MUSCLE AND NERVE DISORDERS IN CHILDREN

The serum enzymes elevated in muscle disorders include
the aminotransferases (transaminases), aldolase, lactate dehydrogenase,
and creatine phosphokinase (CPK). The serum CPK level is a sensitive
and valuable screening test

to demonstrate disease of striated muscle (343).
Skeletal muscle, heart muscle, and brain tissue contain CPK, which
catalyzes the release of phosphate from creatine phosphate. The high
CPK level seen in Duchenne’s muscular dystrophy (50 to 100 times
normal) and other muscle disorders represents leakage from the muscle
cell during necrosis. Aldolase and serum glutamic-oxaloacetic
transaminase levels also may be elevated in muscle disease but are not
as sensitive as the CPK level (352) and are also elevated by hepatic dysfunction.

Cardiac and pulmonary abnormalities are very common in
children with neuromuscular disease. Careful evaluation allows optimal
daily management and an assessment of preoperative risks.

Electrocardiography and echocardiography are used to evaluate cardiac function (66).
Patients with muscular dystrophy may develop cardiomyopathy or mitral
valve prolapse secondary to papillary muscle weakness. Children with
Friedreich’s ataxia, Emery-Dreifuss dystrophy, and infantile myasthenia
gravis may have arrhythmias (99,113,166,288,295,378).

Pulmonary compromise so commonly seen in these patients
can be assessed by questions about shortness of breath, frequency of
pulmonary infections, and more objectively, by pulmonary function or
sleep studies.

Open muscle biopsy usually is performed with local
anesthesia (1% Xylocaine without epinephrine) and sedation. The muscle
must not be infiltrated with Xylocaine. Make a 2.5 cm incision,
preferably following the skin lines, over the belly of the selected
muscle. Expose a 2 × 0.5 cm cylinder of muscle (the long axis parallel
to the muscle fibers), and excise the specimen with a scalpel.
Electrocautery should not be used before removing the specimen. Sutures
at either end of the specimen tied over a tongue blade or muscle biopsy
forceps can be used to maintain specimen length. The procedure is
usually performed on an outpatient basis, and complications are
uncommon.

The vastus lateralis muscle is commonly used as the site
of needle biopsy. The Bergstrom needle, consisting of a cannula and
sliding trocar with cutting blade, typically obtains a specimen of
about 200 fibers. After administration of local anesthesia (1%
Xylocaine without epinephrine), make a stab incision over the belly of
the muscle. Insert the needle into the muscle, and activate the cutting
blade to obtain the specimen. Suction can be applied to the needle hub
to improve the biopsy size (239). Several
repeat specimens may be obtained through the same skin incision by
changing the direction of the needle. Close the skin by a single stitch
or adhesive strip and apply pressure over the muscle for several
minutes to reduce the risk of hematoma formation.

The contractures and foot deformities in patients with congenital myopathies are caused by hypotonia with abnormal

posturing and are usually controlled with stretching therapy, periodic
serial stretching casts, supportive orthoses, or occasionally, tendon
lengthenings.

Dislocated hips can occur at birth or develop later in
children with congenital myopathies. They are usually easily reducible
in early infancy but require prolonged treatment to achieve stability.
Any lax-jointed, low-toned infant or any older child who presents
before walking with an easily reducible dislocated hip without
contractures should be suspected of having a myopathy. The hips are
treated in the early stages similar to those in infants with typical
congenitally dislocated hips, except that the total time of treatment
is often prolonged and stability of the hip is difficult to achieve.

The Pavlik harness is excellent for maintaining
reduction in newborns and young infants. The hips reduce initially in
flexion of about 110° and mild abduction of 45°. Instruct caregivers
not to dislocate a hip inadvertently by positioning it in adduction.
These hips tend to redislocate easily, requiring frequent (initially,
almost daily) adjustment of the Pavlik harness. Prone positioning in
the Pavlik harness is helpful. It is important not to allow the hip to
remain persistently posteriorly dislocated in the Pavlik harness,
because this creates a severe treatment complication. After the hip is
stable, maintain the harness in about 90° of flexion and 45° of
abduction until adequate bony and cartilaginous support develops. There
is no time-honored rule for the length of treatment, but the total
course should be long enough to allow joint stability and formation of
a normal cartilaginous acetabulum.

Treat an older child who has developed contracture of
the hip or whose hip does not easily reduce initially in skin traction
until the femoral head approaches the area of the acetabulum. With the
patient under general anesthesia, gently reduce the hip and apply a
cast to maintain stability. Cast treatment may be necessary for as long
as 6 months. Hip dysplasia after treatment for dislocation from
hypotonia and joint laxity may improve with abduction bracing. Use an
abduction brace and a standing frame with the legs in abduction for
these children, in whom the development of walking skills is usually
delayed. After ambulation is achieved, an abduction brace is helpful,
but most children have difficulty walking in the brace. If dysplasia
persists despite brace therapy in an ambulating child, perform a varus
derotation proximal femoral osteotomy and, if needed, an acetabular
redirectional osteotomy.

Scoliosis that presents at a young age tends to be
progressive, often has a long C-shaped or double-curve pattern, and is
most difficult to treat in a hypotonic patient with respiratory
compromise. The orthopaedic dilemmas include poor tolerance from
respiratory compromise in a thoracolumbosacral orthosis or spinal
fusion with subsequent inhibition of spinal growth in a young child,
resulting in a short trunk. As soon as scoliosis is recognized,
institute treatment by linearly posturing the spine on pads when supine
and, if respiratory capacity permits, by a thoracolumbosacral orthosis
with abdominal relief. Pulmonary function studies of the patient in and
out of the orthosis are necessary to determine the safety of orthotic
treatment. If the orthosis cannot be used, a wheelchair can be modified
with asymmetric lateral supports, a slightly reclined back, and a firm
seat.

If Luque rod instrumentation is desired, contour two
Luque rods, one for the concave side of the scoliosis and one for the
convex side. The Luque rods are available in the same sizes as the unit
rods, and the suggestions for use are outlined above. Before the
operative procedure, obtain lateral bending radiographs to determine
the flexibility of the scoliosis, and bend the Luque rods to achieve no
more than 10° additional correction beyond the preoperative bending
radiographs. Bend the superior end of the convex rod and the inferior
end of the concave rod into the shape of an L. Apply the rod on the
concave side of the scoliosis first, and place the L portion between
spinous processes or through a drill hole in the spinous process to
prevent migration of the rod. If stabilization to the pelvis is
required, bend the inferior end of the Luque rods as described for the
Galveston technique (6). As described for the
unit rod instrumentation, secure the rod to the lamina using the
sublaminar wires. Apply the convex wires in similar manner, and cut and
carefully tighten all

wires.
The two rods are connected inferiorly and superiorly to provide
additional stability. We prefer to interconnect the rods securely to
prevent cephalad-caudad shifting, spinal rotation and loss of pelvic
obliquity correction. Rod connectors can prevent shifting of the rods.
The fusion technique, bone grafting, and wound closure are identical to
that described earlier for the unit rod.

