The ability of plain radiography to accurately describe the bone surface at the head–neck junction of the femur: a study using human bone models

In evaluations of a cam deformity on femoroacetabular impingement, the head-neck junction (HNJ) must be accurately assessed. We conducted this study to determine the ability of plain radiography to visualize the end-to-end bone surface of the HNJ. We used six human bone models. Ten examiners evaluated the degree to which attached stainless wire marker at the 1:00, 1:30, and 2:00 radial plane defined in reconstructed computed tomography can be accurately detected on the bone surface on plain radiographies. We employed 13 plain radiographies: the cross-table lateral view, frog-leg lateral view, Espié frog-leg lateral view, false-profile view, modified false-profile view, 30° Dunn view (DV), 45° DV, 60° DV, 90° DV, 30° modified Dunn view (MDV), 45° MDV, 60° MDV, and 90° MDV. Examiners scored the degree to which the radiographic images accurately detected the stainless wire marker on the bone surface of the HNJ on a scale of 1 point (0% match) to 5 points (almost 100% match). The highest score for the 1:00 plane was 4.98 points on the 45° DV. Similarly, the highest scores of the 1:30 and 2:00 planes were 4.98 points for the 45° MDV and 4.68 points for the 90° MDV, respectively. On these bone model studies, the most suitable plain radiography for describing the HNJ at the 1:00, 1:30, and 2:00 planes were both the 45° DV, the 45° MDV, and the 90° MDV, respectively.