What is an external fixator?
External fixation is a limb lengthening technique where an apparatus is mounted to the outside of the body. The two types of external fixators that are used in limb lengthening are:
- Monolateral fixator: This fixator is mounted to one side of the limb (typically the femur and humerus)
- Circular fixator: This fixator or "frame" is mounted around the limb
Monolateral fixators are usually placed on the outer thigh or arm, or the inner leg. Sometimes they are used to treat broken bones, especially if the bone or the skin is badly damaged.
Circular fixators are mounted completely around the limb. The frame is made of at least two carbon fiber or aluminum rings connected by six struts.
For any type of external fixator, either monolateral or circular, the "frame" is mounted to the body by placing special pins or wires through the skin and into the bone. There is a special coating (hydroxyapatite) on the pins to allow them to stick to the bone. This coating decreases, but does not eliminate, the risk of pin infections. Pin infections are common, but preventable. It’s extremely important that the pins are cleaned once or twice a day.