Duchenne muscular dystrophy occurs in about 3 of 100,000
boys and usually has an early childhood onset, leading to loss of
ability to walk and eventual death (128,229).
It is transmitted genetically as a sex-linked recessive trait and is
due to a mutation or deletion of DNA at a locus (Xp21) on the short arm
of the X chromosome (106,120,163,164,200,312).
About two thirds of the boys inherit the gene abnormality from the
mother, and one third are thought to be due to new mutations. The onset
is initially insidious, often with delayed motor milestones, with
weakness clinically apparent by 3 years age (385).
The weakness first involves the pelvic-girdle musculature, followed by
the shoulder girdle musculature, and then distal musculature of the
upper and lower extremities (2,387).

By 4 years of age, the boy stumbles, falls frequently,
and has difficulty climbing steps and running. Pseudohypertrophy of the
gastrocsoleus (Fig. 178.3), deltoid, and
serratus anterior muscles is secondary to the dystrophic process and
accumulation of fat within the muscles and fibrous tissue. The weakness
results in a wide-based waddling gait associated with increased lumbar
lordosis (Fig. 178.4). Gowers’ sign (Fig. 178.5) is a characteristic way for a child with this type muscular dystrophy to rise from the floor to a standing position (137).
This maneuver may be demonstrated by placing the boy prone on the
floor. First, he crawls into the knee-elbow position; then, with hands
and feet on the floor, he raises his hands consecutively

to
the knees and pushes to an upright posture. The knee reflexes are
diminished and sensation is normal. Progressive weakness is
unremitting, and ambulation becomes more difficult, until between ages
9 and 12 years, the boy loses the ability to walk. Scoliosis and
increasing contractures of the lower extremities develop. The weakness
progresses until total care is required and severe cardiopulmonary
compromise occurs between ages 17 and 22 years (5,14,44,49,173,201,314,319,387).

The diagnosis can often be made on the basis of family
history, clinical presentation, and an elevation of serum creatinine
phosphokinase (often 100 times normal in young children).
Traditionally, muscle biopsy has been used to confirm the diagnosis but
modern techniques of DNA analysis using peripheral blood can provide a
definitive diagnosis, help to identify carriers, and allow prenatal
diagnosis for 70% to 80% of the children (298).
The molecular basis of Duchenne and Becker’s muscular dystrophy is the
absence or abnormality of dystrophin (a subsarcolemmal protein) and
dystrophin-associated glycoproteins (found in the sarcolemma or muscle
cell membrane) (106,120,163,164,200,312). These proteins are found in skeletal, smooth and cardiac muscle, and

brain. In the 20% of children who do not have a diagnosis by DNA
analysis, muscle biopsy can be diagnostic. The biopsy typically from
the vastus lateralis shows muscle fiber degeneration, regeneration,
fibrosis, fatty infiltration, central nuclear migration and
hypertrophic muscle cells (86).
Absence of dystrophin is diagnostic. EMG, rarely required, shows
myopathic changes with muscle action potentials of reduced amplitude
and brief duration. The nerve conduction velocities are normal.

Orthopaedic treatment is aimed at maintenance of
strength and walking ability for as long as practical and prevention of
deformities (144,179,309,353,356,367,381,382).
The single most important factor in maintaining strength is prevention
of prolonged immobilization. If a boy with Duchenne muscular dystrophy
is immobilized by any method, functional losses tend to be permanent.
Therefore, make every reasonable effort to maintain strength by
resistive muscle exercises. The patient should perform stretching
exercises, especially of the muscles most subject to contractures
(e.g., tensor fasciae latae, hip and knee flexors, and ankle plantar
flexors) several times each day.

Prednisone and other steroids have been used
successfully in these children from about 5 years of age to improve
muscle strength (142). Complications from this
treatment include weight gain, hypertension, behavior disturbances,
increased appetite, cushingoid features, and osteopenia. Take into
account chronic steroid useage when administering general anesthesia.

Myoblast transfer therapy to induce dystrophin production has not been successful (206). Attempts are being made to use viral vectors to transfer functional parts of the dystrophin gene to affected individuals.

Muscle weakness predisposes the patient with Duchenne
muscular dystrophy to falls, and relative inactivity results in
osteopenic bone (162). Fractures of long bones
occur in 20% of children with Duchenne muscular dystrophy, typically
occurring with falls during daily activity or physical therapy (26,162,305,320).
These fractures often herald the end of the ambulatory stage. Treat
nondisplaced fractures of the femur and tibia in lightweight long-leg
casts or splints. Encourage weight bearing on the noninvolved leg
immediately and within days on the fractured leg. Bed rest and traction
are contraindicated. Displaced fractures of the lower limbs require
prompt surgical stabilization.

Apply
a lightweight orthosis to the leg over the area of internal fixation
and begin ambulation. The family should be aware that fracture
complications are higher with early mobilization but that the added
risk is necessary to avoid even more serious problems.

Contractures are inevitable in these patients, but
controlling the severity greatly enhances the quality of life. Toe
walking, caused by contractures of the tendo Achilles, can sometimes be
detected in patients as young as 3 years of age, and it responds to
stretching therapy or serial plaster casts. Tendon lengthening in young
ambulatory patients is discouraged because of resulting weakness. For
the ambulatory patient, a nighttime ankle-foot orthosis helps eliminate
the typical equinus posturing of the foot during sleep, and muscle
stretching therapy delays progression of contractures (320).
Despite aggressive therapy, the ability to walk becomes threatened
between 8 and 12 years of age from quadriceps muscle weakness (331);
contractures of the hip flexors (Thomas test), hamstring muscles, and
iliotibial tract (Ober test); and equinovarus deformities of the feet.
As these children lose the ability to walk independently, surgical
releases of lower extremity contractures and long-leg bracing can
prolong standing and ambulation for several years (9,26,29,64,73,156,265,272,279,310,316,320,354,355,367).
When surgical releases are delayed until the children have almost
stopped walking, the severity of weakness usually means that standing
or walking is possible only with knee-ankle-foot orthoses. Earlier
surgery followed by physical therapy and limited bracing (ankle-foot
orthoses) can be just as effective (13,108,179,266).

Procedures used to treat contractures in Duchenne
muscular dystrophy include Yount fasciotomy of the iliotibial tract,
Ober release of the iliotibial band, distal hamstring lengthening,
transfer of the posterior tibialis tendon to the dorsum of the foot,
percutaneous lengthening of the tendo Achilles, and open lengthening of
the tendo Achilles.

The iliotibial tract is released by a combination of the Yount (380) fasciotomy distally and the Ober (245) release proximally. The hamstrings are released distally, and the tendo Achilles is lengthened by a percutaneous method (Fig. 178.6).
The late weakness of the posterior tibialis muscle often causes a varus
deformity of the foot, which is sometimes treated by a posterior
tibialis tendon transfer through the interosseous membrane of the tibia
and fibula to the dorsum of the foot, which maintains a plantigrade
foot. If, however, the varus is not severe and the posterior tibialis
muscle is weak, a tenotomy can be performed easily just posterior to
the medial malleolus (308). The tenotomy is often the treatment of choice, because the child must wear an orthosis in any case.

Postoperatively, remove the long-leg cast after 2 weeks,
and apply a short-leg walking cast for an additional 4 weeks. After
cast removal, remove the button, place the extremity in a brace, and
begin active exercises.

