The termarthrogryposis, amixture of Latin and Greek words, means curved or crooked joint (Hageman et al., 1988). This term was first used in 1923 by Stern. The first medical description of arthrogryposis occurred in 1841, when Otto described an infant with multiple congenital contractures and referred to the condition as “congenital myodystrophy” (Swinyard and Bleck, 1985).

Arthrogryposis refers to a symptom complex characterized bymultiple joint contractures that are present at birth. The muscles in the affected area or areas are replaced by fat and fibrous tissue (Shapiro and Specht, 1993). Although the term arthrogryposis is in wide use, the preferred descriptive term is multiple congenital contractures. These contractures do not represent a syndrome but a compensatory connective tissue response (Swinyard and Bleck, 1985).

Clinical features of arthrogryposis include rigidity of several joints, resulting from short, tight muscles and capsular contractures, dislocation of joints, “featureless” extremities (normal skin creases are absent and there is an increase in the amount of subcutaneous fat), presence of deep skin dimples in the vicinity of affected joints, absence or fibrosis of muscles, and normal intellectual development (Williams, 1978).

According to Hall (1981), the term arthrogryposis multiplex congenita was coined to describe infants with multiple congenital contractures. Confusion has arisen because the term was used as a diagnosis. The term is descriptive, and the presence of congenital contractures only indicates a clinical sign with multiple underlying causes. In general, anything that decreases intrauterine movement may lead to limitation of joint movement and the subsequent formation of contractures. The earlier in development it occurs and the longer the duration of limitation of movement, it will result in more severe contractures at birth.

There are four major causes of congenital contractures (Hall, 1981):

1. 
   

   Abnormal muscle tissue: Examples of this are muscular dystrophy, congenital myopathies, and congenital absence of muscle (amyoplasia).

   
   
2. 
   

   Abnormal nerve function: This includes central nervous system malformations, congenital neuropathy, failure of the nerves to form or myelinate, or exposure to toxins that affect nerve function.

   
   
3. 
   

   Abnormal connective tissue: This interferes with the normal development of tendons, bone, cartilage, or joint tissue.

   
   
4. 
   

   Mechanical limitation to movement in utero: This includes uterine fibroids, oligohydramnios, amniotic bands, or the presence of a multiple gestation.

The incidence of multiple congenital contractures is approximately 1 in 3000 livebirths (Hall, 1985). In one study of 66 cases of arthrogryposis multiplex congenita, the mothers were significantly older than average (Wynne-Davies and Lloyd-Roberts, 1976). Davis and Kalousek (1988) identified 16 cases of fetal akinesia deformation sequence in 948 not yet viable fetuses at 9 to 20 weeks of gestation. The fetal akinesia deformation sequence was defined as joint contractures with or without formation of webs, with intrauterine growth restriction, pulmonary hypoplasia, micrognathia, short umbilical cord, and a short gut (Davis and Kalousek, 1988). In addition, arthrogryposis multiplex congenita has been described in association with cases of failed termination of pregnancy (Hall, 1996). These authors hypothesized that the contractures were due to vascular compromise during attempted termination with a secondary loss of functional neurons leading to fetal akinesia and subsequent contractures. A rupture of membranes with continuous leakage of amniotic fluid after attempted termination may have worsened the existing contractures.

Detailed examination of the fetal extremities is not listed in the most recent American College of Obstetricians and Gynecologists or American Institute of Ultrasound and Medicine (AIUM) guidelines, but it is a critical adjunct to fetal imaging and is needed to diagnose conditions such as arthrogryposis (Bromley and Benacerraf, 1995; ACOG, 2008). The sonographic diagnosis of arthrogryposis is made by observation of the malposition of the limbs (Figure 101-1). The morphologic aspects of the bones are normal but the range of movements is limited (Deschamps et al., 1992). Increased nuchal translucency, polyhydramnios, and cystic hygroma are often observed in association with arthrogryposis (Goldberg et al., 1986; Bui et al., 1992; Hyett et al., 1997; Scott et al., 1999).

Murphy et al. (2002) described three cases of fetal arthrogryposis with severe hypoechogenicity of the long bones that was noted after 30 weeks’ gestation. They speculated that fetal osteoporosis developed as a consequence of absent fetal movement.

Baty et al. (1988) reported the prenatal diagnosis of distal arthrogryposis by sonographic examination at 18 weeks of gestation in a family with two other affected members. Real-time sonographic evaluation demonstrated a flexed position of the fingers and extension of the right wrist, which did not change despite active motion of the shoulders and elbows. The fetal hands were in a fist and the fingers did not extend (Figure 101-2). These authors described the following important variables in the sonographic diagnosis of fetal joint contractures (Baty et al., 1988):

1. 
   

