Congenital Deformity of Lower Limbs

Congenital dislocation of the hip (CDH) is also called developmental dislocation of the hip (DDH). Scholars at home and abroad recognize that it is related to many factors, including (1) congenital factors, such as heredity, fetal position, ligament relaxation, etc. (2) Acquired factors, such as child-rearing methods, countries and nationalities accustomed to carrying their children on their backs, have a low incidence of congenital dislocation of the hip, but a high incidence of tying and wrapping the legs of the newborn together. (3) Gender difference, researchers found that the ratio of female to male is 6:1, the incidence ratio of male and female is very different. In addition, the relaxin in female fetus is more than that in male fetus. It has also been reported that the female fetus has a greater anteversion of the femoral neck than the male fetus and is prone to dislocation. (4) Left and right differences, it is showed that the total number of cases was divided into 4, while the bilateral incidence was 1, the left incidence was 2, and the right incidence was 1. That is to say, the incidence of unilateral disease is three times that of bilateral disease. The incidence on the left side was twice that on the right side.