Arthrogryposis FETAL ULTRASOUND

Arthrogryposis (multiplex congenita) is a clinical or imaging descriptor that denotes congenital non-progressive joint contractures involving two or more body regions. 

Epidemiology

Arthrogryposis has been mostly reported in individuals of Asian, African and European descent with equal incidence in males and females . It is thought to occur in approximately 1:3000-10,000 live births.

Associations

Arthrogryposis can be associated with numerous syndromic as well as non-syndromic associations; over 400 medical conditions and 350 known genes with considerable variability in phenotypic expression have been found.

• syndromic
  • Pena-Shokeir syndrome
  • multiple pterygium syndrome
  • Fowler syndrome
  • Freeman Sheldon syndrome 
• non-syndromic/isolated
  • CNS anomalies: can be present in ~10% of cases 
    • agenesis of the corpus callosum
    • lissencephaly
    • fetal ventriculomegaly
    • aplasia of the cerebellar vermis
  • neuromuscular disorders
    • amyoplasia congenita: some report that this is one of the most common causative associations 

Pathology

Arthrogryposis can result from a number of pathologies. Altered fetal movement (fetal akinesia) is considered a contributor to its pathogenesis. Genetic causes may be present in only 30% of cases.

Radiographic features

Ultrasound

A lack of fetal movement is considered to be a key feature. Abnormalities are present at birth and are not progressive over time. Fixed contractures and lack of mobility results in poor muscle formation and development in affected regions. 

Antenatal ultrasound may additionally show direct evidence of contractures such as:

• abnormal limb/extremity positioning
  • clenched hands
  • knotted fingers
  • persistently extended legs
  • persistently bent legs
• clubbed feet
• scoliosis: long C-shape neurogenic type

and/or indirect features such as:

• short umbilical cord
• oligohydramnios
• polyhydramnios : some forms
• pulmonary hypoplasia
• camptodactyly
• micrognathia