Developmental dysplasia of the hip: early diagnosis and management

Abstract

Limb buds begin to develop embryologically within 3 weeks of fertilisation. The hip joint develops from a block of mesenchyme which differentiates rapidly so that in the 6-week embryo the outlines of the pelvis and femoral shaft may be seen. The cleft which heralds the hip joint cavity begins to develop in the 8 week embryo. Watanable 1 showed that it was not until 11 weeks that it was possible experimentally to dislocate the fetal hip. Active hip movement occurs with progressive muscle innervation and the first fetal kicking is usually felt at about 16 weeks of pregnancy. The hip joint enlarges and matures during the last 20 weeks of intrauterine life. Le Damany 3 demonstrated that the acetabulum becomes relatively more shallow in the last 3 weeks of gestation. In essence, therefore, the femoral head is less completely enveloped by the acetabulum at birth and therefore more vulnerable to displacement.