In an External Fixation System, pins are inserted in the skin into the bone and held in place by an external frame. Thus, there is no placement of Orthopedic implants internally.
The usual indications are open fractures such as a tibia fracture which needs dressings or attention to a wound or flap. It can also be used with closed fractures, for example, unstable radius fracture.
External fixation is most successful in superficial bones, for example, the tibial shaft. Avoid it in deeper bones, e.g. the humerus or femur – here the chance of pin tract sepsis is greater. External Fixators are often used in the management of tibial fractures.
Indications for External Fixators:
- Bad soft tissue damage/ Severe open fractures
- Infected fractures
- For “Damage Control Orthopedics” (where the patient’s initial condition is too critical for prolonged surgery) to maintain length and provide stability. The affix is replaced by definitive fixation (IM pin or pate) once the patient stabilizes. A temporary exfix can be placed over the joint for plateau or pilon fractures that are length unstable. It is later removed when ORIF is performed, once soft tissue swelling subsides.
Advantages of External Fixation
- The method provides rigid fixation of the bones in cases in which other forms of immobilization, for one reason or another, are inaccurate. This is most common in open, severe II and III fractures in which traction or cast methods wouldn’t permit access for Management of the soft tissue wounds and in which dissection and exposure to orthopedic implant an internal fixation appliance would devitalize and contaminate larger areas and might significantly increase the risk of infection or loss of the limb itself.
- Neutralization, compression, or fixed distraction of the fracture fragment is possible with external fixation, as dictated by the fracture configuration. Uncomminuted transverse fractures can be optimally compressed, length can be maintained in comminuted fractures by pins in the major distal and proximal fragments (neutralization mode), or fixed distraction can be obtained in fractures with bone less in one of the paired bones, such as the ulna or radius, or in leg-lengthening procedures.
- The method allows direct surveillance of the limb and wound status, including wound healing, the viability of skin flaps, neurovascular status, and tense muscle compartments.
- Associated treatment, for example, skin grafting, dressing changes, bone grafting, and irrigation, is possible without disturbing the fracture alignment or fixation. Rigid external fixation allows simultaneous and aggressive treatment of bone and soft tissues.
- Immediate movement of the distal and proximal joints is allowed. This aids in the reduction of edema and nutrition of articular surfaces and retards capsular fibrosis, muscle atrophy, joint stiffening, and osteoporosis.
- The extremity is elevated without pressure on the posterior soft tissues. The orthopedic pins and frames can be suspended by ropes from overhead frames on the bed, relieving pressure on the posterior soft tissue part and aiding edema resolution.
- Early patient mobilization is allowed. With rigid fixation, the limb can be moved and positioned without fear of loss of fracture place. In uncomminuted, stable fractures early ambulation is often possible; this may not be the case if these fractures are treated by casting or traction. The use of external fixation also enables the mobilization of some patients with pelvic fractures.
- Insertion can be performed with the patient under local anesthesia if required. If the general medical condition of a patient is such that use of a spinal or general anesthetic is contraindicated, the fixator can be inserted using local anesthesia, although this is not optimal.
- Rigid fixation can be used in infected, non-unions or acute fractures. Rigid fixation of the bone fragments in infected fractures or in infected established nonunions is a critical factor in obliterating and controlling the infection. This is infrequently possible with traction or casting methods, and implantation of internal fixation devices is usually ill-advised. Modern external fixators in such instances can provide rigidity not afforded by other methods.
- Rigid fixation of infected, failed arthroplasties in which joint reconstruction is not possible and in which arthrodesis is desired can be achieved.