Congenital Limb Differences | Overview
What are congenital limb differences?
Babies with congenital limb differences are born with arms, legs, fingers, or toes that are missing, not fully formed, or formed differently.
Some congenital limb differences are related to conditions that affect a specific limb or part of a limb. For instance, radioulnar synostosis affects the forearm while fibula hemimelia affects the lower leg. Other limb differences are related to conditions that may affect many different parts of the body, such as skeletal dysplasia.
Some congenital limb differences tend to occur with one or more other conditions. For instance, some patients with cleft hands also have cleft lip, foot abnormalities, deafness, or congenital conditions that affect the heart and digestive systems.
Congenital limb differences - general
Congenital differences of the arm and hand
- cleft hand
- Madelung's deformity
- radial longitudinal deficiency
- radioulnar synostosis
- ulnar longitudinal deficiency
Congenital differences of the leg and foot
- cleft foot
- congenital short femur/proximal focal femoral deficiency (PFFD)
- femoral anteversion
- fibular hemimelia
- metatarsus adductus
- tarsal coalition
- tibia hemimelia
- tibial torsion
What are the symptoms of a congenital limb difference?
The most common symptoms of congenital limb differences include:
- complete or partial absence of a limb (such as fibula hemimelia or a partial or completely missing bone)
- overgrowth (one limb is much larger than the other limb)
- undergrowth (one limb is much smaller than the other limb)
- a portion of the limb is fused or webbed (commonly seen in fingers or toes)
- duplication (commonly seen as extra fingers or toes)
How common are congenital limb differences?
Some congenital limb differences are more common than others. One out of every 1,000 babies is born with extra fingers or toes for instance. By comparison, amniotic band syndrome occurs in one out of every 10,000 to 15,000 births.
Are congenital limb differences inherited?
Most congenital limb differences occur with no known cause. Certain conditions, such as extra fingers or toes, may be a passed down through families.
What causes congenital limb differences?
While we still don't know what causes most congenital limb differences, certain factors can increase a baby’s risk. These include:
- exposure of the mother to chemicals or viruses during pregnancy
- certain medications taken during pregnancy
Exposure to tobacco smoke during pregnancy may increase a baby’s risk of being born with a limb difference, but more research is needed to confirm that the two are linked.
How are congenital limb differences diagnosed?
Some congenital limb differences are first detected during a prenatal ultrasound, before the baby is born. For instance, 80 percent of clubfeet can be diagnosed through ultrasound by 24 weeks. This gives expecting parents a chance to learn about treatment options and plan ahead before their child is born.
If a limb difference is not diagnosed before birth, it can also be seen and diagnosed as soon as a child is born. The doctor will conduct a physical exam. In rare cases, a doctor may order an x-ray or MRI to confirm the diagnosis. These tests may also help them look for signs of an underlying bone issue.
How are congenital limb differences treated?
The primary goal of treatment is to ensure the child will have as much use of their limb as possible so they have the opportunity grow up to be independent and self-confident.
Depending on the limb difference and how it affects the child, treatment may include:
- physical therapy and occupational therapy to increase strength and function
- splint or brace to support the affected limb
- surgery, such as reconstructive or limb-lengthening surgery, to correct the limb difference
- an artificial limb (prosthetic)