Arthrogryposis occurs when joints become permanently fixed in place – either bent or straight. This permanent position of a joint is known as a “contracture” and affects the movement of the joint.
Arthrogryposis can also be called arthrogryposis multiplex congenital (AMC). For the condition to be diagnosed, two or more areas of the body must be affected, and the condition must be present at birth (congenital). When only one joint is affected, such as club feet, the condition is known as an isolated congenital contracture.
Joints further from the center of the body are most commonly affected, including the arms and especially the legs. Shoulders and hips are not often affected. In some children, the condition is barely noticeable. In others, it is more severe.
The contractures do not worsen over time, so treatments to encourage joint movement can lead to significant improvements. Arthrogryposis doesn’t affect a child’s cognitive abilities or limit their lifespan.
More than 400 diseases can cause isolated or multiple contractures. Some of the causes of arthrogryposis are genetic. Others are due to the conditions in the mother’s womb.
The most common cause of arthrogryposis is decreased movement in the womb. Motion is critical for joints to develop properly, so when the baby doesn’t move as often as it should, joints can become fixed in place.
Arthrogryposis can occur because of:
Connective tissue disorders in the baby
Limited space while developing in the mother’s womb
Low amniotic fluid level
Muscle or neurological problems
Other conditions associated with arthrogryposis include: