Chapman’s Orthopaedic Surgery
3rd Edition

CHAPTER 171
PEDIATRIC APPLICATIONS OF CIRCULAR AND UNILATERAL EXTERNAL FIXATION
Deborah F. Stanitski
D. F. Stanitski: Professor, Orthopaedic Surgery, Medical University of South Carolina, Charleston, SC, 29425.
Over the past decade, external fixation has gained increasing acceptance as a surgical technique in children. The most common applications include incidences of trauma, correction of limb deformity, and limb-length equalization.
The numerous fixators available fall into two general categories: circular fixators and cantilever external fixators. Biomechanical studies have demonstrated that bone formation is enhanced by cyclic axial micromotion and, perhaps, by limited-bending micromotion (23). Torsion, on the other hand, is generally deleterious to bone formation. The Ilizarov-type of circular external fixator, which is less stable to axial loading than are most cantilever systems but relatively resistant to torsion, provides an excellent biomechanical environment for bone formation (42).
Another advantage of circular external fixation is that it is applicable to patients of virtually any size from toddler to large child, obese adolescent, or adult. The system provides three-dimensional adjustability, allowing angulation, translation, rotation, and lengthening when necessary. The Taylor Spatial Frame (5) now allows these parameters to be corrected simultaneously but currently has some ring-size limitations (Fig. 171.1). The traditional Ilizarov external fixator can be constructed with hinges to correct existing limb deformity (Fig. 171.2). Circular external fixation can be used to span adjacent limb segments, to protect potentially unstable joints, or to treat joint contractures (Fig. 171.3).
Figure 171.1. The Taylor Spatial frame allows simultaneous correction of angulation, rotation, length, and translation through the use of six struts and universal ball joints.
Figure 171.2. Preconstructed Ilizarov tibial fixator mimics the deformity and allows gradual correction through hinges placed at the level of the deformity.
Figure 171.3. A: Preoperative photograph of a 3-year-old patient with arthrogryposis and a nearly 90° flexion deformity of the knee. B: Appearance of Ilizarov fixator affixed to the femur and tibia, spanning the knee joint with corrective hinges.
The disadvantages of the traditional circular external fixator are its bulk, the fact that it is difficult to apply and adjust, and that it requires multiple sites for transfixing wires. The traditional Ilizarov external fixator uses 1.5 or 1.8 mm transfixing tensioned wires for bone fixation, with half-pin fixation in the proximal femur. Over the last 5 to
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6 years, a number of surgeons have modified the originally described techniques, substituting half-pins for some of the wires. Specifically, in children, the traditional “medial face” tibial wire (parallel to the medial face of the tibia) has been eliminated in favor of an anteroposteriorly directed half-pin. Affixing half-pins to a circular fixator permits 360° adjustability at the same time it avoids some of the soft-tissue problems of transfixing wires.
Unilateral external fixators by contrast are easy to apply, require a limited number of pin sites, and are less bulky (33). They are applied to only one side of the limb and require usually no more than four to six half-pins per limb segment depending on the type of application. Cantilever systems have some disadvantages. They can be used only on limbs of a certain size, they have less stability to shear stress than circular fixators, they cannot span joints easily, and their ability to correct angulation, rotation, and translation gradually is limited. With many current systems, significant adjustments such as device and pin clamp exchange must be made under general anesthesia. Some systems, including the Heidelberg (5), Orthofix (5), and EBI (5) systems, have gradual but limited correction capabilities.
In this chapter, I provide specific application recommendations. I have had more than a decade of experience
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with both types of devices. The Ilizarov type of fixator remains the more versatile device, but patient acceptance and comfort clearly favor the monolateral fixator.
LARGE PIN AND CANTILEVER SYSTEMS
A number of cantilever devices are available in North America for trauma or limb reconstruction applications, including the Orthofix device (Orthofix, Winston-Salem, NC), EBI Dynafix (EBI Corp., Parsippany, NJ), Smith and Nephew Heidelberg fixator (Smith and Nephew, Memphis, TN), the Hex-Fix (Smith and Nephew, Memphis, TN), and the Synthes External Fixator (Synthes USA, Philadelphia, PA). In each case, application requires pin clamps or pin clamp templates through which half-pins are inserted. The choice of fixator is usually determined by the problem to be addressed and size of the patient. The most commonly used limb reconstruction systems are the Orthofix and EBI, with the Heidelberg system having been recently introduced. These fixators are lightweight devices with the ability to telescope. The technique for insertion of the half-pins, and application of these types of fixators is discussed in detail in Chapter 11 and specifically for the tibia in Chapter 24.
ORTHOFIX UNIT
The Orthofix, available in pediatric and adult sizes, has variable body lengths (Fig. 171.4). The short or standard length devices are used most often on children. Orthofix has two articulating ball joints and uses tapered predrilled half-pin fixation. The telescoping body can be unlocked once fracture or osteotomy callus formation is evident radiographically. This capacity theoretically allows axial loading or dynamization of the bone facilitating callus formation and bone healing. The standard articulated device is used for fracture management and osteotomies (16,35,40,50,53). Its ball-and-joint articulation permits approximately 30° to 35° of angulation; it can be freely rotated.
Figure 171.4. Several lengths of the Orthofix pediatric (top two) and adult (bottom 3) fixators are available.
