Legg-Calve-Perthes Disease | Symptoms and Causes

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.