Arthrogryposis– What Works and What Is Still a Challenge
I want to restate how happy our arthrogryposis/ amyoplasia (AMC)(I use both of these terms together but these are very different diagnoses and may have different treatments) patients and families have been with three procedures.
1) External rotation osteotomy of the humerus. If the arms are really rotated “in” (internal rotation position), function can be difficult as illustrated below. When we cut and rotate the bones outward, function can be dramatically improved. Blog: arthrogryposis-arm-rotation.html
2) Posterior elbow release and triceps lengthening is perhaps my “favorite” operation in arthrogryposis. It is done when the elbows will not bend (flex)- a straight position makes function like bringing the hands to the mouth impossible. This release has been a dramatic functional improvement for patients.
3) Dorsal Carpal Wedge Osteotomy. This operation brings the wrist out of the bent (flexed) position and allows the fingers to function better (if you are a parent, try to make a fist with your wrist maximally flexed- it is really hard). Also, given that some kids have difficulty with one- handed activities, re- positioning the wrists will make the hands function together much easier (imagine clapping).
Now the difficult issues:
1) Finger motion and function. Many children have camptodactyly– a bent (flexed) position of one or more fingers. Blog:camptodactyly.This can limit function to some degree but does not always terribly interfere with function- it depends on how severe the fingers are bent. Additionally, kids may simply have poor finger motion- usually this is difficulty with making a fist. This makes function difficult, specifically grasping objects. Children are resourceful and can adjust to this limitation in a lot of different ways including by using both hands to lift and grab things. Surgeries to improve motion of the fingers have not been typically successful.
2) Thumb position and thumb motion can be difficult in arthrogryposis as well but is usually less of a problem than the fingers. First, the thumb does not need to move especially well to be helpful with activities. As long as the thumb is in a good position and is stable, it can allow the child to grab large objects and pinch smaller ones. Functionally, this is huge! If the thumb is not in a good position (i.e., flexed into palm), function will be hurt both because the thumb is not in a good position and because it can interfere with the fingers. Medicine can help with thumb positioning. Sometimes splinting can help, and sometimes a surgery can be helpful to re- arrange the skin, release tight muscles, and tighten tendons to improve the thumb position. A partial fusion can also be helpful for some children. So while the thumb can be a challenge, we can usually help kids get the most out of their thumbs/ hands. Blog: Arthrogrypotic Thumb
3) The lack of muscle strength will limit active motion (i.e., moving the arm using muscle power only). This is ultimately the greatest challenge for the patient with arthrogryposis. Sometimes, we can move other muscles to make up for the ones that are weak or not working well. These surgeries, called muscles transfers, are helpful but often not ideal for a number of reasons (including the issue that finding good muscles can be difficult in arthrogryposis). For example, to provide active elbow flexion, at least 5 muscle transfers have been recommended. All would agree that none is perfect and all have limitations.
As always, learn more about congenital disorders at: Washington University Hand-Wrist/Congenital-Hand-Disorders