The art of Applying an External Fixator in Orthopedics.
Hippocrates may have been the first one 2400 years ago to describe an apparatus reminding of an external fixator to stabilize a tibia fracture. He used four wooden rods from a cornel tree to hook them to an Egyptian leather ring proximally and distally.
Jean- Francois Malgaine chooses a spike driven into the tibia in guise of strap to stabilize a fractured tibia in 1840 while he innovated even better with a claw-like device in 1843 to kept the fragments of a patella fracture in position percutaneously.
It is mainly in 1894 and 1902 that the concept of the modern external fixator saw light with Clayton Pakhill of Denver, Colorado and Albine Lambotte of Anfwerp, Belgium started using threaded pins to support the fixators.
Companies in Switzerland started building up frames and in 1938, Raoul Hoffman developed a technique based on closed reduction supported by guided percutaneous pin placement. This Hoffman’s technique exemplified the first application of minimally invasive orthopedic surgery.
Others like Gavril Ilizarov of Kurgan in the Soviet Union, invented a new method in treating fractures, deformities or other bone defects. A metal frame is supported by X-crossing pins with additional rings linked to them to structure a montage allowing distraction or compression as well as alignment or rotation. The external rings are linked to each other by threaded rods allowing to change position and re-align the construct without approaching directly the fracture site. The fragments can then be held in position until satisfactory healing isreached witho ut the use of any internal fixation devices.
Such devices are used to repair open and unstable fractures allowing dressing changes. They may be more successful when used for superficial bones like the tibia or the radius but may become more complicated when it is being used for deeper bone like the femur or the humerus or pelvis.
The more the bone are deeper located the more chances there are to developing pin tracts infection. External fixators are mainly using in the management of severe open wounds, infected fractures or open fractures, Burns. Our orthopedic conception of “damage Control” is applied when a patient is found too critical to allow us to perform an orthopedic procedure but in an expeditive way, an external fixator can stabilize the extremity expecting a definitive treatment in a near future. It is also used for treatment of large wounds.
An external fixator brings many advantages like a rigid fixation in a precarious form of immobilization especially in open fractures in which traction or casting or plates or rods are unable to be applied because of risk of infection or the loss of an extremity.
So, an external fixation is a surgical way to stabilize a fracture with rods screwed into bone and exiting the body attached to a stabilizing structure on the outside of the body. It is certainly an alternative to any internal fixation where component providing stabilization are positioned entirely within the patient’s body. An external fixation is an alternative to an internal fixation to stabilize bone and soft tissues at a distance from the operative field. It provides a full access to the relevant skeletal and soft tissue structures, allowing initial assessment and subsequent surgical interventions to restore bone continuity and function.
Most external fixators use Schanz half pins, connecting rods and clamps. We can neutralize or distract or compress any fragments with the external fixator. Length of an extremity can be also maintained while the wounds are allowed to heal or granulate or getting ready for a skin flap. We can easily check on a tense compartment or on the neurovascular status. Dressing changes, skin grafting even bone grafting and irrigation can be performed at any time.
The joints proximally and distally can be as well functional for immediate range of motion allowing a control of the edema, discouraging muscle atrophy or joint stiffness. The more motion the less chances to develop osteoporosis.
Although it wallows an elevation of the extremity when desired, this will reduce swelling in the extremity. With such rigid fixation ambulation will become easier with crutches or walker. The same principles are applied with patient suffering from pelvic fractures.
It is important to perform religiously the pin care to avoid any contamination or colonization of the bacteria at the site of insertion.
One has to understand that an external fixation may be a way of treating any long bone open or comminuted fractures while the damaged sot tissues is managed. It is certainly an alternative to internal fixation. More than being used for stabilization, it can be effective in correcting mal-aligned extremities or in treating leg length discrepancies.
External fixation can be an important tool to a skilled orthopedist in the treatment of mal-union, or in the treatment of a polytraumatized patient with pelvic instability. It can be used as a tool to secure the arthrodesis of a joint and in many pediatric fractures as well. An external fixation is an important tool in the armamentarium of a skilled orthopedic surgeon.
