010-image003b — Figure 10-3 **A and B:** Intraoperative imaging does not allow for simultaneous visualization of wrist and forearm on a lateral view. Obtain a perfect lateral of the wrist prior to imaging the forearm.

Gardner1e-ch010-image004a — Figure 10-4 **A and B:** Post ORIF films obtained with portable x-ray intraoperatively or postoperatively in the PACU.

Gardner1e-ch010-image004b — Figure 10-4 **A and B:** Post ORIF films obtained with portable x-ray intraoperatively or postoperatively in the PACU.

Preoperative Imaging

Preoperative imaging should include wrist and elbow films in addition to forearm radiographs with suspected radial and ulnar shaft fractures.³
In all cases of forearm fracture, we recommend obtaining contralateral forearm radiographs for preoperative planning as well as comparison of the radial bow following ORIF.
Associated injuries with diaphyseal fractures of the forearm include elbow dislocations, PRUJ/DRUJ disruptions, and injury to the interosseous membrane. Obtaining proper distal and proximal imaging is crucial to avoid missing other associated injuries.³^,¹⁰^–¹³
Visualizing the radial bow is important to evaluating proper reduction for functional biomechanics postinjury. The major radial bow extends distally from the bicipital tuberosity to the distal radioulnar joint. The apex of the bow is found just distal to the midpoint of the distance of the radius. Restoration of this bow with surgical intervention is of the utmost importance to allow pronation and supination.²
Deforming forces on the radial and ulnar diaphyses play a major role in fracture patterns and displacement. Depending on where the fracture occurs, the net forces of supination and pronation will exert the displacement seen on injury films. The primary pronators of the forearm are the pronator quadratus and the pronator teres. The primary supinators of the forearm are the supinator and biceps muscles. If a fracture of the radius occurs distal to the supinator forces, but proximal to the insertion of the pronators, the resulting force will lead to a rotational deformity of unopposed supination of the proximal segment and pronation of the distal segment. Fractures distal to the pronator teres will have more balanced net forces and be less deformed rotationally.⁷

Indications for Surgery¹^,³^,⁷^,¹⁰^,¹⁴^–¹⁷

Fractures of the proximal two-thirds of the ulna with >50% displacement.
Monteggia/Galeazzi fracture dislocations.
Greater than 10 degrees of angulation.
Loss of the radial bow.
Both bone forearm fractures are considered fractures of necessity for ORIF.

Imaging in Galeazzi Fractures

The uninjured DRUJ should be assessed with a shuck test prior to prepping and draping to ascertain the patient’s normal motion.³^,¹⁸
Following fixation of the radius, the DRUJ of the injured side may then be assessed and compared to the uninjured. If stability is achieved with the wrist in a supinated position, the forearm may be casted in supination. If stability is not achieved, an appropriate reduction should be confirmed using radiography³^,¹⁸ (Fig. 10-5A and B).
Imaging is focused at the wrist rather than the forearm.
- A lateral of the wrist is adequate when the 2nd and 3rd metacarpal overlap or the pisiform is contained between the volar lip of the scaphoid tubercle and volar aspect of the capitate head.¹⁹
- It is important to critically inspect the image (Fig. 10-6) as overlap of the radius and ulna can be achieved by adjusting the rotation of the forearm, but if this is not done utilizing a true lateral radiograph, malreduction of the DRUJ may occur.¹⁸
Once an adequate lateral has been obtained and manual reduction is confirmed, two 1.6-mm or 2-mm K-wires are inserted percutaneously proximal to the fovea through the ulna and both cortices of the radius.⁴^,⁷
- When placing these K-wires and utilizing a large C-arm, the patient’s elbow can be flexed to 90 degrees while the large C-arm is placed in a lateral position. This will allow real-time assessment of the positioning of the K-wire (Fig. 10-7).
- A similar setup may be done with the mini C-arm though you must ensure that the underportion of the mini C-arm has remained sterile to this point of the case. Mini C-arms are occasionally utilized for pediatric forearm fractures, with the benefit of reducing radiation exposure.²⁰