What Are Casts Made Of?
By Dr. Jeffrey Frederick
January 25, 2013
Category: Treatments
Tags: casts   splints   plaster of Paris   fractures   ulcers   clubfoot  

Orthopedic casts are used to provide stabilization or immobilization to a limb until healing is confirmed.  Historically splints were used to hold fractures in place, dating back to Ancient Egyptians who used wood wrapped in linen, and Ancient Greeks in AD 30 who used waxes and resins.  Arabian doctors used lime from seashells and albumen from eggs whites to make their splints. In Medieval Italy, splints were made from a flour, animal fat and egg mixture.  French surgeons in the 16th century used wax, cardboard, cloth and parchment as their materials of choice. In 1828 doctors in Berlin used a long narrow box filled with moist sand to align the bones of leg fractures.  Finally in the 18th century four military surgeons developed the practice of using plaster of Paris, which is still used today.  Plaster of Paris is made from the powder of milled gypsum, which when added to water becomes hardened due to the calcium sulfate. The technique was developed further by a Dutch Army physician who focused on shortening the time for the casts to harden.  

Plaster casts are used for many reasons in the foot and ankle. Examples included immobilization of fractures, total contact casts for diabetic foot ulcerations, and correction of congenital deformities like clubfoot.  The advantages of good old fashion plaster include its ability to conform well to the area of application, plus it is smoother meaning it won’t snag clothing as easily.  Downsides to plaster materials are that they are heavy and occlusive.  In hot weather especially, plaster casts can encourage growth of bacteria and lead to an infection of hair follicles and sweat glands.  Also, the take around 45 minutes to set, and up to 72 hours to fully dry. 

Due to limitations in the use of plaster of Paris, other casting materials have been developed, most notably knitted fiberglass impregnated with polyurethane.  The benefits of fiberglass are that it is much lighter and dries faster than plaster bandages.  In the 1990s a new waterproof cast lining was introduced which meant the cast could get wet, so patients could bathe and even swim with their cast on!

Thank you for visiting our website!  Please continue to learn more about your foot care needs by reading other informative articles and by visiting our helpful links.  NorthPointe Foot & Ankle is located in Berkley, MI and has been serving people around the Southfield, Berkley, Ferndale, and Royal Oak area for over 30 years.  Request an appointment via our website or call our office at (248) 545-0100.