Forearm Fracture (radius and ulna):
When fractures of the forearm occur in the middle of the forearm bone, it is referred to as the “shaft” of the bone. Forearm Fractures may involve one or both bones. A common way that these fractures occur is after a fall from the Monkey Bars at school. With severe fractures, the arm can appear horribly deformed! When fractures of the radius and the ulna involve the ends of the bone near the wrist, these are called distal forearm fractures.
Treatment of fractures of the shaft of the radius and ulna is decided by several factors:
- Age of the child: The younger the child, the more likely that a simple closed reduction and casting will adequately treat the fracture.
- Degree of deformity: If the arm is visibly crooked, it will often need a manipulation or “reduction” before being placed in a cast.
- Stability of the fracture: Fracture stability is determined by several factors. If the injury occurred with high force, then the supporting soft tissues around the bone may be injured as well. This can make the forearm fracture very unstable. Also, when the bones cannot be aligned end to end, they are more susceptible to changing their alignment in the cast.
There are several terms that your doctor may use to describe the type of break that your child has. These terms can be confusing. Is it a “break” or a “fracture”? The different types of fractures unique to children are described below: The terms break and fracture can be used interchangeably since they mean the same thing.
Torus or Buckle fracture: Torus fractures are common. When the child falls on the outstretched hand, the bone buckles under the weight of the body. Typically, you will see a slight bend in the bone, but only on one side. It literally looks like the bone buckled, but didn’t break all the way through.
These two pictures are of a torus forearm fracture, or a small break in the bone that does not go all the way through the bone. There is usually little if any deformity in the bone. Technically speaking, the bone has failed in ‘compression’, making the small ripple in the bone that you see on the x-ray. These are generally stable fractures, meaning that the alignment will probably not change with protection such a s a cast or splint.
Torus fractures hurt, but will not cause a visible deformity. If you push directly on the arm where it is broken, it will hurt, and the child can localize the spot very clearly. However, they can usually move the wrist joint without much trouble. Because of this, many of these fractures are diagnosed late because it can be difficult for parents to tell if it is broken or not.
Treatment: Torus fractures need protection from further injury and for relief of pain. Although a splint may be sufficient, most kids are so active that the safest treatment is to place them in a non-removable cast below the elbow for about 3-4 weeks.
Greenstick fracture: This is the term that doctors use to describe a when the bone bends and breaks but does not necessarily snap all the way in half. This is the same thing that happens when you try to bend and break a wet stick in half. Greenstick fractures are unique to kids; adult bones wont break this way. A greenstick fracture can certainly look very crooked and usually will need some effort to make it straight again.
Growth plate fractures
The distal end of the radius is a common site for children to sustain a fracture that actually involves the growth plate itself. These can occur in several varieties. However, it is a very forgiving growth plate to injure. The incidence of have residual problems with growth is usually less than 5 percent with the exception of very severe injuries.
Treatment: The principles of treatment for any fracture involving the growth plate are to restore anatomic alignment of the growth plate with the minimum amount of trauma. Most displaced growth plate fractures in the distal radius can be manipulated back into normal alignment and held there with a cast. The growth plate will heal very quickly, so prolonged casting is not necessary. Very few fractures of the distal radius will require surgery. Severe growth plate injuries should be followed with x-rays to confirm that normal growth has returned.
This is an x-ray of a fracture through the growth plate at the wrist. This is commonly known as a “Colles fracture”. The two arrows indicate where the fracture is located, but it can be difficult to see the break in the bone with this view, which is taken from the top of the arm.
Fracture remodeling and forearm fractures.
In the management of pediatric fractures, we rely upon further growth to correct a lot of the bends and kinks that occur during normal fracture healing. In the following series of xrays, we present a typical case of a forearm fracture from the initial injury to the final xray (you can click on any of these thumbnails to see a larger version of the xrays. This is a 4 year old boy who came to the ER with displaced fractures of the distal radius and ulna….
There is posterior angulation through the fracture site, displacement of the ends of the broken bone, and the fracture in this state is in unacceptable alignment. The child was given an anesthetic in the emergency department and the fracture was reduced — manipulated back into position. One week later, the child was seen in clinic, and the fracture looked like this…..
Here the fracture is in acceptable alignment. While the fracture is still somewhat angulated, but the overall alignment of the limb is is considered satisfactory since a four year old child still has a lot of growing to do and the fracture will straighten itself out over time.
In the two xrays above, you can see how there has been some “drift” of the fracture, probably because as the swelling in the arm went down, the cast became a bit too loose. However, new bone, called callus, has started to fill in like a snow drift across the fracture site. This process is called, appropriately enough “drift osteoclasis”. 4 weeks after the initial break, the cast was removed. The arm looked very slightly bent, but not enough to cause the mother any undue concern. Six months later, the child was brought back to clinic for one final xray check and here is the final result:
With these two pictures you can see how the fracture lines are barely distinguishable and as the bone has continued to remodel the deformity lessens and the arm grows straighter and straighter. At this point, only six months after the break, it was already hard to tell which side had been broken.