Use the straight slide-type device or LRS (5) (Limb Reconstruction System) for lengthening (Fig. 171.5). It allows placement of more than two pin clamps when necessary for situations such as bone transport. A swivel clamp
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can be substituted for straight clamps at one or both ends of the bone (Fig. 171.6); this technique may be useful for bifocal osteotomies with acute deformity correction or to eliminate deformity that may develop during lengthening. A variety of angulation and rotation template clamps are now available for more accurate multiplanar corrections (Fig. 171.7). Do not use the standard swivel clamps for lengthening; they are less stable than the standard pin
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clamps. With either the standard articulated body fixator or LRS, insert tapered predrilled half-pins through the clamp templates. Then replace the template with the standard pin clamps and tighten them. For fractures and osteotomies, generally two half-pins above and below the fracture or osteotomy are adequate. The widest pin spread in the clamp provides the best stability. For limb lengthening, use three pins proximal to the lengthening site in the femur and tibia. Two or three are adequate distally, depending on the size of the patient and amount of anticipated lengthening (Fig. 171.8) (1,22,25,46,47,48).
Figure 171.5. A: Orthofix LRS slide lengtheners are available in various lengths, as well as pediatric and adult sizes for limb lengthening. B: Template clamps are placed directly on the lengthening device for parallel pin placement. C: LRS system with pin clamps in place and distraction device above the fixator.
Figure 171.6. Swivel template clamps and swivel pin clamps are available for angular correction.
Figure 171.7. A and B: A new rotation template clamp is now available to allow accurate planning and pin insertion for acute rotational corrections. C: The new angulation template clamp can be affixed to the end of the slide for planned acute angular correction 90° orthogonal to the plane of the swivel clamp.
Figure 171.8. A: Clinical appearance of a patient with Ollier’s disease after tibial lengthening with residual varus deformity of the femur and shortening. B: AP and lateral radiographs following application of LRS system and acute correction of femoral deformity. C to E: Clinical and radiographic appearance at the conclusion of lengthening and bone consolidation.
The T-Garches device (Orthofix) is useful for gradual correction of frontal plane deformity in the tibia—for example, in adolescent Blount’s disease (Fig. 171.9) (59). Small lengthenings can also be achieved with this device. A new template clamp allows correction of acute sagittal plane deformity before application of the device following osteotomy (Fig. 171.10). It is not recommended for large lengthenings; the hinge may not withstand large lengthening forces, and the device, for the most part, accommodates only two proximal tibial pins (Fig. 171.11).
Figure 171.9. A and B: The T-Garches external fixator is ideal for correction of proximal tibial frontal plane deformity. C and D: Clinical and radiographic appearance of a 12-year-old boy with adolescent Blount’s disease and varus deformity of both the tibia and the femur. E: Radiographic appearance following osteotomy of the femur and tibia, and application of an Orthofix external fixator to the femur and T-Garches external fixator to the tibia. F: Radiograph following fixator removal with restoration of normal limb mechanical axis.
Figure 171.10. The new T-Garches template clamp allows accurate pin placement for simultaneous sagittal and frontal plane deformity correction.
Figure 171.11. Only two pins can be placed in the proximal T-Garches fixator. This potentially limits its use, particularly for significant lengthenings.
In applying the LRS systems, standard ball-joint fixators,
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and the T-Garches, it is important to note the length of the device and the pin spread for the particular application. Be certain, for example, in a limb lengthening, that the device is long enough. At least 10% extra length is needed for the tibia and 20% for the femur. The bone-to-fixator distance is relatively large, particularly in the femur. Thus, there is not always a 1:1 ratio between the amount of lengthening the device can achieve (ie, number of turns) and the actual distraction achieved in the limb. Start with some extra length in the device to avoid running out of space.
ORTHOFIX TECHNIQUE FOR FRACTURE AND OSTEOTOMIES
  • In the case of fracture reduction or osteotomy, anticipate whether the device will need to be lengthened or shortened to achieve the correct bone position before determining pin placement. Add a supplemental pin to the fixator body if necessary for segmental fracture stabilization.
  • Once pins are in place, remove the template. Obtain provisional reduction of a fracture or positioning of the bone ends following osteotomy before applying the fixator.
  • Apply the fixator and tighten the pin clamps. Attach the reduction forceps to the clamps and fine-tune the bone position under image intensifier control.
Dynafix
The major generic difference between the Orthofix and the Dynafix (manufactured by EBI Medical Systems) is that the Dynafix itself is used as its own template. Tissue protectors and drill guides are placed directly through the pin clamps. The Dynafix articulated body fixator has mobile joints that allow angulation in the frontal and sagittal
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plane and rotation through the center of the fixator (Fig. 171.12). The snakelike configuration of the device and the multiple fixator body joints permit translation and rotational corrections as well as approximately 30° of angulation at each joint. As with the standard Orthofix unit, these corrections need to be completed during surgery.
Figure 171.12. The EBI Dynafix external fixator allows angulation, translation, and rotation through its “snake-like” configuration.
The lengthening system is similar in concept to the Orthofix LRS (Fig. 171.13 and Fig. 171.14). Both systems use pins with an external shaft diameter of 6.0 mm. The pin clamp spacing and configuration are different between the two devices; thus, it is impossible to exchange devices without changing pin locations.
Figure 171.13. The EBI lengthening system is similar to the Orthofix LRS system.
Figure 171.14. Swivel clamps are available for the Dynafix lengthening system.
A device similar to the Orthofix T-Garches is also available for correction of proximal tibial deformities (Fig. 171.15). Because the pin clamps are applied to the T portion of the device, more than two pins can be inserted if desired. The pins may also be applied either proximal or distal to the T allowing some longitudinal spread of the proximal metaphyseal pins.
