Legg Calve Perthes Disease

Definition

Legg-Calve-Perthes disease (LCPD) is a rare hip disease that affects children. It is a pattern of bone tissue death and repair at the hip which can cause abnormal growth and development in children.

The hip is made of the ball-shaped head of the thigh bone (femoral head) and bowl-shaped socket of the pelvis. LCPD affects the femoral head. There are 4 stages of LCPD:

• Initial—Poor blood flow to the femoral head causes death of bone tissue. Inflammation can cause limping at this stage, which can last several months.
• Fragmentation—The dead bone tissue is removed and replaced by the body. At first the replacement bone is softer and weaker than normal bone and can be altered by normal pressures like walking. The shape of the femoral head changes during this time and the softer bone has an increased risk of a fracture. This stage can last up to 2 years.
• Reossification—The longest phase, often lasting a few years. The newly-shaped femoral head grows stronger.
• Healed—The regrowth of bone is done, and the femoral head shape is now permanent.

Severity of LCPD depends on the child's age when the disease started and how much damage was done during fragmentation.

Normal Hip Anatomy

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Causes

LCPD is caused by an interruption of blood flow to the femoral head. Low or blocked blood flow causes bone tissue death and begins the LCPD cycle. The exact cause of the interruption is not known. Known factors that may lead to loss of blood flow include:

• Changes in the blood supply, which can result in fewer blood vessels or inability of the blood vessels to deliver blood normally
• Problems with blood clots or pooling that may cause pressure or compression inside bone tissue
• Repetitive stress
• Genetics

Risk Factors

LCPD is more common in male and at ages 4-8 years. It is also more common in children with European, Asian, or Eskimo ancestry. Other factors that may increase your child’s chance of developing LCPD include:

• Small or short for age
• Delayed maturity
• Athletic, active child
• Secondhand smoke exposure
• Blood clotting abnormalities

Symptoms

The primary symptom of LCPD is a limp when walking or running. Other symptoms may include:

• Hip pain
• Groin, thigh, or knee pain
• Reduced range of motion in the hip
• Shortening of the leg, or legs that are not the same length
• Muscle weakness in the upper thigh

Diagnosis

You will be asked about your child’s symptoms and medical history. A physical exam will be done. During the exam, your child’s hip will be examined to see how far it can move. The doctor may refer your child to a specialist. An orthopedist focuses on bones and joints.

Images may need to be taken of your child's bones. This can be done with:

• X-ray
• MRI scan
• Bone scans

Treatment

Talk with your doctor about the best plan for you. Options include the following:

Physical Therapy

If your child’s symptoms are mild, your doctor may prescribe physical therapy. A therapist will work with your child to maintain range of motion. You may be taught certain exercises to do with your child at home.

Medical Treatment

Medical treatment is used to improve healing and prevent further injury to the hip.

Medical treatment is used to improve healing and prevent further injury to the hip.

• It may include using crutches, traction, a brace, or cast.
• It is usually done before surgery is recommended for children less than 6 years old.

Surgery

In some cases, your child may need surgery.

• The top of the thigh bone may be resurfaced with metal.
• Bone removal may be done to reposition or reshape the hip bone.
• Rarely, the hip will be replaced.

Prevention

There are no current guidelines to prevent LCPD because the cause is unknown.