Legg-Calve-Perthes disease (also known as Perthes disease) is a rare condition in which the ball head of the femur (femoral head) temporarily loses blood supply. As a result, the femoral head collapses, and the area becomes inflamed and irritated.

As the condition continues to develop, the dead bone cells are absorbed by the body and replaced with new bone cells, and blood flow eventually returns, but the shape of the femoral head will change and will not move smoothly in the hip socket.

Only one hip is affected in the majority of children with Perthes disease.

In 12% of children with this condition, both hips are affected, with both sides not usually affected at the same time.

Symptoms

Signs and symptoms of Perthes disease can include:

• Walking with a limp, which can be painless

• Limited range of motion and stiffness in the hip, thigh, or knee • Pain in the hip, thigh, or knee that increases during activity

What causes Perthes disease?

Perthes disease is of unknown etiology, and there is no clear cause yet.

Blood flow to the femoral head is cut off, and the bone begins to break down.

One in 12,000 children develops Perthes’s disease. Males are infected five times more often than females, but when a female is infected, the condition tends to be more severe. Perthes’s disease most often affects children between the ages of 4 and 10, who are physically active, and younger. The condition tends to be more common in children who have been exposed to second-hand smoke.

Stages of Perthes disease

Perthes disease occurs in four stages:

Phase 1: Necrosis

Blood flow to the femoral head is cut off, causing inflammation, stiffness, and pain in the hip joint. Areas of bone turning into dead tissue (avascular necrosis). On an X-ray, the head of the femur appears less rounded. This stage can last from several months to one year.

Phase 2: Fragmentation

The body replaces dead bone cells with new healthy bone cells. The femoral head begins to remodel into a round shape again, but the joint while still inflamed and painful. This stage can last for up to two years.

Phase 3: Reossification

The femoral head continues to reshape itself into a round shape with a new bone once blood flow returns. This stage can last from one to three years.

Phase 4: Remodeling

Normal bone cells replace the new bone cells, and the femoral head becomes more mushroom-shaped than ball-shaped, and this stage lasts a few years while the bone heals.

Diagnosis & Treatments

How is Legg-Calve-Perthes disease diagnosed?

Children’s bones heal quickly and have a good ability to self-repair. Therefore, early diagnosis and treatment of Legg-Calve-Peretz disease allows as much time as possible for the head of the child’s femur to remodel itself into a spherical shape.

Examinations on, diagnostic procedures for Perthes disease may include:

• • x-ray for information about the structure of the femoral head
• • MRI (magnetic resonance imaging) for information about the severity of the condition
• • blood tests to rule out infection or other conditions

Treatments

The child’s treatment will depend on his age, the range of motion in his hip, and the severity of the condition.

Conservative treatment:

• • activity restrictions

• • anti-inflammatory medication
• • bed rest and traction

• • casting or bracing to o hold the head of the thighbone in the hip socket

• Not allowing movement of the joint (limited movement)

• • physical therapy, to keep the hip muscles strong and promote hip movement

Surgical treatment

If non-surgical treatments prove inadequate, your child may need surgery to hold the head of the thighbone in the hip socket.

A pediatric orthopedic hip specialist can perform a procedure known as a femoral osteotomy, which reorients the way the femoral head fits inside the hip socket. In this procedure, the femur is cut and rotated for better alignment of the femoral head in the hip socket. The bone is then secured with a metal plate and screws

What is the long-term outlook for children with Legg-Calve-Perthes disease?

The two most important factors that determine your child’s outcome are their age at the onset of treatment (usually, the younger the better) and how much of their femoral head is affected.

Diagnosing and treating your child’s Perthes disease early in its development greatly increases the likelihood of a successful outcome. The majority of children treated for Perthes disease have corrections that enable them to walk, play, grow, and live active lives.

Even after successful treatment in childhood, some children develop hip problems later in life. For this reason, many people with Perthes disease continue to receive follow-up care and monitoring from their pediatric hip specialist into adulthood.