The following information consist of the most documented underlying issues that result in joint conttractions. To really move toward an actual treatment or correction of the issues we must query doctors to find out which of the followings affect our children and what can be done to improve thier condition.
Abnormalities of the Muscle Structure or Function
These are called myopathic processes. In these individuals, muscles form
abnormally or develop normally but do not function properly. In most cases,
the cause of this lack of muscle development or abnormality in muscle function
is not known. Some suspected causes include muscle disease such as
congenital muscular dystrophies, mitochondrial disturbances such that the
muscles do not have enough energy to function normally, and abnormalities
of the biochemistry of the muscle.
Abnormalities of the Nerves That Connect
to the Muscles
These are called neuropathic processes. There may have been a failure of the
nerves to form, failure to mature, or failure to function properly. The problem
can be in the brain, in the spinal cord, or in the peripheral nerves and
their connection to the muscle. When the central nervous system and spinal
cord are malformed, as in individuals with neural tube defects (defects in the
closing of the spine), there may be very severe lack of movement. Failure of
neurons to mature or myelinate (formation of the insulation of the nerves)
properly can also lead to lack of normal movement. Arthrogryposis due to
abnormalities in the development and function of the central nervous system
is often accompanied by structural abnormalities that can be seen on imaging
studies or if nerve tissue is examined carefully at autopsy.
Abnormalities of Connective Tissue
In this type of problem, the tendons, bones, joint, or joint lining develop
abnormally in such a way that normal movement cannot occur during fetal
development and contractures are present at birth. Examples of abnormal
connective tissue are seen in diastrophic dysplasia (a dwarfing condition
with clubbed feet and hands) or when there are abnormal tendon attachments.
The tendons may have developed appropriately but may not have
attached to the proper place around the joint or on the bone. If this happens,
normal movement of the joint may not occur during fetal life, leading
to contractures at birth. This is the case in some forms of distal arthrogryposis
(Hall et al., 1982a).