Legg Calve Perthes Disease: Symptoms, Causes, Risks, Complications, Diagnosis and Treatment



Mobility is an important aspect of life, especially for kids. Children love to run around, chase their pets and play with their friends. Any condition that affects their mobility and the ability to perform physical activities will take a toll on their lives.

A childhood condition, called Perthe’s disease or Legg-Calve-Perthes disease affects the hip, where the femur or thigh bone and pelvis meet. This condition emerges when the blood supply is impeded to the ball part of the hip joint. If there is no adequate blood supply to the area, the bone will die and become brittle, making it break more easily. When the bone collapses, this is termed as avascular necrosis.

As the disease progresses, the body will absorb the dead bone cells. In response, the body will produce new ones and change the shape of the head of the femur. However, this may lead to a form of deformity that will eventually cause arthritis in the future.

The incidence of this condition varies by population. However, white people are at a higher risk of developing the condition. Perthes disease affects about one to three in 20,000 children who are below 15 years old. Boys are more susceptible to developing the condition than girls, usually between the ages of three and 12 years old.

Perthes disease is uncommon, affecting about one in 1,200 children. The average onset is by the age of 6 years old. Consequently, the condition affects kids who are very active and athletics and less than 5 percent of those with the disease are affected in both their hips.


One of the earliest signs of Perthes disease is a change in the way a child walks or runs. This is the initial sign most parents would notice. Parents usually observe this during sports activities. The other signs and symptoms of the disease include:

  • Pain – There is a pain in the groin or hip area. However, the pain may radiate to the leg, knee, and thigh. The pain worsens during activities and becomes relieved with rest. Moreover, there are painful muscle spasms in the hip area.
  • Limp – The child may limp while walking or running. The affected bone may cause a limp when the child is moving around.
  • Stiffness – Because of the altered shape of the thigh bone, the movement of the hip can be limited.
  • Muscle wasting – This sign is usually observed at the top of the thigh, near the affected area.
  • Shortening of the leg – The affected leg may become shorter than the other.

When to see a doctor:

The patient should seek medical attention if their movements become limited, leading to the inability to perform simple daily tasks like walking, taking a bath and others. Moreover, the patients need immediate medical attention if they developed fever and unbearable pain.


The exact cause of the temporary reduction of blood flow to the thigh bone is still unclear. In Perthes disease, there is limited blood flow to the ball portion of the hip joint. When this happens the bone becomes weak, brittle and unstable.

There are theories on how this happens. One theory pinpoints that something happens in the blood vessels which supply the blood to the thigh bone. Because of the obstruction of blood supply to the area, the femoral head loses the needed oxygen and nutrients, which are vital for survival.

As a result, the cells in the bone suffer from necrosis or sudden death and the bone softens. It can break easily and can become distorted. Over time, the blood vessels begin to regrow and supply blood to the area again. Since the bones repair itself, the bone in the femoral head regrows but it will take longer.

During this time of regrowth, the main concern is to have the femoral head form a good rounded or spherical shape. This will help in making sure the femoral head fits perfectly into the hip joint.

4Risk Factors

Perthes disease may develop in certain people with risk factors including:

Gender – The children’s gender may affect their likelihood of developing the condition. The prevalence of Legg-Calve-Perthes disease is up to five times more common in boys than in girls.

Age – Children are most commonly affected. It occurs between the ages of 4 and eight years old. However, children can be affected until they reach the age of 15 years old.

Race – White people are more susceptible to developing the disorder than other races.

Genetics – Legg-Calve-Perthes disease is not usually passed down in families but in a small percentage of cases, there were mutations in the COL2A1 gene. These mutations cause the bone abnormalities seen in the patients.

This gene is mainly found in cartilage. In Legg-Calve-Perthes disease, the gene mutation triggers the production of an altered protein.


In general, when Perthes disease is not treated immediately and appropriately, it may lead to a group of complications. Many individuals who develop Legg-Calve-Perthes disease recover without any long-term complications. However, if complications do happen, they may include the following:

Hip arthritis – Children who have Legg-Calve-Perthes disease are at a higher risk of developing hip arthritis when they grow up. This usually affects the hip area and the cause is the abnormal shape of the hip joint.

Permanent hip deformity – Perthes disease may cause the hips to be permanently deformed, especially if the disease occurs between the ages of 6 and eight years old.


To accurately diagnose the condition, the doctor will perform a complete physical examination of the child and the parents might be interviewed for the child’s medical history. The other diagnostic tests the doctor will recommend the following:

Imaging tests – Imaging tests are requested by the doctor to visualize the hip bone and joint. The most commonly-used imaging tests include:

  • X-ray – First, the doctor may request for an X-ray. For first scans, the bones might look normal because it can take one to about two months after the symptoms start. The doctor might recommend series of X-rays to track the progression of the disease.
  • Magnetic resonance imaging (MRI) – The MRI utilizes a strong magnetic field and radio waves to create detailed images of the bones and soft tissues in the body.
  • Bone scan – In a bone scan, a small amount of radioactive material is introduced into the vein and this may show images of the bones, particularly the thigh bone.


As the Perthes disease worsens, the femoral head weakens and becomes brittle, leading to fractures. The main goal of the treatment is to keep the femoral head as round as possible. Moreover, this will help reduce the chances of developing complications.

Surgery is not needed in children younger than six years old since they can still grow taller. The treatment of the condition is designed to protect the hip from further trauma and injury.

Therapy – Physiotherapy entails letting the child practice range of motion exercises to help maintain the mobility of the joints and bones. This is usually recommended in patients who are younger than 6 or 7 years old. The most common therapies include:

  • Physical therapy – When the hip joints stiffen, the ligaments and muscles may shorten. Hence, physical therapy is needed to stretch these parts of the skeletal system. Stretching exercises may become helpful to make the hips more flexible.
  • Traction – When the child experiences pain, traction may help.
  • Crutches – When the hip is affected and the child needs to avoid bearing weight on the affected side, the use of crutches is helpful.
  • Casts – In some cases, the femoral head needs to be located within the socket. To do this, the doctor may request a special type of leg cast to keep the legs spread properly.

Medications – A licensed doctor should request the use of anti-inflammatory medications. Do not try to self-medicate because it’s dangerous. Usually, the doctor will prescribe over-the-counter anti-inflammatory drugs like ibuprofen to relieve the pain and swelling.

Surgery – If a groin muscle has shortened because of too much limping, surgery is needed for it to be released from the bone. There are other surgical methods usually done to treat Legg-Calve-Perthes disease, including:

  • Contracture release – This procedure is used to lengthen the tissues that had shortened during the illness. This will help restore the flexibility of the hip joint.
  • Removal of loose bodies – trimming extra bones around the thigh bonehead is helpful in easing motion and relieving pain.
  • Joint replacement – The kids who have had Perthes syndrome may require hip replacement surgery when they grow older. However, this type of surgery can be hard to understand since there is a higher risk of nerve damage and bone fracture.
  • Joint realignment – For kids older than 6 and eight years old, joint realignment may help restore the set-up to normal. The doctor realigns the hip joint and the bones are held in place while the bone heals.

The condition would take about at least two years to run its course. This time the level and nature of stiffness will change. Some kids may return to normal, while others may suffer from permanent stiffness, disability or a hard time moving around.