Later in the disease process, the child becomes confined
to a wheelchair. At this stage, contractures of the knees and hips are
inevitable. Surgical releases usually are not required; instead, a
program to maintain motion is indicated to prevent the progression of
contracture that would hinder a good sitting position in the
wheelchair. Occasionally, a patient, especially one who earlier refused
surgery to prolong walking or refused orthotics, develops a severe,
rigid equinovarus deformity of the foot that causes pain on the
anterolateral aspect of the foot or the inability to wear shoes.
Multiple tenotomies (tendo Achilles, tibialis posterior, and flexor
digitorum longus) and postoperative casting can achieve a satisfactory
foot position. Severe, stiff longstanding deformity can be corrected
operatively with a tarsal medullostomy, but postoperative foot edema
may persist for at least 6 months.

After surgery, elevate the foot to control edema. Use a
long-leg cast for 1 month, and a short-leg cast for an additional 2
months (Fig. 178.7).

Scoliosis occurs in almost all boys with Duchenne muscular dystrophy (49,168,212,313). During the period that

a boy with Duchenne muscular dystrophy is able to walk, spinal lordosis
develops to compensate for weakness of the trunk and pelvic muscles. By
the time the child must use a wheelchair, a functional kyphosis
typically develops. Wilkins hypothesized that the kyphosis unlocks the
posterior facet joints, causing an unstable spin and progressive
scoliosis (269,366).
For whatever reason, scoliosis typically becomes apparent during the
last months of walking or soon after confinement to a wheelchair (41,78,230,307).
The peak rate of progression occurs between 13 and 15 years, with up to
3° of progression per month. The scoliosis is typically a long C-shaped
thoracolumbar curve that progresses steadily until a severe deformity
results (Fig. 178.8A, Fig. 178.8B).
The scoliosis eventually involves the pelvis, leading to severe pelvic
obliquity and difficulty in sitting, back pain, skin breakdown,
pulmonary compromise, and loss of hand function because of obligatory
use of the hands for support of the trunk (313).
A few patients do not develop the spinal kyphosis but persist with the
lordotic posture after ambulation ceases. They develop a less
progressive scoliosis, but by 6 to 8 years after ambulation ceases,
severe scoliosis usually develops. Various spinal orthoses and
wheelchair adaptations have been used to control the scoliosis, but
none has been totally successful, and at best, they only delayed the
progression of curvature.

Posterior spinal fusion and instrumentation is indicated
for progressive scoliosis of 30° or greater. Preoperative cardiac and
pulmonary evaluation must be done to determine the anesthetic risk. A
vital capacity of less than 35% normal indicates that pulmonary
complications are more likely (178,232,270).

We prefer segmental spinal instrumentation and posterior
fusion with the unit rod or Luque instrumentation with Galveston pelvic
fixation from T2 to the sacrum (37,115,284,329,330,332,362).
The unit rod technique is described earlier in this chapter. The
patients are ventilated for the first 24 hours in the intensive care
unit and then quickly mobilized to return muscle strength and to avoid
pulmonary and gastrointestinal complications. No postoperative bracing
is required.

If the preoperative pelvic obliquity is 10° or less and the scoliosis is 40° or less, fusion to L5 will provide a good result (240,330) (Fig. 178.8C, Fig. 178.8D).

Vertical shifting of independent Luque rods has been reported and can be avoided by crosslinking the rods (37,126,232,240).

Intraoperative blood loss can be extensive (37,232,240,284,296,332,362).
Careful intraoperative hemostasis, use of allograft, and speed will
reduce blood loss. Preoperative autologous blood donation,
intraoperative cell-saver techniques, and reinfusion of postoperative
drainage will reduce the need for homologous transfusion.

Becker’s muscular dystrophy is an X-linked disorder with
a clinical pattern similar to that of the Duchenne type, but it is
milder and with slower progression (22,23,31).
It results from a deletion in the same gene that causes the Duchenne
type. Dystrophin is present but in reduced amounts, typically above 20%
(164,199). Proximal
girdle muscle weakness and pseudohypertrophy are apparent by 7 years of
age, with maintenance of walking ability until age 16 and death
occurring in middle adult life after cardiopulmonary failure (100).
Clinically, the patient with Becker’s muscular dystrophy resembles a
“strong” patient with Duchenne muscular dystrophy in the juvenile
years. The CPK level is markedly elevated, with levels similar to those
seen in Duchenne muscular dystrophy, and the results of muscle biopsy
resemble those in Duchenne muscular dystrophy. Orthopaedic problems
include equinus, cavus, and scoliosis (186).
The early major orthopaedic problem is progressive contracture of the
tendo Achilles, which may be controlled by muscle-stretching therapy
and by a nighttime ankle-foot orthosis to prevent the typical equinus
posturing of the foot during sleep. Periodic serial stretching casts
usually control the mild contractures, and tendo Achilles lengthening
has occasionally been necessary.

Progressive proximal muscle weakness causes a wide-based
gait and exaggerated spinal lordosis. In the teenage years, ambulation
can be facilitated by canes for balance and a knee-ankle-foot orthosis.
Scoliosis can occur and is managed as for the Duchenne type (186).

The term limb girdle muscular dystrophy represents a
group of patients with muscle weakness in a girdle distribution and
autosomal inheritance. Leyden (209) described a type with predominantely pelvic girdle weakness, and Erb (105)
described a shoulder girdle type. Typical findings include elevation of
the CPK level, myopathic changes on EMG, and dystrophic changes on
muscle biopsy. Recent advances in molecular genetics have established
several syndromes with different gene abnormalities that had been
classified as limb girdle dystrophies (87).
There is a wide range of clinical severity. For example, severe
autosomal recessive muscular dystrophy of childhood is characterized by
absence of a sarcoglycan called adhalin (87) and can present with a clinical course similar to that of Duchenne’s muscular dystrophy or with a later onset, milder type.

Orthopaedic problems are similar to those seen in other
types of muscular dystrophies, and the principles of management are the
same.

Facioscapulohumeral dystrophy (Landouzy-Déjérine dystrophy) is transmitted by an autosomal dominant gene,

has an onset usually in adolescence, involves the facial and then the
shoulder girdle muscles, and has a slow progression, with an expected
average to long life span (87,148,204,349). The disease is uncommon, with a prevalence of about 1 in 20,000 (249,250).
The early weakness results in a lack of facial mobility, sloping of the
shoulders, and difficulty in raising the arms above the head. The upper
arm and scapular muscles are involved earlier than the deltoid and
forearm muscles. In longstanding, severe cases, the wrist extensor
muscles are more involved than the flexors, producing a wrist drop
called the praying mantis posture. The CPK level is normal to slightly
elevated, and muscle biopsy shows only slight changes, such as isolated
atrophic fibers and variation in fiber size. The gene abnormality has
been localized to 4Q35, but no gene product has been identified (114,365).

Facioscapulohumeral dystrophy presents as four clinical
variations: typical, as described; late exacerbation type, which may
consist of only mild facial weakness for years and then rapid
deterioration in midlife; infantile type, which has an onset before age
1 year and is severely crippling, requiring a wheelchair by age 9 years
(38); and scapuloperoneal syndrome, in which the peroneal and tibialis anterior muscles are involved early in the illness (16,109).

