Overview Casts for Upper Extremities (Arms, Wrists, Fingers) Casts for Lower Extremities (Hips, Legs, Knees, Ankles) Cast Care & Maintenance Related Programs & Services Contact Us
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What is a cast?

A cast holds a broken bone (fracture) in place and prevents the area around it from moving as it heals. Casts also help prevent or decrease muscle contractions and help keep the injured area immobile, especially after surgery, which can also help decrease pain.

What materials are used in casts?

The hard, outer layer of a cast is made of either plaster or fiberglass. Cotton and other synthetic materials are used to line the inside of the cast to make it soft and provide padding around bony areas, such as the ankle, wrist, or elbow. This also pads nerves and blood vessels.

  • Plaster casts can be molded to your child’s arm or leg. They come in one color, white.
  • Fiberglass casts are more durable and lightweight than plaster casts. They come in a variety of colors and designs.

Can they make waterproof casts?

Special waterproof cast liners may be used under a fiberglass cast so the cast can get wet without falling apart. These waterproof liners can only be used after the injured area has stopped swelling, usually a week or two after the initial injury. Waterproof casts can’t be used after surgery or when pins are used because of the risk of infection.

Your child can take a bath, shower, and even swim in a pool with a waterproof cast. However, they should not sit in a hot tub, go to the beach, or swim in the ocean or a pond while wearing their waterproof cast.

Waterproof casts must get completely submerged in water daily to keep the lining of the cast in good condition. They should be removed by an experienced clinician or technician who understands the specific demands of waterproof casts.

What are split (bivalve) casts?

Medical illustration of a forearm in a split (bivalve) cast, secured with three straps, with the palm facing upward.

For some injuries, the first cast may be split in order to allow room for swelling. The sides of the bivalve cast will be taped with cloth medical tape. The cast is secured from the inside at the top and bottom, so if the tape starts to peel, the cast should not fall apart. You can buy more tape at a local pharmacy in case the tape does start to peel off. If everything looks good at a follow-up appointment, your child’s doctor may apply a new layer of casting material to close the bivalve cast and prevent it from becoming too loose as swelling comes down.

Casts for Upper Extremities (Arms, Wrists, Fingers)

Illustration of a forearm wearing a short arm cast that covers from below the elbow to the hand, leaving the thumb and fingers exposed. Text below reads: Short arm cast.

Short arm cast:

  • Used for forearm and wrist fractures
  • Applied below the elbow to the hand
  • Also used to hold the forearm or wrist muscles and tendons in place after surgery
Illustration of a long arm cast covering the arm from the upper arm to the hand, leaving the thumb and fingers exposed. The text below reads: Long arm cast.

Long arm cast:

  • Used for upper arm, elbow, or forearm fractures
  • Applied from the upper arm to the hand
  • Also used to hold the arm or elbow muscles and tendons in place after surgery
Illustration of a person wearing a shoulder spica cast, which covers the upper torso, shoulder, and arm, immobilizing the arm across the body. Text reads: Shoulder spica cast.

Shoulder spica cast:

  • Used for shoulder dislocations, or after surgery on the shoulder area
  • Applied around the trunk of the body, the shoulder, arm, and hand

Casts for Lower Extremities (Hips, Legs, Knees, Ankles)

Illustration of a lower leg wearing a light purple short leg cast, covering from just below the knee to the toes. The label "short leg cast" is written beside the cast.

Short leg cast:

  • Used for lower leg fractures, ankle fractures, and severe ankle sprains and strains
  • Also used to hold the leg or foot muscles and tendons in place after surgery to allow for healing
  • Applied to the area below the knee down to the foot
  • May be walked on once the fracture is stable enough to bear weight without becoming re-injured
  • Not appropriate for most children under the age of 3, who may kick off the short leg cast
Illustration showing two types of leg casts: a leg cylinder cast covering the lower leg and knee, and a long leg cast covering the entire leg from foot to thigh.

