Definition
Arthrogryposis translated from the Greek literally means "curved
or hooked joints." Hence, this term is used to describe multiple
joint contractures present at birth. There are many causes for
congenital multiple joint contractures, and could be due to abnormal
nerve or muscle development in the womb. However, the commonest form
of arthrogryposis, present in 40% of cases, is a condition called
amyoplasia.
Symptoms
The child is born with multiple joint contractures in all limbs.
In the commonest form of arthrogryposis, called amyoplasia, the
typical deformities are often severe and symmetrical, as follows:
shoulder -- internal rotation deformity
elbow -- extension and pronation deformity
wrist -- volar and ulnar deformity
hand -- fingers in fixed flexion, and thumb-in-palm deformity
hip -- flexed, abducted and externally rotated, often dislocated
knee -- flexion deformity
foot -- clubfoot deformity
Although joint contractures and associated clinical manifestations
vary from case to case, there are several common characteristics,
including the following:
Involved extremities are fusiform or cylindrical in shape, with thin
subcutaneous tissue and absent skin creases.
Deformities are usually symmetric, and severity increases distally,
with hands and feet typically being the most deformed.
Joint rigidity may be present.
The patient may have joint dislocation, especially the hips and,
occasionally, the knees.
Atrophy may be present, and muscles or muscle groups may be absent.
Sensation is usually intact, although deep tendon reflexes may be
diminished or absent.
Contractures
Distal joints are affected more frequently than proximal joints.
Observe flexion versus extension, limitation of movement (fixed vs
passive vs active), and characteristic position at rest; note
severity of all limitations. Distinguish between complete fusion or
ankylosis and soft-tissue contracture.
Range of motion in the jaw frequently is limited.
Intrinsically derived contractures frequently are associated with
polyhydramnios; the contractures are symmetric and accompanied by
taut skin, pterygia across joints, and lack of flexion creases.
Recurrence risk and prognosis are dependent on etiology.
Extrinsically derived contractures are associated with positional
limb anomalies, large ears, loose skin, and normal or exaggerated
flexion creases. Patients have an excellent prognosis and a low
recurrence risk.
Deformities
Deformities in the limbs include pterygium, shortening, webs,
compression (eg, due to cord wrapping), absent patella, dislocated
radial heads, and dimples.
Facies deformities include asymmetry, flat nasal bridge, and
hemangioma. Jaw deformities include micrognathia and trismus.
Other deformities include scoliosis, genital deformities (cryptorchidism,
lack of labia, microphallus), and hernia (inguinal, umbilical).
Other features of the fetal akinesia sequence include intrauterine
growth retardation, pulmonary hypoplasia, and craniofacial anomalies
such as hypertelorism, cleft palate, depressed nasal tip, high nasal
bridge, functional short gut with feeding problems, and short
umbilical cord.
Absent or distorted crease abnormalities are a result of aberrant
form or function in early hand or foot development.
Malformations
Craniofacial malformations may involve the CNS (structural
malformations, seizures, mental retardation [MR]), skull (craniosynostosis,
asymmetry, microencephaly), eyes (small and malformed eyes, corneal
opacities, ptosis, strabismus), and palate (high, cleft, submucous
cleft).
Respiratory problems include tracheal and laryngeal clefts and
stenosis. Hypoplasia, weak muscles, or hypoplastic diaphragm may
affect lung function.
Limb malformations include deletion anomalies, radioulnar synostosis,
syndactyly, and shortened digits.
Skin vasculature abnormalities may cause hemangiomas and cutis
marmorata; distal limbs may be blue and cold.
Cardiac problems include congenital anomalies and cardiomyopathy.
The kidneys, ureters, and bladder may have structural anomalies.
Nervous system problems include loss of vigor; lethargy; slow, fast,
or absent deep tendon reflexes; and sensory deficits.
Muscle malformations include decreased muscle mass, soft muscle
texture, fibrous bands, abnormal tendon attachments, and muscle
changes with time.
Connective tissue abnormalities
Skin webs (pterygia) across joints, with limitation of movement, are
common. Skin dimples are observed frequently over joints where
movement is limited.
Skin may be soft, doughy, thick, or extensible. There is decreased
or increased subcutaneous fat; inguinal, umbilical, or diaphragmatic
hernias; thickness in joints; symphalangism; and abnormalities in
tendon attachment and length.
Associated skin defects include scalp defects, amniotic bands on
limbs, and nail defects.
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Radiographic Appearance
shoulder -- internal rotation deformity
elbow -- extension and pronation deformity
wrist -- volar and ulnar deformity
hand -- fingers in fixed flexion, and thumb-in-palm deformity
hip -- flexed, abducted and externally rotated, often dislocated
knee -- flexion deformity
foot -- clubfoot deformity
Although joint contractures and associated clinical manifestations
vary from case to case, there are several common characteristics,
including the following:
Involved extremities are fusiform or cylindrical in shape, with thin
subcutaneous tissue and absent skin creases.
Deformities are usually symmetric
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Pathology
The cause of arthrogryposis is varied, and not entirely
understood. Certainly, in many cases, abnormal nerve, muscle and
connective tissue development is involved. Lack of movement of
intrauterine movement is also responsible, as in oligohydramnios.
Genetic factors do play a part in many cases, as do environmental
factors like drugs. Incidence of arthrogryposis is one in 3,000 live
births.
In general, there are four causes for limitation of joint
movement before birth:
(1) Muscles do not develop properly (atrophy). In most cases, the
specific cause for muscular atrophy cannot be identified. Suspected
causes include muscle diseases (for example, congenital muscular
dystrophies), maternal fever during pregnancy, and viruses which may
damage cells which transmit nerve impulses to the muscles.
(2) There is not sufficient room in the uterus for normal
movement. For example, the mother may lack normal amount of amniotic
fluid, or have an abnormally shaped uterus.
(3) Central nervous system and spinal cord are malformed. In
these cases, Arthrogryposis is usually accompanied by a wide range
of other conditions.
(4) Tendons, bones, joints or joint linings may develop
abnormally. For example, tendons may not be connected to the proper
place in a joint.
Arthrogryposis is relatively rare, occurring in perhaps one in 3,000
births
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Treatment:
Treatment of arthrogryposis is a challenging problem. It should not
be undertaken by any one doctor, but by a multi-disciplinary team,
including the pediatrician, neurologist, orthopedic surgeon,
geneticist, physical and occupational therapist. The aim of
treatment is to improve function, not cosmesis. Therapy and bracing
is always attempted prior to any consideration of surgical
correction.
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Prognosis
In a child with normal intelligence, with appropriate treatment,
independent ambulation and function can be expected.
Images
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