Chapman’s Orthopaedic Surgery
3rd Edition

This is the most common procedure in persistent physiologic genu varum because it addresses both the varus and the medial tibial torsion. A variety of techniques can be used, including closing-wedge, opening-wedge, oblique, or dome osteotomies. These are essentially the same procedures as for tibia vara or Blount’s disease. A diaphyseal fibular osteotomy is performed concomitantly because the fibula is usually too long and may be contributing to the deformity. The technique of a closing-wedge proximal tibial and diaphyseal fibular osteotomy is discussed in the section on tibia vara (see below). Internal or external fixation to maintain alignment is necessary and usually supplemented by a long-leg cast until complete healing has occurred.

Temporary retardation of growth in the lateral aspect of the proximal
tibial epiphysis with staples is an effective method for correction of persistent physiologic genu varum. If the deformity is severe or there is limited remaining growth, a combined lateral stapling of the distal femoral and the proximal tibial epiphyses may need to be performed. This procedure will not correct any coexistent medial tibial torsion.

Percutaneous closure of the lateral aspect of the proximal tibial epiphysis can be effective in correcting persistent physiologic genu varum in adolescents. The indications are essentially the same as for stapling. However, once complete correction has been achieved, a second procedure may be necessary on the medial side to prevent overcorrection. The proximal fibular epiphysis is usually closed concomitantly. This procedure will not correct any medial tibial torsion.

Tibia vara may occur at any age in a growing child. It was initially classified into two broad groups, depending on the age at clinical onset: infantile, with onset between 1 and 3 years of age; and adolescent, with onset inconsistently described as occurring after 6–8 years of age or just before puberty (33,35,97,110,111,157,158,260). In 1984, Thompson et al. (275) proposed a three-group classification based on the age at onset: infantile (1–3 years), juvenile (4–10 years), and adolescent (11 years or older). The juvenile and adolescent forms are commonly combined as late-onset tibia vara. However, the incidence of recurrent deformity after a corrective valgus osteotomy of the proximal tibia is much higher in the juvenile group, justifying a three-group classification. All three groups share relatively common clinical characteristics, although the radiographic changes in the late-onset groups are less pronounced. Although the exact cause of tibia vara remains unknown, it appears to be secondary to growth suppression from increased compressive forces across the medial aspect of the knee (22,29,33,35,59,60,69,111,157,168,171,172,274,275,286). Familial cases have been reported (23,111,173,250,253).

The natural history of tibia vara is one of progressive varus deformity. Infantile tibia vara can produce the greatest degree of deformity because of the greater amount of growth time remaining. In 1952, Langenskiöld (172) described six stages of progressive deformity in infantile tibia vara. Each grade advanced the degree of physeal growth inhibition (Fig. 169.6). It is possible to restore normal growth and development of the proximal tibial physes in grades I and II and probable grades III and IV. Grades V and VI represent severe damage to the medial proximal tibial physis and probable premature or asymmetric closure. The rate of deformity in grades V and VI is rapid, resulting in severe deformity and articular malformation. There is relatively good interobserver agreement with the use of this classification, especially for the early and late stages (264).

Comparison of the clinical characteristics of the infantile (22,23,33,35,46,90,91,95,97,103,110,111,116,151,167,168,169,172,173,180,181,223,248,260)
and late-onset (juvenile and adolescent) (29,46,129,167,274,275,286) forms of tibia vara shows similarities as well as distinct differences (Table 169.5). The infantile form is the most common (Fig. 169.7). However, the late-onset forms also occur frequently (Fig. 169.8). Anterior cruciate ligament incompetence may occur in severe deformities (28).

Radiographically, fragmentation with a protuberant step deformity and beaking of the proximal medial tibial metaphysis are the major features of infantile tibia vara (Fig. 169.7B) (54,116,151,260). The changes in the proximal medial tibia are less conspicuous in the late-onset forms and are characterized by wedging of the medial portion of the epiphysis, a mild posteromedial articular depression, a serpiginous cephalad-curved physis, and mild or no fragmentation or beaking of the proximal medial metaphysis (Fig. 169.8B) (29,46,54,77,78,254,255 and 256,274,275,286). The differences among the three tibia vara groups appear to be primarily due to the age at onset, the amount of remaining growth, and the magnitude of the medial compression forces on the involved side.

The major deformity that must be differentiated from tibia vara is physiologic genu varum deformity. It is difficult to differentiate these disorders in patients younger than 2 years. Children with tibia vara are typically African-American and obese and have a clinically apparent lateral thrust of the knee during the stance phase of gait. The deformities are progressive and may be asymmetric. Radiographic differentiation may be difficult. Standing radiographs of the lower extremities in children younger than 18 months of age with genu varum deformities are typically normal. However, normal knee radiographs do not eliminate infantile tibia vara from consideration. A metaphyseal–diaphyseal angle greater than 16° is an early prognosticator of infantile tibia vara (Fig. 169.3) (101). After 2–3 years of age, the radiographic characteristics become apparent, and the condition can be classified according to the six grades of Langenskiöld (172). The radiographic changes in late-onset forms of tibia vara are less dramatic but nevertheless diagnostic.

Histopathologic studies indicate a similar pathologic process for all three groups. Only a few biopsies of the proximal medial tibial condyle have been obtained from patients with infantile tibia vara (35,95,111,171,173). Histopathologic abnormalities included islands of densely packed chondrocytes exhibiting a greater degree of hypertrophy than would be expected from their topographic position, areas of almost acellular cartilage, and abnormal groups of capillaries. Langenskiöld (171) and Golding and McNeil-Smith (111), in studies of nine

and six biopsies, respectively, concluded that the abnormalities were localized principally to the physes and that there was no evidence of avascular necrosis.

More extensive histopathologic data are available for the late-onset forms of tibia vara (59,60,223,274,275,286). The major histologic aberrations include the following:

Disorganization and misalignment of the physeal zones

Abnormal histochemical staining and excess of hypocellular matrix

Cystic degeneration and necrosis

Multidirectional clefts and fissures

Transphyseal canals of capillaries

Intraphyseal ossification centers

Increased necrotic chondrocytes throughout the proliferative and hypertrophic zones

Abnormal collagen fibers in the cartilage matrix

Chondrocytes at the apex of the vascular invasion front, which has increased width and length

Extension of noncalcified cartilaginous bars into the proximal and distal metaphyses

These changes are found uniformly throughout the medial and lateral aspects of the physes, although they are quantitatively greater on the medial side. They are remarkably similar to the changes observed in infantile tibia vara and in slipped capital femoral epiphysis, suggesting a common cause (1,2). Lovejoy and Lovell (182) described two patients with late-onset tibia vara associated with slipped capital femoral epiphysis.