Figure 171.15. Like the T-Garches, the EBI T-fixator allows gradual angular correction in the proximal tibia and lengthening.
Heidelberg Fixator
Used in Europe for approximately 5 years, the Heidelberg fixator, designed by Dr. Joachin Pfeil, has recently been introduced to North America (Fig. 171.16). This device is yet another cantilever system. Its proposed benefit, however, is the ability to achieve gradual angular correction through a device called the angulator (Fig. 171.17). Pins are inserted through a drill guide template (Fig. 171-18), which can be applied to the fixator in any plane and allows correction of oblique plane deformity or correction of deformity
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that may arise during limb lengthening such as procurvatum and valgus in the tibia. The surgeon can also apply supplemental bone screws when necessary to enhance stability. A special clamp is also available to allow fixation to the Ilizarov ring system (Fig. 171.19). Experience thus far in North America is limited, but the device has some potentially significant advantages, particularly when gradual deformity correction is desirable. Translational correction must nonetheless be obtained intraoperatively.
Figure 171.16. The Heidelberg fixator has been recently introduced to North America. Similar to other systems, it has several pin clamp types. Lengthening occurs through the body of the fixator itself.
Figure 171.17. The Heidelberg “angulator” allows gradual deformity correction following lengthening.
Figure 171.18. Pins are introduced through a hand-held template that matches the pin clamp.
Figure 171.19. A special Heidelberg clamp allows fixator attachment to the Ilizarov ring system.
Hex-Fix
The Hex-Fix can be used to stabilize pediatric long-bone fractures definitively and in osteotomies in small children or children with particularly small bones, as in the skeletal dysplasias. I prefer to use it for proximal femoral fractures or fractures in very small children (those younger than 4 to 5 years of age) in whom stable fracture fixation is desired. The device can accommodate predrilled or self-drilling (eg, Schanz) half-pins of 4, 5, or 6 mm. There are several types of pin clamps available that accommodate one or two bone pins (Fig. 171.20). The single pin clamps permit flexible pin spacing. The clamps also allow some angulation and rotation, enabling multiplanar half-pin fixation on a cantilever device.
Figure 171.20. The Hex-Fix is particularly useful for fracture fixation in small children. Four, five, or six millimeter pins may be introduced through the pin clamps, which act as their own template. They are available as single or double clamps as shown. Pins and pin clamps are secured using the universal tool.
Generally, insert two pins proximally and distally to the fracture or osteotomy; pin spacing is dependent on the individual situation. There is no limit to the number of pins that can be used other than the ability to put the pin clamps on the bar. The actual bar on which the pin clamps are assembled is available in several lengths, the shortest being 8 inches. Although a distractor unit is available for lengthening, I have no experience using this device for limb lengthening.
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CIRCULAR EXTERNAL FIXATION
The most commonly used circular external fixator is the Ilizarov apparatus. This device is applicable to all limb segments in both the upper and the lower extremities and can be used for deformity correction of both bone and soft tissue, and for limb lengthening (3,5,6,7,8,9,10,11 and 12,15,17,19,20 and 21,24,27,29,30 and 31,32,38 and 39,41,42,43,44 and 45,51,56,57 and 58,61,62 and 63). Acute trauma applications in the child are limited. It is used most commonly for segmental bone loss, in which it can be used for bone transport (11).
In children, the Ilizarov device is applied most commonly to the femur or the tibia. The standard tibial fixator consists of one or two rings proximally and distally depending on the size of the patient. The standard tibial wire “formula” calls for the insertion of four wires proximally and distally (Fig. 171.21) (26). These wires are either 1.5 or 1.8 mm in diameter. Use 1.5 mm wires in the tibia of smaller children, and 1.8 mm wires in the femur and the tibia of heavier children. At each end of the bone, place two “olive” wires and two smooth wires. Generally, place the olive wires transversely in the frontal plane, one olive from the medial and one from the lateral aspect of the bone. Transfix the fibula and tibia with a smooth wire, both proximally and distally. Finally, place two wires
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from anterolateral to posterolateral (one proximal and one distal), parallel to the medial border of the tibia. When bifocal—proximal and distal tibial osteotomies—are planned, use another ring fixed to the mid-diaphysis by two wires (Fig. 171.22). These wires are often two olive wires, or an olive wire and plain wire, depending on the direction or nature of the deformity.
Figure 171.21. A and B: Transverse “Olive” wires are first placed on the most proximal and distal rings. C and D: Two additional olive wires are placed from the opposite direction on the two middle rings. E and F: Smooth wires are placed from the lateral aspect of the leg, parallel to the medial face of the tibia both proximally and distally. G and H: Two smooth wires are placed through the proximal and distal fibula, transfixing the tibia.
Figure 171.22. Bifocal treatment for deformity or lengthening requires an additional middle ring with two-wire or wire and half-pin fixation.
Many modifications have been made to this standard wire “formula” in recent years, generally the substitution of half-pins for wires (discussed in Chapter 32).
In children, I prefer a largely “wired-based” circular fixator. Because the standard medial face tibial wire can often interfere with the pes anserinus tendons, I substitute a half-pin for this wire, leaving the remaining wires as described earlier (Fig. 171.23). In the tibia, the addition of an extra ring in the diaphysis allows bifocal treatment. It is useful for patients with deformities at more than one level (Fig. 171.24), when extensive lengthening is necessary, and in bone transport (Fig. 171.25).
