Figures & data
Figure 1. Definition of the APP concept (a) and radiological inclination (RI) and anteversion (RA) (b). The pelvic reference plane (xy plane) is defined by the iliac anterior superior spines (SIAS) and the pubic spine (SP). [Color version available online].
![Figure 1. Definition of the APP concept (a) and radiological inclination (RI) and anteversion (RA) (b). The pelvic reference plane (xy plane) is defined by the iliac anterior superior spines (SIAS) and the pubic spine (SP). [Color version available online].](/cms/asset/b794cb4e-c334-4ca4-b17e-a902e219f2ca/icsu_a_164041_f0001_b.jpg)
Figure 2. Frontal view of the hemispherical cup for 45° inclination (RI) and different values of anteversion (RA), pelvic inclination (α) and pelvic rotation (β). White lines mark the elliptical rim of the cup as well as its principal axis. The black line indicates the projected normal vector of the cup. (a) No anteversion and no pelvic inclination. (b) Anteversion RA of 15° and no pelvic tilt. (c) Anteversion RA of 15° and pelvic reclination (α = −10°). (d) Anteversion RA of 15° with pelvic reclination (α = −10°) and simulated pelvic rotation in the frontal plane (δ = 5°). The values for the angle between the horizontal line and the principal axis (RI-Line) are also depicted. [Color version available online].
![Figure 2. Frontal view of the hemispherical cup for 45° inclination (RI) and different values of anteversion (RA), pelvic inclination (α) and pelvic rotation (β). White lines mark the elliptical rim of the cup as well as its principal axis. The black line indicates the projected normal vector of the cup. (a) No anteversion and no pelvic inclination. (b) Anteversion RA of 15° and no pelvic tilt. (c) Anteversion RA of 15° and pelvic reclination (α = −10°). (d) Anteversion RA of 15° with pelvic reclination (α = −10°) and simulated pelvic rotation in the frontal plane (δ = 5°). The values for the angle between the horizontal line and the principal axis (RI-Line) are also depicted. [Color version available online].](/cms/asset/1e75cfe6-d485-453c-9c99-0d3cd50e2ece/icsu_a_164041_f0002_b.jpg)
Figure 3. Projected images of simulated cups in AP view (a) and rotated view (b). Both views represent the two images necessary to determine the RI-Lines (RI2 and RI3). The simulated values for inclination (RI), anteversion (RA), pelvic tilt (α), pelvic rotation (δ) and X-ray rotation (β) are indicated in the title lines. (c) Plot of the calculated values for anteversion RA when the RI-Line (RI3 value) is varied by ± 2°. [Color version available online].
![Figure 3. Projected images of simulated cups in AP view (a) and rotated view (b). Both views represent the two images necessary to determine the RI-Lines (RI2 and RI3). The simulated values for inclination (RI), anteversion (RA), pelvic tilt (α), pelvic rotation (δ) and X-ray rotation (β) are indicated in the title lines. (c) Plot of the calculated values for anteversion RA when the RI-Line (RI3 value) is varied by ± 2°. [Color version available online].](/cms/asset/81c6bb58-cc24-48e2-a789-d221ef7f6111/icsu_a_164041_f0003_b.jpg)
Table I. Influence of measurement errors on the calculated values for anteversion RA and inclination RI. In the first column are the varied angular parameters. For example, a deviation of 1° in the value for the pelvic rotation (δ) results in an error of 0.95° in the calculation of cup inclination RI. (The orientation of the cup was simulated by RI = 45°, RA = 15°, pelvic reclination of −10°, pelvic rotation of 2°, and X-ray rotation of 40°.).