The histopathologic abnormalities indicate that asymmetric compression and shear forces acting across the proximal tibial physis result in suppression and deviation of normal endochondral ossification, producing tibia vara. This concept, which reflects the Heuter–Volkmann law, has been confirmed experimentally by Arkin and Katz (13). Golding and McNeil-Smith (111) concluded that children who had significant physiologic varus deformity, walked early and stretched their knee ligaments. This resulted in asymmetric compression with subsequent suppression of posteromedial physeal growth and ultimate formation of an osseous bridge, producing a permanent and progressive varus deformity. This pathogenesis is consistent with Blount’s (33,35) initial observations that infantile tibia vara is first recognized when there is an increase of physiologic bowing during the first 3 years of life. Langenskiöld (172,173) emphasized that necrosis of the physeal cartilage is the principal cause of growth disturbance, leading to varus deformity; he attributed the abnormal cartilage to abnormal pressure or shear in overweight children with physiologic bowleg. Others agreed that abnormal pressure is probably the primary etiologic factor in infantile tibia vara (22,35,46,111,157,162).

In predisposed older children or adolescents with minimal residual deformity after physiologic bowleg, rapid growth and weight gain repetitively injure the posteromedial portion of the proximal tibial physis, resulting in a cycle of varus-growth suppression similar to the cycle described by Golding and McNeil-Smith (111) for the infantile form (127,129,274,275,286). Progressive genu varum deformity is not due to an osseous bridge but is caused by suppression of normal endochondral growth after repetitive local injury (29,162,260,274,275,286). The concept of physeal growth suppression in tibia vara has been confirmed biomechanically by Cook et al. (69) in a finite element analysis. As varus increases, the forces in the proximal medial tibial physis increase. Obesity and mild varus (10°) in older children create enough force to suppress growth. However, Henderson and Green (127) reported a case of late-onset tibia vara in an adolescent with previously documented neutral mechanical alignment, suggesting that, at least in some cases, preexisting varus alignment is not a prerequisite.

If radiographic findings confirm the diagnosis of infantile tibia vara, begin treatment immediately. Orthotic management may be considered for children 3 years of age or younger with Langenskiöld’s grade II and possibly grade III involvement. Approximately 50% to 65% of these in children can be corrected with an orthosis (151,180,232,248). Children with suspected infantile tibia vara with metaphyseal–diaphyseal angles of 10° to 15° are more likely to benefit from orthotic management (232). Use a knee–ankle–foot orthosis with a single medial upright without a knee hinge. Place pads, straps, or elastic webbing over the distal femur and proximal tibia to apply a valgus force. The orthosis should be worn for 22–23 hours each day. Tighten the straps at 1–2-month intervals to provide progressive correction. Obtain standing radiographs at 3-month intervals to document correction of the tibia vara deformity. The metaphyseal–diaphyseal angle should decrease (122). After obtaining an absolute valgus mechanical axis, begin weaning from the orthosis. Follow the child carefully thereafter to ensure maintenance of correction.

A maximum trial of 1 year of orthotic management is currently recommended. If correction is not obtained after 1 year of bracing, corrective osteotomy is indicated. Orthotic treatment is not indicated after 3 years of age or for severe deformities. Bracing children older than 3 years risks delaying performance of a corrective osteotomy. Loder and Johnston (180) showed that delay in performing corrective osteotomy, even by a few months, beyond 4 years of age risks failure to achieve lasting reversal of the physeal inhibition of the proximal tibia. This predisposes a child to repeated operative procedures to maintain a satisfactory result.

Conservative management in the late-onset forms of tibia vara is contraindicated. The children are too large and the remaining growth is too small to allow adequate
correction. Compliance with an orthosis in this age group is difficult to achieve.

The indications for surgical treatment in infantile tibia vara include age 4 years or less, failure of orthotic management, and Langenskiöld grade III or higher. The possible procedures are presented in Table 169.4. Proximal tibial valgus osteotomy with fibular diaphyseal osteotomy is usually the procedure of choice. Perform an anterior compartment fasciotomy concomitantly. Tibial osteotomy techniques include closing-wedge, opening-wedge, dome, and oblique osteotomies. The procedure selected must correct the varus deformity and any associated medial tibial torsion. Tibial length is usually not a problem in infantile tibia vara. It is important that the selected osteotomy overcorrect the mechanical axis of the knee to 5° or more of valgus. This ensures that the supine correction obtained in the operating room is adequate. Overcorrection compensates for the tendency of the knee to fall back into varus after a patient resumes weight bearing because of the depression in the posteromedial articular surface and the ligamentous relaxation laterally. The goal is to transfer the line of weight bearing to the lateral compartment of the knee. Schoenecker et al. (248) reported that correction within 5° of neutral usually proves satisfactory. However, others recommend overcorrection (168,173,180,229). Considering the physeal inhibition phenomena as proposed by Cook et al. (69), overcorrection to absolute valgus alignment is necessary to relieve the excessive compressive forces medially.

Rab (229) described an oblique osteotomy of the proximal tibia for tibia vara. It is a single-plane osteotomy that allows simultaneous correction of the varus and medial tibial torsion deformities and permits postoperative cast wedging, if necessary, to improve position. This ability to adjust the osteotomy postoperatively is important because of the difficulty in achieving satisfactory alignment intraoperatively.

In older children with infantile tibia vara, especially those with Langenskiöld grade IV lesions or higher, a single osteotomy of the proximal tibia is usually insufficient to restore normal alignment and physeal growth. Langenskiöld grades IV and V act effectively as medial physeal arrests. Possible procedures for these children include the following (25,47,65,87,103,117,130,152,158,159,166,177,195,217,229,245,246,247 and 248,255,261,274,275):

Multiple proximal tibial metaphyseal osteotomies and fibular diaphyseal osteotomies

Proximal tibial osteotomy with physeal resection

Intraepiphyseal osteotomy to elevate the medial tibial articular surface (elevation of the medial tibia plateau)

Physeal bridge resection and replacement with interposition material such as fat or Silastic

Hemiepiphysiodesis of the lateral aspect of the proximal tibial epiphysis

Oblique proximal tibial osteotomy

Ilizarov ring fixation system and callotasis technique

In the juvenile and adolescent forms of tibia vara, surgical correction is necessary to restore the mechanical axis of the knee. The same surgical options as those for older children with infantile tibia vara are applicable in these groups. Correction to physiologic genu valgum with careful preoperative biotrignometric planning for the tibial osteotomy is the goal (57). Kline et al. (160) demonstrated that distal femoral varus is a part of the deformity in late-onset tibia vara. Evaluate this possibility, and perhaps consider it in the treatment plan.

Obtain intraoperative radiographs with the knee in extension and with slight varus stress to ensure contact between the medial femoral condyle and the posteromedial articular depression of the proximal tibia. This technique can help minimize undercorrection of the deformity. Aim to achieve at least 5° of valgus at the time of osteotomy. The recurrence rate for the juvenile-onset group approaches 25% overall and is even higher in boys (274,275). Evaluate all juvenile-onset patients with tomography or magnetic resonance imaging (MRI) before surgery for evidence of premature closure or impending closure of the proximal medial tibial physis. If premature closure is not present, a simple closing-wedge metaphyseal osteotomy or oblique proximal tibial osteotomy with correction to physiologic valgus may be performed (229). Correction using the Ilizarov ring fixation system and callotasis may be applicable, especially if there is a significant lower-extremity length discrepancy (227).

