Table 2.

Summary of previous studies examining synovial white blood cell (WBC) count and differential (PMN%) for the diagnosis of periprosthetic joint infection

Article	Joint	Synovial WBC Count Threshold (WBC/μL)	PMN% Threshold	Management of IJD Patients
Spangehl et al. [32]	Hip	1,100 (SN = 20%, SP = 96%)	75% (SN = 24%, SP = 89%)	23 patients with IJD were excluded from analysis
Kersey et al. [17]	Knee	2,000	50%	>50% PMN seen only in four patients with RA with high rate of false positive
Mason et al. [20]	Knee	2,500 (SN = 69%, SP = 98%)	60% (SN = 76%, SP = 89%)	Analysis included four patients with IJD, however no conclusions were made
Trampuz et al. [36]	Knee	1,700 (SN = 94%, SP = 88%)	65% (SN = 97%, SP = 98%)	Excluded
Della Valle et al. [4]	Knee	3,000 (SN = 100%, SP = 98.1%)	65% (SN = 97.6%, SP = 84.9%)	Excluded
Schinsky et al. [28]	Hip	4,200 (SN = 84%, SP = 93%)	80% (SN = 84%, SP = 82%)	Excluded
Cipriano et al. [7]	Hip & Knee	3,444 in IJD (SN = 88.2%, SP = 80.0%)	75% in IJD (SN = 100%, SP = 81.8%)	Separate and comparative analyses of 61 IJD patients and 810 OA patients
		3450 in OA (SN = 91.0%, SP = 93.0%)	78% in OA (SN = 95.5%, SP = 87.3%)

IJD inflammatory joint disease, SN sensitivity, SP specificity