The use of emergency casting as a treatment for orthopedic injuries can be traced to Antonius Mathysen, a Dutch military surgeon, who in 1851 used dressings impregnated with dehydrated gypsum in the management of fractures (1). Today, casting, whether with plaster or synthetic materials, remains the most common method of immobilizing and stabilizing fractures so that healing can occur. In most instances, casting is the definitive treatment. It must be remembered, however, that even a properly applied cast is not a substitute for fracture reduction when needed.

Applying a short arm or short leg cast is within the scope of practice of family physicians, pediatricians, and emergency physicians who have a strong understanding of acute orthopedic injuries in the pediatric age group as delineated in standard reference texts (1,2). With proper training and supervision, personnel working in the ambulatory setting—including physician assistants, nurse practitioners, registered nurses, and technicians—can apply simple casts. It should be noted that a properly applied splint can provide immobilization comparable to that afforded by a cast (see Chapter 101). Consequently, when orthopedic referral is readily available, splinting is generally the initial treatment of choice for those whose experience with casting is limited. The growing popularity among youths of such activities as skateboarding, roller skating, and scooter riding will likely ensure a steady stream of pediatric fractures, affording ample opportunity for clinicians in the acute care setting to gain splinting and casting experience (3).

Distinct differences exist between children and adults in both the nature and management of skeletal injuries. Most differences reflect the fact that unlike the bones of an adult (i.e., anyone who has reached skeletal maturity), those of a child are growing (see also Fig. 101.1). The periosteum of the bones of a child is physiologically quite active. As a result, the potential for healing and, in many instances, for significant remodeling is high. With distal forearm fractures, the remodeling capability is such that injuries with as much as 15 degrees of angulation and 1 cm of shortening will completely remodel without functional sequelae using immobilization alone (4). Nonunion essentially never occurs. Conversely, fractures in children frequently involve the growth plate, posing a risk to ongoing bone growth without proper management (see also Fig. 101.2) (5). Many growth plate injuries result from mechanisms that in adults would cause a ligamentous injury. For example, a severe valgus injury to the knee will often result in a fracture through the distal femoral physis in a child; an adult will usually have only a strain of the medical collateral ligament. With any extremity injury in a child, therefore, the clinician must be highly suspicious of the possibility of a fracture.

Clearly, the most common indication for applying a cast is treatment of a fracture. In all instances, it must first be determined that the position of the fracture is satisfactory. Despite the potential for fracture remodeling in children, it is not correct to assume that remodeling can correct all deformities. Bowing and rotational deformities in particular have limited potential for remodeling.

Instances also occur in which clinical findings suggest a fracture but radiographic studies are negative. When this occurs, it is recommended that the involved extremity be immobilized until a definitive diagnosis can be established. A subtle fracture may be missed, or a nondisplaced Salter-Harris type I fracture at a growth plate may be radiographically invisible. Splinting is generally adequate in this setting. However, in some cases, such as a suspected toddler’s fracture in a young
child, a cast may be preferred. Similarly, it may be preferable to cast rather than splint certain soft-tissue injuries, such as a severe ankle sprain.

Specific injuries for which a nonorthopedist can consider applying a short arm or short leg cast are listed below. As mentioned, proper splinting will generally provide equally satisfactory treatment on a temporary basis. The decision to cast rather than splint should be made only after the nature of any accompanying soft-tissue injuries (e.g., abrasions that require dressing changes) and the potential for ongoing swelling are evaluated. Whenever there is a likelihood of significant swelling, application of a readily removable or adjustable splint rather than a cast is recommended to minimize the potential for neurovascular compromise. Additionally, certain fractures merit urgent orthopedic consultation, including complete fractures of the radius, ulna, and tibia as well as fractures with significant displacement or growth plate involvement. All open fractures warrant emergent orthopedic consultation and evaluation. Even when the nonorthopedist does choose to provide the initial treatment and apply a cast, he or she should always ensure prompt referral to an orthopedic specialist for follow-up care.

The following are indications for a short arm cast (Fig. 102.1): (a) torus fractures of the radius and ulna; (b) nondisplaced Salter-Harris type I fractures of the distal radius (may be a clinical rather than a radiographic diagnosis); (c) clinically suspected scaphoid (navicular) fractures (thumb spica cast) (Fig. 102.2), although an overt fracture on x-ray warrants consultation with a hand specialist first if possible; and (d) nondisplaced, stable metacarpal fractures. The following are indications for a short leg cast (Fig. 102.3): (a) minor fibula fractures (including suspected Salter-Harris type I fractures of the distal fibula), (b) toddler’s fractures, (c) severe ankle sprains, (d) stable fractures of metatarsals, and (e) fractures of the mid- and hindfoot.

In general, successful application of a cast depends more on proper technique than on the specific brand of materials used. Certain types of cast padding are easier to work with than others, but all are satisfactory. The primary decision for the clinician is whether to use plaster or synthetic (fiberglass) casting material. Of the two, plaster is less expensive, has a longer shelf life, and is easier to apply. Fiberglass is lighter, provides superior strength, dries and cures more rapidly, resists water much better, and is unlikely to cause thermal burns. The material chosen usually reflects availability and clinician experience and preference.