If the deformity recurs, indicating significant physeal inhibition, then additional surgery is necessary; techniques include physeal bridge resection and interposition graft, intraepiphyseal osteotomy, elevation of the medial tibial plateau, and physeal excision (117,152,174,177,185,245,248,255,289). Internal or external fixation is usually necessary to maintain alignment until satisfactory healing occurs. Physeal distraction with an external fixator has also been used in Europe (86,88), but it is not widely used. The procedure selected depends on the patient’s age, the amount of growth remaining, and the severity of the deformity. Proximal tibial physeal excision with proximal fibular epiphysiodesis is usually recommended for recurrent deformities with premature medial tibial physeal closure or for patients 12 years of age or older (274). Healing is rapid and the correction permanent. Measure any residual lower-extremity length discrepancy with scanograms, and manage by contralateral epiphysiodesis, when necessary.

Henderson et al. (128) reported results in nine children with late-onset tibia vara treated by hemiepiphysiodesis of the lateral aspect of the proximal tibial epiphysis. The average preoperative varus was 13° (range, 3° to 25°).
They found a correction rate of 7° per year. Three patients required a proximal tibial osteotomy because of incomplete correction. The authors thought that hemiepiphysiodesis was an effective procedure with less morbidity for managing varus deformities of the extremities of obese children. Similar results can probably be anticipated with staples, although they were not used in this study.

In the late-onset form of the disease, a callotasis technique may be beneficial with either a cantilever or Ilizarov ring fixation system. The advantage of this procedure is that it allows slow, progressive correction.

Because the patient is bearing weight, the precise degree of desired correction can be achieved. This procedure is being used more frequently today (see Chapter 171).

The postoperative management of children is similar after any corrective osteotomy of the proximal tibia. Continue immobilization until healing is complete; then place the children on a physical therapy program at home for approximately 2 weeks. After complete rehabilitation, allow them to return to normal activities. Because of associated obesity, these children frequently benefit from a dietary consultation.

Complications during and after a proximal tibial osteotomy are common. They include peroneal nerve palsy, injuries to the anterior tibial artery, and compartment syndromes (88,103,148,187,202,204,249,263). Occurrence of a compartment syndrome may be minimized by performing an anterior compartment fasciotomy at the time of surgery. If a compartment syndrome occurs, temporarily reduce the correction, and perform a four-compartment fasciotomy. Children with the infantile form of tibia vara require long-term follow-up to assess the results of surgery. The deformity may recur, especially in older children and those with advanced Langenskiöld grades. Deformity persisting after skeletal maturity predisposes to degenerative osteoarthritis (137,291).

I prefer a proximal tibial valgus derotation and fibular diaphyseal osteotomy to correct infantile tibia vara. This allows simultaneous correction of both components of the deformity. It is important that the deformity be slightly overcorrected so that the mechanical axis passes medial to the ankle joint. It can be difficult to assess the degree of correction intraoperatively because radiographs on a long cassette cannot be obtained. A helpful hint is to visualize the iliac crest on the involved side. The cord from the electrocoagulation knife can be used to measure the mechanical axis on the fluoroscope. This can be stretched between the anterosuperior iliac spine and the middle of the patella. Its distal extension can then be judged with respect to the ankle joint. Undercorrection is a common problem that prevents adequate alignment. Radiographic contrast material in the knee joint at the time of surgery may also be helpful. Manually manipulate the knee into varus after the osteotomy is internally stabilized, as this gives a more realistic feeling for the alignment of the extremity during weight bearing.

In older children with infantile or late-onset tibia vara, especially the juvenile type, a preoperative MRI may be helpful in assessing the integrity of the physis. However, even if the physis appears open, it may still be abnormal and not respond to normalization of the compressive forces postoperatively. Correction in these children can be accomplished using an Ilizarov frame and callotasis. This allows precise correction of the deformity. Weight-bearing radiographs may be obtained during treatment.

In children with recurrent deformities in whom a physeal bridge is suspected, I would suggest excision of the physis with concomitant correction of both the residual tibia vara deformity and any medial tibial torsion. Postoperatively, patients will need to be evaluated for residual lower-extremity length discrepancy. An appropriately timed contralateral epiphysiodesis will be necessary to achieve relatively equal leg lengths at skeletal maturity.

Biopsy of the lesion at the time of corrective osteotomy or for diagnostic purposes has shown consistent histopathologic features. Grossly, there is a white cartilaginous lesion with well defined margins deep to the insertion of the pes anserinus. Histopathologic findings include acellular or sparsely cellular collagenous tissue, inactive fibrocytes, plump cells resembling chondrocytes in lacunae, and dense, nondescript fibrous tissue (26,45,155,192,208). No giant cells, osteoid, or bone are found within these lesions. The lesions suggest fibrocartilage centrally and tendinous tissues peripherally. They do not involve the physis or epiphysis. Bell et al. (26) observed that the tissue resembles that normally found at the site of the insertion of tendons into cortical bone, as described by Cooper and Misol (70) in 1970. They suggested that these children had abnormal development of fibrocartilage at the insertion of the pes anserinus. The exact mechanism of this abnormal growth is unknown. The defect may be congenital.

All children with tibia vara caused by focal fibrocartilaginous dysplasia present with unilateral bowing. There is no apparent sex or side predilection. The onset is usually before age 1 year, and the deformity progresses until approximately age 2 years and then begins to resolve. During the time of progression, the deformity may become quite prominent, reaching 20° to 30° of varus. Medial tibial torsion and mild tibial length discrepancy (0.5–1.0 cm) are common associated findings (26, 45).
The lesions are characteristically not tender to palpation, and there is no prominence of the proximal medial metaphysis, as seen in infantile tibia vara.

Radiographically, there is a cortical defect in the medial metaphyseal region of the proximal tibia with an area of surrounding sclerosis (Fig. 169.10). MRI will demonstrate dense fibroconnective tissue (192). Computed tomography shows similar findings, with an elliptical fibrous cortical defect but no soft-tissue mass (131,290). On the basis of reported cases, it appears that the metaphyseal lesion resolves spontaneously after age 2 years, followed by correction of the tibia vara deformity. Significant improvement is usually evident by 4 years of age (26,45). Use of an orthosis does not increase the rate of improvement.

Although data are limited, it appears that only children with no evidence of spontaneous correction by 4 years of age are candidates for corrective osteotomy (290). This typically involves a proximal tibial osteotomy distal to the apophysis of the tibial tubercle and a diaphyseal fibular osteotomy. Because of the associated medial tibial torsion, the procedure of choice is a laterally based closing derotation osteotomy or an oblique proximal tibial osteotomy as described by Rab (229).

