Development and remodeling of the hip joint of preterm neonates in sonographic evaluation.

: Background. Recent studies on the developmental dysplasia of the hip emphasize the role of the last trimester of pregnancy in the origin of the pathology. The aim of the study was to evaluate the development of the hip joints of preterm neonates born with different weight and in different periods of pregnancy. Material and metods. 286 hip joints of preterm neonates born between 24 and 37 week of pregnancy and 62 ones of newborns from term deliveries were analysed. The evaluated newborns were divided into 3 groups of preterm ones: with the weight at birth below 1000 g (23 children), between 1000 and 1500 g (40 children), between 1500 and 2000 g (80 children) and a control group- 31 children from term deliveries with normal weight. In every case 4 single sonographic examinations were performed using the method presented by Graf. First, before the 6 week of age (mean 3 weeks), next after the 3rd month af age (mean 14 weeks), next after 5th month of age (mean 23 weeks) and the last one after the 7th month. The evaluation of the remodeling of the hips was based on the observation of changes in a and ss angles. Results. It was found that the lower was the newborn's weight at birth the higher was the b angle. The similar tendency was noticed for the ss angle but was observed only in the group of preterm neonates. When the evaluation was based on the postconceptional age at the examination, it was found that the values of both angles worsened together with age, reaching the worst values between 37th and 42th week of postconceptional age. It proves the theory, that in the last trimester of the pregnancy, the acatabulum becomes more shallow and vertical together with the worsening of the cartilaginous femoral head coverage with time. Conclusion. The presented results show that the worst anatomical parameters of the hip joint can be found at physiological term of delivery.