Leg cylinder cast/long leg cast:

  • Used for knee or lower leg fractures, knee dislocations, or after surgery on the leg or knee
  • Applied from the upper thigh to the ankle or foot
  • Usually applied with the knee bent to prevent walking on the cast
Illustration of a child with a cast covering the pelvis and extending down the right leg, indicating a hip spica cast. The cast covers the waist, hip, and entire leg down to the foot.

Unilateral hip spica cast (also known as single hip spica):

  • Used for thigh (femur) fractures
  • Also used to hold the hip or thigh muscles and tendons in place after surgery
  • Applied from the chest to the foot of the affected leg
A medical illustration of a child wearing a spica cast that extends from the chest down to both ankles, with an opening at the pelvic area, leaving the feet and one knee exposed. © 2019 Boston Children’s Hospital.

One-and-one-half spica cast:

  • Used for thigh (femur) fractures
  • Also used to hold the hip or thigh muscles and tendons in place after surgery
  • Applied from the chest to the foot on one leg, and to the knee on the other leg, with a bar placed between both legs to keep the hips and legs immobile
Illustration of a person wearing a spica cast, which covers the torso, hips, and legs, leaving an opening at the crotch. The cast extends from the chest to the ankles with a bar between the legs.

Bilateral hip spica cast (also known as double hip spica):

  • Used for pelvis, hip, or thigh (femur) fractures
  • Also used to hold the hip or thigh muscles and tendons in place after surgery
  • Long leg: Applied from the chest to the feet, with a bar between both legs to keep the hips and legs immobile
  • Short leg: Applied from the chest to the thighs or knees
Illustration of a child standing with legs apart, wearing tall, light purple leg casts and a band connecting both casts at the ankles. © 2019 Boston Childrens Hospital.

Abduction A-frame cast:

  • Used to hold the hip muscles and tendons in place after surgery to allow time for healing
  • Applied from upper thighs to the feet, with a bar placed between both legs to keep the legs and hips immobile
Illustration showing five stages of clubfoot cast progression, with each leg gradually straightening from left to right as the foot moves from an inward curve to a forward-facing position.

Clubfoot cast:

  • Used to treat clubfoot
  • Applied from upper thigh to toes
  • Usually changed every five to seven days
How to care for your cast

Cast Care & Maintenance

Casts are a common treatment for fractures. Casts are used to immobilize injured bones, promote healing, and reduce pain and swelling while the bone heals. They are sometimes put on an arm or leg after surgery to protect the bone and ensure it remains in proper alignment.

Applying a bone cast

Getting a cast put on is not painful. You and your child will be brought into the cast room by one of our cast technicians. The cast application will vary depending upon what type of cast your child will be receiving. Your cast technician will go over the specific details with you.

What are the steps of getting a bone cast?

  • A stockinette will be placed against the skin to protect it. This will become the cuff around the edges of the cast and will help to keep the padding intact.
  • A layer of soft cotton padding will be wrapped around the stockinette. This will help keep the injured limb more comfortable inside the cast.
  • A layer of fiberglass or plaster cast material will go around the cotton padding. When it dries, the fiberglass or plaster forms a hard, outer shell. This will protect and stabilize the bone while it heals. At this stage, the cast will be white.
  • Finally, if your child has a fiberglass cast, they will be able to choose a color for final layer of the cast.

Your child will feel warmth as the fiberglass gets hard. It will not burn but should feel warm like a bath. This reaction will last about 10 minutes. It will take less than five to 10 minutes for the cast to completely set.

Can my child get a waterproof cast?

This is a good thing to ask about during your appointment. A waterproof cast might or might not be the right option for your child. If your child is eligible for a waterproof cast, they will need to wait at least one to two weeks before switching to a waterproof cast. This is because the tissues around a broken bone often swell at first. Many insurance companies do not cover the cost for a waterproof cast. If not, you may purchase a special waterproof sleeve to protect your child’s plaster or fiberglass cast.