The procedures for focal fibrocartilaginous dysplasia are the same as those for tibia vara. There is no intrinsic osseous pathology that interferes with bone healing. Immobilization in a long-leg cast or a one-and-one-half spica cast is necessary, depending on the child’s age. A spica cast is usually advised for younger children. After healing, there is usually rapid rehabilitation and return to normal activities. Prolonged follow-up is necessary to assess resolution of the lesion and subsequent growth and development of the proximal tibia. Periodic scanograms are necessary to assess the length of the extremities.

A peroneal nerve palsy and persistent valgus deformity into adolescence were reported by Bradish et al. (45) after corrective osteotomy. This appears to
have been a technical problem. No other complications have been reported for operative treatment of this lesion.

Persistent or progressive genu varum deformities are common in children with metabolic disorders such as vitamin D–resistant rickets (hypophosphatemic rickets) or nutritional rickets. Vitamin D–resistant rickets is an X-linked dominant disorder due to vitamin D resistance that results in defective bone mineralization. Affected children typically have bilateral symmetric genu varum; they are relatively short, usually being in the tenth percentile. The varus deformity is due to a combination of bowing and involvement of the distal femur and the proximal tibia. Hematologic studies reveal normal serum calcium and decreased phosphate values. In nutritional rickets, the child has been receiving an unusual diet from the parents.

Radiographically, the features are widening of the metaphyses, widening of the physes, and a cup-shaped relationship between the physis and the metaphysis. The bowing is usually symmetric throughout the femur and the tibia. Marked osteopenia and thinning of the cortices are also common. Obtain serum calcium, phosphorus, and alkaline phosphatase levels, as well as a pediatric endocrinology consultation to confirm the diagnosis.

Medical treatment is important before any form of orthopaedic intervention is considered (96,239). This typically includes oral phosphate supplementation and high doses of vitamin D for vitamin D–resistant rickets, and dietary changes for nutritional rickets. Surgical measures to correct genu varum deformities are usually unsuccessful unless adequate medical control has been obtained preoperatively. If such control cannot be obtained, it is usually best to wait until skeletal maturity before attempting to realign the mechanical axes.

If metabolic control can be obtained and a child is young, observation is appropriate. Spontaneous improvement may occur in children younger than 5 years. However, in older children or those who are not improving spontaneously, surgical treatment is necessary (96,239). This may consist of osteotomies of the distal femur, proximal tibia, or both. If involvement is extensive, proximal femoral and distal tibial osteotomies may be necessary to adequately realign the lower extremities. Cast immobilization postoperatively may result in immobilization-induced hypercalcemia and may require modification of medical management. When osteotomies are done, healing time may be twice normal. It is often advantageous to postpone major alignment procedures until adolescence to minimize the recurrence that is common in younger children.

Children who have end-stage renal disease may manifest renal osteodystrophy. The physes in these children show the same pathologic changes found in tibia vara and slipped capital femoral epiphysis. These include disorganized endochondral ossification at the physeal–metaphyseal junctions. Because end-stage renal failure occurs more commonly in older children who have achieved physiologic valgus alignment, valgus deformities are much more common. Varus is more likely when renal failure occurs at 3 years of age or younger. Renal osteodystrophy has many of the same radiographic features as vitamin D–resistant and nutritional rickets. There is physeal cupping and widening at both the distal femoral and proximal tibial physes. Marked osteopenia and thinning of the cortical bone are also present.

Treatment of genu varum deformities secondary to renal osteodystrophy is similar to that for vitamin D–resistant and nutritional rickets. Surgical treatment is usually postponed until the renal status has stabilized in response to medical treatment, hemodialysis, or kidney transplantation. There will be a rapid recurrence of the deformity if the underlying metabolic bone disease is not corrected first.

Many skeletal dysplasias may result in a progressive genu varum deformity (Table 169.1). Metaphyseal chondrodysplasia (both Jansen and Schmid types), which results in abnormal chondroblast function and chondroid production, is a common cause. Occasionally, these may be difficult to distinguish from rickets. Although the physes are widened and cupped in the Schmid type, the epiphyses are normal, and the presence of short stature may be helpful in making the correct diagnosis.

Genu varum frequently occurs in achondroplasia. This rhizomelic dwarfing condition is due to abnormal endochondral bone formation. Affected children have short stature and characteristic craniofacial features. The genu varum deformity is due to asymmetric growth of the proximal tibial epiphysis and overgrowth of the fibula. These children rarely have knee pain.

For some surgeons, the treatment options for genu varum deformities secondary to achondroplasia must be surgical because orthotic management historically has not been effective. Their usual procedure is a proximal tibial valgus osteotomy and proximal fibular epiphysiodesis (Fig. 169.11). The latter must be done early in childhood to prevent recurrence and progression of the genu varum deformity. Others feel that genu varum in achondroplasia is not associated with functional difficulty or increased risk of osteoarthritis, and surgery may not be recommended (see Chapter 180).

Osteogenesis imperfecta results from a defect in type I collagen and produces varying degrees of skeletal fragility. Repeated fractures often lead to bowing and torsional malalignment of the lower extremities. The distal third of the femur is a common location for these fractures, which frequently result in anterolateral angulation. Residual deformities

after fractures are common, and the varus angulation often increases as a result of repeated fractures. Occasionally, in the more severe cases, osteotomies with intramedullary fixation may be beneficial (see Chapter 180).

Any condition, such as infection or trauma, that damages the physis may result in asymmetric growth and deformity. The distal femur is the most common site of growth disturbance following a physeal fracture. Physeal fractures of the proximal tibia occur much less commonly. The management of genu varum deformities secondary to physeal growth disturbance is complex. If an asymmetric physeal bar is present, it may be resected and grafted with fat or Silastic. The deformity is corrected concomitantly by an osteotomy. If the physeal damage is extensive, complete physeal closure and management of the associated leg-length discrepancy may need to be considered (see Chapter 164).

Retardation of growth about the medial aspect of the distal femur or proximal tibia by medial physeal stapling is a relatively easy, reliable method of correcting a genu valgum deformity if there is sufficient remaining growth to produce satisfactory alignment (Fig. 169.14) (36,105,141,193,221,282,294). If the deformity is pronounced or there is insufficient remaining skeletal growth, a combined stapling of the medial aspect of the distal femoral and the proximal tibial physes may be necessary (105,221).

The medial aspect of the distal femoral epiphysis is palpable at the junction of the maximal metaphyseal flare and the medial femoral condyle. Stapling of the distal femoral epiphysis proceeds as follows.

If the proximal tibial physis is selected for stapling, the procedure is similar to that for the distal femur.

