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When Your Child Needs a Cast

Broken bones, or fractures, are a common hazard of childhood. And although breaking a bone takes only 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 a child and the 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 necessary. A splint supports the broken bone on one or two sides and is adjustable, whereas a cast encircles the entire broken area and needs to be removed by the doctor when the bone is healed.

Types of Breaks

Although a doctor may be able to tell whether a bone is broken simply by looking at the injured area, he or she will also order an X-ray to confirm the fracture and determine exactly what type it is.

Common types of fractures in kids include:

  • buckle or torus fracture: an incomplete, or partial, fracture in which one side of the bone bends, raising a little buckle, without breaking the other side
  • greenstick fracture: another partial fracture in which one side of the bone is broken and the other side bends (this fracture resembles what would happen if you tried to break a green stick)
  • closed fracture: a fracture that doesn't break the skin
  • open (or compound) fracture: a fracture in which the end of the broken bone breaks through the skin (these have an increased risk of infection)
  • non-displaced fracture: a fracture in which the pieces on either side of the break line up
  • displaced fracture: a fracture in which the pieces on either side of the break are out of line. This type of break may require applying pressure to the bones when your child is sedated or surgery to make sure the bones are properly aligned before casting.

Most fractures are easily seen on an X-ray. However, fractures through the growth plate (the area of expandable tissue near the ends of long bones in kids and young teens) often do not show up on X-rays. If this type of fracture is suspected, the doctor will treat it even if the X-ray doesn't show a break.

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.

When the doctor can straighten the bones from the outside of the injury it is called a closed reduction. During a closed reduction, pressure is applied to get the bone fragments back in place. Pain medicine and sedation are typically given through an IV in the arm if a closed reduction is necessary.

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.

Casting

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:

  • short arm casts, which are placed from the knuckles of the hand to just below the elbow. These types of casts are used for forearm and wrist breaks and after some surgeries.
  • long arm casts, which go from the upper arm to the knuckles of the hand. These casts are generally used for upper arm or elbow fractures, but can also be used in forearm breaks.
  • short leg casts, which run from just below the knee to the bottom of the foot. These are usually used for ankle and lower leg breaks or surgeries.
  • long leg casts, which are applied from the upper thigh down over the foot. These casts are used to heal breaks and fractures of the knee, lower leg, or ankle.
  • short leg hip spica casts, which go from the chest to the knees and are used to keep hip muscles and tendons in place after surgery.

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 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:

  • Elevating the limb. Use something soft, like a pillow to raise the injured arm or leg above the heart to reduce swelling.
  • Icing. Put ice in a plastic bag, and then place the bag over the injured area.

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 will probably 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:

  • Keep non-waterproof casts dry. Many casts and splints are not waterproof, so keeping them dry is very important. The doctor may tell you to cover it with a plastic bag or special waterproof sleeve for baths or showers. A cast or splint that isn't waterproof and gets wet may lose its strength and shape and no longer be able to keep the injured bone in place. Wet cotton padding also can cause a rash or infection inside the cast. If your child's cast or splint gets wet, contact your doctor right away.
  • Keep out foreign objects or substances. At some point, the skin inside the cast will probably become itchy. Have your child avoid inserting anything into the cast to relieve itching. This could scrape the skin and lead to infection. You also should not pour baby powder, creams, or oils into the cast.
  • Check for cracks. Be sure to check the cast regularly for cracks, breaks, tears, or soft spots. If you notice any of these things, contact your doctor.
  • Don't alter the cast. Decorating the cast and having friends and family sign it is OK, but things like pulling out the cotton lining or breaking off parts are not.

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:

  • increased pain that isn't better with ice, elevation, and/or pain medication
  • extreme tightness that leads to the hand or foot feeling numb or tingly
  • fingers or toes turning white, purple, or blue
  • loss of movement of toes or fingers
  • a blister developing inside the cast
  • any unusual odor or drainage coming from inside the cast
  • a break in the cast or the cast becoming loose
  • skin around the edges of the cast gets red or raw
  • fever

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 up and down. 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: Kate M. Cronan, MD
Date reviewed: July 2009

Kids Health

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

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