The faciohumeral pattern of muscle weakness occurs in
several diseases that must be differentiated, including myotubular
myopathy, nemaline central cord disease. and mitochondrial myopathy (34).

Orthopaedic problems include a dropped wrist and foot,
scapular instability, and back pain. The dropped wrist is treated by a
splint and the dropped foot by an ankle-foot orthosis with a rigid
ankle in neutral position. Lordosis (Fig. 178.9A, Fig. 178.9B),
which is initially flexible, usually develops in the lumbar spine but
may become so severe and rigid that the sacrum becomes horizontal. The
lordosis produces severe back pain that may be treated by a lumbosacral
orthosis. In ambulatory patients, the orthosis should support the back
but not necessarily correct the lordosis, which may be necessary for
walking. Surgery for back pain is almost never indicated.

Weakness of the serratus anterior, rhomboid, trapezium,
and latissimus dorsi muscles limits elevation of the shoulder by
allowing scapular winging and rotation (Fig. 178.10A, Fig. 178.10B).
If the deltoid muscle is strong and scapular winging inhibits function
so that the arm cannot be raised above the horizontal level, a
scapulothoracic arthrodesis may be effective in improving shoulder
flexion and abduction (42,43,61,177,188,207,321) (Fig. 178.10C). The operation initially should be performed on one side; if helpful, it can be considered for the contralateral side.

The term “congenital muscular dystrophy” is used to
describe an autosomal recessive group of disorders that present with
muscle weakness at birth or shortly thereafter and a dystrophic pattern
on muscle biopsy. Neonatal hypotonia is typical, but some children
present with joint contractures (which may be an arthrogrypotic
picture). The condition tends to remain static, but there can be slow
progression or, alternatively, functional improvement and achievement
of walking ability. Respiratory and swallowing problems depend on the
severity of the weakness. The CPK may be slightly elevated, EMG reveals
a myopathic pattern, and the muscle biopsy indicates severe dystrophic
changes (87,224,384).

A number of syndromes of congenital muscular dystrophy
in association with central nervous system involvement have been
described: Fukuyama-type congenital muscular dystrophy,
muscle-eye-brain disease, and the Walker-Warburg syndrome (87,124,125,190).
Children with congenital muscular dystrophy have severe mental
retardation and guarded prognoses. A subgroup of children with
classical congenital muscular dystrophy with white matter changes in
the brain lack laminin M (merosin), an extracellular protein (87,345).

Orthopaedic care includes obtaining a muscle biopsy, treating contractures, and correcting deformities (182,251,370).
Mild contractures respond to therapy and splinting but tend to recur.
Rigid and recurrent deformities are difficult and are treated as
described in the section on arthrogryposis.

Myotonia is characterized by a sustained contraction or
delayed relaxation of skeletal muscle after cessation of voluntary
contracture or mechanical stimulation. It does not occur spontaneously
but is initiated by voluntary contracture or stimulation and is usually
accentuated by cold or periods of rest (74).
Myotonia is seen in a number of illnesses, such as myotonic dystrophy,
myotonia congenita, paramyotonia congenita, Schwartz-Jampel syndrome,
drug-induced myotonia, and muscle contracture induced by exercise (80,227,344,372). Significant orthopaedic deformities occur in myotonic dystrophy and in Schwartz-Jampel syndrome, which is rare.

Myotonia is best demonstrated clinically by muscle
contracture after a blow to the muscle belly by a reflex hammer or by a
hand-grasp test, in which the patient grasps the observer’s hand, tries
to release, but immediate relaxation fails and an unwinding motion of
the fingers must occur to unclasp the hand (34).
In infants, myotonia may be manifest by delayed opening of the eyes
after closure with crying. EMG demonstrates a characteristic pattern
and confirms the clinical myotonia. The frequency of discharge is
initially increased, followed by a gradual decrease and cessation,
which produces an acoustic pattern that sounds like a dive bomber.

Myotonic dystrophy (Steinert’s disease) is an autosomal
dominant disorder characterized by myotonia, a progressive dystrophic
process of muscle leading to weakness and atrophy and various endocrine
and systemic abnormalities (48,60,75,374).
The molecular abnormality is an unstable expansion of DNA with a
variable number of trinucleotide repeats in the myotonia protein kinase
gene on chromosome 19 (12,35,45,123,151,152,157,216,291,298).

This disorder is classified into congenital and adult forms, which are very distinct.

The hereditary motor and sensory neuropathies are an
inherited group of diseases of peripheral nerves with sensory and motor
involvement. The general clinical characteristics include distal
symmetric muscle weakness, manifested by equinus feet, steppage gait,
cavus feet, and loss of fine motor function in the hands; there is a
mild sensory abnormality, usually causing poor balance and clumsiness
and decreased deep tendon reflexes. Evaluate any patient with distal
muscle weakness and cavus deformity of the feet for hereditary
sensory-motor neuropathy. The disorders have been classified according
to clinical manifestations, pathology, heredity, and electrophysiologic
changes (72,92,94,95,98,130,141,149,185,263,264,277,278,324) (Table 178.2).

Hereditary sensory and motor neuropathy types I and II are most common and constitute the classic forms of

Charcot-Marie-Tooth disease, which is also called peroneal muscular atrophy (54,346).
The hypertrophic form of Charcot-Marie-Tooth disease (type I) is
associated with segmental demyelinization, reduced nerve conduction
velocity, and an enlarged palpable superficial nerve with an insidious
onset in the first or second decade of life. There is a broad range of
clinical severity. The progression is slow, although a wheelchair is
often required in middle to late adult life. Type IA is usually caused
by a duplication of a gene on chromosome 17 for peripheral myelin
protein 22 (PMP-22), a glycoprotein expressed in the myelin sheath.
Type IB, which has a similar presentation to type IA, is caused by a
mutation of the Po gene on chromosome 1n41. The neuronal form of
Charcot-Marie-Tooth disease (type II) is clinically similar to the
hypertrophic form, except that the pathogenesis involves axonal
degeneration and not demyelination, nerve conduction velocities are
near normal, the nerves are not enlarged, and leg atrophy is severe,
producing a stork-leg appearance. Type II has been linked to chromosome
1p35-p36. An X-linked type has an abnormality in the connexin gene at
xq13. The orthopaedic problems of Charcot-Marie-Tooth disease include
pes cavus, claw toes, drop feet, hip dysplasia, and scoliosis (69,358).

Other types of hereditary motor and sensory neuropathy
are type III, or Déjérine-Sottas disease, which is similar to type I
but more severe; and type IV, or Refsum’s disease (92). Of interest to the orthopaedic surgeon is hereditary neuropathy with a liability to pressure palsies (HNPP) (371).
The onset is in adolescence, and nerve palsies can occur with minor
trauma to the peripheral nerves. Extreme care must be taken during
surgery to avoid traction on peripheral nerves and, if possible, to
avoid the use of a tourniquet.