Figure 171.23. A half-pin is often substituted for the traditional Ilizarov medial face wire and affixed to a Rancho cube.
Figure 171.24. A and B: Standing and lateral teleoroentgenograms of a patient with Ollier’s disease and a 13 cm limb-length inequality with bifocal tibial deformity. C and D: The Ilizarov external fixator with bifocal application was used for gradual correction of the proximal and distal deformities as well as 8 cm of lengthening. E: Radiographs at the conclusion of tibial consolidation.
Figure 171.25. Tibial radiographs of a 16-year-old boy who presented following a pedestrian motor vehicle accident with 6 cm of missing bone. Antibiotic cement beads were used as a spacer, and external fixation was applied using a Synthes external fixator. B: The Ilizarov apparatus was applied over the Synthes fixator, which was then removed. A proximal osteotomy was performed and bone transport was initiated to restore the defect. C: Radiographs at the conclusion of bone transport. D: Radiographs following fixator removal.
For femoral fixation I prefer an Italian modification using partial rings proximally, as compared with the original Russian technique, which uses full rings for both the proximal and distal thigh. My technique is as follows.
  • Generally, I use four wires distally—two 1.8 mm olive wires and two plain wires fixed to one or two rings (Fig. 171.26).
    Figure 171.26. Schematic drawing of the Italian modification of standard Ilizarov fixation of the femur. Note that proximal fixation is achieved using half-pins. An empty middle ring is used to facilitate angular or rotation correction as well as lengthening. Distal fixation is traditional through four 1.8 mm transfixing wires.
  • Connect these rings to an empty diaphyseal ring via lengthening rods or hinges depending on the application.
  • Achieve proximal fixation by half-pin, rather than by wire fixation. Determine the diameter of the half-pin by the size of the child.
  • Connect the distal rings to the proximal thigh fixation through oblique supports.
  • Attach the proximal half-pins to one or two “arches,” depending on the size of the patient.
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  • Introduce wires or half-pins on the diaphyseal ring for bifocal application to the femur. Although bifocal lengthening is not recommended, proximal angular or rotational osteotomy can be performed acutely (Fig. 171.27), combined with distal deformity correction and lengthening.
    Figure 171.27. A and B: Preoperative photographs and teleoroentgenogram of a 6-year-old boy with congenital shortening of the femur, fibular hemimelia, and a three-ray foot. C: The Ilizarov technique was used for bifocal application. Acute rotational correction was performed proximally. Elimination of distal femoral valgus and subsequent lengthening was done distally. D and E: The photographs demonstrate symmetric internal and external rotation at the conclusion of treatment. F: Radiographs demonstrate excellent healing of both femoral and tibial lengthening sites.
Circular fixation allows almost limitless modification of the fixator. During lengthening, adjacent joints are at risk for progressive contracture, subluxation, or dislocation. The risk of dislocation is particularly significant in the case of congenitally short limbs, such as the ankles associated with fibular hemimelia, knees or hips in the congenital short femur, and proximal femoral focal deficiency (PFFD). Pre-existing contracture due to trauma, burn, or infection may warrant use of circular fixation for gradual correction of deformity with combined femoral and tibial lengthening. Consider prophylactic incorporation of the foot or tibia in tibial or femoral lengthening, respectively, at the beginning or if there is any indication of subluxation or progressive contracture as lengthening proceeds. Consider extending the fixator to the pelvis when the hip is at risk for subluxation (Fig. 171.28). I recommend fixation of the foot at the initial surgery in any patient undergoing tibial lengthening who has fibular hemimelia or a pre-existing equinus contracture. Comprehensive release of the foot can be maintained with foot fixation and combined with tibial lengthening (Fig. 171.29).
Figure 171.28. A: Radiographs of an 11-year-old girl with a painless fibrous pseudarthrosis of her right hip and a projected limb length inequality of 9 cm. B and C: Radiographs demonstrate Ilizarov fixation of the femur with extension of the fixation to the pelvis to protect the potentially unstable hip. D and E: Radiographs at the conclusion of lengthening demonstrate excellent consolidation of the bone and no disruption of the hip joint.
Figure 171.29. A and B: Clinical appearance and radiographs of a 2 1/2-year-old girl with hemisacral agenesis, recurrent club foot deformity, and a leg-length inequality. C and D: An open soft-tissue release of the foot was combined with gradual correction of residual foot deformity and tibial lengthening using the Ilizarov technique. E: Clinical appearance at the end of treatment.
  • Try to use two metatarsal olive wires and two calcaneal olive wires.
  • In the forefoot, introduce the medially based olive wire through the first and second metatarsals and the lateral wire through the two lateral metatarsals. Fix them to an arch, tensioned no more than 50 to 80 kg. Place the wires in this fashion to avoid flattening the forefoot arch and preclude weight bearing on wires.
  • Introduce one calcaneal wire from the medial side and one from the lateral side, usually diverging no more than 45° (Fig. 171.30).
    Figure 171.30. A variety of options are available for foot fixation using the Ilizarov technique. I prefer hindfoot fixation through the calcaneus using opposing olive wires and forefoot fixation, with the lateral olive wire transfixing the two lateral metatarsals and the medial Olive wire transfixing the two medial metatarsals.
  • Fixation of both the hindfoot and forefoot avoids midfoot deformity and forefoot equinus, which can result from tension on the long toe flexors during lengthening.
