Table 2.

The sensitivity, specificity, positive predictive value and negative predictive value of pelvic radiographs and intraoperative fluoroscopy in the detection of gaps and step-offs in acetabular fractures, with computed tomography as the gold standard.

Imaging and measurements			Sensitivity (%)	Specificity (%)	PPVa (%)	NPVb	Undetected gap/step-off
							Size (mm)	N
Pelvic radio-graphs	Gap	Prec	75	0	100	0	0–10	5
							11–20	6
							> 20	4
		Postd	48	0	100	0	1–4	17
							> 5	14
	Step-off	Prec	58	67	97	8	0–5	8
							6–10	3
							> 10	13
		Postd	21	100	100	33	> 1	34
Intraoperative fluoroscopy		Gap	100	0	30	n/a	1–4	18
							> 5	24
		Step-off	100	35	26	100	> 1	32

Additionally, the size and the number of the undetected gaps and step-offs on pelvic radiographs as well as fluoroscopy are provided. For the postoperative undetected gaps and step-offs the cut-off values presented by Verbeek et al. were used¹⁸.

^aPositive predictive value.

^bNegative predictive value.

^cPreoperative.

^dPostoperative.