Legg-Calve-Perthes Disease

Legg-Calve-Perthes disease (also known as Perthes disease) is a rare condition that affects children’s hips. It starts when the top of the thigh bone (femur) temporarily loses its blood supply.

Because the bone needs fresh blood to get oxygen and nutrients, it starts to die and break down. After the blood flow returns to normal, your child’s bone will slowly repair itself. But it may not have its original shape and size.

Perthes disease is most common in kids ages 5 to 7. But it can affect kids as young as 2 or as old as 12. It progresses in stages. First, your child’s affected bone breaks down from a loss of blood supply. Then, after blood flow is restored, it will start to regrow. The breakdown phase may take up to a year. The rebuilding phase may last two to five years.

How much it affects your child depends on how much their thigh bone changes. Some kids lose more bone tissue than others. This can happen for a few reasons:

• More severe blood supply interruption
• More time without the right blood supply
• They use their bone too much while it’s weakened, causing additional damage

Treatments can help your child’s femur regrow correctly. Most children have no long-term complications after treatment. Kids who continue to have poorly fitted hip joints will have ongoing symptoms. Hip dysplasia can lead to complications like arthritis later in life.

Symptoms of Legg-Calves-Perthes disease

Signs and symptoms of Perthes disease develop over time. You or your child might start to wonder what’s up when symptoms appear and don’t seem to ever get better.

Early symptoms might include:

• A limp: Your child may favor one leg while walking to keep weight off the affected side. A limp often appears before your child notices any pain. They may not know why they’re limping.
• Hip pain: If your child feels pain, it’s usually when their bone first starts to break down. Pain will probably be worse when they move and use that hip.
• Referred pain: Some kids may feel pain in their knees, thighs, pelvises or bellies instead.
• Leg cramps: Your child may have cramps or spasms in the muscles connected to their hip.

Later signs and symptoms of LCPD may include:

• Trendelenburg gait: This is an unusual walking pattern. Weak hip muscles make your child’s pelvis tilt down on the affected side. This will affect how they walk.
• Limited range of motion: Your child may have difficulty rotating their hip. They may not be able to open their thighs out, or turn their knees in as far as usual.
• Muscle atrophy: One of your child’s thighs or one side of their butt may look noticeably smaller than the other.
• Uneven leg lengths: One leg may appear shorter than the other.

Perthes disease causes

Perthes disease happens when something slows or stops the blood supply to the head of your child’s femur. Healthcare providers aren’t always able to find a specific cause.

Blood flow can stop if a blood vessel is blocked or squeezed. Artery disease or a blood clot might block it from the inside.

Swelling might compress a blood vessel from the outside. Sudden trauma or a repetitive strain injury can cause swelling in your child’s hip. This can cut off blood flow to their thigh bone.

1 in 10 cases appear genetic. It’s possible that certain genetic changes can pass through generations in your biological family. Experts have identified that a change in the COL2A1 gene may cause LCPD.

Risk factors

Perthes disease is five times more common in males. About half of kids who develop it have some type of blood-clotting disorder.

Your child may have a higher risk of developing Legg-Calve-Perthes if they have:

• Delayed skeletal growth
• Low birth weight
• Short stature
• Abnormal teeth
• HIV

Environmental factors can also play a role. These are things about where you live or spend time that can affect your health. Your child’s risk of LCPD can increase if they:

• Live in a lower-than-average socioeconomic status
• Are exposed to secondhand smoke
• Play sports or do gymnastics

How doctors diagnose this condition

A healthcare provider will begin with a thorough physical examination. They’ll use X-rays to take pictures of your child’s bones. X-rays can show evidence of Perthes syndrome. They’ll also show its stage and severity. In some cases, your child might need an MRI to see certain features in more detail.

Treatment for Legg-Calve-Perthes disease

Treatment for Legg-Calve-Perthes depends on a few factors, including:

• Its severity
• Its stage
• Your child’s age

In general, younger kids tend to do better with more conservative treatments. That’s because their bones naturally grow and develop faster. Older children might need more help to restore their bone tissue.

Your child’s healthcare team will develop a personalized treatment plan. This may include:

• Restricted activity and weight-bearing: Your child might need to stop or limit walking for a while. They may need crutches or another assistive device to get around.
• NSAIDs: These over-the-counter (OTC) medications help manage pain and reduce inflammation. They include aspirin and ibuprofen.
• Physical therapy: A physical therapist will work with your child to rehab their hip with special exercises. You might need to help your child practice their exercises.
• Traction: An orthopaedic traction device applies gentle, increasing force to gradually stretch your child’s hip into alignment. This treatment takes place over several days.
• A cast or braces: During the remodeling phase, your child might need a cast or brace to keep their bone safely in place.
• Surgery: Some children might need surgery to reshape the bone so it fits into its socket. They might need a joint replacement to extend or reshape the hip socket. Kids older than 7 are more likely to need surgery.

What is the outlook for Legg-Calve-Perthes disease?

It can take your child several years to recover completely from Legg-Calve-Perthes disease. This can intrude on their childhood, to some extent. But when it’s over, they should be able to return to their usual activities.

Perthes syndrome is temporary, but it can cause permanent changes. Kids who don’t get the right treatment soon enough have an increased risk of hip osteoarthritis later in life. But most children don’t have long-term complications.