Synovial Fluid Aspiration Should Not Be Routinely Performed during the Two-Stage Exchange of the Knee

Table 3

Youden-Index in relation to synovial cell count with sensitivity and specificity for histopathologic infection persistence.

Youden-Index	SWBCC (cells/μl)	Sensitivity	Specificity
0.000	99	1.000	0.000
0.071	175	1.000	0.071
0.000	275	0.929	0.071
0.214	350	0.929	0.286
0.286	450	0.929	0.357
0.214	550	0.857	0.357
0.143	650	0.786	0.357
0.000	750	0.643	0.357
0.143	950	0.643	0.500
0.000	1200	0.500	0.500
0.071	1350	0.500	0.571
0.143	1500	0.500	0.643
0.000	1650	0.357	0.643
0.071	2150	0.357	0.714
0.143	2700	0.357	0.786
0.214	2850	0.357	0.857
0.286	3250	0.357	0.929
0.214	4450	0.286	0.929
0.143	5525	0.214	0.929
0.071	6825	0.143	0.929
0.143	10500	0.143	1.000
0.071	13550	0.071	1.000
0.000	14000	0.000	1.000

SWBCC: synovial white blood cell count.