Because not all infants can be screened for DDH by experts, early diagnosis of developmental dysplasia of the hip (DDH) by
primary health care professionals is important. We developed a broadband electroacoustic sound transmission-detection (sonospectrography)
system and explored its utility in 22 patients (average age, 5.9 years; range, 0.3–14 years) with unilateral DDH in this preliminary
study. Distinct from ultrasonography, the sonospectrography system functions by sound transmission and recording through tissues
to differentiate between normal and abnormal hips. All hips were examined at four different hip and knee positions. The normal
hip served as the control. The sonospectrography system was able to detect unilateral DDH. Dysplastic hips had lower sound
transmission values when compared to normal hips in all patients and all four positions; however, the highest (X = 88.8 ± 30.2 Hz)
and lowest (X = 8.3 ± 5.4 Hz) sound transmission mean values were obtained at different positions in the normal hips and those
with DDH. Sound transmission values of dysplastic hips were always lower than that of normal hips when the hip and knee was
flexed during measurements. Sound transmission values decreased with age. The sonospectrography system may offer a new noninvasive
method in the diagnosis of unilateral DDH but requires further study of sensitivity and specificity of detecting dysplastic
hips without subluxation in newborn infants.
Level of Evidence: Level IV, case series. See the Guidelines for Authors for a complete description of levels of evidence.
Each author certifies that he has no commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing
arrangements, etc) that might pose a conflict of interest in connection with the submitted article.
Each author certifies that his institution does not require approval for the noninvasive sound transmission human protocol
for this investigation and all investigations were conducted in conformity with ethical principles of research.