Subjects were assisted to take a supine position so their their pelvises could be parallel to each other and both their coxae could be in a neutral position while undergoing plain hip radiographies.11 (link),12 (link) This study was retrospectively conducted, and hip displacement was measured by two raters (A and B) using plain hip radiographs. The two raters were well-acquainted with pelvic and coxal structures and radiologic indexes, and measured hip displacement in accordance with standardized methods.4 (link)
The outermost edge of the acetabular roof was regarded as the datum point from where the Perkin's line (P-line) was drawn. Likewise, another P-line was drawn from the lateral edge of the sourcil. The former and the latter method were defined as the classic and modified method, respectively (Fig. 2 ).
To evaluate intra-rater reliability, the displacement of 200 hip joints was measured 3 times at intervals of 1 week without data on previous measurements, and an analysis was made of the reliability amongst measured values. In order to evaluate inter-rater reliability, the displacement of 200 hip joints was measured in the same way, and an analysis was made of the reliability amongst mean values.
The reliabilities were evaluated in patients with or without hip dysplasia. In accordance with the descriptions of Ogata et al.13 (link) and Agus et al.,8 (link) the acetabular roof was classified as to the shape of the sourcil. Type I and II cases where the lateral edge of the acetabular roof and that of the sourcil are superimposed, were regarded as normal. On the other hand, type III and IV were classified as hip dysplasia.
The outermost edge of the acetabular roof was regarded as the datum point from where the Perkin's line (P-line) was drawn. Likewise, another P-line was drawn from the lateral edge of the sourcil. The former and the latter method were defined as the classic and modified method, respectively (
To evaluate intra-rater reliability, the displacement of 200 hip joints was measured 3 times at intervals of 1 week without data on previous measurements, and an analysis was made of the reliability amongst measured values. In order to evaluate inter-rater reliability, the displacement of 200 hip joints was measured in the same way, and an analysis was made of the reliability amongst mean values.
The reliabilities were evaluated in patients with or without hip dysplasia. In accordance with the descriptions of Ogata et al.13 (link) and Agus et al.,8 (link) the acetabular roof was classified as to the shape of the sourcil. Type I and II cases where the lateral edge of the acetabular roof and that of the sourcil are superimposed, were regarded as normal. On the other hand, type III and IV were classified as hip dysplasia.
