Fractures in children are extremely common. It is estimated that from birth to the age of 16 years, 30 to 40% children will have sustained a fracture. Fractures are commoner in boys as compared to girls.
How are children’s fractures different?
Children are not merely small adults. Children’s bones possess certain unique properties which make children’s fractures different from adult fractures:
Childrens’s bones have growth plates:
One of the most important features of a child’s bone is the presence growth plates (called physes). Growth plate is responsible for the increase in length of bone with growth. Growth plate is seen on X-rays as a radiolucent line at each end of bone.
Fracture can occur through the growth plate. Fracture through the growth plate can occasionally lead to permanent damage to the growth plate. This can lead to a growth arrest which will lead to shortening of the bone (limb length discrepancy) and/ or deformity.
Children’s bones are more elastic:
Children’s bones are more elastic (have greater modulus of elasticity). This means they can bend to a greater degree before breaking. This leads to unique and incomplete fractures in children. Torus fractures, greenstick fractures and plastic deformations are incomplete fracture patterns unique to children.
Torus fracture is an incomplete fracture seen in children typically less than 5 years age. It occurs when a compression force is applied along the long axis of the bone. The bone fractures at the cortex under compression. This is a stable fracture. The child may not experience significant pain and swelling, so the fracture may be detected after an interval of a few days. Since this is a stable fracture, rigid cast immobilisation is not mandatory. Treatment mainly focuses on pain relief.
Greenstick fracture is a type of incomplete fracture which occurs when a bending force is applied to a bone. The fracture occurs at the cortex under tension while the opposite cortex remains intact. Greenstick fractures need to be reduced to correct the angulation, following which a plaster cast is applied to maintain the reduction.
Plastic deformation is a type of bone in which the bone is bent, but there is no fracture line visible on X-rays. At microscopic level, these injuries are characterised by discontinuity between osteon units of bone. If the deformity is significant and/ or the restriction of motion is significant (which can occur especially in forearm fractures), plastic deformation needs to be reduced and casted.
Unique properties of Children’s fractures:
Remodelling is a unique characteristic of child’s bone. Remodelling implies correction of bony angulation at fracture site after healing.
Remodelling occurs to a greater extent in:
- Younger children remodel to a greater extent than older children.
- Remodelling occurs to a greater extent if the angulation is in the plane of motion of the adjacent joint.