What is a foot or ankle cast?

Foot or ankle casts are orthopedic devices doctors apply to support broken, fractured or injured bones and/or joints in the feet or ankles. They immobilize the injured body part so it stays completely still while it heals. Unlike with splints, doctors have to mold casts to your foot or ankle. Casts provide the most protection and support.

Types of foot and ankle casts 

Doctors have two main types of casts: fiberglass and plaster. Fiberglass casts are lightweight, durable and porous enough to let air circulate to your foot or ankle. They're the number one choice if your doctor needs to X-ray your limb while it heals. They also come in a variety of colors and designs, giving you more options for personalization. Plaster casts are easy to shape because they're made from a cotton bandage covered with plaster. Once the plaster dries, the cast is hard and durable. Doctors can provide different bandage colors to give your cast a unique look.

What to expect from a foot or ankle cast

If you need a cast, your orthopedic doctor starts by placing a stockinette over your foot and/or ankle. They add a thick layer of padding to protect your skin and even out the pressure to promote healing. If you get a plaster cast, your doctor moistens strips or rolls of the materials and applies them over the padding. It usually takes about 15 minutes for the material to start to dry, although it can take up to two days to completely harden. Doctors apply fiberglass casts using the same technique.

Your doctor instructs you on how to take care of your cast. Common instructions include:

  • Keeping the cast dry
  • Placing a plastic bag over the cast when you bathe
  • Keeping your foot elevated for the first three days or so
  • Avoiding placing pressure or bearing weight on that foot
  • Avoiding scratching the skin under the cast with sharp objects

Most casts stay on for six to eight weeks. To remove it, your doctor uses special tools, including a cast saw.

Common conditions that require a foot or ankle cast

The most common reason that anyone needs a foot or ankle cast is if they fracture a bone or bones in their foot or ankle. Stress fractures are caused by the impact from repetitive activities like running, jumping and walking. Ankle fractures need a cast. Some may need surgery if the fracture is severe. 

Find an orthopedic doctor nearby

Mercy Health locations that can treat you