Macrodactyly

When a child is born with a finger or toe that is larger than the others, it may raise questions about their growth and development. This condition, called macrodactyly, is uncommon but treatable.

At Banner Children’s, we offer advanced care and treatments for children with congenital hand and foot differences like macrodactyly, helping them lead active, healthy lives. 

What is macrodactyly?

Macrodactyly is a condition where one or more fingers or toes are much larger than normal. The larger digits may be long, wide, stiff or curved. This happens because bones and soft tissues in the affected digit grow faster than the others.

The condition is a rare congenital (present at birth) limb difference. This means babies are born with it. Macrodactyly can affect one or both hands or feet and more often occurs in the hands than in the feet. It does not spread to other parts of the body.

Sometimes, children with macrodactyly also have syndactyly. This is when fingers or toes are webbed or joined together. 

Types of macrodactyly

There are two main types of macrodactyly:

• Static macrodactyly: Most cases of macrodactyly are static. This means the enlarged fingers or toes grow at the same rate as the rest of the body.
• Progressive macrodactyly: The affected fingers and toes begin at regular size but grow much larger and faster than the unaffected fingers and toes over time.

What causes macrodactyly?

The exact cause of macrodactyly is not known. It is not inherited (passed down from parents to children) but may be caused by a genetic mutation (changes) during development. It is not caused by anything you did or didn’t do during pregnancy.

In most cases, macrodactyly is not linked to another condition but can occur alongside other nerve conditions or syndromes like:

• Neurofibromatosis: A condition that causes tumors to grow along nerves
• Proteus syndrome: A rare condition that causes skin and bones to grow too much
• Klippel-Trénaunay syndrome: A disorder that affects blood vessels, bones and soft tissues
• Hemihyperplasia: A condition where one side or part of the body grows more than the other
• Macrodystrophia lipomatosa: A rare form of localized overgrowth involving fatty tissue

Signs and symptoms of macrodactyly

The main sign of macrodactyly is a finger or toe that is noticeably larger than the others. 

Other symptoms may include:

• Extra fat or thick skin around the affected area
• Stiffness 
• Trouble moving, grasping or using affected digits
• Pain or discomfort, though this is rare
• Difficulty finding shoes or gloves that fit 

In progressive cases, the difference in size can become more extreme as your child grows.

How macrodactyly is diagnosed

Most children are born with obvious signs. If your child has progressive macrodactyly, the signs may not show up until they are older. 

Your child’s health care provider may recommend a physical exam and imaging tests to understand what’s going on. They may use:

• X-rays: To see which bones are affected
• MRI or CT scans: To look at soft tissues like muscles, tendons and nerves
• Ultrasound: To check for blood vessels or tissue differences

You may also work with a genetic specialist or other pediatric experts if they think the condition is linked to a syndrome or other health issue.

Macrodactyly treatment options

Treatment for macrodactyly depends on how severe the condition is, how fast the finger or toe is growing and how it affects your child’s life. The goal is to help the affected fingers or toes work as well as possible. 

Non-surgical treatments

For children with mild cases, surgery may not be needed. Non-surgical care may include:

• Observation: If the digit is not growing quickly or causing problems, it may just be carefully watched over time.
• Physical and occupational therapy: Therapy can help improve strength and movement.
• Custom splints or modified shoes: These help with comfort and function.

Surgical treatments

Surgery is often recommended for children with more severe or progressive macrodactyly. The goal is to improve how the finger or toe looks and works, reduce pain and help your child with everyday activities. 

If your child needs surgery, they will be referred to a pediatric hand specialist or an orthopedic surgeon experienced in treating this condition. 

Surgical options may include:

• Soft tissue debulking: This procedure removes extra fat and other soft tissues that make the digit larger. It can help improve appearance and make movement easier.
• Bone shortening: Involves removing part of the bone to reduce the length or size of the affected finger or toe.
• Growth plate surgery (epiphysiodesis): This technique stops or slows growth in the affected digit to prevent further size difference as your child grows.
• Ray resection: In some cases, the entire finger or toe (including the bone and surrounding tissue) is removed to improve function and appearance. This is usually considered when the overgrowth is severe and other treatments are not effective.
• Tendon or nerve adjustments: May be needed to improve movement and reduce tightness or discomfort. 

Depending on your child's condition, surgeons may perform one or more of these procedures. In some cases, surgery may happen in stages over time.

Your child may need to wear a splint or cast while their finger or thumb heals. They may also have physical therapy, occupational therapy or hand therapy to regain strength and movement. 

What is the long-term outlook for macrodactyly?

With early care and support, most children with macrodactyly can live healthy, active lives. Support from family, school and health care teams can help your child feel confident and strong.

How Banner Children’s can help

At Banner Children’s, we offer complete, family-centered care for children with macrodactyly and other hand and foot differences. This means we involve you in every decision and provide care in a way that’s right for your child.

Your child’s team includes:

• Pediatric orthopedic and plastic surgeons
• Pediatric occupational and physical therapists
• Child life specialists and behavioral health professionals
• Imaging and diagnostic experts trained in working with children

Our pediatric team works with your child’s health care provider and school, so everyone is on the same page. Our goal is to help your child move, play and live as fully as possible.

Make an appointment

If your child has signs of macrodactyly or another congenital hand difference, contact Banner Children’s. We’re ready to help.

Schedule an appointment with a Banner Children’s specialist today.