Is experience alone sufficient to diagnose developmental dysplasia of the hip without the bony roof (alpha angle) and the cartilage roof (beta angle) measurements? A diagnostic accuracy study

Abstract

In the Graf method of hip ultrasonography, the diagnosis of the infantile hip with developmental dysplasia of the hip (DDH) is strictly dependent on the bony roof (alpha angle) and the cartilage roof (beta angle) measurements. In this study, we investigated whether the infant hip could be diagnosed with DDH solely by evaluating ultrasound images obtained in the standard plane, without bony roof and cartilage roof measurements, in respect to different professional experience levels. Two hundred ten hip ultrasounds were randomly selected from patients who presented to our hospital for DDH screening. A total of 6 ultrasound images were obtained for each hip. The hip morphology evaluations were made without the bony roof and the cartilage roof measurements by 2 orthopedic surgery residents; 2 orthopedic surgery specialists, trained in the diagnosis and the treatment of the DDH; and 2 pediatric orthopedic surgery professors, highly experienced in the diagnosis and treatment of DDH. After hip morphology evaluations, the bony roof and the cartilage roof measurements were obtained and hip type evaluations were made by the same raters, according to the Graf method of hip ultrasonography. The highest intraobserver agreements between the hip maturity evaluation before and the hip type evaluation after measurements were .676 (P < .001) and .577 (P < .001) in professors 2 and 1, respectively, and the lowest agreements were .185 (P < .01) and .289 (P < .001) in specialist 1 and resident 2, respectively. The diagnosis of the infant hip as DDH could not be made solely by evaluation of the ultrasound images obtained in the standard plane without the bony roof and the cartilage roof measurements. The bony roof and the cartilage roof measurements were obligatory for the diagnosis of the infant hip as DDH, even in the very experienced pediatric orthopedic surgeons. Level of evidence: 2.