Orthopedic and sports-related injuries are one of the most common reasons for pediatric visits to the emergency department (ED). Approximately half of all children will fracture at least one bone during childhood, and it is estimated that up to 25% of children sustain an injury every year.¹ Youth sports participation at earlier ages has been accompanied by a growing number of sports injuries. Studies suggest most of these injuries are related to falls, recreation, sports, or motor vehicle accidents, but the emergency physician should consider nonaccidental trauma. The diagnosis of pediatric orthopedic injuries is challenging because of growth plates and the difficulty of interpreting pediatric radiographs. The fractures most often missed during an ED visit are those involving the phalanges and metatarsals.² With a better understanding of the growing skeleton, clinicians can improve the accuracy of their diagnoses, leading to more optimal management, fewer complications, and better outcomes.³

The immature skeleton has many special characteristics to appreciate when comparing it to mature, adult bone. First, the growing bone is more porous and flexible, which can lead to unique fracture patterns such as greenstick, torus (buckle), and bowing (plastic deformation). This allows the young skeleton to bend much further and absorb more force before a fracture occurs. The porous cortex of growing bone is why there is less comminution and propagation of fractures than seen in adult fractures.⁴

The growing bone is surrounded by a thick, active periosteum. It is not easily torn or stripped away when bones are fractured, so less displacement usually occurs. The periosteum can act as a hinge during fracture reduction. This active periosteum is the primary reason fractures remodel so well and heal so rapidly in children, making nonunion a rarity.

The most noticeable characteristic on radiographs of children is the presence of the radiolucent physis, or growth plate. The radiolucent cartilage gradually ossifies throughout childhood and adolescence. Understand and recognize each bony region in addition to the physis when assessing orthopedic injuries (Fig. 30-1).

The growing bone begins at the joint surface with the epiphysis and is completely cartilaginous at birth (except for the distal femur). It begins to ossify at various stages during bone development, making it visible on radiographs. Portions of the cartilaginous epiphysis or secondary growth centers can fracture with very little or no radiographic evidence of fracture if ossification has not begun. When radiographs reveal a fracture involving the epiphysis, consider that a much larger, radiolucent piece of cartilage may be attached. The most common sites for cartilaginous injuries are the distal femur, patella, distal humerus, and radial head.

Next to the epiphysis sits the actual growth plate, or physis. The physis is a thin layer of radiolucent, growing cartilage that leads to longitudinal growth of the bone. The physis is situated just between the epiphysis and the metaphysis and is considered the weakest part of the growing bone, weaker than the surrounding ligamentous attachments. Because of this weakness, the same injury mechanism leading to sprains in adults will often cause a physeal fracture in children. In adolescents, the physis may be closing, which also leads to altered forces across the joint. Always consider the stage of physeal closure when assessing injuries near a growth plate.

The metaphysis is the flare lying just between the growing physis and the long shaft of the bone known as the diaphysis. The metaphysis is frequently the site of fractures, including the torus, or buckle fracture. The diaphysis is less commonly injured, but may be associated with transverse and oblique fracture patterns.

The best way to communicate meaningfully with orthopedic consultants is to know the “language of orthopedics” (Table 30-1). When describing an injury, it is important to use the precise anatomic location and morphology of a given fracture. A good rule of thumb when describing any injury is to start with the age, gender, mechanism, location, and degree of soft-tissue damage and finish with an excellent radiographic description of the injury. If the physis is involved, use the Salter–Harris (SH) or Ogden classification systems described in Figure 30-2.⁵

Just over 20% of all fractures in children involve a physis, or growth plate. When recognized and treated properly, most of these heal well. Be aware of the increased risk for complications including partial or complete growth arrest, overgrowth, and malunion. Salter and Harris developed a practical classification system in 1963 that continues to be widely used today (Table 30-2 and Fig. 30-2). The SH classifications depend upon the amount of radiographic involvement seen in the physis, epiphysis, and metaphysis, and carry both therapeutic and prognostic implications. Other classification systems such as the Ogden (Table 30-2 and Fig. 30-2) have been developed, but none are as widely used as the SH classifications.