Splints and casts are supports that are used to protect injured bones and soft tissues. A cast completely encircles the limb with a hard, rigid outer shell (Figures 1 and 2). A splint provides rigid support along just the side(s) of the limb, with soft or open areas in between (Figures 3 and 4). Splints are often used in the immediate post-operative or injury phase, when there is a greater chance of swelling. A splint can better allow for swelling. Your doctor will decide which type of support is most appropriate for you and your arm condition.
Casts are made with plaster or ‘fiberglass’ to form the hard supportive layer, and a soft lining of cotton or similar material for padding. Fiberglass is lighter, more durable, and “breathes” better than plaster. Plaster is less expensive and shapes better than fiberglass for some uses. Both materials come in strips and rolls, and are dipped in water to start the setting process. Most casts have a layer of padding underneath the hard material. X-rays can be taken through casts, but they do block some of the x-ray detail.
Splints can be made with these same materials or with plastic, fabric, or padded aluminum. They can be custom-made, or they may be pre-made. They come in a variety of shapes and sizes, depending on the specific need. They often have Velcro straps, which makes them easier to take on and off.
For fiberglass casts, water compatible padding does exist; ask your doctor if they have it available. Not all injuries can be treated with a waterproof cast. Waterproof casts can be submerged. It is best to avoid water from lakes, rivers and oceans when wearing a waterproof cast because your skin can become irritated if dirt or sand gets inside the cast. When you come in contact with chlorinated water or dirty water, rinse the cast with fresh water when you are done swimming. Allow the inside of the cast to drain as much as possible after it gets wet. If you have a cast that goes past your elbow, be sure to drain the area around the elbow well. The rest of the water will evaporate. Sweat will not harm the cast liner, but consider rinsing the cast with clean water after excessive sweating.
Signs and Symptoms
Swelling due to your injury or surgery is usually worst during the first 2 or 3 days. Swelling can cause pressure in your splint or cast, making it feel tighter. To help avoid or reduce swelling, you should put your hand and arm above your heart by propping it up on pillows or some other support if possible. Elevation helps gravity to drain the blood and fluid that causes swelling out of your hand and arm. This can also decrease pain. If swelling increases too much, a cast or splint can become too tight.
The following signs and symptoms should be watched for, and if they occur, you should contact your doctor promptly for advice:
- Worsening pain
- Numbness and tingling in your hand or fingers, which may indicate excessive pressure on the nerves
- Burning and stinging, which may result from too much pressure on the skin
- Excessive swelling of the hand, which may mean the veins are being blocked
- Loss of active movement of your fingers, which may indicate muscle damage
Sometimes a cast may need to be changed if the cast is too tight or if it gets too loose when the swelling goes down.