[Collagen volume of the umbilical cord in infants with unstable hip joint].

Collagen amounts in the umbilical cord in infants with unstable hip joint and positive Ortolani 's sign were measured and the results were discussed from pathogenetic viewpoint. Incidence of unstable hip and that of neonatal hip with positive Ortolani 's sign were 0.23% and 0.93% respectively, in 4,824 neonates examined during one year: 1980. Biochemical analysis was carried out in the umbilical cords of 8 female neonates with positive Ortolani 's sign and of 8 female babies who were later diagnosed as having unstable hip joint. A control group consisting of 16 normal babies with similar sex, body weight, period of gestation and birth order, corresponding to the above mentioned 2 groups, was also investigated for the purpose of statistical analysis. The amount of hydroxyproline was examined by a modified Woessner 's method and the amount of collagen was calculated by Fredensborg 's method. No significant statistical difference in collagen amounts was found between these three groups. Relationship between amounts of collagen and 9 obstetrical factors relating to congenital dislocation of the hip joint: mother's height, weight and occupation; neonatal sex, birth order, position in the uterus and weight; weight of placenta and length of the umbilical cord, were studied and statistical analysis was made. Amounts of collagen in the cross section of the umbilical cord were significantly lower in neonates with longer umbilical cords.(ABSTRACT TRUNCATED AT 250 WORDS)