Table 1.

Inter- and intraobserver measurements

Measurements			Interobserver			Intraobserver
			ICC (95% CI)	∆	IQR (mm)	ICC 95% CI	∆	IQR (mm)
Preoperative	Gap	Radiographs	0.4 (0.3 to 0.6)	4	2 to 7	0.6 (-0.1 to 0.9)	3	1 to 8
		CT	0.4 (0.2 to 0.6)	8	5 to 12	0.4 (-0.1 to 0.9)	6	2 to 8
	Stepoff	Radiographs	0.4 (0.2 to 0.5)	2	0 to 3	0.6 (0.2 to 0.9)	4	1 to 8
		CT	0.3 (0.2 to 0.5)	5	3 to 9	0.6 (-0.5 to 0.6)	3	1 to 5
Postoperative	Gap	Radiographs	0.4 (0.3 to 0.5)	2	0 to 3	0.7 (-0.2 to 0.8)	2	0 to 2
		CT	0.3 (0.2 to 0.5)	4	2 to 6	0.5 (0 to 0.9)	3	1 to 4
	Stepoff	Radiographs	0.2 (0.1 to 0.4)	0	0 to 3	0.1 (0 to 0.9)	0	0 to 1
		CT	0.4 (0.2 to 0.5)	2	1 to 3	0.3 (-0.4 to 0.7)	3	2 to 4
			Kappa (95% CI)			Kappa (95% CI)
Intraoperative	Gap	Fluoroscopy	0.1 (0 to 0.3)			0 (-0.4 to 0.6)
	Stepoff		0.2 (-0.1 to 0.4)			-0.1 (-0.3 to 0)

ICC = intraclass correlation coefficient; ∆ = median difference; IQR = interquartile range.