Postoperatively, use a knee immobilizer for approximately 2 weeks. Follow up at 2–3-month intervals, and assess radiographically for correction. After the desired amount of correction has been achieved, remove the staples. However, there is frequently rebound overgrowth and slight recurrence of the deformity. Zuege et al. (294) recommended allowing 5° of rebound. Accomplish this by allowing the correction to proceed to slight overcorrection before staple removal. However, Fraser et al. (105) found that the amount of rebound overgrowth was minimal and unpredictable. They also advised against leaving the staples in place for longer than 1 year because of possible premature closure of the physis. The amount of correction can be calculated mathematically on the basis of the width of the physis and the amount of remaining growth (38).

Partial or hemiepiphysiodesis of the medial aspect of the distal femur or proximal tibia has been proposed as a method for gradual correction of genu valgum deformity. The table devised by Bowen et al. (38) can be used to determine the appropriate time for epiphysiodesis. However, because of the variability in the data necessary to make these determinations, a second operative procedure is often required to close the remaining lateral portion of the epiphysis.

Rotational bone blocks, as described by Phemister (218), were once popular. However, the percutaneous techniques of epiphysiodesis using curet, drills, burrs, or a combination of these are now preferred (37,39,58,207,276). These are as accurate and much more cosmetic than the open bone graft epiphysiodesis techniques. Although this technique is most commonly used for lower-extremity length discrepancies, it can also be used successfully in the correction of persistent angular deformities such as genu valgum and genu varum (39).

Correction of a genu valgum deformity by distal femoral or proximal tibial and fibular diaphyseal osteotomies allows full correction of the deformity with a single operative procedure. However, both procedures are extensive and require internal or external fixation to maintain alignment until healing has occurred. In the correction of a valgus deformity, attention must be given to the peroneal nerve because neurapraxia or partial paralysis may occur if the nerve is stretched. The osteotomy may be performed in early adolescence or after skeletal maturity. Several techniques are available, including opening-wedge, closing-wedge, and dome osteotomies. The choice of technique is frequently based on the length of the lower extremity and the individual bones. An opening-wedge or dome-shaped osteotomy adds length to the extremity. DePablos et al. (87) described a progressive opening-wedge osteotomy using an external fixator; a fibular osteotomy is not required, and the osteotomy allows progressive and adjustable correction. Both lower extremities can be corrected simultaneously. Ordinarily, osteotomies are considered for boys age 14 years or older and girls age 12 years or older.

Varus osteotomy of the proximal tibia and diaphyseal osteotomy of the fibula are indicated if the valgus deformity is in the proximal tibia below the knee joint and there is no associated lateral tilt to the articular surface. The osteotomy is usually performed at the junction of the metaphysis and the diaphysis, just distal to the tibial tubercle. If there is associated lateral torsion of the tibia, derotation may also be accomplished. If a closing-wedge osteotomy is to be performed, perform the derotation initially because it frequently decreases the amount of bone requiring resection to correct the angular deformity. After satisfactory correction has been achieved, internal or external fixation is required. Compression plate and screws, crossed Steinmann wires, or an external fixator are suitable. In some cases, the Ilizarov ring fixator and the callotasis technique may be beneficial; this allows slow correction of the valgus and the derotation. Hemichondrodiastasis, or asymmetrical physeal lengthening, has been recommended by some, but it is not popular in the United States. This procedure allows simultaneous correction of limb-length inequality and correction of the genu valgum deformity. Because the physeal plate closes after this procedure, it is best performed for patients in late adolescence.

Treat a genu valgum deformity associated with a valgus alignment of the distal femur with an osteotomy of the distal femur. Deformities in this area are associated with a lateral tilt to the joint line that cannot be corrected by a proximal tibial osteotomy. The osteotomy may be performed through a medial or a lateral approach to the distal femur. The medial approach is more complex because of the proximity of the femoral artery, but it allows easier visualization of the operative site. The lateral approach is simpler, and there is less risk to the femoral artery as it passes posteriorly at the upper margin of a medial incision. Opening- or closing-wedge osteotomies are commonly performed because it is difficult to perform a dome osteotomy of the distal femur. After the osteotomy is complete, internal or external fixation is performed with a compression plate and screws, crossed threaded Steinmann pins, or an external fixation device. See Chapter 30 and Chapter 31 for additional information on osteotomies of the femur and the tibia, respectively.

Valgus deformity usually develops within 5 months of injury, reaches its maximum in 1–2 years, stabilizes, and then
begins to improve by longitudinal growth through the proximal and distal physes (Fig. 169.15) (216). Unfortunately, there are no data indicating how much improvement can be anticipated. Salter and Best (244) found no improvement in 21 patients, and 13 later required proximal tibial varus osteotomies. Visser and Veldhuizen (281) reported no spontaneous improvement in the valgus deformity from the proximal tibial physis but observed some correction in alignment from the distal tibial epiphysis. Taylor (273) found improvement in some patients but not all. Of the 12 children with valgus deformity described by Jordan et al. (153), 11 had documented improvement, although four subsequently required corrective osteotomies. Two of these children had their deformities recur, and two had compartment syndromes. Six children had complete correction of their deformities.

Jackson and Cozen (147) and later Ippolito and Pentamalli (146) observed that deformities of 15° or less usually remodeled completely, especially in young children. The more severe deformities, however, did not completely correct. Bahnson and Lovell (16) found some improvement in the valgus deformities in five children followed for a minimum of 3 years after injury. Balthazar and Pappas (18) reported that two of nine patients who were treated nonoperatively had resolution of their valgus deformity in 1–3 years. Skak et al. (258) found that valgus deformities tended to increase during the first year after injury and then remained constant for 1–2 years and finally improved. Only one of their six patients had residual deformity at final follow-up.

MacEwen and Zionts (183,293) followed seven children with posttraumatic tibial valgus deformities for a mean of 39 months after injury. These children were 11 months to 6 years of age. The valgus deformities progressed most rapidly during the first year after injury and then continued at a slower rate for as long as 17 months. Overgrowth of the tibia accompanied the valgus deformities. The mean overgrowth was 1 cm (range, 0.2–1.7 cm). Clinical correction with subsequent growth occurred in six of their seven patients. They recommended that the
alignment of the lower extremities be measured by the mechanical femoro-tibial angle as described by Visser and Veldhuizen (281) rather than the metaphyseal–diaphyseal angle of Levine and Drennan (176). The latter measured only the alignment of the proximal tibia. Much of the late correction of the deformity is due to distal realignment (183,258,281). The distal epiphysis tends to realign itself perpendicular to the applied forces, resulting in asymmetric growth and an S-shaped appearance of the tibia radiographically (216).

The treatment of proximal tibial metaphyseal fractures must consist of correction of any associated valgus angulation by manipulative reduction and immobilization in a long-leg cast with the knee in extension for 4–6 weeks or until the fracture is well healed (238). If closed reduction is required, it is best performed under general anesthesia. Radiographic evaluation of fracture alignment may be difficult unless radiographs of both lower extremities with the knee in extension are obtained on a long cassette. Greenstick fractures with slight valgus angulation may require that the intact hinged lateral cortex be manually fractured. This usually allows correction of the deformity. Slight overcorrection is desirable (205).

