Ultrasonographic Assessment of the Asymptomatic Neonatal Hip Joint at the University of Benin Teaching Hospital, Benin City

Background The hip joint is a major weight-bearing joint that enables standing, walking, and running. In neonates, Hip abnormalities in neonates can reflect neuromuscular or intrauterine problems. Improper positioning can deform the acetabulum and predispose to developmental dysplasia of the hip (DDH). Early asymmetry or instability warrants further evaluation. The aim of this study was to determine the acceptable normal ranges of acetabular angles (α and β) and percentage femoral head coverage in neonates for clinical practice in our environment, and to note variations between the left and right neonatal hip joints. Methods This study investigates the sonographic characteristics of the normal neonatal hip joint, conducted at the Department of Radiology, University of Benin Teaching Hospital, Benin City. A prospective analysis was performed on the hip joints of 384 randomly selected neonates, who were examined with a 6.5 MHz sector-array transducer on a Sonoace ultrasound scanner. Measurements of the alpha (α) and beta (β) angles, as well as femoral head coverage, were obtained and analyzed. Results The mean α angles for the right and left hips were 51.7 ± 0.3° and 51.9 ± 0.3°, respectively, while the mean β angles for the right and left hips were 47.3 ± 0.33° and 48.1 ± 0.3°, respectively. The mean percentage femoral head coverage was 46.3%±0.4% for the right hip and 46.9%±0.4% for the left hip. This study also found a positive correlation between birth weight and gestational age, and between both acetabular angles and femoral head coverage. In contrast, the mode of delivery and birth presentation showed no significant correlation. Conclusion This study has established the upper and lower threshold values for the α and β angles and the percentage of femoral head coverage. These values were found to be consistent with Caucasian reference values used for comparison. Additionally, the correlative analysis revealed a positive correlation between acetabular angles and femoral head coverage, whereas a negative correlation was observed between the α and β angles.