Radial aplasia is a birth defect of one of the two bones in the lower arm. One bone is the radius the other bone is ulna. The radius is the long bone at the wrist behind the thumb and the ulna is below the radius. These are the two long bones between the wrist and the elbow joint. Aplasia means failure to grow. So the diagnosis of radial aplasia means the radial bone in the arm did not grow. Radial aplasia and radial dysplasia are very common birth defects in the VATER association.

The word dysplasia means abnormal development of an organ. With radial dysplasia this usually means that somehow the radial bone grew abnormally such as the radial bone only growing part way or the radial bone growing in a curve.

Radial aplasia has 4 types of classifications. Type I: there is a short radius: delayed appearance, thumb aplasia (thumb did not grow) Type II: Hypoplastic radius: small short radius; decrease growth rate. Type III: Partial absence of radius: hand radial angulation; ulna hypertrophy. Type IV: Total absence of radius: severe radial angulation. Each of the 4 types and classifications of radial aplasia has its own treatment by the orthopedic doctor and this usually follows a standard medical treatment approach.

Petit wrote the first detailed anatomical description after autopsy of an infant having radial club hands on the right and on the left arms over 250 years ago describing in detail the muscles, tendons, ligaments, blood vessels, bones, joints and deformities of the arms and hands.

With the birth defect of the radial bone there is much to be considered. One not only has to consider the missing bone but the other parts of the anatomy that function along with the bone and what the loss of the bone does to the overall structure appearance and function of the arm itself. The muscles, nerves, tendons ligaments small bones in the wrist and fingers, the joints, forearm and shoulder and blood supply are all affected as well as the angulation of the hand, fingers and arm.

One of the main goals is to have a limb that is not a hinderance but a useful part of the body and a viable productive part of the body. The arms, hands and fingers play a major role in every day life. Each part of the body has a specific job and each part of the body assists in helping with this.

The tendons of the hands and fingers allow us to open and close our hands. The muscles and tendons give us strength to grasp, squeeze and pick things up. Opposition of the fingers such as touching the thumb and index and thumb and all the fingers individually is important for picking things up.

To be able to supinate and pronate the hand from the elbow joint is important. To describe supination think of the position of the hand and arm as you are holding a bowl of soup in the palm of your hand in front of you. The hands are open with the palms facing up and pronation is the palms facing down so you see the back of your hand and fingers. You cannot supinate or pronate without the elbow joint.

The assortment of defects of the radius and hand includes many different problems. These problems include missing thumb or part of the thumb, other fingers, some or all of the bones in the wrist not developing or partially developing, missing muscles and tendons. In some cases the tissue of the hand and arm are involved as is the other bone in the lower arm the ulna which is below the radius. This can happen to one arm or both arms and include the leg or legs.

The cause of this is unknown. Something goes wrong in the first 23 to 28 days after conception. Dareste theory is that during the first few weeks of development environmental factors such as pressure within the uterus causes this. Another theory is by Virchow of an inflammatory cause.

One of the goals after discovering the birth defects is to determine if the problem is able to be corrected or to make the arm, hand, wrist, or finger functional. Some of the problems are not correctable and some parents decide even if they are correctable they chose not to. To correct the problems a physical exam of the arms, hands, fingers, joints, with x-rays and other tests are required. It is also important to know if there are other problems besides the hands, arms and fingers, such as heart defects and others.

With a radial club hand the basic operation has been to put the ulna in the center of the wrist, remove some bones in the wrist, and place the ulna in the space where the bones in the wrist has been removed. It is also possible to use soft tissue and shorten the ulna by placing the wrist on the head of the ulna to produce muscle balance. This can be done when the baby is about 6months old to a year old. After this has been done and the carpus, the wrist and fingers have been aligned with the ulna, a wire is passed down the ulna for about 3 months. After this time the wire is removed, the wrist and arm are splinted for another 3 months.

If the thumb is missing and the decision is made to replace the missing thumb it is usually replaced with the index finger or the big toe. This is done usually when the baby is between 1 and 2 years old . The operation involves muscles, nerves, tendons and blood vessels. Physical therapy is also required after surgery.

If the radial bone is missing it is common for the ulna bone to bend and curve toward the place where the missing bone the radius would have been. This bending is thought to be caused by the skin, tissue and muscle pulling as the child grows.

In the past it was fairly common to replace the absent or dysplastic radial bone using part of another bone called a bone graft from the ulna in the arm, the tibia or fibula which are the two bones in the lower leg below the knee to stabilize the hand in good alignment with the wrist.

Tendon transfers are also being used to stabilize the hand and to provide some degree of controlled motion of the wrist and this is followed by splinting and stretching of the arm.

There are many ways to approach and align radial club hand . A doctor Ilizarov from the former Soviet Union came up with a great idea of stretching the bones. This is done by a special technique of putting pins in the bones at different areas and placing a stretching device frame over these pins on the outside of the skin attached to the pins. Everyday the pins that are attached to the device are turned like a screw and this stretches the bone. This is done over along period of time and also stretches the skin. The goal is to get the desired length of a bone. This technique has been used on short people by stretching the bones in the legs and the bones in the lower and upper arms. The device is worn over a long period of time, is bulky and awkward. Many people are very happy with the length of growth they attain after wearing this device. The scars on the skin from the lengthening of the bone or bones seems to be very acceptable because the length, position, use, and function outweigh the aestetic look of the scars.

The mental anguish and pressure parents feel to have a perfect baby in the begining is very real and it may go on for years. They suffer more than the child does in many ways. As the child gets older they learn to function with whatever they have available to them and adapt. This seems in many cases for parents a time of reflection that hey maybe this isn't so bad. Its my child who is dealing with it better than I am and when you discover that your child can do many things that you never expected them to do you think this really isn't so bad. A parent is actually in awe of the thing s their child is able to do. The problem in the very beginning is we only see things being done one way with the so called normal body because this is what we are exposed to all the time. Two arms, two legs, two hands, 5 fingers on each hand, five toes on each foot. We as humans certainly learn to adapt to our environment.

As the child gets older they wonder why they are so different from their parents, brothers, sisters, friends and people in general. If the surgery to correct some of the problems such as a missing thumb or multiple fingers has not been corrected because the parents want the child to decide when the child gets older some of the kids ask for the surgery and some don't. If it is a functional problem it is important to try and correct this. The aestetic look for a child can be very important also. This should be a decision to be considered with great understanding and input by the child and parents with much love, understanding and compassion.