Understanding the role and purpose of a cast
Casts are used primarily for treating broken bones, but they also help treat ligament and tendon injuries. A cast is full-time protection and support while the injury heals, and it should not be modified or removed unless your specialist approves.
A cast keeps the joint above and below the break from moving, and controls the bone position while it heals. Holding the proper position helps the bone heal on schedule, and keeps your pain down. Pain, muscle cramps and swelling are usually gone before the bone has fully healed, but the cast stays on until your specialist says it is safe to remove. Casts may be cumbersome, but they are an essential part of a safe, predictable recovery.
Why do I have to wait to get a cast?
Severe swelling is the main reason an injury is not cast immediately. A cast is a solid cylinder. It cannot expand with swelling the way skin does, and trapped pressure can damage skin, muscle and nerves. Your specialist may use a splint, sling or wraps until the swelling starts to settle. Proper elevation from day one is a key part of reducing it.
Waterproof vs non-waterproof casts
"Waterproof" is an overstatement, and water-resistant is more accurate. A water-resistant cast starts with a special wrap against the skin followed by the fibreglass cast material, and even then the skin must be dried well to avoid problems. Regular casts use cotton padding that absorbs water and will not dry out, which leads to mould, skin breakdown and even infection, so keep them dry.
May I go swimming with my "waterproof" cast?
If your specialist has approved it, pool swimming is fine, but stay out of lakes, dams and the sea, where natural microbes can cause skin problems or infection. Keep sessions under 2–3 hours, rinse between skin and cast with tap water for about 10 minutes to clear the chlorine. Use a hair dryer on the cool setting to speed up drying. If you notice a rash, or the cast is still not dry after 24 hours, contact your specialist team.
How do I shower or bathe with a cast?
With a waterproof cast you can bathe and shower as normal. Rinse clean water through it afterwards so leftover soap does not cause itching, and let it dry completely before it gets wet again. For a non-waterproof cast, use a reusable cast protector from the pharmacy, or seal the cast in plastic wrap or a bag (check for holes) secured with a strong rubber band, and keep it away from direct spray. Never submerge it.
What if my cast feels tight?
A cast should feel snug for the first 24 to 48 hours, but it should never become tight enough to cause increasing pain. Keep the limb elevated almost nonstop, using proper technique. If that does not help, contact your specialist.
What if my skin itches under the cast?
Do not scratch under the cast with anything: it can break the skin and cause infection. Instead, point a hair dryer under the cast on the cool setting, or hold an ice pack wrapped in a thin towel against it to cool the limb and reduce sweating.
Why and how should I elevate?
Elevation reduces the swelling caused by injury or surgery. That means less tissue damage, less pain, and less need for strong pain medication. Proper elevation means raising the limb to heart level or higher. For a leg, rest the foot on the back of the couch while lying down. For an arm, sit with your elbow on a large pillow in your lap, fingers pointing at the ceiling.
How should I remain active with a cast?
If it is not in the cast, it should be moving. Exercise the muscles around the cast that are not immobilised. With a wrist cast, keep the fingers, elbow and shoulder moving normally. Avoid heavy lifting, pushing, pulling and impact activities, and stop anything that causes pain.