How Plaster Casts are Used to Treat Fractures

Adult male with broken wrist wearing a plaster cast
Medically reviewed by
Written by

Orthopedic casts made of plaster of Paris provide a method of casting that has been used for centuries to immobilize injuries while they heal. But despite their outdated appearance, plaster casts are still used today to treat broken bones and other injuries. As more cutting-edge casting alternatives make their way into the industry, plaster casts are starting to fall out of favor. Medical providers are now choosing to use more modern approaches to immobilization. 

This blog post will provide a comprehensive guide to plaster casting for fractures. We will discuss how plaster of paris works, the steps involved in casting a fracture with plaster, how to care for your cast, and introduce a casting alternative developed for the 21st-century lifestyle. 

What is a Plaster Cast?

A plaster cast is an orthopedic immobilization device made from hydrated calcium sulfate, known as gypsum. Gypsum is mixed with water to form a thick plaster paste that spreads over a bandage or strips of gauze. A medical professional will mold the plaster to the desired contours of the body. Once the plaster of paris has dried, it forms a hard, rigid shell that encases the injured limb. As an inexpensive and non-toxic casting option, plaster of paris is most often used after a fracture reduction to keep the bone in place while it heals. 

History of Plaster of Paris Casts

Plaster casts have been used for centuries to immobilize broken bones and allow them to heal correctly. The first known use of plaster casts dates back to ancient Egypt, where plaster casts were commonly used to treat various injuries. In the 18th century, plaster casts began to be used more frequently in Europe due to advances in medicine. However, its use has declined due to advances in modern casting techniques. 

Is Plaster of Paris Still Used for Broken Bones? 

Adult male wearing a plaster cast for broken wrist
moodboard - stock.adobe

Plaster of paris is still a common orthopedic cast, but newer synthetic materials are increasingly used in casting because of their lightweight material and water-resistant properties.  

How to Cast a Fracture with Plaster of Paris 

When a plaster cast is applied, the affected area is first wrapped in a stockinette. This provides a barrier between the skin and the casting material, which can help to prevent irritation. Plaster strips or rolls are moistened and wrapped around the stockinette. As the plaster dries, it hardens and forms a support for the affected limb. The casting usually sets within a few minutes but can take between 36 and 72 hours to dry completely.

How Long Does a Plaster Cast Stay On For a Fracture?

In general, a plaster cast will stay on for six weeks, depending on age, health, and type of fracture.

How Are Plaster Casts Removed?

Doctor removing plaster cast with a cast saw
annavee - stock.adobe

When the bone has healed, it's time to remove your plaster cast. This must be performed by a medical professional who will use various tools that are effective at cutting through the materials that make up the cast. 

The most commonly used tool for this purpose is a cast saw. This type of saw uses a very thin, vibrating blade that can quickly cut through the materials making up the cast. However, because the blade is so thin, sharp, and fast-moving, it is important to be very careful when using a cast saw. Additionally, technicians may use cast spreaders or ultra-strong scissors. These tools can also effectively cut through the materials making up the cast.

Usually, the entire process takes less than 10 minutes. During this time, the patient will likely feel some pressure and vibration but should not feel any pain. Once the plaster cast has been removed, it is important to take care of the skin underneath. The skin may be dry or irritated from being covered for so long. 

How to Care For a Plaster Cast

When you have a plaster cast, it is important to take care of it to ensure healing and avoid infection. Here are some tips on how to do so: 

  • Keep the cast dry. This means using a waterproof cover when showering or bathing. 
  • Keep the affected limb elevated above heart level to reduce swelling. 
  • Consult your doctor before putting any lotions, oils, or powders on the skin under the cast to avoid skin irritation.
  • Do not stick anything sharp or pointed into the cast, as this could injure the skin underneath. 
  • Avoid activities that can damage the cast or put you at risk of reinjury.
  • If the cast feels loose, contact your doctor or nurse. Do not try to adjust it yourself, as this could cause further damage. 

If you have an itchy cast, or you notice your cast has a foul odor, learn more about how to deal with these common problems. 

Can You Get a Plaster Cast Wet?

When wearing a plaster cast, you have to be extra careful to keep it dry. If the plaster gets wet, it will weaken and may not support your bone correctly. This could prolong your healing time or, in severe cases, lead to re-injury. There are special covers available that can help to keep your cast dry when bathing or washing. Read our in-depth guide for more tips to keep your cast dry in the shower. 

Plaster Cast Advantages and Disadvantages 

Female patient wearing a plaster cast for a wrist fracture
VadimGuzhva - stock.adobe


The use of plaster of Paris bandages hasn't changed much since the 19th century. Its advantages include being relatively inexpensive, typically non-irritating, and they can be easily molded to the contours of your body by most medical providers. 


However, plaster casts can be messy to apply, and they’re not waterproof, so you need to be careful not to get them wet. They can also crack and break if they are not handled properly. Additionally, plaster casts can be quite uncomfortable in summer temperatures and can lead to discomfort and bad odor. And finally, ultrasound waves cannot penetrate through it, so you may not be able to receive x-ray monitoring for your injury while wearing a plaster cast.

When to See a Doctor 

When you have a cast, it's important to take good care of it to prevent infection and other complications. However, even with the best care, problems can still arise. If the skin underneath your cast becomes unbearably itchy, you may be allergic to the plaster. If you notice an unpleasant smell coming from the cast, this could be a sign of an infection. In addition, if you experience numbness, swelling, or bluish fingers, the cast may be too tight. If the cast becomes loose or uncomfortable, call your doctor. These symptoms could indicate more serious problems that need medical attention.

Is There an Alternative to a Plaster Cast? 

For centuries, plaster casts have been used to treat broken bones. However, times have changed. It's time to ditch the casts of the past and upgrade the way medical care is delivered. 

Orthopedic casting technology has advanced to the point where there are now many types of casts available that are much lighter and easier to wear.

Cast21 is a new medical casting alternative developed for the 21st-century lifestyle. Made from lightweight materials, the innovative open lattice sleeve is comfortable to wear and features a quick-drying proprietary formula that streamlines care for patients and providers.

In addition, Cast21 is breathable and waterproof, helping prevent skin irritation and infection. Most importantly, Cast21 does not sacrifice stability or support, providing the same level of protection as a traditional plaster cast. As a result, this cutting-edge product offers a safe and convenient solution for those who have suffered a bone injury. If you require a medical casting treatment, don't settle for an outdated option. Contact our team of professionals and see if the Cast21 solution is right for you. 

Related Blog Posts

Three kids playing in the snow in a winter forest

Winter Cast Care: 9 Tips for Protecting Your Cast from Snow

January 14, 2024

A man with a blue waterproof cast cover on his forearm is shown in the shower, with water droplets visible, indicating the cast cover is protecting his cast while bathing.

What Happens if a Cast Gets Wet Inside?

December 15, 2023

A close-up of a person's forearm and hand giving a thumbs-up gesture. The hand and a significant portion of the forearm are covered in a white, neatly applied cast, indicating a wrist fracture. The background is a neutral, solid color.

Serial Casting: What It Is & How It Helps Muscular Conditions

November 14, 2023