The cause for LCP is unknown. We do know that the blood flow to the ball of the hip is insufficient. It is thought that an abnormality of blood flow causes an interruption in the supply to the femoral head.

The onset of Legg-Calve-Perthes usually occurs when the child is between 3 and 12 years old, though most common ages 5 to 7 years old. Boys are 3 to 5 times more likely than girls to develop the disease.

A child with LCPD is often very active compared to other children.

Children often have a limp and may lean side to side when walking. The limp may get worse late in the day or after activities, but gets better with rest.

Some children complain of pain in the groin, front of the thigh, or knee that gets worse with physical activity. The pain often is worse late in the day and some children may have pain at night. 

Most children have muscle spasms that limit the movement in their hip.

X-rays are used to confirm diagnosis. A bone scan or MRI may also be used.

1. Initial Stage (lasts about six months)

• The child’s symptoms may get better and then get worse.

2. Fragmentation Stage (lasts about eight months)

• This is the stage where the head of the femur breaks down.
• The child’s pain and limp become more obvious.
• There is more loss of motion in the hip.
• The degree of symptoms may vary from child to child.

3. Healing Period (lasts about four years)

• New bone grows in the head of the femur.
  • The pain and limp usually start to improve.
  • Some limitation of hip motion continues.
• The child will gradually return to normal activities.

4. Residual Stage (until growth is complete) 

• The shape of the head of the femur may continue to change until growth stops.

The goal of treatment is for the head of the femur (thighbone) to heal and return to a round shape. Your doctor may tell your child to limit impact activities, like jumping and running. Your child may need to use a walker or crutches. This is important if the child has a lot of pain with walking.

Your doctor may also suggest physical therapy to:

• Stretch muscles that are tight
• Strengthen muscles around the hip
• Work on walking to reduce limping

Most children with Legg-Calve-Perthes disease do well, and long-term studies show good outcomes for most.  However, there are associated risks for the affected hip, such as associated pain, arthritis or further hip dysfunction.

Children diagnosed with Legg-Calve-Perthes disease while young often have the best outcome.