Let us review a recent patient of mine seen in the emergency room after a motorcycle crash: An 18-year-old gentleman lost the control of a motorcycle he was piloting when the front wheel hit a rock. He was projected and sustained multiple body abrasions and a one system injury with an isolated left lower extremity comminuted and open fractures of the tibia. Multiple 2-3 centimeters wound over the anterior and posterior aspect of the left leg. X-Rays and CT scan showed an extensively comminuted fracture involving the proximal and mid-shaft but luckily an intact fibula. Through the multiple wounds, many bony fragments and necrotic tissues were exposed or extruded. A posterior splint was applied after evaluation and IV antibiotic started prior to a tour in the operating room.
In the Operating room, the irrigation of the wounds with a debridement of the soft and hard tissues were performed followed by the application of an external fixator held in position by two crossed half-pins proximally in the metaphyseal area and two others in the diaphyseal area at the distal aspect of the tibia, holding the comminuted fracture of the tibia well aligned, in a stable construct.
CT Scan AP View CT Scan Sagital view (Lateral)
Post Op stabilization Frame with Half-pins
Plateau with Rods and Half-pins available in a tray in the operating room during each similar case.
Our gentleman will need to learn how to perform the pin-care to avoid any infection. One will suggest the cleaning of the pins site with Peroxide or Betadine while bacitracin ointment is applied. Others may decide to clean it simply with saline and apply an ointment. He will learn how to use a pair of crutches or a walker for ambulation with non-weight bearing on the extremity involved.
Occasionally it may be difficult for the operating surgeon to use an external fixator in a pathologic bone or in a bone which had recently benefited from another external fixation or other kind of fixation like a plate or a rod. In anyway, it is better to apply an external fixator in the operating room under sterile conditions and under C-Arm control. Contrarily, the removal of an external fixator can be performed in an office under mild sedation.
External fixation is generally used when an internal fixation is not appropriate or when it is contraindicated but in most of the time as a temporary decision until a definitive treatment is chosen. It can allow a surgeon to perform a limb lengthening procedure
after proper osteotomy until bone gradually grow into the gap through the process called distraction osteogenesis. The external fixator can do the “job” for many weeks and even for 3 to four months and even longer if needed. We can even allow to bear a little weight to stimulate fracture healing but in the same token, the half-pins cans can become lose.
The transfixing pins may damage nerves or vessels or tether ligament while impinging on joint motion. It is important to realize when an external fixator has finished to perform the duty, we requested from it. Overlooking the contact between the fragments of bone will assure proper osteogenesis or discourage any over-distraction at the osteotomy site. Finally, a common problem is the pin-site infection which needs to be avoided if one desire a functional outcome of the external fixator.
I took the opportunity to extend my knowledge of the art of manipulating an external fixator in the treatment of long bones fractures. I was happy to address our residents in such topic so they can avoid repeating the mistakes of their elders. In a country like Haiti. With the conditions of our streets and the level of poverty, one will have to weight well the benefits in using such device in the practice of Orthopedics.
Maxime Coles MD
Boca Raton FL
References:
1- Calhoun JH. LIF Leadbetter BR et AL, Biomechanics of the Ilizarov Fixator for Fracture Fixation: Clin Orthop for Relat Res, 280: pp 15-22. 1982.
2- Jones CP, Youngblood CS, Waldrop N, Davis WH, Pinaur MS: Tibial Stress Fracture Secondary to Half-pins in circular Ring External Fixator for Charcot Foot, Foot and Ankle Int. 35(6): 572-577. 2014.
3- Kenwright J, Garner T, Mechanical influences on Tibial Fracture Healing. CORR, 355: pp177-190,1998.
4- Garci, Cimbrelo. Marti-Gonzalez, Circular External fixation in Tibial Non-Union. Clin Orthop Clin Res., 419:65-70. 2004.
5- Hildebrand F, Giannoudis P. Krettek C, Pape HC. Damage Control: Extremities Injury, 39:678-689. 2004.
6- Egol KA, Tejwani NC, Capla EL. Wolinsky PL, Koval KJ, Staged management of high energy proximal tibial fractures: OTAT type 4) The results of a perspective standardized protocol. JOT, 19 (7) : pp 448-455. 3005.