Arthrogryposis

Arthrogryposis Arthrogryposis (multiple congenital contractures) has various causes and appears as many different syndromes. The basic classification for therapeutic and prognostic purposes divides affected children into those who have only limb involvement, those with limb and trunk, craniofacial or visceral involvement, and those with severe central nervous system dysfunction. Decreased fetal movement is an important etiologic factor. A multidisciplinary approach is required to evaluate these children, and early physical therapy is essential. Arthrogryposis is a term used to describe multiple congenital contractures.(1) It is not a specific diagnosis, because there are more than 150 conditions in which multiple congenital contractures may be present. It is important to determine the cause of the contractures in each case. A specific diagnosis provides the basis for proper therapy and an accurate prognosis, and it helps determine whether the condition has a genetic basis. Over the past 20 years, progress has been made toward a better understanding of why congenital contractures occur, which varieties can recur in families, and which therapies are most useful.

One in 200 infants is born with dislocated hips and one in 500 has clubfoot, but only about one in 3,000 is born with multiple congenital contractures. A newborn with multiple contractures usually appears quite deformed at birth, yet the prognosis may be very good.

Causes of Congenital Contractures

As basic research has progressed, it has become clear that any disorder associated with a decrease in intrauterine movement may result in contractures.(2) The earlier that fetal movement is decreased, the worse the contractures will probably be at birth. The causes of decreased intrauterine movement fall into four categories: (1) neurophatic, resulting from absent, abnormal or nonfunctional nerves, including both the central nervous system and the peripheral nerves; (2) myopathic, due to muscles that fail to form or function normally or that undergo a degenerative or dystrophic process in utero; (3) abnormal connective tissue or joints, which limit movement by abnormal attachments or structure, and (4) decreased space in which the fetus can move, due to uterine abnormality, amniotic fluid leakage or other conditions. Any one of these four mechanisms can lead to decreased movement of the fetus in utero.

Normally, a fetus moves almost continuously. The movement seems to be necessary for normal growth of the limbs and joints. If the fetus stops moving, the joints become stiff; it is then difficult for them to stretch and resume normal movement in utero. The longer that there is decreased movement, the more likely it is that the fetus will have very stiff joints and develop webs across the joints by the time of birth.

Frequently, the pregnancy history reveals that the baby born with arthrogryposis has kicked or moved less than other fetuses in utero. Otherwise, the pregnancy is usually uncomplicated; rarely is there a history of illness, medication ingestion or another maternal problem. About half of the time, because of the contractures, the baby is either in breech or transverse presentation when labor starts. Often, delivery is difficult because a baby with contractures cannot be molded during delivery. About 5 percent of children with arthrogryposis are born with fractured bones.

Initial Evaluation

In evaluating a child with arthrogryposis, the physician should obtain a detailed history of the pregnancy and the delivery and also a family history.(1) Careful documentation of the kind of contractures found in the newborn is important in distinguishing a specific subtype. The infant's position at rest and range of passive and active motion should be documented with photographs, because physical therapy will soon alter and increase the range of motion. Newborns with multiple congenital contractures are frequently "squashed" or deformed in several areas of the body. Since many of the deformities will resolve over the first few weeks, these features should also be photographed. The initial position in which the baby presents may help the physician reach a specific diagnosis.

Frequently, a team of physicians will evaluate the status of an infant with multiple congenital contractures. In addition to the family physician, the team may include a neurologist, an orthopedic surgeon, a pulmonologist, a physiatrist and a geneticist. If there are visceral anomalies, consultation with other specialists may be required.

Physical Examination

The neonatal physical examination helps to define additional abnormalities that may be associated with the contractures. Almost every other type of congenital anomaly has been reported in children with arthrogryposis. It is important to note abnormal creases, hypoplasia of digits, birthmarks and the relative size of involved areas.

The lungs are the most frequent site of involvement, besides the limbs. In addition to moving in utero, the fetus has respiratory movements, which are necessary for normal development of the lungs. If the fetus has not moved much, the lungs may be hypoplastic. Pulmonary hypoplasia is the most common cause of death in children with congenital contractures.

Categorization

Children with arthrogryposis can be placed in three categories: (1) those with limb involvement only; (2) those with involvement of the trunk, craniofacies or viscera, as well as the limbs, and (3) those with severe central nervous system dysfunction.(2) The complete differential diagnosis is extensive, but generalization can be made about the three groups. Children with limb involvement only(1) tend to respond well to physical therapy and do reasonably well. Children with other areas of involvement(2) may do well, depending on the specific diagnosis, but children with central nervous system dysfunction fare very poorly--50 percent die in the first year.

