Types of Congenital Hand Deformities

Congenital hand deformities are abnormalities of a baby’s hand that are present at birth. Orthopedic hand surgeons at Hassenfeld Children’s Hospital at NYU Langone diagnose and treat children with all types of hand deformities. There are many types; the following are those most often seen.

Polydactyly

A baby born with polydactyly has more than five fingers on one hand. An extra finger is often a small piece of soft tissue that can be simply removed. Sometimes, the extra finger contains bones but not joints. Very rarely, the extra finger is a fully functioning digit. A baby may be born with several extra fingers.

There are several different types of polydactyly. Radial polydactyly means there is an extra thumb. Ulnar polydactyly means there is an extra pinky finger. When an extra digit is located in the center of the hand, it is called central polydactyly.

Polydactyly is the most common congenital hand deformity. It affects boys and girls equally. Black children are more likely to have ulnar polydactyly, and Asian and white children are more likely to have radial polydactyly.

Syndactyly

Syndactyly is a condition in which two or more fingers fail to separate when a baby is in the womb, resulting in “webbed” fingers at birth. It usually involves the middle and ring fingers.

If the entire length of the fingers is completely fused, the condition is called complete syndactyly, and when the digits are joined for only part of their length, it is called incomplete syndactyly. When the adjacent finger bones are also fused, it is called a complex syndactyly. Syndactyly is more common in white children than in children of other backgrounds, and it affects twice as many boys as girls.

Symbrachydactyly

Symbrachydactyly is underdevelopment of the hand. Babies born with this condition have small or missing fingers. They may also have webbed fingers or a short hand or forearm.

In mild symbrachydactyly, the hand has slightly short, mobile fingers with minor webbing. The hand bones, or metacarpals, and some of the finger bones, known as phalanges, and the thumb are present. In moderate symbrachydactyly, the baby is missing most or all of the finger bones and instead has small projections of skin and soft tissue. The thumb is usually present, but it may be short. In severe symbrachydactyly, the baby has either a partial thumb or no thumb and no fingers.

Clubhand

A baby born with radial clubhand has a hand that turns inward, causing limited range of motion at the wrist. It involves the radial, or thumb, side of the forearm and hand. The forearm may be shorter than normal, and a person may have a small thumb or no thumb. As a result, a child with the condition may have trouble performing tasks that require his or her hands. Radial clubhand may be associated with blood, heart, intestinal, or spinal abnormalities.

Ulnar clubhand is much less common than radial clubhand and involves shortness or absence of the ulnar bone—the bone in the forearm on the side of the pinky finger—as well as the other tissues on that side of the hand and wrist. It also causes the wrist to be bent at an angle. This condition may be associated with muscle or bone abnormalities in other limbs or in the spine, such as scoliosis or clubfoot.