What Is Legg Calve Perthes Disease?

Legg-Calve-Perthes disease (often shortened to Perthes disease) is a rare orthopaedic condition that affects the hip joint in children.  

This condition is more common in children assigned male at birth (AMAB) than those assigned female at birth (AFAB) and is usually diagnosed between the ages of 2 and 10. Perthes disease can result in significant disruption to childhood activities over months and years during the course of the condition. 

Many cases will resolve on their own without long-term consequences. However, some people will continue to have ongoing symptoms and may go on to develop complications later in life.

Overview

Legg-Calve-Perthes disease (named after the three physicians, Arthur Legg, Jacques Calve and Georg Perthes, who first identified the condition in the early 1900s) affects children, usually between the ages of three to twelve. The majority of cases occur in children between the ages of five and seven.¹ The condition is rare, occurring in only 1–3 children in every 10,000. 75–80% of cases are found in children AMAB.² Usually, only one hip is affected, but 8–24% of children with the diagnosis will have the condition in both hips.³ 

The hip joint is a ball and socket joint located at the junction of the femur (thigh bone) and the pelvis. The ball is the head of the femur (also known as the femoral head), and the socket is a cup-shaped cavity in the side of the pelvis (known as the acetabulum). 

In Perthes disease, the blood supply to the femoral head is temporarily disrupted, resulting in its bone tissue starting to die. This is called avascular necrosis. The dead bone breaks down, and the femoral head becomes deformed, losing its spherical shape. The hip socket can also develop deformities of angle and shape. These changes can make the hip joint move less smoothly and easily and cause pain. 

The blood supply to the hip joint will eventually restore itself, and once this happens, new bone tissue grows once more. This phase can last for several years.⁴ In some cases, new bone cells are laid down in the right shape to maintain the ball of the hip joint, allowing smooth functioning of the ball in the hip socket. In others, the new bone is laid down less regularly, and this can result in a permanent hip deformity. 

Causes and risk factors of perthes disease

Legg Calve Perthes is a complex disease and its causes are not fully understood by medical professionals. Several factors may contribute, and research is ongoing in this area. 

Childhood obesity, socioeconomic deprivation and exposure to smoking have all been proposed as potential risk factors. Hip damage incurred through injury or due to prolonged or excessive mechanical forces could also predispose to the development of the condition.

Perthes disease does sometimes affect more than one member of the same family, but this is not always the case. Research has suggested that there could be a genetic link,^{1, 2}, but further studies are needed to confirm this.

Signs and symptoms of perthes disease

Perthes disease typically involves one or more of these symptoms:

• Hip pain 
• Thigh, groin or knee pain in the affected leg 
• Limping 
• Reduced range of movement in the hip joint, which may feel like stiffness

Symptoms tend to start gradually and are often worse after activity but improved by rest. Normal activities of children of this age –  including running, jumping, and other movements – may be significantly affected.

Management and treatment for perthes disease

As well as addressing the immediate symptoms of Perthes disease, treatment aims to prevent complications in the longer term, which can arise from permanent deformity of the hip joint. 

The key factor here is the maintenance of the correct position of the ball in the socket during the healing phase when the bone of the femoral head is regrowing. The socket acts to mould the shape of the new bone growth, helping it to reform in its original spherical shape. This improves the fit of the joint and determines how easily and smoothly it will move. 

If the shape of the femoral head after bone regrowth is deformed, there is a greater risk of early degenerative disease of the hip joint and the potential for longer-term problems. 

A range of treatments are available and can be used in combination.

Non-surgical treatments include:

• Pain relief - such as anti-inflammatory medication
• Physiotherapy (or physical therapy) - to improve joint movement and strengthen abdominal, thigh, hip and groin muscles
• Use of casts and braces - to maintain correct alignment of hip joint
• Reduction of weight-bearing to reduce symptoms and rest the joint through:
  • Modification of activities
  • Walking aids such as crutches or frames.
  • Wheelchairs
  • Temporary periods of bed rest

Surgical treatments such as pelvic osteotomy and femoral osteotomy may be used to improve the alignment of the hip joint and prevent complications. Osteotomy surgery involves cutting, re-aligning and re-shaping the bone to improve function.