Initial Prognosis

Within two or three weeks after birth, the physician begins to perceive whether the affected infant is active, feeds well and interacts with the environment. Within three to four months, the physician develops a sense of how well the infant will respond to various therapies. It is important to start physical therapy at a very young age, to prevent further muscle loss from atrophy.(3)

Laboratory Studies

Laboratory studies are not particularly useful in defining the specific types of arthrogryposis, unless there is a myopathy; in that case, a muscle biopsy may be helpful and may actually identify the problem. Nevertheless, because we know very little about the natural history of various conditions with arthrogryposis, it is important to perform studies and watch for change over time. Generally, some kind of orthopedic surgery will be necessary. At the time of surgery, tissue for muscle biopsy should be taken, and appropriate histologic and electron microscopy studies should be done.(4)

The central nervous system should be evaluated for cranial nerve function, head size and growth pattern, and structural abnormalities (using ultrasound examination through the fontanelle). CNS abnormalities cloud the prognosis for the child with multiple congenital contractures.

Subtypes

AMYOPLASIA

One-third of all cases of arthrogryposis fit the description of amyoplasia, a condition characterized primarily by limb involvement, with a highly specific position of the limbs in the newborn period.(5) The typical position consists of internal rotation of the shoulders, fixed extended elbows, flexed wrists and severe equinovarus deformities of the feet. The knees and hips may be in almost any position, but usually the involvement is symmetric and all four limbs are affected.

Children with amyoplasia have fairly severe contractures at birth. With physical therapy, however, they usually attain a much improved range of motion. These children are usually able to walk. They are, in general, of normal to high intelligence. The condition is sporadic; interestingly, it occurs with increased frequency among one of monozygous twins.(6) Children with this disorder have an increased incidence of gastroschisis and bowel atresia, which suggests that amyoplasia may have a vascular origin.

DISTAL ARTHROGRYPOSIS

Many children with multiple congenital contractures have involvement primarily of the hands and feet.(7) One relatively common form of distal arthrogryposis has an autosomal dominant mode of inheritance. It is characterized by overlapping of the fingers in the newborn period; the feet can be in a variety of abnormal positions. Both the hands and the feet show a good response to physical therapy. There can be a fair amount of variability in this disorder within an affected family.

GORDON SYNDROME

In Gordon syndrome, involvement of the hands and feet is similar to that in distal arthrogryposis, and the mode of inheritance is also autosomal dominant. However, children with this syndrome have short stature, and half of them have cleft palate.(7)

WHISTLING FACE

The dominantly inherited condition called whistling face or Freeman-Sheldon syndrome shows the same changes in the hands and feet as distal arthrogryposis, usually with greater involvement of the elbows, knees and hips. There is also involvement of the face; the periorbital and periocular muscles may be fibrosed and contracted, making the face look as though it is puckering up to whistle. Children with this condition may have limited jaw opening as well.

SEVERE AND LETHAL ARTHROGRYPOSIS

About one-third of children born with multiple congenital contractures have a severe or lethal form of arthrogryposis. The mothers of these infants may present during the pregnancy with polyhydramnios, or decreased movement may be discovered on ultrasound examination. Many of the severe forms are rare autosomal recessive conditions, but they are usually fairly consistent within a family. The most frequent forms are usually incompatible with survival past the neonatal period; examples are the lethal multiple pterygium syndromes and the Pena-Shokeir phenotype.

Children with lethal multiple pterygium have marked webs across their joints.(8) Those with the Pena-Shokeir phenotype have intrauterine growth retardation, fixed contractures (ankylosis of joints), micrognathia, prominence of the bridge of the nose, depressed tip of the nose and pulmonary hypoplasia.(9) In addition, these children usually have short umbilical cords and may have short gut syndrome. Studies of the Pena-Shokeir phenotype have led to the conclusion that normal fetal movement is necessary for the normal development of a variety of structures in the body.

Recurrence Risk

Many forms of arthrogryposis originate from or are associated with a single-gene defect. Frequently, however, it is not possible to arrive at a specific diagnosis of a particular type of arthrogryposis. In this situation, the empiric observation of recurrence risks is useful in counseling the family. When the specific diagnosis is unknown, there is a 5 percent chance that another child will be born with the same condition or that an affected adult will have an affected child.(10) Experience also shows that if another child is born with the disorder, this child will be affected in much the same way as the previous child was, but the recurrence risk for the family then rises above 5 percent.

In general, children with arthrogryposis are born into families without any history of the disorder. If it is not possible to make a diagnosis on clinical grounds, empiric recurrence risks should be used.

