Table 2. A staging system for prosthetic joint infection risk (part 1) [19].

Stage = infection type + systemic host grade + local extremity grade; e.g I-A-1, III-B-2

Category	Grading	Description
Infection Type	I	Early postoperative infection (< 4 weeks postoperatively)
	II	Hematogenous infection (< 4 weeks' duration)
	III	Late chronic infection (> 4 weeks' duration)
Systemic host grade	A	Uncompromised (no compromising factors)
	B	Compromised (1 to 2 compromising factors)
	C	Significant compromise (> 2 compromising factors) OR one of the following:     - Absolute neutrophil count <1000     - CD4 t cell count < 100     - Intravenous drug abuse     - Chronic active infection at other site     - Dysplasia/neoplasm of immune system (e.g. Myelodysplasia, CLL)
Local extremity grade	1	Uncompromised (no compromising factors
	2	Compromised (1-2 compromising factors)
	3	Significant compromise (> 2 compromising factors)