Analysis of selected anthropometric parameters in infants in relation to the risk of developing hip dysplasia

Introduction
Despite the known risk factors for the occurrence of DDH, such as the breech presentation, we still do not know all the factors that determine the more frequent incidence of dysplasia in female children. The aim of the study was compare anthropometric parameters of boys and girls in the first months of life, and to relate these measurements to cases of children diagnosed with developmental hip dysplasia (DDH).

Material and methods
502 children were enrolled in the study – 273 (54.4%) girls and 229 (45.6%) boys. The mean age at the time of the examination was: 1.8 ±0.9 months, boys; 1.98 ±1.4 months girls. The statistical analysis covered the birth weight, body weight at the time of the examination, length of pregnancy, type of delivery and pelvic measurements.

Results
In the study, we observed a higher frequency of DDH in the group of girls: 15 cases in 13 (4.76%) girls. We observed relationship (p = 0.023322) between the week of pregnancy at time of delivery and the incidence of DDH. Pelvic dimensions did not show such a relationship. The group of girls with dysplasia (n = 13) differed from the group of healthy girls in terms of the week of pregnancy (p = 0.040014) and in terms of birth weight (p = 0.048079).

Conclusions
Boys and girls do not differed significantly in terms of pelvic width and hip spacing. The hypothesis that it is the differences in the structure of the pelvis that may contribute to the more frequent incidence of DDH in girls is not confirmed.