Journal of Orthopedics & Rheumatology

Research Article

Does a Normal Hip Ultrasound at 3-6 Months of Age Predict a Normal X-ray?

Paez CJ1, Hansen CH1, Bomar JD2, Upasani VV2* and Pring ME2

1University of California, San Diego Medical Center, 200 West Arbor Drive, MC 8894, San Diego, CA 92103
2Rady Children’s Hospital, San Diego 3020 Children’s Way San Diego, CA 92123
*Address for Correspondence: Upasani VV, Rady Children’s Hospital, San Diego 3020 Children’s Way San Diego, CA 92123, USA; Phone (858) 966-6789 / Fax: (858) 966- 7494; E-mail: vupasani@rchsd.org
Submission: 30 September 2021;
Accepted: 04 November 2021;
Published: 10 November 2021
Copyright: © 2021 Paez CJ, et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Objective: Ultrasound (US) may be used to diagnose/monitor developmental dysplasia of the hip (DDH) prior to femoral head ossification, after that, radiographs (XR) may become a better choice. The objective of this study was to compare US to XR performed on the same day for diagnosis or monitoring of DDH in patients 3 to 6 months of age.
Methods: 92 patients (183 hips) ages 3 to 6 months who were seen for hip screening for DDH were retrospectively reviewed. All patients had a same-day hip ultrasound and plvis radiograph. Alpha angle, hip stability, femoral head coverage, acetabular index (AI), IHDI grade, and break in Shenton’s line were recorded and used to diagnose the hip as normal or dysplastic.
Results: 17.5% of hips were diagnosed with DDH based on XR, 12% of hips were diagnosed with DDH on US. Thirteen hips were read as normal on US but dysplastic on XR. Using XR as the definitive diagnosis, US had sensitivity of 59% and specificity of 98%. Using US as the definitive diagnosis, XR had sensitivity of 86% and specificity of 92%.
Conclusion: In the 3-6 month age group, US alone may underdiagnose hip dysplasia and be inadequate to guide treatment decisions. In this age group, we suggest that pelvis radiographs be used when deciding to either initiate or conclude DDH treatment based on the higher sensitivity of the exam.