Table 4.

Results of the tests of independency of tibial positioning: angular measurement precision of oblique tibial positioning compared to straight parallel positioning in the CT-scanner gantry.

Reproducibility of tibial angular measurement results of various parallel (0°) and varying off-z-axis (15 and 45° deviated) double oblique positioning of the tibiae on the CT-table in the gantry during scanning to test for independency of tibial positioning.
Tibiae: n = 20 Positioning: three times CT-scans: 60	Intraobserver Agreement			Interobserver Agreement
Angle	Coefficient of variation for repeated measurements (%)	Overall mean	95% Confidence interval	Coefficient of variation for repeated measurements (%)	Overall mean	95% Confidence interval
Tibial torsion angle (TTA)	0.24	175.81	0.81 to 3.23	0.41	175.85	0.31 to 0.50
Tibial varus angle (TVA)	0.30	184.17	0.22 to 0.37	3.02	183.94	0.00 to 5.00