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Fibular Hemimelia

What Is Fibular Hemimelia?

Children who have fibular hemimelia are born with a short or missing fibula (one of the two bones in the lower leg). Other bones in the leg, ankle, and foot can be affected too. 

Most children with fibular hemimelia (FIB-you-luhr heh-me-MEE-lyuh) have it in one leg, but some have it in both. Experts who treat bone problems have several options to help kids with a hemimelia.

What Are the Signs & Symptoms of Fibular Hemimelia?

Here are some of the things that parents might see when a baby is born with hemimelia:

  • When all or some of the bone is missing in one leg, the leg is shorter than the other. Doctors call this a leg length discrepancy.
  • Because shinbone is missing, the ankle joint may not form properly. The ankle and foot might look different from normal.
  • The child's knee and lower leg might bend inward.
  • The child's lower leg may bow out.
  • The foot may have fewer than five toes.

A baby with hemimelia can have problems that parents won't see. Doctors can find these through physical exams and tests:

  • The hip joint may be more shallow than usual.
  • Some of the ligaments (strong, flexible bands of tissue) that hold the knee together may be weak or missing.

What Causes Fibular Hemimelia?

Scientists and doctors don't know exactly why babies are born with fibular hemimelia. But they do know that nothing a mom does during pregnancy causes the problem. Parents can't stop it from happening, but they can help kids get the best care.Illustration: fibula shown on a baby's leg

How Is Fibular Hemimelia Diagnosed?

Often, doctors know that a fibula is short or missing before a baby is born. That's because prenatal (before birth) ultrasound scans show the baby's bones as they form and grow.

If a mom didn't get a scan while pregnant, doctors will see the fibular hemimelia when the baby is born. They may order these tests to learn more:

  • X-rays will show what the bones and joints look like.
  • MRIs will let doctors see ligaments and other soft tissue in the foot and joints.

How Is Fibular Hemimelia Treated?

Treatment depends on how an individual child is affected. Some children with fibular hemimelia have very mild limb length difference and need very little treatment. Others have a large limb length difference and unstable joints.

When a child has fibular hemimelia, the leg may not grow as fast or as long as it should. Kids might have trouble standing or walking. Getting the right treatment is important.

Different experts work as a team to treat fibular hemimelia. The team is led by specialists (doctors and other providers who treat bone and muscle problems). They work with other specialists as needed. Your child's team also might include physical therapists and an .

The care team will come up with a plan to help your child stand, walk, and play like other kids. The plan will be based on:

  • how much bone is missing
  • how much difference there is in the length of the legs
  • how the problem might affect your child as he or she grows
  • whether your child has foot or ankle problems

You might need to bring your child for a series of visits over several months before the care team decides on a treatment. This gives the team time to understand how your child will grow and what the difference in leg length might be.

Sometimes, there isn't a lot of difference in leg length. Kids might just wear a special shoe or shoe insert. But most kids need surgery.

Surgery to Treat Fibular Hemimelia

Doctors do different surgeries depending on a child's situation. Most kids get surgery to help their legs grow to the same length. Others need surgery to stand and walk. Some kids only need one surgery. Others have several surgeries during their growing years.

Epiphysiodesis

When kids have small differences in leg length, the care team might suggest a surgery called epiphysiodesis (ep-i-fiz-ee-uh-DEE-sis). For this surgery to work, kids must still be growing.

During the surgery, one or two of the growth plates in the longer leg are scraped or compressed with surgical plate and screws. A growth plate is an area at the end of the bone where new growth happens. The surgery slows or stops the longer leg from growing so the shorter leg can catch up.

Leg-Lengthening Surgery

Kids who get leg-lengthening surgery usually need a few operations over several years. The surgery can add about 8 inches (13 centimeters) to the shorter leg.

In this surgery, the orthopedic team places a lengthening device on the shorter leg. The device might be on the outside of the body or inside the bone.

Other Surgeries

In addition to fixing leg length differences, some kids need surgery to help them stand and walk. These surgeries repair bones, muscles, and joints that didn't form properly because of the hemimelia.

Treatment for Severe Fibular Hemimelia

Sometimes orthopedic experts know that surgery won't help a child to stand or walk properly. A child might have one leg that is very much shorter than the other or a foot problem that can't be fixed. For these kids, a prosthesis offers the best chance to live an active life.

Doctors might amputate (do surgery to remove) part of the foot or leg so the child can wear a prosthesis. Orthotists then fit the child with a prosthetic lower leg.

New prosthetics mean kids who have had an amputation can run, climb, and jump like other kids. Most kids can play sports.

Kids who wear prosthetic legs need to see an orthotist at least once a year. The orthotist will adjust the prosthesis or make a new one as the child grows.

What Can Parents Do?

Helping children with fibular hemimelia reach their full potential takes many years. Kids need medical care until they are fully grown. Because of this, doctors want parents to play a big role in treatment.

Here are things you can do:

  • Talk to your child's care team about treatment and healing. Ask questions. Find out what each surgery is for and how to care for your child afterward.
  • Take your child to all medical appointments. Some surgeries need to be done at the right time in the child's growth. Missing that time may mean kids can't get the surgery or it won't work as well.
  • If your child is old enough, talk about treatments and what to expect. Include older kids in surgery decisions when you can. Doctors can often schedule a surgery so it doesn't interfere with an activity your child wants to do.
Date reviewed: March 2018
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