Plain Radiography
Plain radiographs (see the image below) are the foundation of treatment and are all that is needed for most distal radius fractures (DRFs). If the DRF is placed in traction as an early part of treatment, traction radiographs are very helpful. Often, the fragments cannot be adequately identified or assessed on the injury films; the traction views are often the first radiographs that define the fragments. Final reduction films must be evaluated for adequacy of reduction and for an assessment of stability, even though this is an area with no clear guidelines.
Posteroanterior radiograph demonstrating typical features of common distal radius fracture: loss of radial length, loss of radial tilt, and comminution at fracture line.
Computed Tomography
Computed tomography (CT) is considered by many to be useful for evaluating the articular fracture lines in an intra-articular fracture, particularly one that is comminuted, and it is sometimes helpful for planning the approach. A CT scan may be very helpful for determing optimal treatment in cases where the subchondral bone is comminuted. If the subchondral bone, particularly in the weightbearing areas of the scaphoid facet or the lunate facet, is highly comminuted, an approach that unloads the subchondral bone is warranted (eg, external fixation and bridge plating; see Treatment).
In the view of others, however, CT adds expense and delay but rarely changes the intraoperative game plan. Highly comminuted fractures that are only comminuted in the metaphysis or the distal shaft do not need a CT scan. Experience here is necessary, in that there are no clear guidelines or criteria for when to obtain a CT scan.
It should be kept in mind that whereas plain films underestimate the number of fracture lines, CT overestimates the number.
CT is necessary in planning intra-articular osteotomies for nascent malunions and mature malunions. Three-dimensional (3D) reconstructions may look impressive in presentations, but to date, they have not been very helpful in preoperative planning or postoperative assessment.
One study examined whether the locations of DRFs correlate with the areas of attachment of the wrist ligaments. [9] Using data from CT scans of acute intra-articular DRFs, the study noted that articular DRFs 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, the area 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. [9] This is a very interesting approach that will likely become a standard part of understanding DRFs in the future, especially if the method can be refined.
The threshold for treatment, though not clearly defined, often involves assessing the degree of displacement (measured in millimeters). Both plain films and CT scans have been evaluated for their accuracy at the 1-mm level. Neither modality can reliably be read at this level, which adds to the challenge of treating DRFs.
Magnetic Resonance Imaging
Magnetic resonance imaging (MRI) is not indicated for evaluation of bony anatomy. Physical examination, the foundation of any workup, is limited by pain and swelling in the acute phase, and the examination of wrist ligaments by physical examination is limited. An MRI can be considered in the setting of a high-energy injury (eg, a fall from a height or a motor vehicle accident) for the assessment of ligamentous injuries.
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Posteroanterior radiograph demonstrating typical features of common distal radius fracture: loss of radial length, loss of radial tilt, and comminution at fracture line.
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Lateral radiograph demonstrating other common features (also see preceding image) of distal radial fracture: loss of normal volar tilt and documentation that comminution is primarily in dorsal metaphysis.
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Volar surface of radius.
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Dorsal surface of radius.
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Radial surface of radius.
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Ulnar surface of radius.
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Distal surface of radius.
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Posteroanterior radiograph of normal wrist.
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Lateral radiograph of normal wrist.
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Volar anatomic landmarks important for volar approach. Region marked "pronator fossa" is covered by pronator quadratus (PQ) . It extends distally to PQ line, marked in blue. Watershed line (WS) marks highest crest (most volarly projecting surface) of radius. Red X marks volar radial tuberosity, which lies just off PQ. It is usually not dissected and therefore usually not seen, but it is easily palpable clinically. VR = volar radial ridge.
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Percutaneous pinning with Clancey technique, posteroanterior view.
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Percutaneous pinning with Clancey technique, lateral view.
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Dorsal plate fixation using Synthes Pi plate, posteroanterior view.
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Dorsal plate fixation using Synthes Pi plate, lateral view.
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Three-column concept of wrist anatomy.
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Standard (bridging) external fixation using Orthofix RadioLucent external fixator.
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Nonbridging external fixation using Howmedica Mini-Hoffman external fixator.
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Volar fixed-angle plate using Orthofix Contours VPS plate, posteroanterior view. This is facet posteroanterior view, which is tilted at same angle as tilt of distal articular surface, thus allowing assessment of intra-articular vs extra-articular placement of screws. Note that distal screws engage both radial styloid fragment and dorsal ulnar fragment.
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Volar fixed-angle plate using Orthofix Contours VPS, lateral view. This is not facet lateral view, and distal articular surface is not seen tangentially. Consequently, some screws appear to be intra-articular; however, posteroanterior view demonstrates that they are not. Note also that distal screws do not past-point dorsal cortex but instead stop few millimeters short of dorsal cortex. Because of difficulty of evaluating screw length, even with fluoroscopy, screws should stop 2-4 mm short of dorsal cortex.
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Posteroanterior view of fragment-specific fixation. Hardware to radial side is radial pin plate. Pins hold fragment in place, and pin plate gives greater stabilization to pins. Hardware to ulnar side is dorsal pin plate (also see image below), which holds dorsal ulnar corner in place. Image courtesy of Rob Medoff, MD.
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Lateral view of fragment-specific fixation. Hardware on volar side (known as wireform) is supporting subchondral bone. Hardware in center of image is pin plate along radial border of radial styloid and serves to hold large radial styloid fragment in place. Small pin plate is situated along dorsal surface. Image courtesy of Rob Medoff, MD.