Cavus feet (Fig. 178.12A) are
commonly seen in peripheral neuropathies, spina bifida, poliomyelitis,
Friedreich’s ataxia, spinal cord lesions, and several less common
neurologic illnesses. The pathogenesis involves muscle imbalance,

but the specific mechanism is unknown (32,33,252,283,287).
A cavus foot has a pathologic elevation of the longitudinal arch of
less than 150° on the lateral radiograph at the intersection of the
axis of the first metatarsal and the calcaneus (169).
There are three forms of pes cavus, as determined by the orientation of
the os calcis during stances: pes cavovarus if the os calcis is
inverted; pes calcaneocavus if the os calcis pitch (long axis of the os
calcis to the floor) is greater than 30° or the long axis of the tibia
to the long axis of the os calcis is greater than 130°, and pes
equinocavus if the os calcis pitch is less than 20° (287).

In Charcot-Marie-Tooth disease, a pes cavovarus
deformity combined with decreased proprioception results in difficulty
in walking, lack of balance, and painful callosities. The peripheral
neuropathy initially causes weakness of the intrinsic muscles of the
foot and peroneal muscles, resulting in a forefoot drop, relative
shortening of the long toe extensors because of the forefoot drop, and
hyperextension at the metatarsophalangeal joints. Hyperextension leads
to a secondary tightening of the long toe flexor tendons and to flexion
of interphalangeal joint and a claw toe deformity. The posterior
tibialis muscle initially remains strong, and the first metatarsal
droops more than the remainder of the forefoot. During stance, the
plantarflexed first metatarsal forces the foot into supination, and
contracture of the relatively strong posterior tibialis tendon holds
the heel in varus (Fig. 178.12B). Initially,
the foot is flexible, but the plantar fascia also shortens,
contributing to the depression of the first metatarsal and a fixed
varus deformity of the heel. The rigidity of the heel varus is
determined by the Coleman lateral block test (Fig. 178.12C),
in which a plantarflexed first metatarsal is allowed to hang over a 2.5
cm block, eliminating the forced forefoot pronation (negating the
tripod effect); if the heel returns to a neutral position with this
maneuver, the hindfoot deformity is not fixed (58,59,252). Therefore, attention may be directed toward the midfoot and forefoot.

The patient progressively becomes more clumsy, and as
the cavovarus deformity becomes more rigid, painful calluses develop
over the heel, the base of the fifth metatarsal, and the head of the
first metatarsal (tripod foot). Subsequent bony adaptations result in a
rigid equinocavovarus foot deformity (Fig. 178.13).

Treatment of the cavus foot depends on the patient’s
age, flexibility of the foot, bony deformity, and muscle imbalance. In
the early stages, the whole foot may be slightly supinated, the arch
moderately elevated, and the great toe slightly cocked upward. As soon
as the diagnosis is confirmed, begin daily manipulation of the foot to
resist the depression of the first metatarsal, stretching of the
plantar fascia and tendo Achilles, and extension of the toes. A
nighttime ankle-foot orthosis in a neutral ankle position is
recommended to prevent the foot from dangling into the equinus posture
during sleep and to delay the onset of a fixed deformity. A supple foot
can be treated nonoperatively by manipulation followed by serial
stretching in a short walking cast, followed by an ankle-foot orthosis
with a rigid ankle in neutral position and a lateral heel extension to
resist varus.

If fixed soft-tissue or bony deformity develops, surgery
becomes necessary to maintain a plantigrade foot. The goals of surgery
are to correct deformity, restore muscle balance, and if necessary,
stabilize the foot. Rigid deformities, usually consisting of a heel
varus and a plantarflexed first metatarsal, must be corrected before
tendon transfers are performed.

In children younger than 12 years of age, triple arthrodesis is contraindicated (364).
Other procedures that can be performed include a plantar medial release
to reduce the midfoot contracture; extension osteotomy of the first
metatarsal to correct a rigid plantarflexed first metatarsal; transfer
of the extensor hallucis longus tendon to the neck of the first
metatarsal and interphalangeal fusion (Jones procedure); transfer of
the extensor digitorum longus tendons to the third cuneiform (Hibbs
procedure); transfer of the posterior tibialis tendon through the
tibiofibular interosseous membrane to the dorsum of the foot to remove
a deforming force and achieve dorsiflexion of the ankle; Dwyer or
medial translation calcaneal osteotomy to correct heel varus if the
heel does not correct with the Coleman block test; and a metatarsal
osteotomy to correct the forefoot (90,91,161,181,273,297,302,333,359,361).
In children younger than 8 to 10 years of age, the heel and first ray
are usually flexible and will correct with soft-tissue releases and
serial casting. Hindfoot equinus and tendo Achilles contracture are
often present. Tendo Achilles lengthening should not be performed
simultaneously with the plantar medial release because it is important
to have a stable hindfoot to allow correction of the longitudinal arch
with serial casting. In the older child with greater weakness, a rigid
hindfoot, and fixed plantar flexion of the first metatarsal, the
plantar medial release is combined with an extension osteotomy of the
first metatarsal (and adjacent metatarsals if required), calcaneal
osteotomy, and a posterior tibialis tendon transfer to the dorsum of
the foot (Fig. 178.14A, Fig. 178.14B). In the skeletally immature, avoid damage to the first metatarsal physis when performing proximal osteotomies.

In the rigid, skeletally mature foot, definitive
procedures include radical plantar fascial release (Steindler plantar
flexor tenotomy) to relieve midfoot cavus; transfer of the posterior
tibialis tendon through the tibiofibular interosseous membrane to the
dorsum of the foot to achieve dorsiflexion of the ankle; transfer of
the extensor hallucis longus tendon to the neck of the first metatarsal

and
interphalangeal fusion (Jones procedure); correction of claw toes by
interphalangeal joint arthrodesis; and extensor tendon release or
transfer, calcaneal and metatarsal osteotomies to correct a rigid cavus
foot; or as a salvage procedure for severe deformity, triple
arthrodesis to correct severe heel varus and severe midfoot deformity
and achieve hind foot stability (7,10,57,90,91,176,181,210,281,325,361,376) (Fig. 178.15A, Fig. 178.15B). Tendon transfer is rarely indicated in the adult foot without an associated bone realignment.

Long-term review of patients with triple arthrodesis
indicates satisfactory results, but there is a high incidence of
radiologic ankle and midfoot arthritis (289,364).
A study of triple arthrodesis using force plate analysis demonstrates
increased midfoot load bearing and load concentration under the
metatarsal heads (318). The incidence of
pseudarthrosis, typically in the talonavicular joint, is reported to
occur up to 25% of the time. This can be symptomatic and require
revision surgery (289).

Postoperatively, allow weight bearing after 2 weeks, and remove the cast and Kirschner wire 6 weeks after surgery.

Postoperatively, maintain the cast for 6 weeks. Apply
serial stretching casts on a weekly basis to obtain adequate
correction, if desired, beginning about 1 week after surgery.

Postoperatively, triple arthrodesis typically requires
12 weeks to heal. In patients in whom continued ambulation and standing
are necessary for maintenance of function, walking may begin as soon as
tolerable, but periodic radiographs are necessary to verify proper foot
position.

