Legg-Calve-Perthes Disease

What is Legg-Calve-Perthes disease?

Legg-Calve-Perthes disease (also known as Perthes disease or Legg Perthes) is a temporary condition in children in which the ball-shaped head of the thighbone (femoral head) loses its blood supply. As a result, the head of the thigh bone collapses, and the area becomes inflamed and irritated.

As the condition runs its course, the body will absorb the dead bone cells and replace them with new bone cells. The new bone cells will eventually reshape the head of the thighbone, but the result can be a deformation that can cause arthritis later on.

For the majority of children with Legg-Calve-Perthes, only one hip is ever affected. In 10 to 12 percent of children with the condition, both hips are affected but not usually at the same time.

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

Signs and symptoms of Perthes disease can include:

  • pain in the hip that is aggravated during activity
  • pain in the thigh or knee area
  • walking with a limp (can be a “painless limp”)
  • pain that goes away with rest

What causes Legg-Calve-Perthes disease?

Perthes disease is idiopathic, which means that there is no known cause for the disease. It occurs in about one out of every 12,000 children. Boys are five times more likely to be affected than girls, but girls’ cases can be more severe. Affected children are usually between 4 and 10 years old, very physically active and small for their age. The condition tends to be more common in children who’ve been exposed to second-hand smoke.

What are the stages of Legg-Calve-Perthes disease?

Legg-Calve-Perthes disease goes through four phases of changes that affect the head of the thighbone:

Phase 1 — Necrosis

The blood supply to the head (ball) of the thighbone is interrupted, so the hip joint becomes inflamed, stiff and painful. Portions of the bone turn into dead tissue (avascular necrosis). The ball of the thighbone becomes less round in appearance on x-rays. This phase can last from several months up to one year.

Phase 2 — Fragmentation

The body “cleans up” the dead bone cells and replaces them with new, healthier bone cells. The head of the thighbone begins to remodel into a round shape again. The joint is still irritated and painful. This phase can last from one to three years.

Phase 3 — Reossification

The head of the thighbone continues to model itself back into a round shape with new bone. This phase lasts for one to three years.

Phase 4 — Remodeling

Normal bone cells replace the new bone cells and the remodeling continues. To complete the healing process, this phase can last a few years.

How we care for Legg-Calve-Perthes disease

Boston Children's Hospital orthopedic surgeon Arthur Thornton Legg, MD, first recognized and described Legg-Calve-Perthes disease in 1910. Since then, Boston Children’s hip specialists have built up a vast body of knowledge of, and experience with, Legg-Calve-Perthes disease, and we’ve pioneered advanced techniques for re-shaping the femoral head and optimizing joint function and longevity.

Whatever hip treatment your child requires, you can have peace of mind knowing that, as national and international orthopedics referral centers, Boston Children’s Orthopedic Center and Child and Young Adult Hip Preservation Program have deep experience treating children with every kind of hip condition, some of which few other pediatric hospitals have ever encountered.

Download our patient fact sheet for Legg-Calvé-Perthes disease to learn more about the condition, view helpful illustrations and find out how the hip specialists in the Child and Young Adult Hip Preservation Program provide comprehensive care throughout each patient’s treatment.