Skip to main content

Casts at Children’s Mercy

Why do I need a cast? 

Casts protect 
(immobilize) a fracture, wound or soft tissue injury. They keep the injured area covered and hold the area in place while it heals. 

Casts are also used to protect an area following surgery to allow for bone and soft tissue healing, wound healing or healing of the surgical incision.

Types of casts


For many years, plaster casts were the only material available for casts. The white material in a plaster cast is heavier and takes longer to dry than newer fiberglass options. However, plaster is more easily shaped or molded around the injured area. This makes it a better choice for some circumstances where it’s very important to shape the cast so that the fracture aligns correctly during the healing process. Plaster cannot get wet, as this damages its integrity.


Fiberglass casts come in a variety of colors. They are lighter in weight than plaster but do not allow for as much shaping as plaster. Fiberglass itself can get wet, but it is the padding beneath that ultimately determines whether a cast is waterproof.

There is a type of fiberglass called semirigid, which may be used when follow-up is not specifically necessary since it may be removed at home without a special cast saw. It is still fiberglass and provides adequate protection for a variety of injuries, but the adhesive allows it to be removed one time at home during a directed timeframe without the need to return to clinic for cast removal. Semirigid casts can be made with regular (non-waterproof) padding or waterproof padding.

Cast care

Proper care of non-waterproof casts (plaster and fiberglass)

Plaster casts and fiberglass casts without waterproof padding must be protected to prevent them from getting wet. If a plaster cast gets too wet, it can damage the integrity of the cast and it is difficult to adequately dry the cast padding. Also, if the sock and cotton padding under the cast is unable to be sufficiently dried, the skin can become irritated and even begin to break down or develop wounds which can remain unseen until the cast is removed.

Do not put anything beneath the cast, as this can cause scratches or sores and objects can become stuck beneath the cast.

Do not pull padding out from beneath the cast or attempt to alter/remove the cast yourself, as this could cause injury and disrupt the healing process.

Proper care of waterproof fiberglass casts 

Fiberglass can get wet, but it is the special waterproof padding that fully makes a cast (fully) waterproof.  This material is intended to be wet (completely soaked or submerged) every day to avoid skin irritation.   

You can use any type of clean water (such as baths, showers and swimming pools) to get your cast wet each day. You may bathe normally, but any soap or shampoo should be sufficiently rinsed from beneath the cast, as should chlorine from pools.   

After bathing or swimming, allow the casted extremity to drip dry and wrap a towel around it for 10-15 minutes. Then, complete the drying process by blowing cold air beneath the cast with either a fan or a hair dryer on cold. Your health care provider will give you instructions on a recommended timeframe to completely dry your cast padding. 

Do not put anything beneath the cast, as this can cause skin sores which may get infected due to getting wet. Also, it’s possible for objects to become stuck beneath the cast. 

Do not pull padding out from beneath the cast or attempt to alter/remove the cast yourself, as this could cause injury and disrupt the healing process.

Tips for extremity swelling 

Swelling for a few days up to one week following an injury is normal.  A splint or cast should be fairly snug, but if it seems to be increasing in tightness, call your doctor.

To help with swelling, try these strategies: 

Elevation – Elevation is the most important aspect to control extremity swelling, as this allows the excess fluid to return to the rest of your body. You will need to elevate the affected area for a minimum of 2-3 days following an injury. For arm casts, the fingers shoulder be above the elbow, elbow above the shoulder and shoulder above the heart. For leg casts, the foot and ankle need to be above the level of the heart, which is often accomplished with multiple pillows beneath the cast while lying down. Avoid placing pillows directly underneath the heel to prevent a pressure sore from developing. 

Motion – Wiggling toes and fingers also helps swelling by pumping the fluid back towards your heart and preventing stiffness. Any movement of the toes and fingers that the splint or cast allows should be safe to do. If it were not, then the specific toes or fingers would be immobilized to prevent movement. 

Ice – Ice or cold objects applied to the outside of a splint or cast can be helpful for swelling as well. This often requires 20-30 minutes before the cooling sensation penetrates the cast layers.  It is important to place something absorbent between the cold object and the cast so the cast stays dry when the object begins to melt.

Why choose Children’s Mercy for your child’s fracture care 

Children’s Mercy has the pediatric expertise and experience to give your child the best possible care for their fracture. We understand that children and teens can heal from fractures differently than adults, so our providers can more accurately assess the appropriate treatment plan for them. 

Local health care providers across the region refer their pediatric patients to Children’s Mercy for follow-up care after their initial visit at the time of the fracture. Ask your health care provider for a referral or contact us at (816) 234-3075 for more information.