Developmental dysplasia in male infants: risk factors, instability and ultrasound screening.

Abstract

To evaluate the relationship between risk factors and presence of developmental dysplasia of the hip (DDH) in male infants, and to compare the efficiency of different ultrasound (US) screening protocols. 1321 male infants were included in the study. Ultrasound examinations were performed by combining Graf's static method and Harcke's dynamic method. The relationship between the risk factors and DDH and the effect of risk factors on sonographic worsening in type 2a hips were assessed by the chi-square test and Fisher`s exact test. The incidence of DDH was 1.4%. 13% of the cases had type 2a morphology, among whom in 3.1% sonographic deterioration occurred. The treatment rate was 1.8%. The rate of follow-up US was 17.5%. No risk factor was found to have a statistically significant influence on DDH (= type 2b morphology). Among the 32 cases with DDH, 23(72%) had a risk factor or positive clinical finding while 9(28%) did not (p:0.006). Risk factors do not have a statistically significant relationship with DDH in male cases. In our study 28% of the cases with DDH would be missed by a selective US screening protocol. We recommend assessment of all male infants with hip US.