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CHAPTER 8 • Fractures of the Distal Radius and Ulna

from ulnocarpal impaction and/or TFCC tear. 12,176,215 Plain radiographs may not reveal early physeal stress fracture. If the diagnosis is suggested clinically, additional studies may be indicated. Technetium bone scanning is sensitive but nonspe- cific. Magnetic resonance imaging (MRI) is usually diagnostic, demonstrating the characteristic “double line” on coronal T1 and gradient echo sequences. 128 Galeazzi Fracture Children with Galeazzi injuries present with pain, limited fore- arm rotation, and limited wrist flexion and extension. Neurovas- cular impairment is rare. The radial deformity usually is clinically evident. Prominence of the ulnar head is seen with DRUJ disrup- tion. Ligamentous disruption is often subtle and may be evident only by local tenderness and instability to testing of the DRUJ. IMAGING AND OTHER DIAGNOSTIC STUDIES FRACTURES OF THE DISTAL RADIUS AND ULNA Plain radiographs are diagnostic of the fracture type and degree of displacement. Standard anteroposterior (AP) and lateral radiographs usually are sufficient. Complete wrist, forearm, and elbow views are recommended in cases of high-energy inju- ries or when there is clinical suspicion for an ipsilateral frac- ture of the hand, wrist, or elbow. More extensive radiographic evaluation (e.g., computed tomography [CT], MRI) is typically reserved for evaluation of suspected or known intra-articular fractures or associated carpal injuries (e.g., scaphoid fractures, hook of hamate fractures, perilunate instability); these situa- tions are most commonly encountered in older adolescents. There has been increasing enthusiasm for the use of ultra- sound in the diagnostic evaluation of distal radius and ulna fractures. 28,60,99,144,156,164 Two independent studies have demon- strated the feasibility and accuracy of bedside ultrasound for diagnosing nondisplaced fractures. 28,164 Ultrasonography is most useful in cases of suspected fractures in the absence of plain radiographic abnormalities, or in very young children in whom the skeletal structures are incompletely ossified. Since ultrasound machines are now commonplace in emergency departments and used by many nonradiology physicians, usage as a screening diagnostic tool is evolving. Radiographic evaluation should be performed not only to confirm the diagnosis but also to quantify the degree of displace- ment, angulation, malrotation, and comminution (Fig. 8-10). Understanding of the normal radiographic parameters is essen- tial in quantifying displacement. In adults, the normal distal radial inclination averages 22 degrees on the AP view and 11 degrees of volar tilt on the lateral projection. 73,139,150,183,222 Radial inclination is a goniometric measurement of the angle between the distal radial articular surface and a line perpendicular to the radial shaft on the AP radiograph. Volar tilt is measured by a line across the distal articular surface and a line perpendicular to the radial shaft on the lateral view. Pediatric values for radial inclination and volar tilt may vary from adult normative values, depending on the degree of skeletal maturity and the ossifica- tion of the epiphysis. Indeed, radial inclination is often less than 22 degrees in younger children, though volar tilt tends to be more consistent regardless of patient age.

As noted above, advanced imaging may be helpful in cases of intra-articular extension to characterize fracture pattern and joint congruity. This may be done by AP and lateral tomograms, CT scans, or MRI. Dynamic motion studies with fluoroscopy can provide important information on fracture stability and the success of various treatment options. Dynamic fluoroscopy requires adequate pain relief and has been used more often in adult patients with distal radial fractures. In Galeazzi fractures, the radial fracture is readily appar- ent on plain radiographs. Careful systematic evaluation of the radiographs will reveal concurrent injuries to the ulna and/or DRUJ (Fig. 8-11). A true lateral radiograph is essential to iden- tify the direction of displacement and thus to determine the method of reduction. Rarely are advanced imaging studies, such as CT or MRI scan, necessary. Figure 8-10.  Angulation of the x-ray beam tangential to the articular surface, providing the optimal lateral view of the distal radius. The wrist is positioned as for the standard lateral radiograph, but the x-ray beam is directed 15 degrees cephalad. (Reprinted by permission from Springer: Johnson PG, Szabo RM. Angle measurements of the distal radius: A cadaver study. Skel Radiol. 1993;22(4):243–246. Copyright © 1993 International Skeletal Society.)

CLASSIFICATION OF FRACTURES OF THE DISTAL RADIUS AND ULNA Distal Radius and Ulna Fractures

Distal Forearm Fractures: GENERAL CLASSIFICATION

Physeal fractures  Distal radius  Distal ulna

Distal metaphyseal (radius or ulna) Torus Greenstick Complete fractures Galeazzi fracture–dislocations Dorsal displaced Volar displaced