An Overview of Perthes Disease

Perthes disease is a condition of the hip joint that begins in childhood and can lead to hip pain as well as long-term damage to the hip joint. The cause of Perthes disease has been the subject of numerous theories, but no clear source had been identified. Many people who have Perthes disease during childhood develop early hip arthritis, often requiring hip replacement in adulthood. Treatment is best determined by the stage of disease and age at which the condition is diagnosed.

Properly called Legg-Calvé-Perthes disease (LCPD) this condition was named after the healthcare providers who first described the disease in the early 1900s, but the condition still remains incompletely understood.

Treatment remains controversial, sometimes requiring surgery in the childhood years, other times being managed with nonsurgical treatments. Younger children often do best with nonsurgical treatment, whereas children diagnosed at a later age may do better with surgical intervention. Research is ongoing to determine the causes, prognostic factors, and ideal treatment of Perthes disease.

Symptoms

Perthes disease tends to occur in children between the ages of 4 and 10 years old. It can occur during a broader range of ages, but it most commonly emerges in those childhood years. The condition is much more commonly seen in boys than girls. Many children diagnosed with Perthes disease are found to be skeletally immature compared to other children their age; they often appear younger than their chronological age.

Most children who have this condition will develop mild hip discomfort or a limp that brings this condition to the attention of their healthcare provider. The most common signs of Perthes disease include:

• Mild discomfort in the hip joint
• Limping while walking
• Decreased hip range of motion

In addition to these symptoms, muscle weakness can develop in the extremity and more advanced cases of this condition. One specific test that your healthcare provider will look for is a so-called "Trendelenburg sign." When standing on the affected leg, an abnormal tilting of the pelvis is indicative of weakness in the abductor muscles of the hip. This Trendelenburg sign is often seen in children with Perthes disease.

Children who develop Perthes disease have a problem with the bone and cartilage of the ball-and-socket hip joint. Over time, there is deterioration and deformity of the femoral head, the ball of the joint. Other conditions can also cause deterioration and deformity of the femoral head, and these conditions need to be considered as possible diagnoses as well as Perthes disease. Some other conditions that can mimic the signs of the disease include sickle cell disease and corticosteroid treatment.

Causes

The cause of Perthes disease is not well understood, and there have been numerous studies to investigate the source of this condition. There is a question of possible genetic mutations and blood clotting disorders that may contribute to the development of Perthes disease. However, the cause remains unknown.

Diagnosis

Diagnosis of Perthes disease is based on the clinical findings described above, as well as imaging studies to assess the degree of damage to the femoral head. There is no blood test that will diagnose Perthes disease. The diagnosis of this condition is made after eliminating other possible causes of deterioration to the bone of the femoral head.

X-rays are typically obtained to assess the degree of damage to the bone of the hip joint. These X-rays are used to classify the extent of the Perthes disease. While classification of Perthes disease has been around for a long time, the utility of this classification in guiding treatment and offering a prognosis is a subject of controversy.

In addition, MRIs are being used more commonly to evaluate children who have Perthes disease. Again, the utility of these tests in guiding treatment decisions is not entirely clear. While the tests are often done, there is limited evidence about how much these tests will offer information about the best treatments and prognosis.

Treatment

In general, there are three options for treatment of children with Perthes disease. The first option is to treat with physical therapy to address restrictions in motion and weakness of the muscles surrounding the hip. The second option is to use a brace to immobilize the hip joint. The third option is a surgical procedure to realign the bone around the hip joint to try to remove pressure from the affected part of the femoral head. There are no medications, injections, or other pharmacologic interventions that have been shown to help with this condition. Ultimately, the goal of treatment is to try to minimize long-term damage to the hip joint while the condition spontaneously resolves.

Treatment of Perthes disease is guided best by the age of onset of symptoms. Children less than 6 years of age seem to do best with nonsurgical treatments. Between the ages of 6–8, there have been similar results with both surgical and nonsurgical treatments. The results of surgery seem to be best when performed shortly after the diagnosis, rather than after a longer time has passed. Children over the age of 8 years old tend to have better results with surgical intervention.

Determining the best timing of surgery and which children will benefit the most from surgical intervention are subjects of ongoing research. Even with surgical intervention, children who have Perthes disease often develop permanent damage to the hip joint. This is generally well-tolerated in the teenage and young adult years. Young adults who had Perthes as a child will typically resume all normal activity without hip problems. As these individuals age, most will develop arthritis in their 50s, often requiring hip replacement surgery.

Summary

Perthes disease was described more than 100 years ago but remains a bit of a medical mystery. The cause of Perthes disease is not clear, and the ideal treatment remains controversial. In general, younger children do best with nonsurgical intervention, whereas surgery may be the best option in older children. Even with ideal treatment, children who have Perthes disease often develop arthritis of the hip joint later in adulthood. A hip replacement surgery is often necessary for these people.