PCL 8- External fixator

External Fixator

Method of immobilizing bones to allow a fracture to heal. External fixation is accomplished by placing pins or screws into the bone on both sides of the fracture. The pins are then secured together outside the skin with clamps and rods. The clamps and rods are known as the "external frame."


Types of External Fixator
1. Standard pin fixator
2. Ring fixator
3. Hybrid fixator


Advantages
- The method provides rigid fixation of the bones in cases in which other forms of immobilization, for one reason or another, are inappropriate.
- allows direct surveillance of the limb and wound status, including wound healing, neurovascular status, viability of skin flaps, and tense muscle compartments.
- associated treatment, for example, dressing changes, skin grafting, bone grafting, and irrigation, is possible without disturbing the fracture alignment or fixation
- Immediate motion of the proximal and distal joints is allowed. This aids in reduction of edema and nutrition of articular surfaces and retards capsular fibrosis, joint stiffening, muscle atrophy, and osteoporosis.

Disadvantages
- Meticulous pin insertion technique and skin and pin tract care are required to prevent pin tract infection.
- The pin and fixator frame can be mechanically difficult to assemble by the uninitiated surgeon.
- The equipment is expensive.
- The frame can be cumbersome, and the patient may reject it for aesthetic reasons.
- Fracture through pin tracts may occur.
- Re fracture after exfix removal may occur unless the limb is adequately protected (e.g. by walking cast application), until the underlying bone can again become accustomed to stress.
- Joint stiffness may occur if the fracture requires that the fixator immobilize the adjacent joint. e.g. an exfix placed over the ankle for a pilon fracture as there was insufficient space for pins in the distal tibial fragment.

Complications
1. Pin tract infection
2. Neurovascular impalement
3. Muscle or tendon impalement
4. Compartment syndrome
5. Refracture