The claw toe deformity (Fig. 178.16)
is caused by intrinsic muscle weakness that allows the long toe flexor
muscles to continue to flex the interphalangeal joint and the long toe
extensor muscles to extend the metatarsophalangeal joint without
stability provided by the weak intrinsic muscles. Callosities develop
over the heads of the proximal phalanges from contact in the shoes and
under the metatarsal heads. Initially, clawing is flexible and should
receive daily manipulative therapy. Fixed clawing requires operative
treatment, which is usually performed simultaneously with other
procedures for the cavus foot. Our choice of treatment of the second to
fifth toes includes a tenotomy of the long extensor tendons, dorsal
capsulotomy of the metatarsophalangeal joint, and arthrodesis of the
interphalangeal joint if the toes cannot come down into 20° of passive
flexion.

After surgery, the toes are protected by a well-padded
short-leg cast with the plantar surface extending well past the
phalanges, or have the patient wear a hard-sole wooden shoe until
interphalangeal arthrodesis has occurred in about 4 weeks.

There is a 10% incidence of scoliosis in hereditary motor and sensory neuropathy types I and II (157).
The other types of hereditary sensory-motor neuropathy also have
associated scoliosis, but the incidence is unknown. Progressive curves
between 20° and 40° in immature patients are treated by a
thoracolumbosacral orthosis until maturity. The amount of progression
after treatment is unknown. Progressive curves greater than 40° to 50°
in immature patients are treated by a posterior spinal fusion and
instrumentation. The patterns are similar to those seen in idiopathic
scoliosis. The fusion should include the measured curve (i.e., Cobb
method) and additional vertebrae as necessary to achieve adequate
truncal balance because of the associated truncal weakness. No patients
in our series have required fusion to the sacrum or to the

cervical
area. Because there is a high incidence of failure of
somatosensory-evoked potential monitoring, preparation must be made for
a wake-up test (195).

Intrinsic muscle weakness (Fig. 178.17)
interferes with fine motor coordination, as in writing, and wrist
weakness makes sports and carrying heavy objects difficult. Most
patients tolerate the weakness by adjusting their lifestyle or by using
simple adaptive equipment. In some patients with type I hereditary
sensory-motor neuropathy and moderate weakness, opponensplasty with
intrinsic muscle reconstruction is helpful (234,375). Kling and Drennan (192) reported on a small group of patients with type II

hereditary sensory-motor neuropathy who developed severe upper
extremity atrophy, which leads to a functionless hand. An orthosis may
help to maintain a neutral posture.

Severe bilateral hip dysplasia has been reported in patients with onset of neuropathy in the first decade of life (198,357).
The dysplasia can be asymptomatic or minimally symptomatic and may
remain undetected until early adolescence. Children with
Charcot-Marie-Tooth disease need to be evaluated radiographically to
detect early dysplasia. Typically, the femur has mild coxa valga and
anteversion, and the superolateral corner of the acetabulum is
deficient, which allows lateral subluxation during ambulation (Fig. 178.18).
The acetabular dysplasia is treated by redirection of the acetabulum by
single, double, or triple innominate osteotomies or shelf arthroplasty,
depending on the severity of the deformity (286,323).
The Chiari procedure may be necessary if severe changes in the
acetabulum prevent the femoral head from being fully reduced into the
true acetabulum.

Hereditary sensory neuropathies are characterized by
decreased specific sensory perceptions, painless ulcerations, and
Charcot joints. There are four major hereditary sensory neuropathies:
autosomal dominant hereditary sensory neuropathy, autosomal recessive
hereditary sensory neuropathy, familial dysautonomia (Riley-Day
syndrome), and familial sensory neuropathy with anhidrosis (248,259).

Patients with autosomal dominant hereditary sensory
neuropathy have marked loss of sensation to pin prick and temperature
in the lower extremities that can result in severe trophic changes. The
upper extremities are less involved. A nerve biopsy shows a decreased
number of myelinated sensory fibers. In autosomal recessive hereditary
sensory neuropathy, the sensation of touch is more severely affected
than those of pain and temperature, but the upper and lower extremities
are severely affected, and nerve biopsy shows a total absence of
myelinated sensory nerve fibers.

Familial dysautonomia, a disease of the peripheral
nervous system secondary to a gene defect at the 9q31-33 locus, is
characterized by a reduction in small and large myelinated nerve
fibers. Clinical manifestations include a labile blood pressure,
insensitivity to pain, abnormal gastrointestinal mobility, lack of
fungiform papillae on the tongue, ataxia, areflexia and kyphoscoliosis.
It occurs in Ashkenazi Jews with a prevalence of 1/3600. The children
develop a progressive kyphoscoliosis, and death usually occurs in
infancy or childhood from chronic pulmonary insufficiency and
aspiration (267,268,379).
Familial sensory neuropathy with anhidrosis is characterized by
decreased temperature perception, intact touch sensation, absent axon
reflex to histamine, below-normal intelligence, and anhidrosis.

Orthopaedic problems in patients with hereditary sensory
neuropathy include Charcot joints, joint dislocations, fractures,
chronic osteomyelitis, and severe kyphoscoliosis (215,256).
Treatment of spinal deformity is difficult because of the typical high
rigid kyphosis, osteopenia, labile autonomic nervous system, and
insensitivity to pain. Spinal fusion and instrumentation have a high
incidence of complications but is beneficial (280).

Friedreich’s ataxia (i.e., hereditary spinocerebellar
ataxia) is the most common spinocerebellar degenerative disease. It
usually is autosomal recessive, although it may be autosomal dominant
or sex linked (20). The gene abnormality is on chromosome 9 (55).
The onset is at the end of the first decade and is characterized by
progressive ataxia of the limbs and of gait, the presence of Romberg’s
sign, absent knee and ankle reflexes, extensor plantar responses,
dysarthria, scoliosis, pes cavus, weakness, loss of position and
vibration sense in the legs, cardiomyopathy, and diabetes (30,131,202).

By the age of 15 years, most patients are severely
ataxic; by 20 years of age (average, 15.8 years), most are confined to
a wheelchair; and by 40 years of age (average, 36 years), death occurs
from cardiopulmonary failure (47,160,338).
Sural nerve biopsies show axonal degeneration; the central nervous
system exhibits changes in the posterolateral columns of the spinal
cord and cell loss in the deep cerebellar nuclei. Muscle biopsy reveals
fiber group atrophy characteristic of denervation (88).

Although there is no known cure for Friedreich’s ataxia,
treatment of the orthopaedic deformities of pes cavus and scoliosis
substantially enhances the quality of life, especially in the less
severely involved patient.

Spinal deformities develop in virtually all patients who are poor ambulators and in about half of those who initially

learn to walk and run. The most common deformity is a long C-shaped
scoliosis, and severe pelvic obliquity develops as the curve
progresses. A kyphosis is usually associated with the scoliosis, and a
progressive spinal deformity decreases pulmonary capacity and
jeopardizes sitting posture (66,81,150,157,228,294).
In a series of patients followed at the Alfred I. duPont Hospital for
Children (Wilmington, DE), the average age at onset of scoliosis was
7.6 years (range, infancy to 13 years) (8). In
a mild deformity, a soft thoracolumbosacral orthosis with a large
abdominal relief provides trunk support and may delay progression of
the curve, but the orthosis must not compress the chest and further
compromise respiratory function (228).
Pulmonary function evaluations before and after application of the
orthosis are used to determine safe parameters, because often an
orthosis decreases the tidal volume by as much as 20% (8).
In severely compromised patients, the posterior half of an orthosis may
be used alone, but this is less effective. Typically, scoliosis is
progressive, and when the curve reaches 40° to 45°, a posterior spinal
fusion from the high thoracic area to the sacrum with internal fixation
is recommended. In a child younger than 10 years old with a progressive
scoliosis greater than 60°, surgery is indicated.

