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Congenital hand deformities

What are congenital hand deformities?

baby-photoCongenital hand deformities are present at birth and may become a challenge for children as they continue to grow and learn to interact with their environment through the use of their hands. The degree of deformity can vary from something minor, such as a digital disproportion, to a more severe deformity, such as total absence of a bone.

Seeking a consultation with a hand surgeon as early as possible is an important part of the treatment process. Even if reconstructive surgery is not a possibility, there are many different types of prosthetic devices that can be used to increase the function of your child’s hand.

Classifications of congenital hand deformities

The classifications for hand deformities can vary and may change as more knowledge is obtained regarding each of the conditions. The following seven groups of hand deformity classifications have been accepted by the American Society for Surgery of the Hand (ASSH):

Problems in development of the parts

This occurs when parts of the body stop developing while the baby is in the womb, causing either a complete absence of a part of the body, such as the hand, or a missing structure, such as part of the arm bone. Surgery is not typically used in the case of a complete missing part. Instead, children may be introduced to prosthetic devices early in their childhood. Types of this classification include, but are not limited to:

  • Radial Clubhand - A radial clubhand is a deformity that involves all of the tissues on the radial side (thumb side) of the forearm and hand. There may be shortening of the bone, a small thumb or absence of the thumb. This type of birth deformity occurs in one out of every 55,000 births. 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 and may involve underdevelopment of the ulnar bone (the bone in the forearm on the side of the little finger), or complete absence of the bone.

Failure of the parts of the hand to separate

With this type of deformity, the parts of the hand, either the bones and/or the tissues, fail to separate in the womb. The most common type of this classification is syndactyly, in which two or more fingers are fused together. According to some sources, syndactyly occurs in seven out of every 10,000 live births. There is a familial tendency to develop this deformity, which usually involves both hands and affects males more often than females. If the fingers are completely fused together, it is considered complete. There are two types of syndactyly, including:

  • Simple Syndactyly - Involves fusion between only the tissues of the fingers
  • Complex Syndactyly - Involves fusion between the bones

Contractures of the hand

Contractures of the hand are another example of a failure of the hand to separate. Typically the result of a failure of the cells to differentiate in utero, contractures are an abnormal pulling forward of the digits of the hand, usually caused by problems with the muscles or skin.

One of the common types of this classification is congenital triggering, which occurs when one of the digits is unable to extend. Congenital triggering is usually seen in the thumb and may take some time during a child’s development before it is noted that the child cannot extend the thumb. Approximately 33% of contractures improve on their own, therefore surgery is usually not performed until the second year of life, but preferably before the age of three.

Duplications of digits

Duplication of digits, also known as polydactyly, occurs most often with the little finger. In the American-American population, the incidence of duplication of digits is one in 300 live births. Thumb duplications occur in .08 per 1,000 live births. There are 3 degrees of polydactyly, including:

  • Type 1 Polydactyly - An extra digit is attached by skin and nerves
  • Type 2 Polydactyly - An extra digit with normal parts is attached to the bone or joint
  • Type 3 Polydactyly - An extra digit with normal parts is connected to an extra normal metacarpal bone in the hand

Undergrowth of digits

Underdeveloped fingers or thumbs are associated with many congenital hand deformities, but may not always require surgical treatment to be corrected. Underdeveloped fingers may include:

  • A smaller-than-normal finger
  • Missing muscles in the finger
  • Underdeveloped or missing bones
  • Complete absence of a finger

Overgrowth of digits

Overgrowth of digits, also known a macrodactyly, causes an abnormally large digit. This condition is more commonly seen in males and may also involve the hand and forearm. In most cases, only one digit—usually the index finger—is involved; however, in rare circumstances, all parts of the finger (or thumb) are affected. Surgical treatment for this condition is complex and the outcomes may be less than desirable. We may recommend amputation of the enlarged digit in certain cases.

Congenital Constriction Band Syndrome

This occurs when a band forms around a finger or arm, causing problems that can affect blood flow and normal growth. Ring constrictions are congenital (present at birth) and occur in one out of every 15,000 live births. This condition may be associated with other problems such as clubfoot, cleft lip, cleft palate, or other craniofacial anomalies. The cause of the ring constrictions is unknown. Some theories suggest that amniotic banding may lead to ring constrictions around a finger or limb.

With this condition, there are four degrees of severity, including the following:

  • Constrictions that cause deformities beyond the constriction
  • Constrictions that are associated with the fusion of parts of the finger
  • Constrictions so severe that part of the finger will need to be amputated from the process
  • Other generalized problems with the skeletal system

These are a rare and complex group of problems.


We will determine the best treatment option for your child based on the following criteria:

  • 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

Your child’s treatment may include:

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

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