Table 2.

Classification system of prosthetic joint infection according to McPherson et al. [10]

Category	Grade	Description
Infection type	I	Early postoperative infection (<4 weeks postoperative)
	II	Hematogenous infection (<4 duration)
	II	Late chronic infection (>4 weeks duration)
Systemic comorbidities	A	Uncompromised (no compromising factors)
	B	Compromised (1–2 compromising factors)
	C	Significantly compromised (>2 compromising factors) or one of the following:  • Absolute neutrophil count <1000  • CD4 T cell count <100  • Intravenous drug abuse  • Chronic active infection, other site  • Dysplasia or neoplasm of immune system
Local status	1	Uncompromised (no compromising factor)
	2	Compromised (1–2 compromising factors)
	3	Significantly compromise (>2 compromising factors)