Unusual Forms

Some unusual forms of arthrogryposis are of particular concern. In one form, for example, malignant hyperthermia occurs with exposure to anesthesia. Because surgical treatment is frequently needed for children with congenital contractures, it is important to be aware of that small risk.

Banker(4) has shown that about 5 percent of cases of arthrogryposis have a myopathic basis. In families with myopathic disorders, the manifestations of arthrogryposis can be so variable that one infant may be severely affected and another child may be only mildly affected.

There are X-linked forms of arthrogryposis; therefore, the possibility that a male child has an X-linked disorder should be considered.(11)

Prognosis

Most children with arthrogryposis who survive the first year or two of life have a relatively good prognosis for a long life, unless they have other medical problems.(3) For this reason, a program of vigorous physical therapy and orthopedic correction is important. A number of advances in orthopedic procedures have been made in recent years. Fewer surgical procedures are being performed, but these are more definitive and seem to be increasing the likelihood of maximal functional improvement. The expectation is that the child with arthrogryposis should be able to be ambulatory and live an independent life.(3)

A few children with arthrogryposis have significant mental retardation. A surprising number of these children have chromosomal mosaicism; therefore, if a child has multiple congenital contractures and mental retardation but no specific diagnosis can be made, fibroblast chromosome studies should be considered to determine whether chromosomal mosaicism is present.(12)

Increasing the range of joint motion is critical to correcting muscle atrophy and improving the joint function. It is important, however, not to be too vigorous with physical therapy, since permanent damage to the joint surface can occur. Adults with arthrogryposis tend to have degenerative arthritis more often than unaffected individuals do.

Final Comment

Arthrogryposis is seen in many different conditions. The role of the physician is to take a careful history, define the features that are present and begin physical therapy. REFERENCES (1) Hall JG. An approach to congenital contractures (arthrogryposis). Pediat r Ann 1981;10:15-26. (2). Hall JG. Arthrogryposes (congenital contractures). In: Emery AE, Rimoin DL, eds. Principles and practice of medical genetics. New York: Churchill Livingstone, 1983. (3) Arthrogryposis multiplex congenita. Symposium. Clin Orthop 1985;194:1-123. (4) Banker BQ. Arthrogryposis multiplex congenita: spectrum of pathologic changes. Hum Pathol 1986; 17:656-72. (5) Hall JG, Reed SD, Driscoll EP. Part I. Amyoplasia: a common, sporadic condition with congenital contractures. Am J Med Genet 1983; 15:571-90. (6) Hall JG, Reed SD, McGillivray BC, et al. Part II. Amyoplasia: twinning inamyoplasia--a specific type of arthrogryposis with an apparent excess of discordantly affected identical twins. Am J Med Genet 1983;15:591-9. (7) Hall JG, Reed SD, Greene G. The distal arthrogryposes: delineation of newentities--review and nosologic discussion. Am J Med Genet 1982; 11:185-239. (8) Hall JG, Reed SD, Rosenbaum KN, Gershanik J, Chen H, Wilson KM. Limb pterygium sydromes: a review and report of eleven patients. Am J Med Genet 1982;12:377-409. (9) Hall JG. Analysis of Pena Shokeir phenotype. Am I Med Genet 1986;25:99-117. (10) Hall JG. Genetic aspects of arthrogryposis. Clin Orthop 1985;194:44-53. (11) Hall JG, Reed SD, Scott CI, Rogers JG, Jones KL, Camarano A. Three distinct types of X-linked arthrogryposis seen in 6 families. Clin Genet 1982;21:81-97. (12) Reed SD, Hall JG, Riccardi VM, Aylsworth A, Timmons C. Chromosomal abnormalities associated with congenital contractures (arthrogryposis). Clin Genet 1985;27:353-72.

PHOTO : Newborn with amyoplasia. Note the symmetric involvement of limbs with internal rotation of

PHOTO : shoulders, extended elbows and equinovarus deformity of the feet.

PHOTO : Older child with amyoplasia. Note symmetric involvement. With age, the elbowsflex as the

PHOTO : bones grow, but the fibrous bands do not.

PHOTO : Newborn with distal arthrogryposis. Note ulnar deviation of fingers and distal limb

PHOTO : involvement.

PHOTO : Hand of newborn with distal arthrogryposis. Note overlapping fingers at rest.

PHOTO : Arthrogryposis with popliteal webs, representing one type of lethal pterygiumsyndrome.

PHOTO : Newborn with arthrogryposis associated with tuberous sclerosis. Note depigmented patches

PHOTO : on trunk. The positioning of the limbs is different from that in both amyoplasia and

PHOTO : distal arthrogryposis.

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