  • Once the distraction phase has been completed, remove the foot fixation, allowing the ankle and foot to regain motion while the tibial lengthening site consolidates. If prophylactic circular fixation has been applied to the tibia during femoral lengthening, remove it once femoral
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    distraction has been completed as long as there is no significant concurrent contracture of the hip.
OSTEOTOMY TECHNIQUE
  • Perform osteotomy of long bones for deformity correction or lengthening through a 1 to 1.5 cm incision, with minimal periosteal stripping generally using a sharp, thin ¼-inch osteotome.
  • Predrill the bone with a 2.7 mm or 3.2 mm drill to avoid crack propagation from the osteotomy into the adjacent half-pins, which could considerably weaken fixation.
  • Avoid large incisions with subperiosteal exposure of the bone and insertion of retractors to minimize scarring and promote bone healing.
  • There is no need to make a true “corticotomy” as described by Ilizarov, because the periosteal blood supply is more critical than the endosteal supply. Furthermore, the endosteal blood supply usually re-establishes itself within a matter of days following osteotomy.
SPECIAL APPLICATIONS
THE FOOT
Circular external fixation is used to correct foot deformity (32) by one of three approaches: (1) correction by distraction alone; (2) soft-tissue release and tendon lengthening combined with distraction; and (3) osteotomy and distraction. The choice of method depends on the child’s age and whether the deformity is bony alone or combined with soft-tissue contractures. Ilizarov originally described correction of all soft-tissue deformity through closed distraction or “bloodless” surgery (28,32). This situation may present itself in the child younger than 4 to 5 years old with a multiply operated club foot in poor position. In my experience, an attempt at correction by closed distraction alone may be unacceptably painful and, owing to the scar stiffness, may result in wire cut-out thorough osteopenic bone. In this situation, perform a conventional comprehensive release first, followed by fixation of the foot and tibia with appropriate hinge placement and subsequent gradual correction (Fig. 171.31). This surgery avoids the problem of wire migration.
Figure 171.31. A and B: Clinical and radiographic appearance of a girl with fibular hemimelia and a four-ray equinovarus foot following two previous attempts to correct her foot deformity. C: Comprehensive foot release was combined with gradual independent correction of the forefoot and hindfoot deformities and tibial lengthening.
Apply this technique only to stiff feet in poor position, the goal being to produce a plantigrade foot.
The distraction rate in soft-tissue corrections is limited by patient discomfort, skin tension, and the tolerance of neurovascular structures. Slight overcorrection is recommended due to soft-tissue elasticity which can cause rebound following apparatus removal. Once correction has been achieved, maintain the fixation an additional 6 to 8 weeks. Use orthotics after the removal of the fixator to maintain the correction.
Tibial fixation should span the leg with two rings. A total of four wires, or two wires and two half-pins, are adequate fixation in the tibia because there is no tibial osteotomy. The number of wires in the foot and complexity of the apparatus depends entirely on the nature of the deformity.
With bony deformity in the older child, osteotomy is usually necessary (Fig. 171.32). The nature of the deformity determines the location of the osteotomy. If the hindfoot is neutral and the problem is midfoot cavus or supination, use a midtarsal osteotomy. Hindfoot fixation can be neutral with respect to the tibial fixation. Place hinges between the hindfoot and forefoot, centered over the apex of the deformity. A hindfoot that is not in neutral may be addressed in one of two ways. If cavus exists with hindfoot deformity, use a V-shaped osteotomy to address the hindfoot and midfoot independently. Additional fulcrum wires are necessary, usually in the midfoot and talus to ensure that correction occurs through the osteotomy and not
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through joint distraction. If the midfoot and forefoot are relatively neutral with respect to one another and the hindfoot is the problem, use a crescent-shaped osteotomy. Perform the osteotomy from the lateral side through the calcaneus and neck of the talus. Place wires superior and
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inferior to the osteotomy with appropriate hinge location to avoid translation of the foot during correction.
Figure 171.32. A and B: This nearly skeletally mature boy with fibular hemimelia has a fixed deformity of his foot and limb shortening. C: An open crescentic osteotomy was performed through the talus and calcaneus with resection of the deforming tight fibular anlage. D: Lateral foot radiograph at the conclusion of correction. E: Radiographs following fixator removal.
JOINT CONTRACTURES
Circular external fixation can be used to correct joint contractures in children due to trauma (Fig. 171.33), infection, and burns. Unfortunately, to date, most surgeons’ long-term experience has been disappointing. As with conventional soft-tissue and capsular release, the recurrence rate is high despite prolonged periods of posttreatment bracing. Furthermore, as with conventional surgery, depending on the duration of the deformity and the nature of the articular cartilage, the surgeon’s goal may be limited to reorienting rather than increasing the arc of motion. The joints most commonly involved in the pediatric patient are the knee and ankle. The usual deformities are knee flexion and ankle equinus contractures.
Figure 171.33. A: A lawnmower accident resulted in a severe flexion deformity of this knee. Open posterior release achieved no improvement in knee position, and the Ilizarov external fixator was applied to the femur and tibia with hinges at the approximate center of rotation of the knee. B: Appearance at the conclusion of correction.
In the knee, the rate of correction is usually limited by the neurovascular bundles, in particular the sciatic nerve.
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Apply circular fixation to span the adjacent femur and tibia to provide an efficient lever arm. Hinges must be located as close to the center of rotation of the knee joint as possible to avoid joint compression or subluxation. After obtaining correction, depending on the preoperative range of motion, use the hinges to assist in moving the knee during physical therapy. At the ankle, center the hinge placement over the center of the talar dome to avoid anterior subluxation of the talus in the ankle mortise.
