Leg Cast Facts

A cast is an orthopedic mold used to immobilize a limb after a bone fracture. The cast is designed to hold the limb in its normal position of alignment to cause the bone to heal and create new bone in the area of the break. Casts are made for both the upper extremities (arms) as well as the lower extremities (legs). Leg casts are molded and created specifically to the needs of the person wearing it for optimal healing.

Types

• There are four kinds of casts used when a leg is broken: plaster, brace, synthetic and splints. Plaster casts are made with strips of gauze in a wet plaster material. The gauze then dries over the following 24 to 48 hours, hardening into a solid mold. A brace is a cast made of a hard plastic material that can be applied when the break is stabilized and maintained while the leg heals. A cast made of fiberglass also contains plastic strips. This type of cast is lighter to wear than a plaster cast and also comes in a variety of colors. A half cast is known as a splint that is made of slabs of plaster. This kind of cast is temporary and will have to be replaced by one of the other kinds of casts.

Lengths

• There are a number of different sizes and styles of leg casts that are used depending on the type of fracture. A short leg cast is applied below the knee and to the foot. This kind of cast is for lower leg fractures and severe sprains/strains. A cylinder cast is applied from the thigh to the ankle of the injured leg and is used in cases of leg surgeries, knee and low leg fractures, as well as knee dislocations. A long leg cast immobilizes from the thigh to the toes. Fractures using a long leg cast include low leg fractures where it is necessary to go as high on the femur (long upper leg bone) as possible. For patients with femur fractures, a spica cast may be used. This kind of cast molds around the hip as well as the other uninjured leg.

Healing

• A leg cast will have to stay on for weeks and up to a few months depending on the bone that was fractured, and if any additional treatments were necessary, such as surgeries. Healing time for injuries in the legs take longer because those bones have to support the weight of the entire body and need to be stable. Fractures of the femur bone can stay on as long as 12 weeks, whereas tibia or fibula fractures may remain in a cast for 10 to 24 weeks.

Contraindications

• Some situations exist where casts are not recommended. A person who suffers from a mortis fracture (a fractured bone in the ankle) will not be able to wear a short cast. A long leg cast will not be used if there are injuries to the knee (unlike a cylinder cast) or if there is evidence of displaced bone (fractured parts of the bone that cannot be aligned properly). For injuries where a cast may be contraindicated, other treatments are necessary, such as surgical realignment or external fixation (screws and other devices to set the bone) to put the bone in place.