Legg-Calvé-Perthes disease

What is Legg-Calvé-Perthes disease?

Legg-Calvé-Perthes disease (or Perthes disease) is a rare condition in children in which the ball-shaped head of the thigh bone, referred to as the femoral head, loses its blood supply. As a result, the femoral head collapses. The body will absorb the dead bone cells and eventually replace them with new bone cells. The new bone cells will eventually reshape the femoral head of the thigh bone. Legg-Calvé-Perthes disease causes the hip joint to become painful and stiff for a period of time.

Legg-Calvé-Perthes disease goes through four phases of changes that affect the head of the femur. The phases include:

  • Phase 1 - Initial phase. Blood supply is absent to the femoral head and the hip joint becomes inflamed, stiff, and painful. Portions of the bone turn into dead tissue. The ball of the thigh bone becomes less round in appearance on X-rays. This phase can last from several months up to 1 year.
  • Phase 2 - Fragmentation phase. The body cleans up the dead bone cells and replaces them with new, healthier bone cells. During this stage the femoral head may collapse and continue to become less round. The joint is still irritated and painful. This phase can last from 1 year to 3 years.
  • Phase 3 - Reossification phase. The femoral head begins to heal with new bone and model itself back into a round shape with new bone. This phase lasts for 1 year to 3 years.
  • Phase 4 - Healing phase. Normal bone cells continue to replace the new bone cells. This last phase can last a few years to complete the healing process.

What causes Legg-Calvé-Perthes disease?

The cause of Legg-Calvé-Perthes disease is unknown. It is 4 times more likely to occur in boys than girls and is uncommon in African-Americans. Legg-Calvé-Perthes disease can be seen in children 2 years to 12 years of age. The majority of cases affect only 1 hip.  20% of patients may develop Perthes in the other hip but it usually does not occur at the same time.

What are the symptoms of Legg-Calvé-Perthes disease?

The child typically complains of pain in his or her hip that is aggravated by activity. Sometimes, they will also experience pain in their thigh or knee area. The child usually walks with a limp and reports that rest will alleviate the pain. Over time, you may notice muscle loss in the upper leg and hip. 

The symptoms of Legg-Calvé-Perthes disease may resemble other conditions or medical problems of the hip. Always consult your child's doctor for a diagnosis.

How is Legg-Calvé-Perthes disease diagnosed?

In addition to a complete medical history and physical examination, diagnostic procedures for Legg-Calvé-Perthes disease may include:

  • X-rays. A diagnostic test that uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.
  • Bone scans. A nuclear imaging method to evaluate any degenerative and/or arthritic changes in the joints; to detect bone diseases and tumors; to determine the cause of bone pain or inflammation.
  • Magnetic resonance imaging (MRI). A diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body.

Treatment for Legg-Calvé-Perthes disease

Specific treatment for Legg-Calvé-Perthes disease will be determined by your child's doctor based on:

  • Your child's age, overall health, and medical history
  • The extent of the condition
  • Your child's tolerance for specific medications, procedures, or therapies
  • Expectations for the course of the condition
  • Your opinion or preference

The goal of treatment is to preserve the roundness of the femoral head and to prevent deformity while the condition runs its course. Treatment options are dependent on the amount of hip pain, stiffness, and X-ray changes over time, as well as how much of the femoral head has collapsed.

Typically, the first step of treatment is to regain hip motion and eliminate pain that results from the tight muscles around the hip and the inflammation inside the joint.

Treatment may include:

  • Rest
  • Activity restrictions
  • Medications, such as ibuprofen
  • Bed rest
  • Physical therapy (to keep the hip muscles strong and to promote hip movement)
  • Casting or bracing (to hold the femoral head in the hip socket, permit limited joint movement, and allow the femur to remold itself into a round shape again)
  • Surgery (to hold the femoral head in the hip socket)
  • Crutches or wheelchair (in some cases)

Long-term outlook for a child with Legg-Calvé-Perthes disease

The ultimate goal in Legg-Calvé-Perthes disease is to diagnose the condition early in order to allow as much time as possible to let the femoral head remodel back into a round shape. Other treatment goals include controlling pain, maintaining hip motion, and preventing continued hip deformity.

The 2 most critical factors that determine the outcome are the child's age and how much of the femoral head is affected by this condition.

The more severe the case, the greater the likelihood that the child may experience limited hip motion, differences in leg lengths, and further hip problems in adulthood.

Visit the International Perthes Study Group to learn more.