Amyoplasia congenita of the lower extremity: report in a premature baby.

Amyoplasia congenita is a diagnostic subgroup of children with arthrogryposis multiplex congenita (AMC). AMC is a relatively rare syndrome characterized by multiple joint contractures at birth. Amyoplasia congenita is the most common type of this syndrome with an occurrence rate of 1 in 10,000 live births, and mainly refers to the disorders with limb involvement. In this report, the author presents a premature baby with amyoplasia congenita, whose hips showed flexion, abduction, and external rotation contractures. The knees showed fixed extension contractures, so that his lower extremities were cylindrical with absent skin creases at birth.