Joint contractures and muscle weakness present before birth, typically affecting two or more areas of the body.
More Information on Arthrogryposis Multiplex Congenita
Arthrogryposis literally translates to “stiff joints”. There is no known cause for this disease. When arthrogryposis affects two or more parts of the body it is called Arthrogryposis Multiplex Congenita (AMC). These forms with an unknown cause are the most common. In fact, patients with AMC or Amyoplasia should be discussed specifically and not confused with genetic forms of stiff joints. The other forms with a genetic basis such as Escobar Syndrome, Popliteal Pterygium Syndrome, Polymicrogyri, Distal Arthrogryposis, Larsen Syndrome, conditions caused by RYR1 Mutations as well as others are unique and will be discussed separately.
AMC will present at birth or even in utero with lack of fetal movement. The child often appears the worst in the newborn period and it can be quite frightening for the parents and the physicians. The stiff child has been cramped in the mother’s uterus for nine months and as a result, it can take up to two years to know what function will return. Physiotherapy helps to determine how much can resolve. I was once given emergency privileges in a hospital to examine a newborn infant who all the physicians in the neonatal intensive care unit were sure would not survive. They wanted to stop feeding the infant and allow her to pass peacefully. After examination, it was determined that the child had AMC. She is now six years old, running with her friends and attending a normal school with nothing more than small braces on her feet.
AMC has no known cause and when tested genetically is normal. Whether it is a failure of migration of tissues during fetal development not allowing muscles to form or a viral illness that impacts the fetus, there is no known treatment or prevention.
Infants should have all known causes of stiff joints tested for genetically and with possible MRI of the brain and spinal cord. Known conditions should be ruled out.
Given that the condition is relatively rare, few surgeons and therapists are experienced enough to treat this disease effectively. Arthrogryposis requires very complex treatment and should only be undertaken by physicians, surgeons, and allied health professionals who are not only familiar with the disease but also have a high level of expertise in treating arthrogrypotic patients.
I believe that if a child is to have surgery, there must be an expected outcome that can change the child’s life. To achieve the best functional outcomes, I take into account the underlying muscle strength of the patient, outline realistic goals, assess the potential benefits of treatment, and partner with an exceptional team of experienced medical professionals to provide treatment. This ensures that children do not undergo multiple painful surgeries that make very little change in their condition.
Over the past four years, we, at the Paley Institute, have made great strides in treating the hip, knee and foot in patients with AMC. Often treated at the same sitting with the help of physical therapy, I can achieve hips and knees with increased range of motion and flexibility, without the use of external fixation and without causing increasing stiffness. Having a leg that is straight but stiff allows the child to walk if before they could not. If the knees cannot bend, as the child grows it is difficult to sit in classrooms, cars, airplanes, theaters, work desks, etc. The goal is to increase the arc of motion, not lessen it in an already stiff jointed disease. Specifically, for example, in the case of a fixed flexed knee, it is treated by loosening the joint capsule and all of the muscles that attach behind the knee. The nerves that cross the knee, such as the sciatic and peroneal nerves, are also loosened from their attachments. The femur bone near the hip is often shortened and rotated in position. All of this allows the knee to fully straighten and maintain a good deal of bending.
Elbows can be loosened and muscles transferred to allow for active elbow flexion. While in the United States the triceps is often the muscle used for this transfer, the Latissimus Dorsi, if present, is a muscle that is much stronger and not missed nearly as much. Transfer of this muscle allows the person to eat independently without having to bend to the table or do twisting maneuvers to lift a utensil to their mouth.
Wrists can be brought up from the flexed position if this allows the person to be more functional. In addition, thumbs can be brought out of the palm and fingers separated. All of this is done with a combination of bony and soft tissue surgery.
Patients with AMC may develop scoliosis, a twisting and curving of the spine and kyphosis, bending forward of the spine. These must be treated very carefully in AMC patients. First, one does not want to lose the ability to sit or stand when having a spinal fusion (operative management of scoliosis or kyphosis). Second, AMC patients may develop problems above and below the level of surgery and this needs to be predicted. Third, neurologic injury during surgery is much more common in AMC and must be avoided.
While each patient is individualized, as the severity of the disease varies greatly between patients, AMC can be managed and often patients can be helped to be much more independent than ever thought before.