Displaced fractures also require correction of any residual angulation. However, normal apposition is not always necessary. There are limited indications for open reduction of these fractures. Inability to correct a significant valgus deformity by manipulation under general anesthesia rather than failure to close the medial fracture gap is currently the major indication. Most angulated displaced fractures are amenable to reduction by nonoperative methods.

The final step in initial management is to advise the family that although anatomic alignment of the fracture has been obtained, the possibility of valgus angulation and tibial overgrowth exist as a natural consequence of this fracture. This information prepares the family for complications if they occur.

Assess fracture alignment radiographically at least weekly during the first 3 weeks after injury. Correct any loss of alignment. During this initial period, children should avoid bearing weight to minimize compression forces and the possibility of valgus angulation within the cast.

Treatment of valgus deformities after proximal tibial metaphyseal fractures is predominantly nonoperative with prolonged observation. The use of orthoses has been suggested, but there is no evidence to substantiate the efficacy of this method (89,133,146). MacEwen and Zionts (183) recommended observation until early adolescence. If spontaneous improvement fails to provide sufficient clinical correction, surgical intervention may be necessary. McCarthy et al. (188) reported no difference in the long-term results between 10 patients treated nonoperatively and five managed operatively.

The major indications for surgical intervention include severe valgus deformities (>25°) and failure to achieve satisfactory correction by the immediate preadolescent years. All children should be allowed 2–4 years of growth after injury to allow spontaneous correction to occur. Most deformities of 15° or less resolve, and those that are 25° or more may not. Deformities between 15° and 25° must be carefully followed. The development of a medial thrust during this observation period is an indication for surgical intervention to prevent laxity in the medial collateral ligament.

The operative procedures to correct genu valgum deformities after proximal tibial metaphyseal fractures are similar to those for other valgus deformities and include the following:

Medial physeal stapling

Medial physeal epiphysiodesis

Osteotomy with internal or external fixation

Because the deformity is usually restricted to the tibia, these procedures are most commonly applicable to the proximal tibia. They are described in the section on physiologic genu valgum. If surgical intervention is contemplated, it is important to assess the degree of tibial-length inequality. Surgery must address the valgus deformity and residual tibial overgrowth. In young children with severe genu valgum deformities that are not improving with spontaneous growth and development, a corrective osteotomy may be indicated. This should include shortening of the tibia by approximately 5 mm to allow recurrent overgrowth. Similar consideration is necessary in the early adolescent years when surgical intervention is planned.

Recurrence has been attributed to the same overgrowth phenomenon that led to the initial valgus deformity. Balthazar and Pappas (18) reported that the valgus deformity recurred, although lesser in magnitude, in six children undergoing a proximal tibial varus osteotomy. Four of the six also had further longitudinal overgrowth of the tibia. DalMonte et al. (80) reported recurrent valgus deformities in 7 (44%) of 16 patients after proximal tibial osteotomies. The recurrence rate for children younger than 5 years was 60%, and for those between 5 and 10 years of age, it was 36%. The authors concluded that the osteotomy is essentially a second fracture and therefore has the same risks of deformity. If surgery is undertaken, families should be advised that the deformity can recur and that prolonged follow-up is required.

With the recent demonstration that the majority of children with genu valgum following a proximal
tibial metaphyseal fracture will undergo spontaneous correction during growth, I now feel that these children should be observed for as long as possible. Only a severe disabling deformity should be considered for early surgical correction. Deformities persisting into adolescence can be corrected with a proximal tibial or distal femoral medial hemiepiphyseal stapling (or both). Typically, this allows for rapid correction of any residual deformity. I try to avoid corrective osteotomy because this may induce the same genu valgum deformity that followed the initial fracture.

Metabolic causes of pathologic genu valgum include vitamin D–resistant rickets, nutritional rickets, and renal osteodystrophy. These disorders are more likely to produce genu valgum rather than genu varum. This is due to their later onset, at which time the physiologic valgus alignment of the knee has already been achieved. Renal osteodystrophy is the most common metabolic disorder producing genu valgum (12,19,32,62,75,81,132,143,210). Oppenheim et al. (210) described changes in the lateral proximal tibial epiphysis and metaphysis in children with renal osteodystrophy similar to those seen in the medial proximal tibia in Blount’s disease.

Treatment is generally initiated after correction of the underlying metabolic disorder. Treatment before that time has a high incidence of recurrence. After the metabolic condition has been controlled, treatment may be by either osteotomy or physeal stapling of the distal femur or proximal tibia. The latter is a particularly effective method, provided there is sufficient remaining growth (Fig. 169.16).

Injuries to and about the distal femoral or proximal tibial epiphyses is a common cause of genu valgum (142,233). The deformities are progressive and require surgical treatment if there is an asymmetric physeal bar or bridge. The extent of the bar can be assessed by tomography or, preferably, MRI. Treatment options consist of physeal bar excision and grafting with fat or Silastic (Langenskiöld [169] procedure), together with a corrective osteotomy. If the bar is extensive, then complete physeal closure and corrective osteotomy may be performed, with delayed management of the leg-length discrepancy (see Chapter 164).

Ambulatory children with neuromuscular disorders, such as cerebral palsy, often have a pes valgus and excessive external tibial torsion that may produce a progressive genu valgum. This is more likely to be a torsional malalignment than a true genu valgum deformity. Treatment may involve soft-tissue releases to restore muscle balance and osteotomies to correct torsional and angular deformities (see Chapter 177).

Osteomyelitis may cause genu valgum directly by damaging the physis or producing a reactive hyperemia and asymmetric growth stimulation. Asymmetric physeal arrest is managed similarly to trauma (see Chapter 176).

Genu valgum will occur in children with skeletal dysplasia, including multiple epiphyseal dysplasia, spondyloepiphyseal dysplasia, metaphyseal dysplasia, and pseudoachondroplasia. Treatment is based on the diagnosis. Orthotic management is usually ineffective in skeletal dysplasia. Surgery with either stapling or corrective osteotomies is usually necessary (Fig. 169.17) (see Chapter 180).

Juvenile rheumatoid arthritis may produce a progressive genu valgum deformity, but
this is uncommon. Correction can be achieved by physeal stapling (240). In older children and adolescents, an osteotomy may be necessary.

Prophylactic bone grafting has been used for the deformed tibia before a pathologic fracture occurs (179,191,266,270). This was thought to strengthen the deformed area and decrease the risk for pathologic fracture. The technique described by McFarland (191) is the most common procedure. A long corticocancellous graft from the opposite tibia is placed posteriorly, spanning the deformity in the normal biomechanical longitudinal axis of weight bearing. Lloyd-Roberts and Shaw (179), however, reported success in only three of their seven patients, while Tachdjian (270) reported success in all five children. Recently, Strong and Wong-Chung (266) prevented fracture in six of nine children with a prepseudarthrosis secondary to neurofibromatosis. Paterson (213), however, felt that the procedure was indicated primarily for cystic prepseudoarthrosis. Tachdjian (270) suggested concomitant curettage and bone grafting of any cystic lesions.

