Vasiliki Chatziravdeli - ۲ndOrthopaedic Department, “Papageorgiou” General Hospital of Thessaloniki, Thessaloniki, Greece
Christos Kazas - ۲ndOrthopaedic Department, “Papageorgiou” General Hospital of Thessaloniki, Thessaloniki, Greece
Dimitrios Metaxiotis - ۲ndOrthopaedic Department, “Papageorgiou” General Hospital of Thessaloniki, Thessaloniki, Greece
Ilias Chatziioannidis - ۲nd Neonatal Department and Neonatal Intensive Care Unit, Aristotle University of Thessaloniki, “Papageorgiou” General Hospital of Thessaloniki, Thessaloniki, Greece
Georgios Mitsiakos - ۲nd Neonatal Department and Neonatal Intensive Care Unit, Aristotle University of Thessaloniki, “Papageorgiou” General Hospital of Thessaloniki, Thessaloniki, Greece
Elissavet Diamanti - ۲nd Neonatal Department and Neonatal Intensive Care Unit, Aristotle University of Thessaloniki, “Papageorgiou” General Hospital of Thessaloniki, Thessaloniki, Greece

Background: Developmental dysplasia of the hip (DDH) is a condition with variation among ethnicities and regions. We aimed to investigate the effect of a gestational week of birth on the sonographic acetabular hip angles of newborns. Methods: We prospectively scanned the hips of neonates born in a single, tertiary hospital during their first week of life, using the Graf sonographic method. Demographics, obstetric history of the mother, birth weight, parity, presentation, family history of developmental dysplasia of the hip (DDH), gender, mode of delivery, single/multiple birth, and gestational age were recorded. Acetabular α and β angles were measured, and hip type was determined according to Graf’s classification. Patients were divided according to the gestational age of birth (<۳۷ weeks, ۳۷-۳۸, ۳۸-۳۹, ۳۹-۴۰, >۴۰ weeks). Results: From May- October ۲۰۲۰, ۳۴۲ babies (۶۸۴ hips) were examined (۵۲.۹% males / ۴۷.۱% females). ۷۶.۷% were Caucasian-Greek, and ۸۸.۳% were term babies. There was a significant difference between the α-angles of the right and left hip in both genders. More females had Type II hips than males. Subgroup analysis did not reveal a significant difference in hip angles of term babies. There was no correlation between birth weight or gestational age and hip angles. Female gender and the existence of maternal thyroidopathy were positively correlated with Type II hips. Conclusion: Gestational birth age in term infants is unimportant regarding acetabular hip angles. Female gender and maternal thyroidopathy appeared to be related to hip type. Further investigation may be warranted to elucidate the effect of maternal thyroidopathy and hip development. Level of evidence: II

hip angle, Hip dysplasia, Gestational Age, Greece, Sonographic