By: Kathryn M. Peck, M.D.
Radial longitudinal deficiency (RLD) is a condition in which the radius bone of the forearm is underdeveloped or absent, resulting in the hand and wrist that angles toward the thumb-side of the forearm. It is a congenital condition (present at birth) in which the radius (the inner bone that connects the elbow to the forearm) did not form correctly in the womb. The radius may be malformed or missing.
IN RADIAL LONGITUDINAL DEFICIENCY:
• The affected arm is smaller, and stiffness of the fingers and elbow are often present
• The forearm curves inward because the radius is malformed or missing
• The thumb is either very small or missing
• The severity of the condition is different in each child
CAUSES OF RADIAL LONGITUDINAL DEFICIENCY:
A baby’s arm forms between week 4 and week 8 of pregnancy, and by week 8, the arms are fully formed but very small. In some instances, a cause cannot be determined for radial longitudinal deficiency. In other cases, it can be part of a syndrome that affects multiple body parts, including VACTREL, Holt Oram Syndrome, Fanconi’s Anemia, and TAR Syndrome (Thrombocytopenia Absent Radius syndrome).
The heart, kidneys, intestines, blood cells, and limbs form at about the same time. Therefore, problems in these other areas need to be evaluated and often treated before the arm is treated.
Radial longitudinal deficiency can sometimes be seen on ultrasound. After the baby is born, diagnosis is confirmed through a physical exam and x-rays.
The main goal and benefit of treat is to improve the child’s ability to function with the condition, in addition to improving the appearance of the hand.
Treatment is based on each child because it depends on the complexity of the condition.
• Splinting or casting
• Physical therapy (to help increase strength and function)
• Prosthetics (in the case of missing parts or bones)
• Adaptive Aids (to help with daily activities such as getting dressed and personal hygiene)
• Surgery (to help reposition the wrist, stabilize or create a thumb, or lengthening the shorten arm to help with daily care.
In most cases, surgery is done before the child reaches school age but generally not before 6 months of age. In all cases, the goal of surgery is to repair any associated abnormalities, and improve range of motion and function.
Radial longitudinal deficiency requires a comprehensive approach to the child and family to give the best possible outcome.