Detection of Hip Dysplasia in Infants Using Audible-Frequency Acoustic Transmission Measurements

Developmental hip dysplasia (DDH) is present in 0.2-0.3% of human newborns. Diagnosis may be made by skilled physical examination, or more commonly by utilizing hip ultrasound imaging. The latter is limited by availability, cost and skill, especially in low resource setting and in the developing nations. A low-cost, easy to use and sensitive DDH screening method would be helpful to assist with early detection, facilitating early and more effective intervention and thereby minimize chronic disability. The current study investigated the utility of an acoustic screening method for DDH. The primary hypothesis is that audible sound transmission through the hip joint is affected by DDH and that these transmission changes are detectable. The method was tested in a clinical setting using a compact system. This involves inputting a brief acoustic signal at one location and measuring the transmitted signal at another. Two different transmission configurations were tested. A decrease in acoustic transmission at certain frequencies was appreciated in DDH patients at the affected side with sensitivity of 80% and specificity of 50-79% depending on the exciter location. The higher accuracy was achieved when the excitation was performed at the anterior superior iliac spine and the transmitted signal was measured at the trochanter. Soothing the infants (e.g., using a feeding bottle, a pacifier, etc.) significantly helped in avoiding crying and movement artifacts that can interfere with the method.