Perthes disease is a condition that affects the hip in children between the ages of four and eight. The condition is also referred to as Legg-Calve-Perthes disease in honor of the three physicians who each separately described the disease.
In this condition, the blood supply to the growth center of the hip (the capital femoral epiphysis) is disturbed, causing the bone in this area to die. The blood supply eventually returns, and the bone heals. How the bone heals determines what problems the condition will cause in later life. This condition can lead to serious problems in the hip joint later in life.
Until recently, all treatment (operative and nonoperative) was focused on a concept called hip modeling. The goal of treatment has been to mold the femoral head back into a round (spherical) shape and keep it in the hip socket (acetabulum). According to several large studies, the results of this approach have been only “modestly successful.”
Less than half the children treated for Pethes disease end up with a spherical, well-contained femoral head. And no one has been able to identify why some children respond to treatment while others do not. Some experts think there is a need to work more with the cause of the problem (loss of blood to the hip, impaired healing, altered biology) rather than just the effects of the disease (femoral head necrosis, deformity, and collapse).
Improved understanding of the pathogenesis of this condition is starting to open doors. New avenues for research centered on pathologic-based rather than symptom-based treatment are being explored. The hope is to find some way to prevent Perthes from developing in the first place. A second goal is to treat the condition quickly and successfully when it does occur, thus preventing some of the long-term effects today’s generation with Perthes will suffer later in life.
Most of the newer information comes from experimental studies on pigs and dogs. It’s looking more and more like a complex problem with multiple causal factors — not just one effect. The new theories include ischemic injury leading to changes in the mechanical properties of the articular (joint) cartilage, change in mineral (calcium) content of the bone, disruption of the growth plate, and an impaired repair process.
With this new understanding comes an effort to rethink our current treatment approaches using hip modeling. For example, it is believed that putting load on the deformed hip will make the problem worse. So sometimes are restricted from weight-bearing activities in order to reduce the load on the hip. But whether or not this treatment strategy really makes a difference is unknown. Studies to investigate the effect of weight-bearing versus non weight-bearing in treating Perthes are needed.
New avenues for research centered on pathologic-based rather than symptom-based treatment are being explored. The hope is to find some way to prevent Perthes from developing in the first place. A second goal is to treat the condition quickly and successfully when it does occur, thus preventing some of the long-term effects today’s generation with Perthes will suffer later in life. It may turn out that hip modeling is still the best way to go but experts hope to find more specific treatment that will yield better short-term and long-term results.