Optimal Timing of Ultrasound for the Diagnosis of Developmental Hip Dysplasia in Infants: 1st or 5th Week?

Abstract

Objective: Ultrasonography (US) is a useful, easy, and accurate screening method for the diagnosis of neonatal developmental dyspla- sia of the hip. The purpose of this prospective and cross-sectional study is to determine the optimal timing of US for the evaluation of the hip joints in newborns. Methods: We enrolled consecutive 27 [18 girls (66.7%) and nine boys (33.3%)] newborns in this study. Two experienced radiologists (S .T. and M.O ̈ .) performed standard hip US examinations at the 1st and 5th weeks of age according to the method described by Graf. We assessed the relationship between femur head and acetabulum and compared the results of evaluation obtained between the 1st and 5th weeks. Additionally, we evaluated the agreement between the two radiologists. Results: None of the babies were found to have subluxation or dislocation by clinical examination. The US measurements regarding the ossification and the diameter of femur head, bony, and cartilaginous roof at the 1st and 5th weeks were similar (for all infants, P > .05). In our series, no hip was defined as Graf’s type IIb or higher. In total, four (14.8%) right hips and six (22.2%) left hips (total 10 hips) were classified as Graf’s type IIa (physiologically immature) at the 1st week of evaluation. A total of seven hips spontaneously returned to their normal positions during the following 4 weeks. However, two (7.4%) right and one (3.7%) left hip joints were still classified as type IIa at the 5th week of evaluation. Graf type of hips was reported as similar in all the infants by the 1st and 5th week of measure- ments (n ¼ 54, P > .05, for each). There was no interobserver variability between the two radiologists with respect to Graf’s classifica- tion (j > 0.81). The blunt/round shape of acetabular rim defined in 10 hips at the 1st week was improved to an angular shape in the eight hips at the 5th week (P ¼ .008). Conclusion: Early US screening along with normal physical examination can diagnose some hip disorders in babies. Most of the abnor- mal findings detected at the 1st week of US screening recovered spontaneously at the 5th week. Infants with normal US measurements at the 1st week may be excluded from the follow-up, and those with suboptimal findings may be monitored by physical examination and repeated US scans.