Is Prematurity a Protective Factor Against Developmental Dysplasia of the Hip? A Retrospective Analysis of 660 Newborns

Abstract

Purpose In Middle Europe developmental dysplasia of the hip (DDH) has an incidence of up to 5.9 %. The rate of congenital hip dislocation as the worst complication of a growth disorder of the hip is between 1.5 % and 2.5 %. Among known risk factors of DDH are breech position, multiples, foot deformities and family history. The aim of this retrospective study was to investigate prematurity as a risk factor for developmental dysplasia of the hip (DDH).

Materials and Methods The hips of 283 infants who were born before the 38^th week of gestation or earlier, and those of 377 infants who were born after the 37^th week of gestation, none of whom had other risk factors for DDH, were compared using the ultrasound technique according to Graf et al., within the first week after birth. Both hips of all infants were included in the study.

Results Surprisingly, the difference in alpha angles between the two groups was statistically extremely significant, favoring the preterm infants. Moreover, we found a physiological curve of alpha angle development with a peak after the 31^st week of gestation. The incidence of pathological dysplasia was not significantly different in the two groups.

Conclusion Our results suggest that prematurity is not a predisposing factor for DDH, but rather is protective for hip development.

Zusammenfassung

Ziel Die Inzidenz der kongenitalen Hüftdysplasie in Mitteleuropa beträgt bis zu 5,9 %. Die kongenitale Hüftluxation als schwerste Komplikation liegt zwischen 1,5 und 2,5 %. Zu den akzeptierten Risikofaktoren der Hüftdysplasie werden die Beckenendlage, Mehrlingsgeburten, Fußdeformitäten und familiäre Häufung gezählt. Das Ziel dieser retrospektiven Datenerhebung ist die Untersuchung der Frühgeburtlichkeit als Risikofaktor für das Vorliegen einer Hüftdysplasie.

Material und Methode Daher wurden die Hüften von 283 Neugeborenen, welche vor der 38. Schwangerschaftswoche oder früher, und jene von 377 Neugeborenen, welche nach der 37. Schwangerschaftswoche geboren wurden, mit der Hüftultraschallmethode nach Graf et al. in der ersten Woche postpartal untersucht.

Ergebnisse Überraschenderweise war der Unterschied der Alpha-Winkel zwischen den beiden Gruppen äußerst signifikant zugunsten der Frühgeborenen. Darüber hinaus konnten wir eine physiologische Entwicklungskurve mit einem Höchstwert nach der 31. SSW darstellen. Die Inzidenz der Hüftdysplasie war nicht statistisch signifikant unterschiedlich in beiden Gruppen.

Schlussfolgerung Unsere Daten deuten darauf hin, dass die Frühgeburtlichkeit kein Risikofaktur für die Hüftdysplasie darstellt, sondern wahrscheinlich protektiv auf die Hüftentwicklung wirkt.

Key words

graf ultrasound - hip development - congenital hip dysplasia - hip ultrasound screening - developmental dysplasia of the hip

Publication History

Received: 26 November 2019

Accepted: 14 April 2020

Article published online:
28 July 2020

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