ANGULAR DEFORMITIES OF THE LOWER EXTREMITIES IN CHILDREN

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).