Medical Knowledge

The pediatric skeleton has unique features that allow for growth and contribute to patterns of injury different from those of an adult. The periosteum of a child is thicker and stronger and has greater osteogenic potential, leading to more rapid callus formation in the setting of fracture. The cortex of pediatric bone is more porous, making it more flexible and able to withstand a greater degree of deformation.¹ In addition, remodeling (correction of fractured bone alignment) is generally more predictable. For these reasons, children are generally less likely than their adult counterparts to require surgical management of uncomplicated fractures.² However, they are also susceptible to unique complications, including growth arrest.³

The immature long bone comprises different anatomic regions. Longitudinal bone growth occurs at the location of the physis, or growth plate. The physis separates the articular end (epiphysis) from the metaphysis, which is the subterminal, actively growing section of the long bone. Adjacent to the metaphysis on the side opposite the physis is the diaphysis.

The physis is composed of radiolucent cartilage that is weaker than bone and therefore more susceptible to fracture.^1,2 Although uncommon, growth disturbance can occur as a complication of physeal fracture and is related to a number of factors, including the location within the affected physis. Classification of physeal fractures is paramount to guiding management, assessing risk, and predicting prognosis.¹ In Figure 53-1, label the parts of the immature long bone as described in the text.

Figure 53-1 The anatomic regions of the immature long bone, displaying the locations of the epiphysis, cartilaginous physis, metaphysis, and diaphysis.