Before any anticipated surgical procedure, pulmonary
evaluation must be performed. Severe postoperative respiratory problems
are seen with a vital capacity less than 25% normal (228).
An intense respiratory rehabilitation program, emphasizing inhalation
strength, coughing, and maintenance of good pulmonary hygiene, can
temporarily improve respiratory ability by about 15% to help during the
perioperative period. After surgery, the pulmonary function usually
returns to the preoperative level and gradually declines, but one study
suggests an improvement (271).

We prefer segmental fixation with the Luque rods and
Galveston pelvic fixation or the unit rod in this group of patients
because they allow rapid postoperative mobilization, which helps in the
general care and especially inpulmonary care (39,258).
Patients with spinal muscular atrophy typically have severely
osteopenic bone, and supplementary bone grafts are necessary to achieve
an adequate fusion mass. Loss of pelvic fixation due to the rods
cutting out of the ilium anteriorly requires revision because colonic
perforation can occur (228). In young children
with a large deformity and osteopenic bone, do not attempt an extensive
correction, and use the smaller ¼ or ³/16 inch rods. Rod
connectors when using Luque rods prevent rod shift and increasing
deformity. For 3 to 4 months postoperatively, a thoracolumbosacral
orthosis can be used when the patient is sitting or standing to give
additional support and to prevent the wires of the Luque rod or unit
rod from pulling loose from the osteopenic bone. In patients with
severe respiratory compromise with a large curve, the usual methods of
internal fixation may be impossible, and halo-dependent traction
followed by spinal fusion and limited instrumentation may be the only
reasonable alternative. Anterior spinal fusions generally are not
recommended in patients with spinal muscular atrophy because
postoperative respiratory compromise is severe (8,228).
Postoperative ventilation for 24 to 48 hours in an intensive care unit
is often required. For all patients, the period of immobilization
should be only a few days, and sitting or ambulation should be started
as soon as tolerable, except for the rare problem requiring the
halo-dependent technique. Even in this situation, the patient can be up
in a wheelchair in overhead traction during the day.

Contractures develop in the upper and lower extremities
and are more frequently seen in the severely weak children. Flexion
contractures of the elbow and adduction contractures of the shoulder
are common but rarely a functional problem. Bedridden infants assume a
frog-leg position, and lower extremity contractures occur with the hip
in flexion abduction, the knee flexed, and the foot in equinus.
Wheelchair-dependent patients develop flexion contractures of the hip
and knee and equinovarus deformity of the foot (107).
Ambulatory patients have only mild contractures, which seldom interfere
with walking. A maintenance motion-therapy program with intermittent
splinting can control most contractures, and surgery is seldom
required. Soft-tissue procedures are effective in reducing contractures
but are indicated only if a contracture inhibits some functional
ability or becomes painful. Surgical releases are used to get these
children into long-leg braces or a standing frame. Hip flexion
contractures require release of the fascia lata, sartorius, rectus
femoris, and iliopsoas. Knee flexion contractures require tenotomy of
the medial and lateral hamstrings and iliotibial band. Foot deformities
seldom require surgery, but a severe equinovarus contracture
occasionally causes a skin ulceration on the foot. Tenotomy of the
tendo Achilles and posterior tibialis tendon with manipulation and
casting for 6 weeks with lightweight plastic material are usually
adequate to correct the foot posture.

Hip instability is a common problem in the more severe types of spinal muscular atrophy (107,294,341).
Hip dislocation was seen in 50% of the functional group I children, 39%
of group II, 37% of group III, but it did not occur in group IV,
according to an unpublished series. The highest incidence of hip pain
occurred in the group II children. In children who are limited
ambulators or confined to a wheelchair and have a mobile painless
dislocated hip, nonoperative management is recommended.

Initial therapy for all contractures consists of passive stretching and serial splinting to improve joint motion (132,251).
Passive stretching exercises are performed at least four times daily
and are guided by the patient’s parents, who are trained and supervised
by physical therapists.

Avoid
rigid cast fixation for most patients. Many parents tend to exercise
the extremity as a unit, and this should be discouraged; specific
attention should be directed to passive stretching of independent
joints. After each joint is passively stretched, apply thermoplastic
splints between sessions to maintain position. The thermoplastic
splints require frequent modifications as the patient grows and the
joint mobility increases. In the knee and elbow, the contractures may
be so severe that radiographs are occasionally necessary to determine
the proper plane for passive flexion and extension exercises.

The goals of treatment of the upper extremity in
children with arthrogryposis are to provide an extremity that can be
brought to the mouth and stabilized for feeding and to provide for
toilet care or pulling up from sitting (370).

Passive stretching exercises have been the most
successful to obtain motion, but the wrist, shoulder, and fingers are
the most resistant. The elbow achieves the most significant benefit
from the stretching therapy, and mild changes substantially improve the
ability to dress, self-feed, and care for personal hygiene. Defer most
surgery until the patient is old enough to demonstrate functional
achievements (211).

A derotation osteotomy of the humerus is occasionally
useful if the hand is in a nonfunctional position from shoulder
rotation. Perform the derotation osteotomy at the proximal third of the
humerus, and immobilize the site in a shoulder spica cast until healing
occurs. Tricepsplasty

(i.e., lengthening of the triceps tendon and posterior capsulotomy of the elbow joint) is recommended by Williams (369) to restore motion to the extended elbow (235).
Unfortunately, some motion is lost with growth. Flexor muscle power to
the elbow can be facilitated by triceps tendon transfer, but this is
done at the expense of active extension. In our experience, the
pectoralis transfer by fascia lata extension through to the ulna has
been most desirable. The maintenance of the triceps function is very
helpful for the mobility of the patient. Transfer of function can be
successful only if an adequate range of motion has been obtained by
conservative or, if necessary, surgical methods.

The wrist flexion deformity can be managed by a proximal
row carpectomy or wrist fusion toward the end of growth. Surgery of
small joints of the hand has not been successful in achieving motion or
improving function (21).

At 2 to 3 weeks postoperatively, replace the cast by a
dial lock brace to allow flexion and block extension just below a right
angle. Gradually increase the extension over the next month, and have
the patient exercize the elbow into flexion several times daily.

Postoperatively, hold the arm in the flexed position for 1 month, after which general physical therapy can begin.

After surgery, use a long-arm cast for 3 weeks, followed
by a short-arm cast for an additional 2 to 3 weeks. After removal of
the cast, have the patient wear a wrist splint part time, usually at
night, to prevent recurrence of the flexion deformity.

After surgery, place the wrist in neutral, and apply a
long-arm cast. This cast is worn until the arthrodesis is firm, usually
10 to 12 weeks.

The knee deserves early aggressive attention, because
most patients with arthrogryposis can walk or stand if the knee is in a
suitable position (317). Motion from at least
15° to 45° of flexion is desirable but may not be obtained in rigid
extremities. Rigid knees that have 35° to 40° of flexion are stable for
standing and sitting; full extension makes sitting awkward, and
excessive flexion makes standing impossible. Knee flexion contractures
(65% of patients) are more common than extension contractures (6%).
Daily passive stretching with thermoplastic maintenance splinting is
the most effective treatment to increase motion in infants and young
children. Forty percent of patients can be managed by nonoperative
treatment programs (339).

