There are two long bones comprising the forearm, the radius and the ulna. When the radius fails to develop normally (ie, radial hypoplasia or dysplasia), an inward rotation or collapse of the wrist can result towards the thumb side. This is referred to as a club hand, or radial club hand, deformity. The affected arm is shorter, with curving of the forearm and stiffness of the elbow and fingers. In many cases, some element of hypoplastic thumb is also present.
See “Hypoplastic Thumb” section for further details. The occurrence of radial dysplasia is usually sporadic, meaning that it occurs by chance and for no apparent reason. However, it may be associated with other defects or syndromes. The condition occurs 1 in 55,000-100,000 babies.
Hand function is severely affected in radial club hand deformity. Treatment is aimed at stabilizing the wrist, with the hand seated in a proper configuration. The muscles and tendons on the radius side of the forearm are also underdeveloped and shortened. Treatment must also RadialClubXRinclude stretching or lengthening of these elements to balance the hand on the wrist.
Depending upon the severity, surgically correcting a radial club hand deformity can be done in one or more stages. Serial casting before surgery can help stretch the tight muscles, ligaments, and tendons. This should be started in the first few months of life. Surgery is then performed to reposition the hand centrally on the wrist. This is called centralization. Alternatively, prior to centralization, stretching of tight structures can be achieved with initial application of an external distraction device. This device is placed surgically on the hand and forearm and is gradually adjusted at home on a daily basis to move the hand more centrally and stretch out tight anatomic structures. When the desired position is achieved, the centralization procedure is then performed.
It is not uncommon for children to require multiple surgeries over the course of their lifetime to help correct residual curvature, lengthen the forearm, or improve hand function.