Plain Radiography
Plain radiography is the primary means of evaluating hand injuries beyond the history and physical examination. Any significant injury to the hand should be assessed with posteroanterior (PA), lateral, and oblique views. A 30° pronated lateral view for second and third metacarpal fractures and a 30° supinated lateral view for fourth and fifth metacarpal fractures are helpful. [11, 12] (See the images below.)
AP radiograph of 4th and 5th metacarpal fractures following intramedullary pinning.
Carpometacarpal injuries
Carpometacarpal (CMC) fractures and dislocations are frequently difficult to visualize or fully characterize with standard radiographic projections. Additional oblique views, fluoroscopy, or computed tomography (CT) may be necessary. Additionally, traction radiographs can sometimes best demonstrate the bony and ligamentous injuries and their severity. This is accomplished by distracting the involved digits and obtaining multiple radiographic views.
CMC dislocation results in subtle loss of joint space as viewed on the anteroposterior (AP) projection. Often, this is seen as a broken sawtooth sign at the CMC joint. This sign may be accompanied by displacement noted on lateral or oblique views.
Assessing closely for other additional injuries is important. Because significant force is required to disrupt the strong CMC ligaments, fracture-dislocation of one CMC joint is often accompanied by an injury to one or more of its neighbors.
Metacarpal head fractures
Evaluation of these injuries may require additional imaging studies. Specifically, tomograms or CT scans may be necessary to visualize the fracture and degree of articular displacement.
The Brewerton view (metacarpophalangeal [MCP] joint flexed 65° with the dorsum of the proximal phalanx flat against the radiograph cassette and the beam angled 15° ulnar to radial) profiles the collateral recesses and is helpful for collateral ligament avulsion fractures.
Metacarpophalangeal dislocations
Most commonly, lateral radiographs reveal the dorsal displacement of the proximal phalanx. In more severe and complex dislocations, there may also coexist a metacarpal head fracture.
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AP radiograph of displaced 4th and 5th metacarpal fractures.
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Lateral radiograph of displaced 4th and 5th metacarpal fractures.
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Oblique radiograph of 4th and 5th metacarpal fractures.
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AP radiograph of 4th and 5th metacarpal fractures following intramedullary pinning.
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Lateral radiograph of 4th and 5th metacarpals following intramedullary pinning.
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Complex 2nd metacarpophalangeal (MCP) dislocation in skeletally immature patient; note position of finger and dimpling of skin on volar hand.
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Radiograph of complex 2nd metacarpophalangeal (MCP) dislocation in skeletally immature patient (same patient as in Image 6).
