Influence of sex and age on sonographic infant hip indices

Ultrasound is a non-invasive, cheap and readily available imaging modality for studying the infant hip. Early detection of developmental hip subluxation, acetabular dysplasia and the prevention of late presentation of a developmentally dislocated hip with consequent secondary premature degenerative arthritis are goals that all practitioners should strive for. Provision of axial indices of alpha and beta angles of the infant hip joint in Kano, Nigeria using ultrasonography to establish a normogram as reference values for further studies is the objective of this study. This descriptive prospective study was conducted at the Radiology Department of Aminu Kano Teaching Hospital, Kano state, Nigeria. Successive four hundred appropriately consented infants were recruited for this study. The axial angle relationships of both hip joints were measured using 7.5 MHz linear transducer of Mindray DP-8800 Digital plus ultrasound machine. The mean alpha and beta angles for both hips in females were 56.590 and 49.580 respectively while those for males were 56.730 and 50.530 respectively. Minimum and maximum alpha angle for both hips ranged from 380 to 780 while the beta angles ranged 290 to 660 respectively. The age group 1-3 months has the highest frequency of respondents (251) while age group 10 - 12 months has the lowest (22). There was no statistically significant difference in the alpha and beta angles between males and females hips and age of the infants did not affect the hip indices. The study showed no statistical significant difference in the measured alpha and beta angles between males and females. Age of measurement in infants did not affect the hip indices.