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When Your Child Needs a Cast


A cast is a big, hard bandage that's usually made of material like fiberglass or plaster. Casts keep bones in place while they heal.

Kids get casts for many reasons. Usually they’re for broken bones, but kids also might get casts to help bones and surrounding tissues grow properly, or to aid healing after a bone surgery.

A cast wraps around the broken area and needs to be removed by a doctor when the bone is healed. Depending on the age of the child and type of break or healing needed, a cast can be on for as little as 4 weeks or as long as 10 weeks.

Before Getting a Cast

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

Splints are usually held in place by fabric fasteners, velcro, or tape. A doctor or orthopedic technician will teach you the best way for your child to wear the splint and how to ensure a good fit.

Types of Casts

Casts usually are made of:

There are many types of casts. The most common casts are:

Getting a Cast

Applying a cast requires a few simple steps. First, doctors wrap several layers of soft cotton around the injured area. Next, the plaster or fiberglass outer layer is soaked in water. The doctor wraps the plaster or fiberglass around the soft first layer. The outer layer is wet but will dry to a hard, protective covering. Doctors sometimes make tiny cuts in the sides of a cast to allow room for swelling.

Once the cast is on, the doctor will probably recommend that your child prop the cast on a pillow or stool for a few days to reduce swelling and pain in that area. A child who has a walking cast (a foot or leg cast with a special device implanted in the heel to allow for walking) shouldn't walk on it until it's dry (this takes about 1 hour for a fiberglass cast and 2 or 3 days for a plaster cast).

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

The area around any 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.

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

Casts rarely cause any problems if they are applied and cared for properly. Sometimes, sores can develop if the splint or cast is loose fitting and rubs the skin. These sores can get infected. Tight-fitting splints or casts can make fingers or toes turn bluish. Fixing the cast or splint can relieve tightness.

Call 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. The doctor or a physical therapist can recommend special exercises to help the bone and surrounding muscles get back in working order.

Date reviewed: August 2015


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

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