Fractures of the bones of the Forearm (the Radius and Ulna)

Broken arms are common in children.  They tend to be fearless, daring, and like to jump on or off anything that is available.  While the jump is usually good, the landing isn’t always perfect.  Broken arms vary in severity from the most minor crack in the bone to the grossly crooked arm!  Fortunately, most of these fractures can be treated without surgery.

Fractures of the 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.  These 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 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. 

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.

These two pictures are of a torus 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.

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.

Complete or Displaced fractures of the forearm

This simply means that the bone broke all the way in half, just as you would imagine.  When you see this on the x-ray, it makes sense. Some falls are severe enough to completely fracture the end of the radius, producing both displacement (the bones don’t line up end to end) and angulation (the arm is crooked).  In this case the arm will look visibly deformed; deciding whether or not your child has a fractures is usually not difficult.  Often termed “Colles Fractures”, they are said to have a ‘dinner fork’ deformity to the arm.

Distal radius fractures occur at the end of the bone near the wrist joint.  These are among the most common fractures that we see in children.  These fractures typically occur after a fall on the outstretched arm.  If you watch the kinds of activities that your child does every day, it is remarkable that they aren’t more common!

This is a picture of a displaced distal forearm fracture. The arrows indicated the fracture lines in the ulna (at the top of the x-ray) and the radius.

This is a picture of the same fracture after a reduction. A reduction means that a doctor has straightened the arm. Click here for more information about reductions. Displaced fractures of the distal radius are usually treated with manipulation of the arm to attempt to restore normal alignment to the bones.  Because the fractures occur very close to the growth plate, they have an excellent capacity to remodel with time.  If there is any residual angular deformity after the fracture has healed, it will remodel as long as it is in the place of motion of the wrist joint.

Treatment of forearm fractures

Most forearm fractures in children are treated without surgery.  This very different from adults.  There are several reasons for this.  Kids have an amazing ability to heal their fractures. This is due in part to the strong tissue that surrounds the bone called the "periosteum” Periosteum is a very active tissue that helps the bone heal, but also helps the Surgeon to realign the bones properly,  As kids grow, the bone that was broken will gradually return to the same shape that it was before the fracture, a process called “remodeling”. 

The treatment for a broken arm depends on where the bone is broken and if the alignment of the bone is acceptable.  Many simple cracks in the bone simply require a splint or a cast.  If the bone is very crooked, the surgeon will need to be make it straight again before putting on a splint or a cast.  This process is called a “reduction”.

Q. When is the alignment “good enough”? 

A. Many parents will notice that after their child has their broken arm manipulated and put in a splint or cast that the bones do not look perfectly lined up.  A common comment from parents is, “ I’m not a doctor, but those bones don’t look quite right to me”.  So, how can you tell when it will be OK?  There are several good ‘rules of thumb’ for parents to note.  First, the younger the child, the greater the potential for remodeling of the fracture with growth.  Second, although angulation of the fractures bones can remodel, it is best if the overall longitudinal alignment is fairly straight, or the arm will look crooked for some time.  Third, when the ends of the bone are overriding one another, they can still heal and remodel, ultimately making a single bone again.

Q. When is surgery needed?

A. Fractures of the forearm need surgery in two situations:  One is when the fractured bone sticks out through the skin, and the second is when a reasonable alignment of the bone cannot be maintained in the cast.  There are a variety of different techniques for fixing forearm fractures in children, ranging from the use of plates and screws to placement of metal pins down the center of the bone to hold proper alignment.

Q. What is a compartment syndrome?

A. Compartment syndrome occurs when the swelling in the arm or leg becomes so severe that the soft tissues of the limb begin to lose their blood supply.  A thick, unyielding tissue termed “fascia” surrounds the bone and muscle of the forearm.  When swelling occurs within the fascial sheath of the arm, it can become severe enough to disrupt the blood supply to the muscles and nerves of the arm.  If this lasts more than 6 hours, the damage can be irreversible.

There are five common signs of a compartment syndrome following a fracture:

• Pain:  This is always the first sign.  A splinted fracture in a child should be reasonable comfortable.  You should be able to get the pain under control with simple measures such as loosening the wrapping of the splint, elevation, ice, and some pain medicine that your doctor prescribed.  If the pain cannot be controlled in this manner, you should seek immediate attention in the emergency room.
• Pallor:  This simply means that the fingers appear pale.  Typically, if you push on your fingers, they will blanch and then turn pink again.  If the fingers won’t blanch and appear dusky, try loosening the splint.
• Paresthesias:  This refers to tingling in the fingers, like they are going to sleep.
• Pulselessness:  If the splint will allow you to feel up where you would normally feel your pulse, check for it.  If all of the other symptoms are there and you can’t feel the pulse, seek evaluation immediately
• Paralysis:  This is a late sign of compartment syndrome.  If the swelling has lasted long enough to damage the nerves to the arm, then paralysis of the affected limb is the result.

Q. How would I know if my child has a compartment syndrome?

A. The most common sign of a compartment syndrome is pain that cannot be controlled with elevation of the limb, pain medicine, or loosening of the bandages.  Most splinted fractures in children are reasonably comfortable with simple measures.  If not sure, return to the emergency room and have a doctor check the arm for you.

Compartment syndrome is a surgical emergency.  The diagnosis is suspected based on the examination of the child’s arm, and confirmed by actually measuring the pressure in the arm compartments.  Most emergency rooms have the capability to do these measurements quickly. If a compartment syndrome is found, then immediate surgical release of the tight compartments must be done immediately to prevent further permanent damage to the arm.