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Arthrogryposis
multiplex congenita is characterized by multiple joint contractures
(especially of the upper limbs and neck) and amyoplasia, typically
without other serious congenital abnormalities. Intelligence is
relatively normal.
Any condition that impairs in utero movement (eg, uterine malformations, multiple gestations, oligohydramnios) can result in arthrogryposis multiplex congenita (AMC). AMC is not genetic, although in some genetic disorders (eg, spinal muscular atrophy type I, trisomy 18), incidence of arthrogryposis is increased. AMC can result from neurogenic, myopathic, or connective tissue disorders. Congenital myopathies, anterior horn cell disorders, and maternal myasthenia gravis have been proposed as causes of the associated amyoplasia.
Symptoms and Signs
Deformities are prominent at birth. AMC is not progressive; however, the condition that causes it (eg, muscular dystrophy) may be. Affected joints are contracted in flexion or extension. Shoulders are usually adducted and internally rotated, the elbows extended, and the wrists and digits flexed. Hips may be dislocated and are usually slightly flexed. Knees are extended; feet are often in the equinovarus position. Leg muscles are usually hypoplastic, and limbs tend to be tubular and featureless. Soft-tissue webbing sometimes occurs over ventral aspects of the flexed joints. The spine may be scoliotic. Except for slenderness of the long bones, the skeleton is radiographically normal. Physical disabilities may be severe. Intelligence is usually unimpaired or mildly abnormal.
Other abnormalities that rarely accompany arthrogryposis include microcephaly, cleft palate, cryptorchidism, and cardiac and urinary tract abnormalities.
Diagnosis
and Treatment
Evaluation should include a thorough assessment for associated abnormalities. Electromyography and muscle biopsy are useful to diagnose neuropathic and myopathic disorders. Muscle biopsy typically shows amyoplasia, with fatty and fibrous replacement of tissues.
Early orthopedic and physical therapy evaluations are indicated. Joint manipulation during the first few months of life may produce considerable improvement. Orthotics may help. Surgery may be needed later to align the angle of ankylosis, but mobility is rarely enhanced. Muscle transfers (eg, surgically moving the triceps so that it can flex the elbow) may improve function. Many children do remarkably well; 2⁄3 are ambulatory after treatment.
Last full review/revision November 2005
Content last modified November 2005
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