A Study of Stress Factors in Perthes' Disease of the Hip, Using the Finite Element Method

Perthes’ disease is associated with impaired blood flow (avascularity) to the upper end of the femur at the hip joint in children. It affects boys more than girls, with a peak incidence about the age of 4 years. The cause of the avascularity is unknown but local stress factors are thought to be involved. Symptoms of the disease include pain and limping. X-ray examination of the femoral head (Fig 1) reveals supero-lateral flattening of the bony femoral head (epiphysis), thickened cartilage infero-medially (‘tear-drop distance’), and radiological translucencies in the femoral head and neck. In a normal hip joint the femoral head is almost spherical, but in Perthes’ disease the femoral head gradually becomes deformed. In some older children, the deformed femoral head becomes indented by the outer margin of the hip joint socket (‘hingeing’).

B.S. Choo, A.D.C. Hogg, R.G. Burwell, A. Moulton and B.S. Worthington