UPPER EXTREMITY
In general, it is easier to apply cantilever fixation than circular fixation to the upper extremity. At present, circular fixation is optimal for complex deformities that cannot be corrected acutely (Fig. 171.34). It is also useful if the wrist needs to be spanned, for example, in lengthening of radial or ulnar club hand (12,37). Metacarpal wires can be fixed to a half-ring and attached to the forearm fixation (10,12,37,49,64).
Figure 171.34. A and B: Clinical and radiographic appearance of 6-year-old girl with a right radial club hand and no history of prior intervention. C: The ulna was centralized through an open procedure and the wrist stabilized with a transfixing Kirschner wire. Lengthening of forearm was then undertaken. D: The ulna was lengthened by more than 89%.
Cantilever fixation can be combined with circular fixation of the forearm, and the two methods can be used independently for deformities such as those associated with multiple hereditary exostosis (Fig. 171.35). In general, half-pin fixation is easier and safer to apply to the forearm than transfixing wires. The fact that the ulna is subcutaneous throughout its length makes half-pin fixation
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attractive. Half-pins can be attached in a multidirectional fashion to rings if desired. Two half-pins proximal and distal to the osteotomy site are enough for deformity correction or lengthening.
Figure 171.35. A and B: Radiographs and clinical appearance of a 16-year-old girl with multiple hereditary exostoses with forearm shortening and deformity. C and D: Circular fixation was applied to the radius around a small Orthofix LRS fixator for gradual correction of radial deformity and ulnar lengthening. E and F: Clinical and radiographic appearance of the forearm at the conclusion of treatment.
The humerus is the most easily lengthened long bone (Fig. 171.36) (10). Perform osteotomy distal to the deltoid insertion. Two half-pins proximal and distal to the osteotomy or lengthening site are adequate in the arm. Insert the most distal pin just proximal to the olecranon fossa. The next most proximal pin must avoid the path of the radial nerve. Place it with open technique.
Figure 171.36. A and B: Clinical appearance and radiographs of 13-year-old boy with 10 cm of right humeral shortening due to septic growth arrest of the proximal humerus at the age of 2 years. C and D: Radiographs at the conclusion of distraction and following consolidation.
TRAUMA APPLICATIONS
OPEN FRACTURES
At present, open fracture is the most clear-cut indication for external fixation of pediatric long-bone fractures (4,14,16,34,35,47,50,53,55,60). Depending on the size of the limb segment, apply a four-pin fixator (Hex-Fix, Orthofix, Dynafix) after irrigation and debridement of the open wound. Locate the fixator to minimize interference with subsequent wound management such as local or free flaps and skin grafts. In the case of segmental bone loss, circular fixation can be used to transport bone for definitive bone reconstruction of bone loss.
MULTIPLE TRAUMA
Multiple trauma, particularly if combined with a concurrent severe closed head injury, is a strong indication for fixation of major long bone fractures in the pediatric patient. Those patients who require frequent computed tomography (CT) scans, magnetic resonance imaging (MRI) studies, or the operations for treatment of their associated injuries are more easily managed with stable fracture fixation. Traction or spica casts make this difficult, and spica casts may interfere with management of abdominal or chest trauma. Patients who experience spasticity or who are uncooperative following head injury are best managed with rigid stabilization of their long-bone fractures. Even in the very young child, small cantilever unilateral external fixators, such as the Hex-Fix, can be adapted to long-bone fractures, particularly of the femur and tibia.
FEMORAL SHAFT FRACTURES
Operative management of isolated femoral diaphyseal fractures using external fixation has become accepted in patients older than 5 to 6 years of age (14,22,34,35,50,52,55). Immediate spica treatment is still preferred in small children, and older adolescents may be treated with intramedullary rodding. Current literature supports operative treatment of this intermediate age group between age 5 and 11 to 12 years, reporting excellent results with external fixation decreasing hospitalization, promoting early patient mobilization and return to school, decreasing psychosocial family stress, with an acceptable complication rate (2,4,14,16,34,50,52,53,55). A recent report (18) also demonstrated a clear cost savings when compared with traditional skeletal traction followed by spica-cast immobilization. The major concern when using external fixation in these fractures is the risk of refracture. The incidence of refracture can be minimized by early weight bearing, early fixator dynamization, and mobilization of the knee. Anecdotal reference is made by some to suggest that the most common fracture pattern susceptible to refracture is a transverse diaphyseal fracture. In my experience, the most important factors in refracture are a stiff knee and lack of weight bearing during fracture healing.
FLOATING KNEE
Ipsilateral concomitant fracture of both the femur and the tibia produces a floating knee. Operative stabilization of both the tibia and the femur are indicated. Depending on the skeletal maturity of the patient, intramedullary fixation of the femur, using either reamed or flexible implants, can be combined with external fixation of the tibia. In the younger child, external fixation can be applied to both the femur and the tibia. It allows rapid mobilization of the patient, motion of the knee and ankle, and normal shoe wear. Weight bearing can be initiated as soon as patient can tolerate it in most cases.
PELVIC FRACTURES
Although they are relatively rare in children, unstable pelvic fractures, particularly open-book type fractures of the pelvis, can be treated with external fixation as in the adult (52). Posterior disruptions can be addressed by internal fixation and combined with an anterior fixator (see Chapter 17). For more details on the treatment of pediatric fractures, see Chapter 164.
