Timing of appearance of ossification centers in femur determined by ultrasound

Objective To study the timing of appearance of ossification centers in femur.Methodis Between May 2010 and December 2010,20 232 hips of 10 116 normal infants received hip ultrasound examination for congenital disease screening.The infants' hip ultrasonography was retrospectively analyzed to study the timing of appearance of ossification centers in femur.Results The study recruited 5531 male infants and 4585 females.The infants aged 10-226 days old (mean age,67±0l.46days).Among them,ossification center on both side of femurs were found on 17t6 (17,0％ ) infants.The earliest timing of appearance of the first ossification center was 30 days old,while the latest appearance of the first ossification center was seen on a 226 days old infant.The ossification centers were increasing with aging,and most of the ossification centers appeared between 2 to 5 nonths (60-179days,60.3％).Logistic regression analysis showed that age,sex,birth age,birth weight,birth length,current weight,current length,feeding patterns were risk factors associated with the timing of appearance of ossification centers in femur.Conclusions Uhrasonography is senaitive and accurate to detect the ossification centers in femur. Key words: Ultrasonography;  Femur head