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When Your Child Needs a Cast

Broken bones, or fractures, are a common hazard of childhood. And although a bone can break in a split-second fall off the jungle gym or a quick collision on the soccer field, the healing process takes a bit longer.

In most cases, a child who breaks a bone will need a cast. A cast is a big, hard bandage made of fiberglass or plaster that keeps bones in place while they heal. Depending on the age of the child and type of fracture, a cast can be on for as little as 4 weeks or as long as 10 weeks.

For minor fractures, a splint may be all that is needed. A splint supports the broken bone on one or two sides and is adjustable; a cast encircles the entire broken area and needs to be removed by a doctor when the bone is healed.

Types of Breaks

A doctor might be able to tell whether a bone is broken simply by looking at the injured area. But the doctor will order an X-ray to confirm the fracture and determine what type it is.

Because their bones are softer and more likely to bend than break in half, kids are more likely to have incomplete fractures (fractures that go partially through the bone). Common incomplete fracture types include:

Mature bones are more likely to break completely. A stronger force will also result in a complete fracture of younger bones. A complete fracture is one that extends completely through the bone and sometimes causes the bone to break into several pieces. Types of complete fractures include:

Other common fracture terms include:

Also common among kids are growth plate fractures. These are breaks through the growth plate alone or through the growth plate and the area around it. Growth plate fractures are seen in kids until they reach late adolescence. At this point the growth plates close and cannot be fractured. These fractures range from mild to serious and require treatment by an orthopedic specialist.

Before Getting a Cast

For displaced fractures, the bone will need to be set, or realigned, before a cast is put on so that it will heal in a straighter position. To set the bone, the doctor will put the pieces of the broken bone in the right position so they can grow back together into one bone (this is called a closed reduction).

A closed reduction involves the doctor realigning the broken bone so that it heals in a straighter position. The child is given sedation, which is a medicine, usually through an intravenous line (IV) during the closed reduction. Realigning the bones is a painful procedure, so sedation is given so the child won't feel it. A cast is then put on to keep the bone in position. You can expect another X-ray to be taken immediately after the procedure to make sure the bones are in good position after the realignment is done.

If the fracture is complicated or more serious, an open reduction might be necessary. Open reduction is a surgical procedure in which an incision is made in the skin and metal pins and plates are attached to the broken bone fragments to better stabilize the break while it heals. This is done under general anesthesia.


Casts usually are made of either:

Having a cast put on is a relatively simple process. First, several layers of soft cotton are wrapped around the injured area. Next, the doctor or orthopedic technician wraps a layer of plaster or fiberglass around the soft first layer. The outer layer is damp but will dry to a hard, protective covering. Doctors sometimes make tiny cuts in the sides of a cast so that there is room for swelling if it occurs.

There are many types of casts, for all types of breaks. The most common casts are:

Sometimes splints are worn for a few days (usually between 3 to 7) before a cast is made. This allows for swelling to subside so that the cast can provide the best fit for your child.

Splints are usually held in place by fabric fasteners, velcro, or tape, but they should not be rewrapped or removed, even if a child is experiencing some discomfort. Only a doctor or orthopedic technician should adjust a splint.

Short-Term Cast Care

The area around the break will probably be a little sore and swollen for a few days, so the doctor may recommend acetaminophen or ibuprofen to help ease any pain.

The doctor might also recommend raising the body part with the fracture. Use something soft, like a pillow, to raise the injured arm or leg above heart level to reduce swelling and pain.

If the cast or splint is on an arm, the nurse or technician will give your child a sling to help support it. A sling is made of cloth and a strap that loops around the back of the neck and acts like a special sleeve to keep the arm comfortable and in place. A child with a broken leg who is mature enough and of adequate height probably will get crutches to make it a little easier to get around.

Sometimes a "walking cast" (a foot or leg cast with a special device implanted in the heel to allow for walking) can be used, though your child shouldn't walk on it until it's dry.

Long-Term Cast Care

For bones to heal properly, certain steps must be taken to make sure the cast can do its job. These tips can help keep a cast in good shape:

When to Call the Doctor

When splints and casts are applied properly and care instructions are followed, complications are rare. Sometimes sores can occur if the splint or cast is loose fitting and rubs the skin. These sores can become infected. Tight fitting splints or casts can cause fingers or toes to turn bluish — this can be relieved by fixing the cast or splint.

Contact your doctor if you notice any of the following:

Cast Removal

Once the bone is healed, the cast will be removed with a small electrical saw. The saw's blade isn't sharp — it has a dull, rounded edge that vibrates from side to side. This vibration is strong enough to break apart the fiberglass or plaster but won't hurt skin. Don't attempt to remove the cast on your own.

Once the cast is off, the injured area will probably look and feel different to your child. The skin will be pale, dry, or flaky; the hair will look darker; and the muscles in the area will look smaller or thinner. This is all temporary. Over time, with some special exercises recommended by the doctor or a physical therapist, the bone itself, and muscles around it, will be back in working order.

Reviewed by: Yamini Durani, MD
Date reviewed: October 2012

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Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor.
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