Arthrogryposis: Introduction and Classification

Abstract

Arthrogryposis is a heterogeneous condition defined as multiple congenital contractures in two or more different areas of the body. Amyoplasia is the most common form of arthrogryposis occurring in about 1/10,000 live births. It presents a sporadic condition. The incidence of upper limb deformities due to amyoplasia is high (72–84.8%). The patients with amyoplasia have typical deformities of upper extremities: the shoulder joints are held in adduction, the elbow joints—in extension (less often in flexion), the wrists—in flexion, the thumbs adducted, and the fingers’ joints—in varying degrees of flexion. The muscles are either absent, reduced in size, or replaced by fibrous or adipose tissue. The classification of upper limbs deformities is based on the level of spinal cord injury. All deformities are divided into two groups (differ from each other by the level of damage of the spinal cord and range of passive and active motion in all joints of the upper limb): isolated forms and complex forms (the latter present amyoplasia in combination with other pathology—obstetric palsy, cerebral disorders, and congenital hand anomalies).