Imaging Studies
General radiography principles
Anteroposterior and lateral views of the wrist, forearm, and elbow are required when forearm fracture is suspected from clinical findings.
Forearm radiographs, which include distal joints, are inadequate for absolutely excluding associated wrist and elbow injuries, as diagnosis of radioulnar dislocation requires the x-ray beam to be centered at the joint.
In addition to diagnosis and follow-up, radiologic imaging plays a decisive role in the treatment of distal forearm fractures. Computed tomography (CT) and direct CT arthrography have become important tools in treatment of intra-articular distal radius fractures. Direct CT arthrography allows not only analysis of the fracture pattern, but also detection of accompanying injuries of the carpus, especially the scapholunate ligament and the ulnocarpal complex. Plain radiographs should also be analyzed for accompanying injuries. [3]
With forearm fracture, painful limitations in range of motion, especially of pronation and supination, are often due to underdiagnosed torsional deformity; new methods can make these torsional differences visible and quantifiable through the use of sectional imaging. In the presence of torsional deformities, radiologic measurements can help one decide if an operation is needed or not. Decisions must be made together with the patient by taking clinical and radiologic results into account. [8]
Ultrasound-guided infraclavicular block is a safe and effective method in the management of pain during closed reduction of forearm fracture in pediatric patients in the ED. It can be used safely in emergency rooms and has a high level of both parental and operator satisfaction. [16]
Radiographs taken at 2-week follow-up have resulted in a change in treatment in 3.1% of cases. Given the low cost and the minimal risk of radiographs of an extremity, it is believed that the benefits outweigh the costs of routine radiographs taken 2 weeks after surgical treatment of distal forearm fracture. [17]
Nightstick fracture
Defined as an isolated midshaft ulnar fracture, usually resulting from the forearm being held in protection across the face, nightstick fracture can also occur with excessive supination or pronation. This type of fracture requires orthopedic referral; the forearm can be immobilized with a long-arm splint with 90º of elbow flexion and with the hand in a neutral position. Some advocate that, after 1 week, the splint or cast should be replaced by a prefabricated functional brace, which allows better wrist mobility and return to function. [18] Open reduction internal fixation (ORIF) becomes necessary when displacement greater than 5 mm or angulation greater than 10º persists.
A systematic review of trials and observational studies that assessed the outcomes of nightstick fracture after above- or below-elbow immobilization, bracing, and early mobilization found that early mobilization was associated with the shortest radiologic time to union (mean, 8.0 wk) and the lowest mean rate of nonunion (0.6%). Fractures that were treated with above-elbow immobilization, below-elbow immobilization, or bracing had longer mean radiologic times to union (9.2 wk, 9.2 wk, and 8.7 wk, respectively) and higher mean rates of nonunion (3.8%, 2.1%, and 0.8%, respectively). [19]
Monteggia fracture
Monteggia fracture is defined as a fracture of the ulna (usually the proximal one third) with dislocation of the radial head. Anterior radial head dislocation is most common (60%), yet medial, lateral, and posterior dislocations also occur. Isolated proximal ulnar fractures are rare. Always suspect a Monteggia fracture/dislocation, and closely examine the radial head for dislocation or other evidence of injury.
Radial head dislocation can be missed when radiographs are misinterpreted, falsely negative, or inadequate. It also may go unrecognized when the dislocation reduces spontaneously prior to imaging. A line drawn through the radial shaft and head must align with the capitellum in all views to exclude dislocation.
Immobilize with a long-arm splint (with elbow flexed 90° and forearm neutral). Children may be treated by reduction and casting; adults require admission for ORIF.
One study assessed the efficacy of the following treatment strategy for Monteggia fracture based on the ulnar fracture pattern: closed reduction for plastic/greenstick fractures; intramedullary pin fixation for transverse/short oblique fractures; and ORIF for long oblique/comminuted fractures. Results show that none of the 57 patients treated according to this strategy experienced failure. However, 6 of 32 patients who were treated less rigorously demonstrated recurrent radiocapitellar instability (3 patients), loss of ulnar fracture reduction requiring revision surgery (2 patients), or both events (1 patient). All treatment failures occurred in complete fractures treated nonoperatively. [20]
Galeazzi fracture
Galeazzi fracture is defined as a fracture of the distal one third of the radius, with dislocation of the distal radioulnar joint (DRUJ). It is also known as a reverse Monteggia fracture. Galeazzi fracture is 3 times more common than the Monteggia lesion. This fracture is considered highly unstable and comes under the category of fracture of necessity because it necessitates surgical treatment. [1] Disruption of the DRUJ when overlooked results in a higher rate of morbidity.
Shortening of the radius by 5 mm, fracture of the base of the ulnar styloid, widening of the DRUJ space by 2 mm, and subluxation of the DRUJ are all associated with DRUJ pathology. Obtaining comparison views of the uninjured wrist may be helpful. A 10-20° rotation from normal radiographic position may give false-negative or false-positive readings for DRUJ dislocation. Immobilize with a long-arm splint (with elbow flexed 90° and forearm pronated). Treatment requires admission for open reduction internal fixation (ORIF).
Concomitant radius and ulna fractures
Concomitant fractures usually result from a significant force applied directly to the forearm, or from major multisystem trauma. Swelling and deformity indicate the diagnosis, and radiographic confirmation is usually straightforward. Compartment syndrome is a potential complication because of the degree of tissue injury and swelling involved. Treatment usually requires admission for an urgent ORIF, although in children younger than 10 years, if reduced to less than 10° of angulation, these fractures may be treated by casting alone.
(See the image below.)
Essex-Lopresti fracture
Essex-Lopresti fracture is defined as a fracture of the radial head and dislocation of the DRUJ, with partial or complete disruption of the radioulnar interosseous membrane.
Acute Essex-Lopresti injury is a rare and disabling condition of longitudinal instability of the forearm. When diagnosed early, patients report better outcomes with higher functional recovery. [21]
Torus (greenstick) fracture
Torus fracture is the most common childhood fracture; it accounts for for 500,000 emergency attendances per year, according to a study in the United Kingdom. [22]
Torus fracture occurs in children with only a moderate degree of trauma and can be managed with a long-arm cast for 4-6 weeks when angulation is less than 10°. All cases require orthopedic referral.
(See the images below.)
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Fractures of the radius and ulna with dorsal angulation of distal fragments.
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Torus fracture of the radius.
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Torus fracture of the radius.
