Waterproof Arm Cast Provides a Breathable Alternative to Plaster

Engineers Develop Lightweight Arm Cast That’s Waterproof and Itch-Proof

By Emma Taggart on December 12, 2019

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A post shared by CAST21 (@cast21official) on May 28, 2019 at 4:22pm PDT

If you’re prone to injuries and broken bones, you’re probably all too familiar with wearing heavy plaster casts. Not only do they get in the way of daily activities Because of their bulkiness, but they’re also itchy and become smelly when worn for long periods of time. Fortunately, Chicago-based startup Cast21 has come up with a more hygienic, lightweight, and breathable alternative to the traditional plaster cast that will drastically improve the life of anyone with a broken limb.

The Cast21 team is made up of a trio of engineers from the University of Illinois—Jason Troutner, electrical engineer Justin Brooks, and biomedical design engineer Ashley Moy. Together they designed an elegant, wide-mesh cast that can be fitted in around 10 minutes. The sleeve painlessly slips over a person’s hand and onto their arm. It's then filled with a patented liquid resin that becomes a malleable gel after around 3 minutes. The doctor can then adjust the gel to perfectly hug the broken bone, giving it the support it needs to move back into place. The best part? As the resin hardens, it produces an exothermic reaction, providing soothing heat to the injured area.

“The majority of fractures happen in children, adolescents and the elderly. Those saws are very loud and all this debris flies off and it’s very messy, it can be extremely frightening. The cast saw also presents a risk of burns to the patient,” says Cast21’s VP of engineering Veronica Hogg. “Our product does not require that at all. It’s designed so that a physician can take clinical shears, snip through the tabs, and pull it open easily. It was designed to completely eliminate the use of a cast saw and make the healing process far more pleasant for the patient.”

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The criss-crossed, breathable design allows wearers to satisfy an itch, and the waterproof material means you can even shower and swim while wearing one. Patients can also choose between gel colors, that can be combined to create artistic gradients. And if it gets dirty, it’s easy to wipe off stains with water. This innovative product certainly beats the ugly plaster cast, and it can even be signed by your friends and family too!

Cast21's cast isn't available to the public yet, and, as of now, the company only has a forearm model designed in a medium size. However, the engineers plan to create casts for all parts of the body. “The idea is to prove that this technology works right now, we are past the prototype stage and have a fully functioning model in place for the forearm,” says Hogg. “We hope this technology can span across the entire body. We are looking forward to having a lower limb model for ankle fractures soon.”

As for cost, Cast21 is aiming to make its product accessible to as many people as possible. “We want it to be competitive, and reachable to a large population. We don't want this to be a luxury product,” says Hogg. “We are still conducting research in price sensitivity, and the final cost to the patients will be depending on their insurance and doctor.”

Find out more about this cast on the Cast21 website.