REFERENCES
Each reference is categorized according to the following scheme. *, classic article; #, review article; !, basic research article; and +, clinical results/outcome study.
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+ 6. Bell DF. Treatment of Post-traumatic Sequelae by the Ilizarov Technique. In. Letts M, ed: Management of Pediatric Fractures. London: Churchill Livingstone, 1993:711.
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+ 8. Bell DF, Boyer MI, Armstrong PF. The Use of the Ilizarov Technique in the Correction of Limb Deformities Associated with Skeletal Dysplasia. J Pediatr Orthop 1992;12:283.
+ 9. Cattaneo R, Catagni M, Johnson EE. The Treatment of Infected Nonunions and Segmental Defects of the Tibia by the Methods of Ilizarov. Clin Orthop Rel Res 1992;280:143.
+ 10. Cattaneo R, Villa A, Catagni MA, Bell DF. Lengthening of the Humerus Using the Ilizarov Technique. Description of the Method and Report of 43 Cases. Clin Orthop Rel Res 1990;250:117.
+ 11. Cattaneo R, Villa A, Catagni MA, Tentori L. Limb Lengthening in Achondroplasia by Ilizarov’s Method. Int Orthop 1988;12:173.
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! 13. Chao E, Hein T. Mechanical Performance of the Standard Orthofix External Fixator. Orthopaedics 1988;11:1057.
+ 14. Clinkscales CM, Peterson HA. Isolated Closed Diaphyseal Fractures of the Femur in Children. Comparison of Effectiveness and Cost of Several Treatment Methods. Orthopaedics 1997;20:1131.
* 15. Dal Monte A, Donzelli O. Tibial Lengthening According to Ilizarov in Congenital Hypoplasia of the Leg. J Pediatr Orthop 1987;7:135.
* 16. DeBastiani G, Aldegheri R, Renzi-Brivio L. The Treatment of Fractures with a Dynamic Axial Fixator. J Bone Joint Surg 1984;66B:538.
* 17. DeBastiani G, Aldegheri R, Renzi-Brivio L, Trivella F. Limb Lengthening by Callus Distraction (Callotasis). J Pediatr Orthop 1987;7:129.
+ 18. Doane RM, Stanitski DF, Stanitski CL. Treatment Cost of Isolated Femoral Shaft Fractures in Children. External Fixation Versus Traction. Submitted to Journal Pediatric Orthopaedics.
+ 19. Eldridge JC, Bell DF. The Correction of Severe Growth Abnormalities Following Purpura Fulminant Using the Ilizarov Technique. Orthop Trans 1992–1993;16:861.
+ 20. Fabry G, Lammens J, Van Melkebeek J, Stuyck, J. Treatment of Congenital Pseudarthrosis with the Ilizarov Technique. J Pediatr Orthop 1988;8:67.
+ 21. Ghoneem HF, Wright JG, Cole WG, Rang M. The Ilizarov Method for Correction of Complex Deformities. J Bone Joint Surg 1996;78A:1480.
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! 23. Goodship AE, Kenwright J. The influence of induced micro-movement on the healing of experimental tibia fractures. J Bone Joint Surg 1985;67B:650.
+ 24. Grill F. Correction of complicated extremity deformities by external fixation. Clin Orthop Rel Res 1989;241:166.
+ 25. Guidera KJ, Hess WF, Highhouse KP, Ogden JA. Extremity Lengthening. Results and Complications with the Orthofix System. J Pediatr Orthop 1991;11;90.
# 26. Hamdy RC, Stanitski DF. A Visual Presentation of Ilizarov Tibial Lengthening. The Journal of Orthopaedic Techniques 1995;3:55.
+ 27. Huang SC, Kuo KN. Differential Lengthening of the Radius and Ulna Using the Ilizarov Method. J Pediatr Orthop 1998;18;370.
# 28. Ilizarov GA. The Principles of the Ilizarov Method. Bull Hosp Jt Dis 1988;48:1.
# 28. Ilizarov GA. The Tension-Stress Effect on the Genesis and Growth of Tissues. Part I. Clin Orthop 1989;238:249.
* 30. Ilizarov GA. The Tension-Stress Effect on the Genesis and Growth of Tissues. Part II. Clin Orthop 1989;239:264.
* 31. Ilizarov GA. Clinical Application of Tension-Stress Effect for Limb Lengthening. Clin Orthop 1990;250:8.
+ 32. Ilizarov GA, Shevtsov VJ, Kuzmin NV. Method of Treating Talipes Equinocavus. Ortop Travmatol Protez 1983;5:46.
+ 33. Kamegaya M, Shinohara Y, Shinada Y. Limb Lengthening and Correction of Angulation Deformity. Immediate Correction by Using a Unilateral Fixator. J Pediatr Orthop 1996;16;477.
+ 34. Kirschenbaum D, Albert MC, Robertson WW, Davidson RS. Complex Femur Fractures in Children. Treatment with External Fixation. J Pediatr Orthop 1990;10:588.
+ 35. Klein W, Pennig F, Brug E. Dynamic Axial Fixation for Femoral Fractures in Children. Presented at the International Congress. Evolution of External Fixation. June 1990, Montpellier, France.
+ 36. Knapp DR, Price CT. Correction of Distal Femoral Deformity. Clin Orthop Rel Res 1990;255:75.
+ 37. Lammens J, Mukherjee A, Van Eygen P, Fabry B. Forearm Realignment with Elbow Reconstruction Using the Ilizarov Fixator. A Case Report. J Bone Joint Surg 1991;73B:412.