Many possible bone-grafting procedures have been used to treat an established congenital pseudarthrosis of the tibia (41,42 and 43,98,100,191,225,228). Morrissey et al. (199) reviewed 167 operations performed in 40 patients. The Farmer procedure, using a composite bone graft from the opposite tibia, demonstrated the best result, with a success rate of 53% (100). Other procedures had lower success rates, including onlay grafts (13%), bypass grafts (7%), Sofield procedure (25%), sliding grafts (33%), bone allograft (17%), and autogenous grafts (10%).

Surgical excision of the pseudarthrosis, correction of the angular deformity of the tibia, and rigid internal fixation in addition to bone grafting have improved the rate of primary union. Stabilization has been achieved with compression plates and intramedullary rods. The former is rarely used because of difficulties involved in achieving adequate fixation (6,213). The most common methods at this time are tibial or dual tibial and fibular intramedullary rods. These techniques usually transfix the ankle and subtalar joints to adequately stabilize the distal tibial segment (4,9,17,63,108,278). These joints are progressively freed with growth of the tibia and proximal migration of the rod. This method does not result in significant stiffness of the joints. Postoperatively, immobilize with a unilateral hip spica cast followed by a long-leg cast and then a knee–ankle–foot orthosis. Anderson et al. (9) reported that 10 of 13 pseudarthroses healed with an intramedullary rod technique. However, their mean follow-up time was short (6.9 years).

Several researchers used extending intramedullary rods and bone grafting (e.g., double cortical onlay, cancellous) (31,102). These rods extended with growth, decreasing the need for revision surgery and protecting the union until skeletal maturity. They were not inserted across the ankle or subtalar joint. Bitan et al. (31) reported satisfactory
extension of the rods in four of seven patients when these rods were used in revision surgery after primary union. Fern et al. (102) recommended that the outer sleeve of an extendable rod be inserted across the pseudarthrosis site to provide more strength and decrease the risk of refracture. They reported primary union in all five patients in whom extendable rods and bone grafting were used. All rods expanded with growth up to a maximum of 6.4 cm.

The use of intramedullary rods, especially those that stabilize the hind foot, and cancellous bone grafting increases the rate of primary union. The correction of anterior or anterolateral bowing undoubtedly enhances healing by allowing compression across the pseudarthrosis. These rods are not removed until after skeletal maturity because the tibia may undergo progressive bowing or refracture.

Electrical stimulation has been used in the treatment of congenital pseudarthrosis of the tibia for the past two decades (20,48,164,214,215,251,267). The various techniques include implanted direct-current bone growth stimulators and external stimulation devices with pulsating electromagnetic fields. The addition of electrical stimulation has improved success rates after bone-grafting procedures (213,214). Most reports recommend that electrical stimulation be used in conjunction with internal fixation and bone grafting. In 1982, Kort et al. (164) observed that the most important variable in healing was the radiographic morphology of the nonunion. Patients with spindled bone ends, a large gap, and gross mobility had a poor prognosis, whereas those with a cystic or sclerotic transverse fracture and a gap of less than 5 mm had better responses.

Paterson and Simonis (214) described a technique of excision of the pseudarthrosis and abnormal tissue, fibular osteotomy, intramedullary rod fixation (i.e., large Steinmann pin or Kuntscher nail), cancellous bone grafting, and an implanted direct-current electrical bone growth stimulator. The leg was protected in a long-leg plaster cast until clinical and radiographic healing was achieved. Weight bearing was allowed and encouraged. They reported primary union in 20 (74%) of 27 patients. The average time for union was 7.2 months (range, 3–18 months). During a mean follow-up period of 3.8 years (range, 6 months to 10 years), no refractures were reported. The reasons for failure in seven patients included inadequate correction of the anterior tibial bowing, poor internal fixation, incorrect placement of the cathode, and extensively diseased bone. Brighton et al. (48) reported that only one of four patients with congenital pseudarthrosis of the tibia healed with direct-current stimulation from an implanted single cathode. However, they did not excise abnormal tissue, provide internal fixation, or use bone grafting. The extremities were immobilized in a plaster cast, and weight bearing was not allowed. They thought that the results did not prove the efficacy of this technique for congenital pseudarthrosis of the tibia.

In 1981, Bassett et al. (20) reported the results in 34 patients with congenital pseudarthrosis of the tibia treated with pulsed electromagnetic fields (PEMFs) by way of external coils. They reported that 17 of 34 patients achieved complete healing with reconstitution of the medullary canal. An additional seven (21%) patients achieved union with function but required continued protection with an orthosis. Healing of the pseudarthrosis occurred in 24 (71%) of 34 patients. Analysis of the failures demonstrated that most occurred in male patients with a history of early fracture (younger than 1 year) and with an atrophic, spindled, hypermobile pseudarthrosis. The researchers did not employ any additional surgical procedures in the initial treatment. However, after early healing was demonstrated radiographically, surgical realignment, immobilization, and bone grafting were combined with the PEMFs. This did not have an adverse affect on the ultimate outcome. In 1982, Sutcliffe and Goldberg (267) reported the results of 49 patients treated for congenital pseudarthrosis of the tibia with PEMFs. The definite end point of treatment was reached in 37 patients, and in 26 (70%) of them there was a successful outcome. Fifteen pseudarthroses healed with PEMFs alone. The remaining 11 patients required subsequent surgery, usually cancellous bone grafting, and a second course of PEMFs before healing was obtained.

It appears that electrical stimulation may help induce bone formation in the area of a pseudarthrosis and abnormal tissue. Electrical stimulation alone is effective in approximately 50% of the successful cases. In the remainder, additional procedures are necessary before primary union can be achieved, including excision of the pseudarthrosis and abnormal tissue, correction of existing deformity, intramedullary fixation, and cancellous bone grafting. However, in approximately 30% of cases, electrical stimulation with or without surgical intervention results in failure. The incidence of refracture appears to be low.

Free vascularized bone grafts represent another popular procedure for congenital pseudarthrosis of the tibia (64,68,84,85,93,108,112,121,154,175,196,219,220,259,272,277,284,285,295). Vascularized rib, iliac crest, and fibula grafts have been used, and the latter appears to be superior in congenital pseudarthrosis of the tibia (64,68,84,85,92,108,121,154,175,219,220,284,285). The graft can be ipsilateral if it is of sufficient size (68,196,259,295). The procedure consists of transferring the contralateral fibular diaphysis on its vascular pedicle with a cuff of muscle to maintain the periosteal blood supply into a defect created by resecting the pseudarthrosis and abnormal soft tissue on the involved side (Fig. 169.21). Supplemental cancellous bone

grafting may be included to facilitate bone healing. The fibular graft is advantageous because it is straight, a long segment can be harvested, and it tends to hypertrophy after healing. Leung (175) reported three successful microvascularized iliac crest grafts in congenital pseudarthrosis of the tibia. He thought that it was easier to harvest the iliac crest and there was a more rapid healing because the graft was predominantly corticocancellous bone rather than cortical bone alone. Iliac crest grafts ranging from 3 to 10 cm may be obtained in children age 4 years or older. Rib grafts are less advantageous because of their curvature. Hagan and Buncke (121) reported that this curvature does not tend to correct with growth after satisfactory incorporation and the curvature may increase. Use of extensive corticocancellous grafting may prevent progressive bowing of the vascularized rib graft. Donor site problems after vascularized fibula transfers have been reported (209).