The orthopaedic surgeon will decide on the best course of treatment for each individual case. This will depend on factors such as the age of the child, the stage of maturation of their skeletal system and the degree and location of damage to the hip joint. 

Diagnosis of perthes disease

Healthcare professionals use a combination of physical examination, diagnostic imaging techniques, and detailed patient history to confirm a diagnosis of Perthes disease and to differentiate it from other orthopaedic conditions with similar presentations. 

X-rays can show the shape and structure of the hip joint. Magnetic Resonance Imaging (MRI) can give more detailed information about abnormalities of the joint, the level of blood flow and the stage of the disease process, including the extent and location of damage to the structure of the hip.

Following thorough evaluation, the condition is usually classified using one of several systems, for example, the Herring lateral pillar classification system.⁵ This information helps clinicians to decide on treatment plans and gives an indication of prognosis. 

Progression of the condition and effectiveness of treatment may be evaluated through the ongoing use of X-rays and MRIs.

Complications

Many Perthes disease hips will heal on their own and without any long-term problems. However, some people will continue to have ongoing symptoms, such as hip pain, reduction in hip mobility or a shortening of the leg on the affected side, which affects walking and other activities. 

In addition, the hip joint can remain permanently deformed if the femoral head fails to regrow into the optimal shape. This deformity can contribute to more rapid wear and tear of the joint surfaces, which in turn can increase the chance of the development of degenerative arthritis (osteoarthritis) in later life. Severe osteoarthritis may need to be treated with surgery such as a hip joint replacement, and this may be needed at a younger age than normal in people who had Perthes disease as a child. 

Children who develop Perthes disease earlier tend to have fewer long-term problems than those who develop it at a later stage of childhood. This is due to the greater capacity of the skeletal system in younger children to regenerate and repair. Children AFAB may be at greater risk of longer-term problems than those AMAB due to their skeletons often maturing earlier. Children who were overweight at the time of onset of the condition also have a greater risk factor for longer-term complications.^{4, 5}

FAQs

What is legg calve perthes disease?

Legg-Calve-Perthes disease is a paediatric orthopaedic condition affecting the hip joint . The condition involves inadequate blood supply to the femoral head, resulting in the bone dying and breaking down. This can cause pain and problems with hip movement. The condition is self-limiting and resolves itself but can last from several months to several years. A variety of treatments can be used to reduce symptoms and prevent longer-term complications.

How can I prevent perthes disease?

The causes of Perthes disease are not fully understood and are thought to be multifactorial. As such, there are currently no specific recommendations about how to prevent the development of the condition. However, factors such as previous injury, obesity during childhood and exposure to smoking may increase the risk of its development.

How common is perthes disease?

Perthes disease is rare and thought to occur in only 1 to 3 children in every 10,000. Children with AMAB are four times more likely to develop the condition than children with AFAB. 

When should I see a doctor?

Symptoms of Perthes disease include pain in the hip, knee, thigh or groin, limping (including painless limp), feelings of stiffness in the hip and reduced hip motion. Consult a healthcare professional if your child is experiencing these hip problems.

Summary

Legg-Calve-Perthes disease is a rare condition, occurring in only 1–3 children in every 10,000. The majority of cases occur in children between the ages of five and seven. Inadequate blood supply to the femoral head causes bone death and breakdown, leading to pain and hip movement restriction. 

The causes of Perthes disease are considered to be multifactorial but not fully understood – previous injury, childhood obesity, and exposure to smoking may increase risk.  

Normal childhood activities –  including running and jumping – may be seriously impacted. Although it is often self-limiting, resolving itself, it can last from several months to several years, and some children develop long-term complications. Treatment aims to address both current symptoms and to prevent complications in the longer term, which can arise from permanent deformity of the hip joint. Various conservative and surgical treatments can be used.

Consult a healthcare professional if your child is experiencing hip, knee, thigh or groin pain, is limping or has feelings of stiffness in the hip joint and reduced hip motion.