Rockwood Children CH8

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SECTION TWO • Upper Extremity

Figure 8-12.  Dorsally displaced physeal fracture (type A). The dis- tal epiphysis with a small metaphyseal fragment is displaced dorsally ( curved arrow ) in relation to the proximal metaphyseal fragment.

Salter–Harris type I fractures also usually displaced dorsally. Volar displacement of either a Salter–Harris type I or II fracture is less common (Fig. 8-13). Nondisplaced Salter–Harris type I fractures may be indicated only by a displaced pronator fat pad sign (Fig. 8-14), 177,220 ultrasound, 28,99,155 or tenderness over the involved physis. 143,155 A scaphoid fat pad sign may indicate a scaphoid fracture (Fig. 8-15). 94 Salter–Harris type III fractures are rare and may be caused by a compression, shear, or avulsion of the radial origin of the volar radiocarpal ligaments (Fig. 8-16). 9,125 Triplane-equivalent fractures, 160 a combination of Salter–Harris type II and III frac- tures in different planes, have similarly been reported but are rare. CT scans may be necessary to define the fracture pattern and degree of intra-articular displacement in deciding best treatment options.

Figure 8-11.  Lateral radiograph depicting volar subluxation of the dis- tal ulna in relation to the distal radius, a pediatric Galeazzi equivalent. Careful inspection reveals a distal ulnar physeal fracture.

Distal radius and ulna fractures are classified according to frac- ture pattern, type of associated ulnar fracture, and direction of displacement, angulation, and rotation. Most distal radial metaphyseal fractures are displaced dorsally with apex volar angulation. 191 Volar displacement with apex dorsal angulation occurs less commonly with volar flexion mechanisms. Distal radial and ulna fractures are then defined by their ana- tomic relationship to the physis. Physeal fractures are classified by the widely accepted Salter–Harris system (see below). 27,177 Metaphyseal injuries are often different from their adult equiva- lents, due to the thick periosteum surrounding the relatively thin metaphyseal cortex. Metaphyseal fractures are generally clas- sified according to fracture pattern and may be torus fractures, greenstick or incomplete fractures, or complete bicortical inju- ries. Pediatric equivalents of adult Galeazzi fracture–dislocations involve a distal radial fracture and either a soft tissue disruption of the DRUJ or a physeal fracture of the distal ulna. Physeal Injuries The Salter–Harris system is the basis for classification of phy- seal fractures. 176 Most are Salter–Harris type II fractures. 27 In the more common apex volar injuries, dorsal displacement of the distal epiphysis and the dorsal Thurston–Holland metaph- yseal fragment is evident on the lateral view (Fig. 8-12).

Figure 8-13.  Volarly displaced physeal fracture (type B). Distal epiphysis with a large volar metaphyseal fragment is displaced in a volar direction ( curved arrow ). (Reprinted fromWilkins KE, ed. Operative Management of Upper Extremity Fractures in Children . Rosemont, IL: American Academy of Orthopaedic Surgeons; 1994:21, with permission.)