! 38. Lavini F, Renzi-Brivio L, deBastiani G. Psychologic, Vascular and Physiologic Aspects of Lower Limb Lengthening in Achondroplastics. Clin Orthop Rel Res 1990;250:138.
+ 39. Miller LS, Bell DF. Management of Congenital Fibular Deficiency by Ilizarov Technique. J Pediatr Orthop 1992;12:651.
+ 40. Noonan KJ, Price CT. The Pearls and Pitfalls of Limb Lengthening and Deformity Correction via Unilateral External Fixation. Iowa Orthop J 1996;16:58.
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# 41. Paley D. Current Techniques of Limb Lengthening. J Pediatr Orthop 1988;8:73.
+ 42. Paley D, Catagni M, Argnani F, et al. Treatment of Congenital Pseudarthrosis of the Tibia Using the Ilizarov Technique. Clin Orthop Rel Res 1992;280:81.
! 43. Paley D, Fleming D, Catagni M, et al. Mechanical Evaluation of External Fixators Used in Limb Lengthening. Clin Orthop Rel Res 1990;250:50.
+ 44. Plawecki S, Carpentier E, Lascombes P, et al. Treatment of Congenital Pseudarthrosis of the Tibia by the Ilizarov Method. J Pediatr Orthop 1990;10:786.
+ 45. Pouliquen JC, Coelin JD, Langlais J, Pauthier F. Upper Metaphyseal Lengthening of the Tibia by Callotasis. Forty-seven Cases in Children and Adolescents. J Pediatr Orthop 1993;2B:49.
+ 46. Pouliquen JC, Gorodischer S, Vernevet C, Richard L. Femoral Lengthening in Children and Adolescents. A Comparative Study of a Series of 82 Cases. Fr J Orthop Surg 1989;3:162.
+ 47. Price CT. Limb Lengthening for Achondroplasia. Early Experience. J Pediatr Orthop 1989;9:512.
# 48. Price CT. Metaphyseal and Physeal Lengthening. Instr Course Lect 1989;38:331.
+ 49. Price CT, Cole D. Limb Lengthening by Callotasis for Children and Adolescents. Early Experience. Clin Orthop Rel Res 1990;250:105.
+ 50. Price CT, Levengood G, Zink W. The Treatment of Pediatric Fractures with Dynamic External Fixation. Techn Orthop 1989;4:74.
+ 51. Rajacich R, Bell DF, Armstrong PF. Pediatric Application of the Ilizarov Method. Clin Orthop Rel Res 1992;280:72.
+ 52. Reff RB. The Use of External Fixation Devices in the Management of Severe Lower Extremity Trauma and Pelvic Injuries in Children. Clin Orthop Rel Res 1984;188:22.
+ 53. Scavenius M, Ebskov LB, Sloth C, Torholm C. External Fixation with the Orthofix System in Dislocated Fractures of the Lower Extremities in Children. J Pediatr Orthop 1993;2:161.
+ 54. Schlenzka D, Poussa M, Osterman K. Metaphyseal Distraction for Lower Limb Lengthening and Correction of Axial Deformities. J Pediatr Orthop 1990;10:202.
+ 55. Shih HN, Chen LM, Lee ZL, Shih CH. Treatment of Femoral Shaft Fractures with the Hoffman External Fixator in Prepuberty. J Trauma 1989;29:498.
+ 56. Stanitski DF. Treatment of Deformity Secondary to Metabolic Bone Disease with the Ilizarov Technique. Clin Orthop Rel Res 1994;301:38.
+ 57. Stanitski DF, Bullard M, Armstrong P, Stanitski CL. Results of Femoral Lengthening Using the Ilizarov Technique. J Pediatr Orthop 1995;15:224.
+ 58. Stanitski DF, Shahcheraghi H, Nicker DA, Armstrong PF. Results of Tibial Lengthening Using the Ilizarov Technique. J Pediatr Orthop 1996;16:168.
+ 59. Stanitski DF, Srivastava P, Stanitski CL. Correction of Proximal Tibial Deformities in Adolescents Using the T-Garches External Fixator. J Pediatr Orthop 1998;18:512.
+ 60. Tolo V. External Skeletal Fixation in Children’s Fractures. J Pediatr Orthop 1983;3:435.
+ 61. Trivella GP, Brigadoi F, Aldegheri R. Leg Lengthening in Turner Dwarfism. J Bone Joint Surg 1996;78B:290.
+ 62. Velazquez RJ, Bell DF, Armstrong PF, et al. Complications Using the Ilizarov Technique in the Correction of Limb Deformities in Children. J Bone Joint Surg 1993;75A:1148.
* 63. Vilarrubias JM, Ginebreda I, Jimeno E. Lengthening of the Lower Limbs and Correction of Lumbar Hyperlordosis in Achondroplasia. Clin Orthop Rel Res 1990;250:143.
+ 64. Villa A, Paley D, Catagni MA, et al. Lengthening of the Forearm by the Ilizarov Technique. Clin Orthop Rel Res 1990;250;125.
! 65. Young NL, Bell DF, Anthony A. Paediatric Pain Patterns During the Ilizarov Treatment of Limb Length Discrepancy and Angular Deformity. J Pediatr Orthop 1994;14:352.
! 66. Young NL, Davis RJ, Bell DF, Redmond DM. Electromyographic and Nerve Conduction Changes after Tibial Lengthening by the Ilizarov Method. J Pediatr Orthop 1993;13:473.