Potential for Change in US Diagnosis of Hip Dysplasia Solely Caused by Changes in Probe Orientation: Patterns of Alpha-angle Variation Revealed by Using Three-dimensional US

Abstract

Use of 3D three-dimensional US showed that alpha angles measured at routine 2D two-dimensional US of the hip can vary substantially between 2D two-dimensional scans solely because of changes in probe positioning. Not only could normal hips appear dysplastic, but dysplastic hips also could have normal alpha angles. Three-dimensional US can display the full acetabular shape, which might improve DDH developmental dysplasia of the hip assessment accuracy.