Recurrence of a knee deformity is common, and in
juvenile and adolescent patients, recalcitrant contractures, often with
posterior subluxation of the tibia, respond to two-pin traction. Place
the proximal pin in the proximal metaphysis of the tibia, so that the
anterior traction reduces the knee subluxation, and place the distal
pin in the distal metaphysis of the tibia, so that longitudinal
traction can reduce the flexion contracture of the knee. The two-pin
traction method requires prolonged hospitalization and may be combined
with hamstring lengthening and posterior capsulotomy. Recurrence of the
flexion deformities may occur in growing children because the joint
capsule and rigid periarticular soft tissues do not stretch adequately
during growth.

A few patients develop marked bony and cartilaginous
joint deformities, making joint motion impossible. An osteotomy,
usually of the distal femur, is used to reposition the knee to 35° of
flexion, which allows adequate sitting and standing. The angulation of
the distal femur causes a mild iatrogenic cosmetic deformity.

In the extended knee, the joint is often rigid and
resistant to therapy. The patella may be dislocated laterally, and the
tibia may be dislocated anteriorly. A radiograph of the knee may be
necessary for orientation before initiating to stretching therapy. For
the dislocated knee in the infant, apply longitudinal skin traction to
the tibial area of the legs, initially at 1 lb (0.45 kg) and
progressing to a maximum of 5 lb (2.25 kg). Continue traction until the
tibial plateau is beneath the femoral condyle, and then initiate
flexion therapy. As soon as the knee can be flexed to about 30° in the
reduced position, discontinue traction and apply splints to maintain
reduction. If reduction cannot be achieved by traction, open reduction,
consisting of

a
quadriceps lengthening, release of the lateral patellar retinaculum,
and occasionally, knee ligament lengthening is necessary (65). After flexion is acquired, prolonged orthotic management is necessary to maintain motion.

In patients with arthrogryposis, the hip joint is frequently contracted (82%) and dislocated (58%) (290).
The absolute treatment goal for hip contractures is to obtain a
functional position of motion in the flexion–extension plane, which is
a major benefit. At birth, the hips are frequently in a nonfunctional
position of abduction, flexion, and external rotation (i.e.,
Buddha-like position) and should be passively stretched and sprinted.
In the newborn, a cloth band can be wrapped around the proximal part of
the leg to reduce the abduction contracture. In patients between 1 and
3 years of age, casts are applied to the legs, with a bar incorporated
between the casts to control abduction and rotation, and the hips are
passively stretched, placing the patient in a prone position. A hip
flexion contracture of 30° is acceptable, because the lumbar spine can
provide adequate compensatory motion. If adequate correction has not
been obtained in the patient by 2 years of age, a soft-tissue release
is helpful, or a varus extension intertrochanteric osteotomy may allow
the desired position without producing additional muscle weakness. If a
rigid contracture prevents ambulation, trochanteric osteotomies can
reposition the extremity at about 35° of hip flexion and bring the hip
out of the abducted position to allow adequate sitting and standing (290).

Hip dislocation is typically teratogenic and can be
bilateral or unilateral. Occasionally, there is a reasonably mobile,
nonteratogenic dislocated hip that can be treated in a manner similar
to a typical congenitally dislocated hip if treatment is initiated
before 3 months of age. Bilateral hip dislocations are best left
untreated and attention directed toward obtaining adequate motion (172).
A teratogenic unilateral hip dislocation was formerly thought to cause
severe contractures, pelvic obliquity, and secondary scoliosis, but
this is not always the case in arthrogryposis (84).
An ipsilateral knee flexion contracture should be corrected before
reduction is attempted, because knee therapy can redislocate the hip.
Skin traction (i.e., a home traction program) and passive stretching
therapy are used to obtain as much hip motion as possible (183).
Occasionally, the femoral head reduces to the level of the acetabulum,
and a closed reduction can be performed similar to that done for a
typical congenitally dislocated hip, but postoperative casting should
not allow the hip to contract in a nonfunctional position.

By the time a child is 1 year old, most teratogenic
unilateral dislocations of the hip require open reduction through an
anterior approach, extensive soft-tissue release, and possibly femoral
shortening to obtain an adequate reduction. After surgery, a maximum of
6 weeks of casting from the thorax to the toes, followed by prolonged
orthotic control, is necessary for adequate joint remodeling.
Inadequate reduction with subsequent redislocation or subluxation does
occur. if the hip cannot be reduced adequately, the pelvic obliquity is
treated by an intertrochanteric femoral osteotomy to position the leg
functionally, and a shoe lift is used to accommodate the limb length
discrepancy until a properly timed ipsilateral epiphysiodesis is
performed (28,257). If
there is any question about obtaining good motion, it is better to
leave the unilateral hip dislocation unreduced. A stiff hip produces a
more significant problem than the other possible related conditions.

The most common (84%) foot deformity in arthrogryposis
is talipes equinovarus. Convex pes valgus, calcaneovalgus, and
cavovarus deformities are seen occasionally. These severely deformed
feet are often extremely stiff, and the goal of treatment is to obtain
a pain-free plantigrade foot at maturity.

At birth, the talipes equinovarus is treated by serial
taping and passive stretching therapy. The passive stretching is
performed four times each day, and the taping is changed every other
day to reflect changes in position. Thirty-one of the 80 patients in
our series have had successful nonsurgical treatment, even though a
perfect result was not obtained (251). In
patients with nonplantigrade feet but reasonable motion, a
posteromediolateral release was satisfactory in 15 of 20 feet. After a
posteromediolateral release, prolonged orthotic care and extensive
passive stretching are necessary.

Recurrence in patients older than 10 years of age is
best treated by a triple arthrodesis. In the rigid foot, a talectomy
performed when the child is between 1 and 2 years old gives the most
satisfactory plantigrade foot (84,138,145,170,191). Recurrence after the age of 10 years is best treated by a triple arthrodesis.

Postoperatively, change the long-leg cast at 2 weeks to
a short-leg cast for an additional 10 weeks. Allow weight bearing about
1 month after surgery. After the cast is removed, use a solid
ankle-foot orthosis to maintain position.

The reported incidence of scoliosis varies from 0% to 42%, but a figure of about 20% seems acceptable (159,260).
Noncongenital scoliosis may be present at birth or may develop in early
childhood; it is progressive, becomes rigid, and is associated with
pelvic obliquity (83,116,304).
Congenital scoliosis is far less common. A thoracolumbosacral orthosis
is preferred in curves between 20° and 40°, and a posterior spinal
fusion and instrumentation is preferred in progressive curves of more
than about 40°. Because the scoliosis tends to be rigid, the fusion
should not be delayed in progressive curves, or a severe deformity will
develop. Arthrodesis is difficult to achieve, and a high incidence of
pseudarthrosis is reported.

In severe curves with pelvic obliquity, an anterior
release followed by a posterior spinal fusion to the sacrum with
instrumentation enhances correction of the curve and pelvic obliquity (233).