Background Acetabular anatomy on AP pelvic radiographs depends on pelvic orientation during radiograph acquisition. However, not all parameters may change to a clinically relevant degree with differences in pelvic orientation. This issue may influence the diagnosis of acetabular pathologies and planning of corrective acetabular surgery (reorientation or rim trimming). However, to this point, it has not been well characterized. Questions/purposes We asked (1) which radiographic parameters change in a clinical setting when normalized to neutral pelvic orientation; (2) which parameters do not change in an experimental setting when the pelvis is experimentally rotated/tilted; and (3) which of these changes are ''ultimately'' relevant based on a prespecified definition of relevance. Methods In a clinical setup, 11 hip parameters were evaluated in 101 patients (126 hips) by two observers and the interobserver difference was calculated. All parameters were normalized to an anatomically defined neutral pelvic orientation with the help of a lateral pelvic radiograph and specific software. Differences between nonnormalized and normalized values were calculated (effect of normalization). In an experimental setup involving 20 cadaver pelves (40 hips), the maximum range for each parameter was computed with the pelvis rotated (range, À12°to 12°) and tilted (range, À24°to 24°). ''Ultimately'' relevant changes existed if the effect of normalization exceeded the interobserver difference (eg, 37% versus 6% for prevalence of a positive crossover sign) and/or the maximum experimental range exceeded 1 SD of interobserver difference (eg, 27% versus 6% for anterior acetabular coverage). Results In the clinical setup, all parameters except the ACM angle and craniocaudal acetabular coverage changed when being normalized, eg, effect of normalization for lateral center-edge angle, acetabular index, and sharp angle ranged from À5°to 4°(p values \ 0.029). In the experimental setup, five parameters showed no major changes, whereas six parameters did change (all p values \ 0.001). Ultimately relevant changes were found for anteroposterior acetabular coverage, retroversion index, and prevalence of a positive crossover or posterior wall sign. Conclusions Lateral center-edge angle, ACM angle, Sharp angle, acetabular and extrusion index, and craniocaudal acetabular coverage showed no relevant changes with varying pelvic orientation and can therefore be acquired independent from individual pelvic tilt and

Technology has always played an important role in global politics, economics, security, and culture. It has continuously shaped the structure of the global system, its actors, and the interactions between them and vice versa. However, theories of International Relations (IR), and in particular those of International Political Economy (IPE), have performed little to theoretically conceptualize technology as a powerful factor within explanations of change in global affairs. Although technology often is implicitly present in the theories of IR and IPE, it is often interpreted as an external, passive, apolitical, and residual factor. This essay argues that to develop a better understanding of transformation in global affairs, technology has to be integrated more systematically into the theoretical discussions of IR ⁄ IPE. Technology should be understood as a highly political and integral core component of the global system that shapes global affairs and itself is shaped by global economics, politics, and culture. This paper makes the case for an interdisciplinary approach, which systematically incorporates insights of Science and Technology Studies (S&TS) to provide a better understanding of how technology and the global system and politics interact with each other. In so doing, it opens the field to a richer understanding of how global systemic change is impacted by technology and how global politics, economics, and culture impact technological evolution.

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