Casts hold an injured part of your body in place, especially while you’re healing after a bone fracture. They’re either fiberglass or plaster. You may need surgery to realign your bone before a healthcare provider puts a cast on.
A cast firmly holds a part of your body in place. Healthcare providers use casts to stabilize and protect your body after an injury.
Healthcare providers refer to wearing a cast as a form of immobilization — it prevents that part of your body from moving. Unlike splints, you can’t take a cast off or adjust it while you’re wearing it.
Casts are most commonly used to hold a part of your body in place while you’re healing after a bone fracture (a broken bone). You might need a cast after other injuries or some types of orthopaedic surgery, too, but that’s much less common.
Your provider will custom-fit a cast to the part of your body that has a broken bone, including your:
There are two types of casts — fiberglass and plaster. Fiberglass casts are more common. Fiberglass is lighter and more durable than plaster. It’s also porous (not airtight) so air can get through it, which can make wearing a cast more comfortable. You might be able to choose a specific color if you need a fiberglass cast.
Plaster is easier to work with and form to your body’s shape, but most providers use fiberglass these days. You might need a plaster cast if you experience a displaced fracture (your broken bone is pushed out of its usual place). Plaster can sometimes be better than fiberglass because it’s easier to mold around your bone, but it’s still less common.
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Before a healthcare provider puts a cast on your body around the broken bone, they’ll examine your injuries. They’ll also set (realign) your bone to make sure it heals back together correctly. Depending on which type of fracture you experience, you might need a closed reduction or surgery to set your bone.
During a closed reduction, your provider will physically push and pull your body on the outside to line up your broken bones on the inside. They’ll give you a type of anesthesia to make sure you don’t feel pain during the closed reduction.
The most severe fractures need surgery. The most common type of bone fracture surgery is internal fixation. Your surgeon will insert pieces of metal into your bone to hold it in place while it heals. They’ll give you general anesthesia so you sleep through the surgery.
Your provider will put a cast on once they’ve set your bone and it’s safe to immobilize it.
A healthcare provider will apply a cast to your body in layers:
It can take anywhere from 15 minutes to around an hour to apply a cast. How long it takes depends on which type of cast you need and where on your body you need it. Smaller casts (like on your wrist) take less time, and bigger casts (like on your legs) take longer to apply.
It depends on which type of cast you’re getting. Fiberglass casts start drying right away and might only take a few hours. Plaster casts usually take a day or two to completely harden.
Be careful with your cast while it’s still drying. It won’t have its full strength or protection until it’s hardened all the way. Fiberglass will look and feel rough when it’s dry. Plaster will look smooth and white when it’s hardened.
Your provider will give you specific instructions for taking care of your cast while it’s drying.
For the first few days after you get a cast, you should:
Casts are usually the best way to protect a bone while it heals after a fracture. They’re extremely safe and effective. Once your bone has healed, it’s quick and easy to remove a cast.
Follow your provider’s instructions about which activities you can do, and what you should avoid while you have a cast.
Casts have very few risks. The most serious complications can include:
It depends on which type of fracture you have and where the broken bone is. Most people need to wear a cast for six to eight weeks. It might take more or less time depending on how quickly your bone heals.
The best way to prevent complications while you’re wearing a cast is to take good care of it:
Your provider will remove the cast with a special saw. A cast saw has a blade that cuts through the cast, but it’s not sharp enough to hurt your skin underneath.
Your provider will cut the cast in several places, usually along both sides. Then, they’ll spread and open the cast and lift it off. They’ll use scissors to cut through the protective padding and stockinette layers.
Never try to remove the cast at home. Only a trained healthcare provider can safely remove a cast.
Contact your provider right away if your cast hurts, especially if the pain is getting worse. Talk to your provider if you notice any of the following changes:
A note from Cleveland Clinic
Breaking a bone can go from a shocking, scary experience to a frustrating one when you have to wear a cast for what feels like way too long. Casts can be annoying (and itchy!), but they’re the best way to make sure your bone is safe and stable while it heals.
Talk to your healthcare provider about what you can and can’t do while you’re wearing a cast. They’ll let you know how to bathe, move and exercise to make sure you heal correctly and as fast as possible.
Last reviewed by a Cleveland Clinic medical professional on 08/11/2023.
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