Casts and splints are orthopedic devices that are used to protect and support fractured or injured bones and joints. They help to immobilize the injured limb to keep the bone in place until it fully heals. Casts are often made from fiberglass or plaster. Splints are also called half-casts and provide less support than casts.
Casts and splints are orthopedic devices that are used to protect and support broken or injured bones and joints. They help to immobilize the injured limb to keep the bone in place until it fully heals.
Casts differ from splints because they provide more support and protection for a limb that is injured or broken. They are made from materials like plaster or fiberglass that can be easily molded to the shape of the injured arm or leg.
Splints, also known as half-casts, provide less support than casts, but are faster and easier to use. They also can be tightened or loosened easily if the swelling in the arm or leg increases or decreases.
Ready-made or off-the-shelf splints are available in many different sizes and shapes. In some cases, custom-designed splints must be used. Velcro straps make it easier for the patient or healthcare provider to put the splint on or take it off.
Casts and splints are used when a bone is broken. They can also be used following orthopedic surgery. Sometimes splints are used immediately following an injury due to swelling of the affected area. After the swelling goes down, then a full cast might be applied to the injured limb.
A cast might have to be replaced during the healing process if the injured area becomes less swollen and the cast gets looser. In that case, the cast might be replaced with a splint to provide more freedom of movement.
Casts are partly made from fiberglass or plaster, which form the hard layer that protects the injured limb and keeps it immobilized.
Fiberglass has several advantages compared to plaster. It weighs less, so the cast made from it will be lighter. More durable and porous, fiberglass allows air to flow in and out. Fiberglass is the better choice in case the limb must be X-rayed during the healing process. It is also available in a variety of colors.
Plaster costs less than fiberglass and is more malleable (is more easily shaped) than fiberglass in certain cases.
Before the casting material is applied, a stockinette is placed around the area that will be covered by the cast. Afterwards a layer of padding made of cotton or another soft material (Webril®) is rolled on to further protect the skin. The padding also provides elastic pressure to help healing.
Plaster comes in strips or rolls that are moistened and rolled on over the padding. Plaster materials are made from dry muslin that is treated with starch or dextrose and calcium sulfate.
After the process of applying the casting material is completed, the material will start to dry in about 10 to 15 minutes. The temperature of the skin might rise as the plaster is drying because of a chemical reaction that occurs. When plaster is used, it can take from 1 to 2 days for the cast to harden completely. The patient must be careful during this period because the plaster might break or crack while it is hardening. The cast will appear smooth and white after it hardens.
Like plaster, fiberglass materials come in rolls. Strips are moistened and applied to form the cast. The cast will appear rough after it has dried.
Your doctor will remove the cast with a special cast saw when the bone has healed sufficiently. The cast saw has a flat, rounded metal blade that vibrates. It can cut through the cast without injuring the skin underneath. The doctor will cut the cast in several places, usually along both sides of the cast. The cast is then spread and opened and a special tool is used to lift it off. Scissors are used to cut through the protective padding and stockinette layers which then are removed.
Complications can range from minor to severe and may vary according to the length of time that the cast is worn.
Pressure sores: A sore may develop on the skin under the cast. This can happen because the cast was too tight or did not fit correctly, causing excess pressure on one area.
Compartment syndrome: This is a major complication caused by a tight or rigid cast that constricts a swollen limb. When the pressure inside the cast builds up, it can cause damage to the muscles, nerves or blood vessels in the area covered by the cast. The damage may be permanent if it is not discovered and treated promptly. Call your doctor or visit the emergency room immediately if you notice any of the following symptoms.
Last reviewed by a Cleveland Clinic medical professional on 04/17/2017.
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