The pediatric skeleton is fundamentally different from that of an adult, resulting in distinct injury patterns when a child experiences trauma. Unlike dense, brittle adult bones that tend to break completely, a child’s bones are still developing and possess characteristics that allow them to absorb force differently. This difference is why certain types of fractures are seen almost exclusively in children. Common fractures are often incomplete breaks or those involving the specialized zones of growth.
Why Children’s Bones Fracture Differently
A child’s bone structure is more resilient due to its higher collagen content, which grants it increased elasticity and pliability. This allows the bone to bend or deform before fully fracturing. The outer layer, called the periosteum, is also much thicker and stronger in children. This robust covering acts like a sleeve, sometimes keeping a fracture partially stable and contributing to rapid healing.
Another defining difference is the presence of the physis, or growth plate, a layer of developing cartilage located at the ends of long bones. This area is responsible for the bone’s eventual length and shape. However, it is also structurally weaker than the surrounding bone and ligaments. While the elasticity and thick periosteum protect the shaft, the growth plate represents a distinct zone of vulnerability where forces are often transmitted.
Common Incomplete Fracture Patterns
The increased flexibility and protective periosteum often result in incomplete fractures, where the bone does not separate into two distinct pieces. The most frequently occurring types are Greenstick and Torus fractures, typically affecting the long bones of the forearms. These breaks are more common in younger children because their bones have not yet fully ossified.
Greenstick Fracture
The Greenstick fracture is an incomplete break where the bone bends and fractures only on the tension side, while the opposite side remains intact, held together by the strong periosteum. Greenstick fractures usually involve the mid-shaft of the long bones and require a cast for immobilization to ensure proper healing and alignment.
Torus Fracture
A Torus fracture, also known as a buckle fracture, is a compression injury often seen near the wrist joint in the distal radius. This occurs when a longitudinal force, such as a fall onto an outstretched hand, causes the bone to crumple or bulge outward at the metaphysis. Buckle fractures are considered stable and are managed conservatively with immobilization, sometimes requiring only a removable splint.
The Nature of Growth Plate Injuries
Injuries involving the physis, or growth plate, are unique to children and represent a type of fracture that carries the highest risk of long-term complication. These fractures occur because the cartilaginous growth plate is the least resistant part of the growing bone structure. They account for approximately 15% to 30% of all childhood fractures, peaking during periods of rapid growth.
Physicians use the Salter-Harris classification system to grade the severity of these injuries based on which parts of the bone are involved. This system helps determine the treatment plan and predict the potential for future growth disruption. Fractures that cross into the joint surface or crush the growth plate itself, such as Salter-Harris Types III, IV, and V, have a poorer prognosis.
The main concern with a growth plate injury is the potential for growth arrest, which can lead to permanent issues like limb length discrepancies or angular deformities as the child continues to grow. If the injury is not treated promptly and correctly, a bridge of bone may form across the growth plate, prematurely fusing the bone. Therefore, growth plate fractures require specialized pediatric orthopedic evaluation and follow-up to monitor the limb’s continued development.