Fractures

Fractures in children are not the same as fractures in adults. Children’s bones are more plastic and flexible then adult bones, because they contain more small blood vessels, located in small canals within the bone, which are needed for growth. This flexibility causes children to have different fracture patterns then adults. Children’s bones also have a thicker soft tissue covering around them then adult bones called periosteum. The periosteum can impart some stability to a fracture.

Children’s bones also have growth centers call the physis. Fractures involving the physis have their own set of considerations and potential complications.

A buckle fracture is a very common but not very serious fracture frequently seen in children. One side of the bone buckles from a compressive force, while the other side of the bone stretches, but does not separate. This fracture is seen near the ends of the long bones, especially the radius.

These fractures are stable, meaning they will not change their position over time. This type of fracture is treated with simple immobilization using a cast or brace which acts to protect the fracture from further injury and helps keep the child comfortable. This fracture usually heals within three to four weeks.

A greenstick fracture is another type of fracture which is very common in children. With a greenstick fracture, one side of the bone bends and the other side of the bone separates. The fracture usually leads to some visible deformity of the fractured bone and is most commonly seen in the forearm.

Treating this type of fracture is a little more complicated then treating a buckle fracture. These fractures often need to be reduced or pushed into a better alignment. The goal of manipulation is to complete the fracture, thereby, straightening the bone.

Sometimes, a child’s bone can bend without any apparent fracture. This is called plastic deformation. The effected bone actually has a number of tiny fractures in it that are not visible on x-ray. This type of fracture also need to be manipulated and straightened. This type of fracture is most commonly seen in the forearm.

Fractures in children can remodel. This means that a fracture which heals in a slightly bent fashion will tend to straighten with growth. The amount of remodeling that can occur depends on the location of the fracture ( fractures closer to the physis remodel more), the direction of the deformity (deformities that are in the plane of the range of motion of the nearby joint remodel better), and the child’s age (the younger the child, the more remodeling).

Because children’s fractures remodel, we can accept alignments of fractures in kids that we cannot in adults. A lot of these fractures will straighten out on their own. Still, when treating fractures, we attempt to make our reductions perfect.

Growthplate Fractures

There is a separate classification for the various fractures which involve the growth plates in a growing bone. This is called the Salter-Harris classification.

The Growth plate (physis) is found at each end of the long bones. The long bones are found in the arms and legs. Examples of long bones are the humerus, radius, ulna, femur, tibia, and fibula.

The main concern with fractures involving a growth plate is the potential for the development of a growth arrest. Growth arrest can lead to deformities and limb length discrepancies. The risk of growth arrest is dependent on the severity and the fracture pattern.

A Type 1 Salter-Harris (SH) fracture is a fracture that passes right thru the growth plate. It can be a mild fracture which is not displaced or a severely displaced fracture. Mild SH 1 fractures happen frequently in children because a child’s growth plate is weaker then the bone or ligaments around it.

Often when a child turns their ankle, the growth plate is injured instead of the ankle ligaments. A mild fracture at the distal fibula growth plate results instead of a sprain. These fractures heal reliably in a few weeks and carry almost no risk of growth arrest.

A displaced fracture carries a high risk of growth arrest. The goal of treatment of the acute fracture is to reduce the fracture to an anatomic position as soon as possible. This will decrease but not eliminate the risk of a growth arrest developing.

A type 2 fracture, which is pictured above, begins in the growth plate and then leaves the growth plate and exits the bone thru it’s metaphysis The metaphysis is the part of the bone which is the transition from the end of the bone to the shaft of the bone.

A type 3 fracture begins in the growth plate and then leaves the growth plate and exits the bone thru the nearby joint. This type of fracture adds the risk of developing arthritis in the joint if it is not aligned properly when displaced.

A type 4 fracture begins in the metaphysis travels thru the growth plate and exit the bone thru the joint. This type of fracture has a particularly high risk of developing a growth arrest. Since the joint is involved there is also a risk of developing arthritis if there is some incongruence of the joint surface.

A type 5 fracture is a compression fracture of the growth plate. This is a relatively rare injury.

The treatment for a growth arrest depends on the size of the arrest and the amount of growth remaining. If the size of the arrest is less than 25 -30% the size of the growth plate and there is more than 2 years growth remaining, then the arrest can be excised. If the size of the growth arrest is greater than 25-30% the size of the growth plate and there is more than 2 years of growth remaining, then the remainder of the growth plate is closed to avoid a deformity. This could lead to a limb length inequality when the lower extremities are involved.