holding hands
holding hands
holding hands

Congenital Hand Differences

What are congenital hand differences?

Congenital anomalies are hand or finger differences that are present at birth. Any type of difference in a newborn can become a challenge for the child as they grow. Hand differences can be particularly disabling when severe as the child learns to interact with the environment through the use of their hands. The types of differences can include extra fingers and thumb, fused fingers, under or overgrowth of the hand, fingers and arm and missing fingers and thumb or bones of the arm.

Early consultation with a hand surgeon is an important part of the treatment process for the child born with a hand deformity. Even if reconstructive surgery is not possible, there are many different types of prosthetic devices that can be used to increase function.

What are the different types of congenital hand differences?

The classifications for hand differences can vary. This classification has been accepted by the American Society for Surgery of the Hand.

Problems in formation of the parts

This occurs when parts of the body stop developing while the baby is in the womb. This causes either a complete absence of a part of the body, such as the hand, or a missing structure, such as part of one of the arm bones. In the case of the complete missing part, surgery is not done. Instead, these children may get a prosthetic device early in their childhood. Types of these classification include:

  • Radial clubhand. A radial clubhand is a difference that involves all of the tissues on the thumb side (radial side) of the forearm and hand. There may be shortening of the bone, a small thumb, or absence of the thumb. Deformities of the wrist are usually operated on around 6 months of age.
  • Ulnar clubhand. An ulnar clubhand is less common than a radial clubhand. This difference may involve underdevelopment of the ulnar bone (the bone in the forearm on the side of the small finger), or complete absence of the bone.

Failure of parts of the hand to separate

With this type of hand difference, the parts of the hand, either the bones or the tissues, fail to separate in the womb. The most common type of this classification is syndactyly. Syndactyly is when 2 or more fingers are fused together. There is a familial tendency to develop this difference. If the fingers are completely fused together, it is considered complete. There are 2 types of syndactyly:

  • Simple syndactyly. This involves fusion between only the soft tissues of the fingers.
  • Complex syndactyly. This involves fusion between the bones and finger nails.

Pediatric Trigger Thumb

Pediatric trigger thumb occurs when the thumb is unable to fully straighten (extend) and often gets stuck in the bent (flexed) position. The cause of the triggering is due to thickening of the tendon which “pops” as it slides through the protective sheath that covers the tendon. Some of these cases improve on their own. Surgery is usually not done until the second year of life, but preferably before the age of 3. 

Duplications of fingers

Duplication of fingers is also known as polydactyly. The small finger is the finger that is most often affected.

Undergrowth of fingers

Underdeveloped fingers or thumbs are associated with many congenital hand differences. Surgical treatment is not always required to correct these hand differences. Underdeveloped fingers may include the following:

  • The finger is small
  • Muscles are missing
  • Bones are underdeveloped or missing
  • There is complete absence of a finger

Overgrowth of fingers

Overgrowth of fingers is also known as macrodactyly, which causes an abnormally large finger. In this situation, the hand and the forearm may also be involved. In this rare condition, all parts of the finger (or thumb) are affected; however, in most cases, only one finger is involved (usually the index finger). Surgical treatment of this condition is complex and the outcomes may be less than desirable. Sometimes, amputation of the enlarged finger is recommended.

Congenital constriction band syndrome

This occurs when a tight tissue band forms around a finger, arm or leg, causing problems that can affect blood flow and normal growth. Ring constrictions are congenital (present at birth). This condition may be associated with other birth differences, such as clubfoot, cleft lip, or cleft palate. The cause of constriction rings is unknown although some theories suggest it is due to a piece of the amniotic membrane that breaks of and wraps around the body part. Treatment usually involves release of the tight bands and reconstruction of the finger depending on the severity of the

Treatment for congenital hand deformities

Specific treatment for congenital hand differences will be determined by your child's doctor based on:

  • Your child's age, overall health, and medical history
  • Extent of the condition
  • Cause of the condition
  • Your child's tolerance for specific medications, procedures, or therapies
  • Expectations for the course of the condition
  • Your opinion or preference

Treatment may include:

  • Limb manipulation and stretching
  • Splinting of the affected limbs
  • Tendon transfers
  • External appliances (to help realign misshapen fingers or hands)
  • Physical therapy (to help increase the strength and function of the hand)
  • Correction of contractures
  • Skin grafts. These involve replacing or attaching skin to a part of the hand that is missing skin or has been removed during a procedure.
  • Prosthetics. These may be used when surgery is not an option, or in addition to surgical correction.

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