[Pathogenesis of hip osteoarthritis].

Coxarthrosis is the most frequently occurring hip disease, is the most common type of osteoarthritis in general and is the second most frequent cause of chronic invalidity. Causes are inherited hip diseases (e.g. dysplasia), growth diseases (e. g. Perthes' disease, slipped capital femoral epiphysis), injuries (fractured femur, fractures of the femoral head or acetabulum, necrosis of the femoral head), and inflammatory, rheumatic or metabolic diseases. Hip deformities such as hip dysplasia or protrusio acetabuli lead to increased mechanical deterioration as a result of the pathological anatomy and hence to a chronically progressing degeneration (coxarthrosis). Primary coxarthrosis usually begins between the 50th and 60th year of life; the secondary disease can develop even earlier depending on cause.