External fixators are instruments used to fix fractured bones and maintain its alignment using a frame placed outside the body. The frame is attached to the bone by pins and wires that enter the body through the skin. Thus the position of the bone can later be manipulated if required without the need to open a surgical wound.
Because the pins and wires penetrate the skin, it is very important to take good care and sterilization of the site of their entry to avoid introduction of bacteria into the body. After bone healing the fixators with the attaching pins and wires are removed.
There are two main types of external fixators:
This consists of one or more metal bars placed outside the body. They are attached through clamps to pins penetrating the skin to fix the bone.
Ring fixators (Ilizarov fixators):
A number of metal rings are placed around the affected limb. Wires are inserted through the skin to penetrate the bone and exit through the skin on the opposite side of the limb. Both ends of the wires are fastened to the metal rings outside the body.
All metal rings are attached to each other by threaded rods, thus forming a rigid construct that support the bone. Also, changing the position of the rings in relation to each other can be done to correct bone deformities and to lengthen bones.
Advantages of external fixators:
- It does not require a large surgical wound. This helps minimize the pain and blood loss and does not impact the blood supply to the bones.
- The position of the bone can be readjusted without the need for another surgery.
- Can be used to treat open fractures in which there are large wounds over the fractured bone.
- Can be used in cases with bone infection and burns.
- Daily care for the pin entry site in the skin is required.
- May limit the amount of movement in the nearby joints.
Common uses for external fixators:
- Fix open fractures
- Bone lengthening
- Fusion of joints
- Gradual correction of bone and soft tissue deformities.