In 1990, Weiland et al. (285) reported on the long-term results in 19 consecutive children with congenital pseudarthrosis of the tibia treated with a vascularized fibula graft. The mean age at surgery was 5.1 years (range, 1.4–11.4 years). The mean follow-up was 6.3 years (range, 2–11 years). They reported that 18 (95%) of the 19 pseudarthroses healed. The lower-extremity length discrepancy at follow-up was a mean of 1.6 cm (range, 0–4 cm). Sixteen of the children had been treated with electrical stimulation techniques, which failed, for at least 1 year before surgery. However, the fibular graft hypertrophied rapidly, and no graft fractured during follow-up. Five patients required secondary procedures for nonunion and angulation. Only one child failed and subsequently required an amputation. Four patients ultimately achieved healing, although they required nine bone-grafting procedures. Two children had fractures through normal bone distal to the vascularized bone graft; they also required bone-grafting procedures to achieve union. Morbidity of the donor site was minimal, but one patient sustained a nondisplaced fracture of the tibia through a screw hole, and a 20° valgus deformity requiring osteotomy developed in another. Thirteen tibiae had residual deformity: valgus deformity (five patients); anterior angulation (two patients), or both (six patients). The mean valgus deformity was 25° (range, 5° to 45°), and the mean anterior angulation was 24° (range, 10° to 30°). Two patients with a valgus deformity required correction with an osteotomy. Four patients had anterior bowing of more than 20°, but none required additional surgery. All children
were treated with orthoses until skeletal maturity was achieved.

The five basic steps of free vascularized bone grafts are applicable whether iliac crest or fibula graft is used (220):

The procedure is usually performed with two surgical teams. One team harvests the vascularized bone, and the second prepares the recipient site. Some form of internal fixation is usually necessary to maintain alignment of the extremity. One advantage of microvascularized bone grafts is the simultaneous correction of any residual deformity and possible tibial lengthening, depending on the mobility of the tibial segments. Prolonged immobilization is necessary until healing occurs, with protected weight bearing allowed thereafter. Weiland et al. (285) maintain their children in hip spica casts for 2–3 months to allow healing. After healing occurs, protected weight bearing with a knee–ankle–foot orthosis is allowed. The orthosis is worn until skeletal maturity (see Chapter 36).

The Ilizarov method has been shown to be effective in achieving union at the pseudarthrosis site and in simultaneously correcting any associated angular deformity and lengthening of the tibia to restore length (85,99,119,144,211,224). The apparatus can be used in four ways: compression of the pseudarthrosis, compression with metaphyseal tibial lengthening, compression followed by distraction for hypertrophic nonunion, and distraction alone for hypertrophic nonunion. Excellent short-term results for union were reported. Whether the union is maintained in the long term remains uncertain.

In children with persistent congenital pseudarthrosis of the tibia after previous surgical procedures, an amputation may be advised. This should be a Boyd or Symes ankle-disarticulation amputation of the foot (82,134,149,189). See Chapter 175 on principles of pediatric amputation and Chapter 120 and Chapter 122 on lower-extremity amputations and prostheses. Amputation with appropriate prosthetic fitting allows rapid rehabilitation and return to normal function. McCarthy (189) recommended amputation for several criteria: failure to achieve bony union after three surgical attempts, a significant lower-extremity length inequality (usually 5 cm or greater), development of a deformed foot, undue functional loss from prolonged hospitalizations, and high medical costs.

The Boyd or Symes amputation is usually the procedure of choice. It preserves the heel pad and distal tibial epiphysis, which allows end bearing on the stump. The bone and skin are lengthened as a unit to avoid problems with overgrowth (82). A below-knee amputation through the pseudarthrosis produces a poor end-bearing stump for ambulation. The abnormal tissue and previous surgical scar provides poor skin coverage and predisposes to breakdown. There are also the problems of overgrowth and frequent revision. Amputation above the pseudarthrosis site provides better skin coverage, but there are problems with bony overgrowth.

Jacobsen et al. (149) reported the results of Symes amputation in eight children with pseudarthrosis of the tibia. The average age at amputation was 8.2 years, and the mean follow-up was 5.9 years. These children had a mean of 3.8 surgical procedures performed before amputation. None of the pseudarthroses healed, but with an appropriate Symes prosthesis, the children were able to engage in normal activities, including sports. The lower-extremity length inequality and some of the angular deformity were corrected within the prosthesis. Herring et al. (134) reported that 21 children (none with congenital pseudarthrosis) who had 23 Symes amputations had better psychological functioning than children undergoing multiple corrective surgical procedures. The better psychological function correlated with their better orthopaedic function. The level of family stress influenced the child’s behavior, self-perception, and intelligence. The physicians thought that an early Symes amputation in a young patient was compatible with good athletic and psychological functioning, which closely approached that of a nonhandicapped child of the same age. Similar results were reported by Davidson and Bohne (82) for 23 children, including one with a congenital pseudarthrosis of the tibia that did not heal.

Because of the complexities associated with the treatment of pseudarthrosis of the tibia, it is recommended that Symes amputation be discussed as an alternative method of treatment with the parents and child from the outset. Discussion should not be delayed until later in the treatment. Tell the family of the difficulties that will be encountered in attempting to obtain primary tibial union and satisfactory function.

Osteotomy to correct posteromedial bowing of the tibia is rarely indicated. If severe medial bowing persists after 3 or 4 years of age, corrective osteotomy may be considered. Bone healing is not a problem after a corrective osteotomy or a fracture because there is no underlying bone disorder affecting healing (8,83,165,231). Hofmann and Wenger (138) suggested corrective osteotomy in cases of severe bowing with progressive shortening during the first 5 years of life. They thought that an osteotomy would add length by correcting the deformity and realigning the physes perpendicular to the axis of weight bearing, stimulating growth. These concepts were not confirmed clinically. Osteotomy can realign the tibia, but it has a minimal effect on the ultimate lower-extremity length inequality. Krida (165) reported that all three patients treated by corrective osteotomies had significant residual leg-length discrepancies.

Lower-extremity length discrepancy is the most common sequela of posteromedial


angulation of the tibia and fibula. Most affected children have enough inequality (2 cm) to require equalization. The procedure performed to equalize the leg length depends on the estimated tibial length inequality at maturity and the predicted normal height of the child (see Chapter 170).