Waterproof casts are ideal for baths, showers, and swimming pools. Your child should not wear their waterproof cast in the ocean, a hot tub, at the beach, or in a pond. Sand and debris can get inside the cast and irritate the skin.

Waterproof casts must get completely submerged in water daily to keep the lining of the cast in good condition. When the time comes, make sure an experienced clinician or technician removes your child’s waterproof cast.

Moving around while in a cast

If your child has a broken leg and has been instructed not to bear weight on their cast, there are many kinds of assistive devices to help them get around:

  • Crutches
  • Walkers
  • Wagons
  • Wheelchairs
  • Reclining wheelchairs
  • Kneeling scooters (appropriate for adolescents)

Removing a cast

Cast removal can be a scary thing for children. The cast technician will use an oscillating saw to remove the cast. An oscillating saw does not spin, it rapidly vibrates back and forth. The cast saw makes a lot noise. Some children are afraid of this at first, but start to laugh when they feel the vibration of the saw cutting through the cast material.

It is very important to tell your cast technician if your child has picked out some of the padding or placed anything inside the cast.

How do you care for a cast?

Once your child has been fitted with a cast there are important guidelines to follow. Our cast technicians will go over these instructions with you and your child.

Cast care

  • Keep the cast clean and dry. The best way to keep a cast dry when bathing is to put two bags over the cast. Place a bag on the cast, then apply a towel around the top of the cast with tape, followed by the second bag. This does not make the cast waterproof, but it will help protect it from splashing. If the cast does get splashed on, you can use a hairdryer on cool or low to dry it. If the cast gets very wet you will need to have the cast changed within 24 hours, as the moisture can damage the skin underneath the cast.
  • Check the cast often for cracks or breaks. If you find one, contact your child’s doctor.
  • Cover the cast while your child is eating to prevent food spills and crumbs from entering the cast.

Skin care with a cast

  • Do not scratch the skin under the cast by inserting objects or fingers inside the cast.
  • Do not put small toys or objects inside the cast.
  • Avoid sand, dirt, and mulch. Loose particles may work their way into the cast and irritate your child’s skin.
  • Do not put powder or rub lotion inside the cast.

Keeping your child comfortable

  • You can use a hair dryer on a cool setting to blow air under the cast and cool down hot, itchy skin, but never blow warm or hot air into the cast.
  • Elevate the cast above heart level to decrease swelling.
  • Encourage your child to move their fingers or toes to promote circulation.
  • If the cast irritates your child’s skin, contact your pediatrician or clinic. They may be able to suggest measures you can take at home to protect your child’s skin.

Caring for a body cast

Older children with body casts may need to use a bedpan or urinal in order to go to the bathroom. The following tips will help keep the body cast clean and dry and prevent skin irritation:

  • Keep the genital area as clean and dry as possible.
  • Use a diaper or sanitary napkin around the genital area to prevent leakage or splashing of urine.
  • Place toilet paper inside the bedpan to prevent urine from splashing onto the cast or bed.

What should I do if my child’s cast has gotten wet?

If your child’s cast has gotten wet, please contact us immediately at 617-355-6021.

Unless your child has a waterproof cast, a wet cast can lead to complications and needs immediate attention.

A nurse will decide if your child needs to be seen that day, or the next. If your child’s fiberglass or plaster cast has gotten wet, your child may need to be seen that day.

If your child’s cast gets wet after normal business hours, please contact the orthopedic physician on call through the page operator at 617-355-6000. Your child may need to be seen in the emergency department to have their cast changed.

When should I call my child's doctor?

  • Fever greater than 101 degrees Fahrenheit
  • Increased pain
  • Increased swelling above or below the cast
  • Complaints of numbness or tingling
  • Drainage or foul odor from the cast
  • Cool or cold fingers or toes