In Perthes disease – colloquially called Perthes disease – (synonyms: Calvé-Legg-Perthes disease; Calvé-Legg-Perthes osteochondrosis; Calvé-Legg-Perthes syndrome; coxa plana idiopathica; juvenile femoral osteochondrosis; juvenile femoral head necrosis; juvenile osteochondrosis of the caput femoris; juvenile osteochondrosis of the femoral head; Legg disease; Maydl disease; Calvé-Legg-Perthes disease [osteochondrosis deformans coxae juvenilis]; Perthes disease; osteochondropathia deformans coxae juvenilis; osteochondrosis deformans coxae juvenilis; Perthes-Clavé-Legg-Waldenström disease; Perthes disease; Perthes osteochondrosis; ICD-10-GM M91. 1: Juvenile osteochondrosis of the femoral head [Perthes-Legg-Calvé disease]) is an aseptic bone necrosis of the caput femoris (femoral head; head of femur).
The cause of aseptic bone fibrosis is ischemia (reduced blood flow) of the caput femoris without the presence of infection.
Sex ratio: boys to girls is 4-5: 1.
Peak incidence: the disease occurs predominantly in childhood. It usually affects children between 3 and 10 years of age, and in rare cases continues until the end of puberty.
The incidence (frequency of new cases) is approximately 10 cases per 100,000 inhabitants per year (in Germany).
Course and prognosis: In the majority of cases, Perthes disease is unilateral. In 15-20% of cases, both sides are affected. The course of the disease is inconsistent, so therapy must be individualized. The prognosis depends on the classification (see “Classification”): Catterall III and IV as well as Hering C are associated with a worse prognosis. The following factors enter into the prognosis: Age at onset (less than 6 years is favorable), extent of motion restriction, femoral head involvement, and additional femoral head risk factors (e.g., obesity). The goal is to prevent early coxarthrosis (osteoarthritis of the hip joint).
