Diagnosing Arthrogryposis in Children

Doctors at NYU Langone are highly experienced in diagnosing arthrogryposis. This rare condition occurs when a lack of muscle development causes stiffening and tightening, known as contracture, in the joints, muscles, and tendons of the limbs, hands, feet, and other parts of the body, giving them a curved or rounded appearance. These contractures are permanent and lead to joint and bone problems. 

In most cases, the exact reason a child develops arthrogryposis is unknown. The condition arises before birth, when something interrupts muscle development. Arthrogryposis can result from limited space in the womb, a leakage of the amniotic fluid surrounding the baby, or exposure to viruses that affect the baby’s development. Arthrogryposis can also be a consequence of certain rare genetic disorders. 

No two children with arthrogryposis are affected in exactly the same way. Some have very mild contractures in one area of the body, such as the foot, that do not affect their day-to-day function. Others have more severe or widespread contractures and muscle weakness that restrict movement throughout the body. Some children develop complications, such as repeated lung infections that occur after food is inhaled into the lungs, because of weakness in the chest muscles.

Arthrogryposis can be diagnosed during pregnancy but is often missed until a baby is a few months old. Getting an accurate diagnosis as early as possible is critical to selecting the most effective treatment for your child. At NYU Langone, we use a variety of methods to identify symptoms of this condition, and if possible, the underlying cause.

Prenatal Ultrasound

During pregnancy, most women receive an ultrasound exam—a test that uses sound waves to create an image—to determine how well the baby is growing. These images can reveal whether the baby has enough room to develop properly or is positioned unusually in the womb, which can lead to arthrogryposis. 

Ultrasound can also be used for a detailed examination of the baby’s limbs and joints, to see whether they appear abnormally flexed or rotated or have an unusual shape. Information from ultrasound images, combined with the mother’s reports of the baby’s movements during pregnancy, may help to diagnose arthrogryposis before or shortly after the baby is born.

Physical Exam

An orthopaedic surgeon may examine your baby if a prenatal ultrasound or a pediatric exam showed abnormal flexing or rotation of the baby’s limbs and joints. In a physical exam, the surgeon looks at the position and flexibility of the baby’s joints at the shoulders, elbows, wrists, and thumbs, checking for signs of weakness, unusual bending, or rotation. Some babies with arthrogryposis are born with dislocation in one or both hips or with clubfoot, in which both feet are twisted inward at the ankle.

MRI Scans

MRI, which uses a magnetic field and radio waves to create detailed images of tissue and organs, is used to look at the development and position of an infant’s muscles and joints. This imaging test allows the doctor to study, in detail, specific areas affected by arthrogryposis, which can help to determine the extent of the condition and select the best treatment for your child.

Muscle Biopsy

A muscle biopsy test is used to examine your child’s muscle tissue for signs of inflammation or other features that may help to gauge the severity of the condition and to determine whether arthrogryposis is caused by an underlying muscle or nerve condition. The surgeon inserts a thin needle into the muscle to obtain a small sample that is analyzed under a microscope. This test is performed in the operating room while a child is under anesthesia. 

Electromyogram Testing 

Electromyogram testing is used to understand how your child’s muscles and nerves are functioning in a specific limb. A technician places one or more small needles through the skin and into the muscle to measure electrical activity while the muscle is resting or during contraction. 

Genetic Tests

Doctors may take a small blood or skin sample to look for genetic abnormalities, called mutations, that are found in some people with arthrogryposis, although in most cases there is no genetic cause of the condition.

After diagnosis, our doctors develop an individualized treatment plan that considers each child’s unique set of symptoms, as well as any underlying conditions.

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