Classification and nomenclature of external fixators

Classification of external fixators has graduated from simple device names to a more descriptive system based on frame configuration. Fixators are of the simple pin, clamp, or ring type. Two classification systems are currently being used to categorize fixators. In one, they are defined as type I, type II, or type III fixators. In the second classification system, the categories are more descriptive. Fixators are broadly defined either as unilateral or bilateral. Within each of these categories, there are one-plane or two-plane frames. In veterinary orthopedics, further adjectives, such as double-clamp, single-bar, two-pin single-bar, and double-bar, are employed to describe some of the more popular configurations. Many configurations are not easily definable because complex arrangements of pins and clamps are sometimes necessary to adapt the frame to the fracture bone successfully.