Congenital Hand Disorders (Pediatric)
Babies born with hands that are different than the normal hand have a congenital hand difference. Millions of steps are required for a normal hand to be formed; a failure in any step will result in a congenital disorder. Some of these congenital differences are believed to be caused by a genetic cause and others occur because of unknown causes, research efforts to further understand these problems are ongoing.
Approximately 5% of babies are born with a congenital difference of the hand. There are many kinds of hand differences that present at birth and each one of them can be treated differently. This is why it is very important for a child with a hand difference to be evaluated by a hand surgery specialist. Depending of the type of anomaly, treatment will be recommended by the hand surgeon, the treatment may be surgical and non-surgical depending on each individual case.
Immediately after the birth of a baby with a congenital difference of the hand, parents will feel pain, anger and even guilt, which are normal emotions to have. Family members must cope with their feelings, but hand surgeons can provide very important information and support to make this experience a better one.
Common Congenital Hand Differences
Syndactyly (Webbed Fingers)
Syndactyly, derived from the Greek syn meaning together and dactylos meaning digit, is a failure of differentiation in which the fingers fail to separate into individual appendages. The syndactyly can be simple (only soft tissue is conjoined) or complex (bone, nail elements and soft tissues are conjoined).
The normal hand develops during the 5th to 8th week of gestation. Fingers start to develop joined together because of a substance (denominated AERMF) that is present in every one of us. This substance should disappear during the 6th to 8th week of gestation to allow finger separation, when the substance fails to disappear syndactyly occurs. Syndactyly is twice as common in boys as in girls, it occurs in 1 of 2000 live births and most commonly the long and ring fingers are conjoined. This difference can be part of many genetic syndromes, thus an evaluation by a specialized physician is important to rule out these associations.
Syndactyly can be treated with an operation; depending on each case the hand surgeon will decide the appropriate treatment. The goal of the surgery is to allow independent movement to each finger, in order to obtain a good result each finger must have all the bones and soft tissues complete. Timing of the procedure is decided in an individual basis ranging from 3 months to 1 year, but prompt evaluation by the hand specialist is always crucial.
When surgery is decided to be used, the hand surgeon completes a thorough preoperative planning, a series of incisions (zig-zag pattern) are made to separate the digits and almost always skin graft will be used to cover the site where the separation is performed. Sometimes these skin grafts can get a darker color than the child’s own skin because of the cicatrization process. Usually, after surgery the hand is immobilized in a splint and dressing changes are only done 2 to 4 weeks later to allow proper skin healing.
Radial Club Hand
Radial club hand is a longitudinal deficiency of a bone, the radius, in the forearm; this congenital difference occurs in 1 of 30,000 to 100,000 live births. It consists of an absent or incomplete radius, absent or incomplete thumb, deviation of the wrist toward the thumb’s side (radial) and some degree of neuromuscular deficiency. Sometimes the problem may appear in both upper extremities. Many mechanisms have been implicated in cause of this difference, irradiation, environmental factors and nutrition among others have been studied but the real cause is still unknown. As other congenital differences radial club hand can be associated with other genetic syndromes such as VACTER, Holt-Oram Syndrome, TAR syndrome and Fanconi’s anemia.
The child with this difference must undergo a thorough evaluation including heart, spine, and kidneys, where other anomalies can be present. After these related problems have been ruled out or treated the hand surgeon will start treating the child with splints, casting and non–surgical manipulation to avoid or improve contractures.
Between 6 months and 1 year some patients with this problem will require a surgical procedure. This surgery is known as a “Centralization/radialization of carpus on ulnar epiphysis”. With this surgery the hand specialist relocates the hand over the existing normal bone “the ulna” making the hand to be aligned with this normal bone. This procedure corrects the deformity and in some cases allows movement of the wrist. Usually, the patient will be immobilized with a cast for four to 6 weeks after surgery. In some occasions, this surgery must be accompanied by other procedures to further straighten the arm and to allow correct movement of the hand.
Generally the affected arm will be shorter than the normal one. When this difference is too severe the hand surgeon can perform a lengthening procedure around 6 and 8 years of age. The other important component of this difference is the absence or underdevelopment of the thumb. Hand surgeons can improve this problem with a procedure called “pollicization” this means to make the thumb out of the index finger. The thumb is the most important finger of the hand and because grasping is one of the most important functions humans have, the reconstruction of a thumb may provide a better function to the hand in selected cases. Usually the results of these procedures are advantageous; the decision to proceed with them depends on each individual case.
Camptodactyly is the term that describes a flexion deformity of one of the fingers; the finger with this difference is bent and cannot be straightened. Camptodactyly can be caused by problems in the tendons the ligaments or the bones of the finger. This difference presents in approximately 1% of the population, the cause of this difference is not known but it can be associated with other congenital differences or syndromes this is why prompt assessment by a specialist is required.
An experienced hand surgeon must examine the hand of the child in order to initiate appropriate treatment. Usually camptodactyly can be managed without surgery, passive stretching exercises or finger splinting may correct the deformity. Some surgical procedures can be indicated by the hand specialist when the flexion contracture of the finger is larger than 30°. Surgical procedures depend on each case individually, but tendon excisions and transfers can be performed to correct this difference. Although correction can be obtained, the risk of residual flexion is always present.
Clinodactyly refers to the curving of the fifth (little) finger toward the fourth (ring) finger. This difference occurs because of a misshaped bone of the fifth finger. This minor difference can be found in a completely normal child, but it’s also a common finding in patients with Down and Klinefelter syndrome. This difference does not require any treatment, finger and hand function is normal.
Congenital Trigger Finger
Trigger finger refers to a difference in which the digit, almost exclusively the thumb in children, locks or catches when it’s flexed and extended. Apparently this is a condition that develops after birth and is present at 1 year of age in as much as 3.3 per 1000 live births. In one third of the cases the condition can be present bilaterally.
The tendon that allows flexion of the thumb glides through a series of pulleys before getting to the tip of the finger. When one of the pulleys (A1) is too tight or the tendon gets swollen the movement is not smooth and the tendon starts to lock or catch in its trajectory. The symptoms can progress to the point where the thumb is completely locked and contractures may develop, often a nodule (Notta’s nodule) can be palpated at the base of the finger.
Hand surgeons must evaluate this condition early on in order to initiate prompt treatment and avoid contractures. In 30% of the patients, the trigger finger recovers spontaneously. Usually depending on the age of presentation the treatment will change, between one and three years of age surgery is usually considered if the condition is still present.
The surgical procedure when indicated consists of opening the pulley that causes the tight passage for the tendon. Usually this requires a small incision on the base of the finger; the child is immobilized for one week with a soft bandage after which they return to normal activities. The risk of recurrence is minimal but appropriate surgical technique is important because of the close relation with important nerves of the finger and the pulley.
Aplasias / Duplications / Hypoplasias
Other examples of common differences that are treated at our center are duplications, aplasias and hypoplasias. All of these congenital differences arise from errors during the genetic development of the hand. Hand surgeons can actively participate, explaining, treating and counseling parents when one of these stressful events occurs. Absences (aplasias) are described by level, as in amelia (absent limb) and adactyly (absent digit(s). Another important absence occurs when a central portion of the hand is missing. Often functional without treatment, cosmetic considerations must be addressed, and may be improved with surgical procedures performed by trained hand surgeons. Duplications and hypoplasia (undergrowth), can also require treatment. In order to improve function or esthetical appearance hand surgeons should be consulted in order to obtain the best results.