   The gestational age of the fetus.

   
   
2. 
   

   The timing of the development of the joint contractures.

   
   
3. 
   

   The severity of the joint contractures.

   
   
4. 
   

   The index of suspicion of the ultrasonographer.

   
   
5. 
   

   The skill, patience, and previous experience of the sonographer.

   
   
6. 
   

   The divergence of the affected joints from the neutral position.

   
   
7. 
   

   The amount of joint movement.

   
   
8. 
   

   The presence of other sonographically detectable anomalies.

   
   
9. 
   

   The persistence of findings over time.

Amyoplasia is the most common cause of joint contractures. Sepulveda et al. (1995) diagnosed a case of fetal amyoplasia at 19 weeks of gestation with absent fetal movements, severe multiple congenital contractures, hydrops fetalis, and polyhydramnios. No spontaneous fetal movements were seen over a 40-minute period of observation. Autopsy of this affected fetus revealed small groups of poorly developed muscle fibers within areas of fat. These authors noted that fetal movements were absent during intrahepatic venous sampling in the fetus with amyoplasia. This was in contrast to their previous observations that second trimester fetuses normally react with vigorous movements during fetal blood sampling.

Stoll et al. (1991) studied two children born to a mother with myasthenia gravis. Her first pregnancy was a 33-week-old fetus with multiple flexion contractures, which died 1 hour after birth from respiratory insufficiency. Her second pregnancy was remarkable for an abnormal ultrasound examination at 20 weeks, which showed decreased fetal movements and multiple flexion contractures. In myasthenia gravis, a maternal factor is transferred to the fetus, which affects the fetal joints. This has been confirmed in an animal model by injecting pregnant mice with plasma from women who have antibodies to the acetylcholine receptor (Jacobson et al., 1999). Many pups were stillborn and showed fixed joints.

Goldberg et al. (1986) described a case of fetal arthrogryposis at 30 weeks of gestation in a fetus with scalp edema but no ascites. Moderate polyhydramnios was present. In this fetus, the lower extremities were tightly flexed and crossed in a squatting position. No normal limb activity was noted. These authors stated that late identification of arthrogryposis was valuable in minimizing the birth trauma associated with the vaginal delivery of an infant with fixed joints.

More recently, three-dimensional (3D) surface-rendering images were used to show the fixed postural abnormalites of the fetal extremities (Ruano et al., 2003). When viewed in real time, the authors were able to show that there was absence of fetal movement, leading to a diagnosis of fetal akinesia deformation sequence.

More than 150 conditions are known in which multiple congenital contractures are a predominant sign (Hall, 1985). In a review of 155 patients with arthrogryposis, Sarwark et al. (1990) noted that 43% of patients had amyoplasia, 35% had other contracture syndromes, 7% had the dominantly inherited form of distal arthrogryposis, 6% had multiple congenital anomalies, and 2% had chromosomal abnormalities.

Amyoplasia is the single most common cause of multiple congenital contractures. A very specific limb positioning exists in this condition. There is a marked decrease in muscle mass. Contractures are symmetric, with all four limbs affected. Affected patients have a round face with a mild micrognathia and a midline hemangioma. Intelligence is normal in this condition.

Distal arthrogryposis refers to syndromes in which there are congenital distal contractures but the proximal joints are largely spared (Beals, 2005). There is a lesser degree of involvement of the extremities and preservation of good muscle tone and bulk. Affected patients have a clenched-fist deformity of the hand, occasional congenital dislocation of the hip, mild to severe positional deformities of the foot, and normal intelligence (Baty et al., 1988). In most distal arthrogryposis conditions, the function of the hands improves with time, use, and physical therapy.

Currently, there are 10 different syndromes described that have a common pattern of distal congenital contractures, minimal proximal contractures, and other findings (Bamshad et al., 1996; Beals, 2005). All are inherited as autosomal dominant conditions with variable expression. This group of conditions includes Freeman–Sheldon syndrome, (also known as distal arthrogryposis type 2A), which presents with a distintive facies, flexion, and ulnar deviation of the fingers and vertical talus. Congenital contractural arachnodactyly (Beals syndrome), also known as distal arthrogryposis type 9, presents with ear deformities and finger contractures. This condition is in the differential diagnosis for Marfan syndrome.