. 2019 Jun 28;8(7):933. doi: 10.3390/jcm8070933

Table 1.

The key role played by the microbiological diagnosis (highlighted in bold) in the most commonly adopted peri-prosthetic joint infection (PJI) definitions, published from 2011 to 2018 [9]. Muscoloskeletal Infection Society (MSIS); Infectious Diseases Society of America (IDSA); International Consensus Meeting (ICM); European Bone and Joint Society (EBJIS).

Definition Source	MSIS 2011 [1]	IDSA 2013 [2]	ICM 2013 [3]	ICM 2018 [4]	Proposed EBJIS 2018 [5]
Scoring system	1 of the 2 Major Criteria OR ≥4 of 6 Minor Criteria *	≥1 Positive Criteria *	1 of the 2 Major Criteria OR ≥3 of 5 Minor Criteria *	1 of the 2 Major Criteria OR Minor criteria scoring ≥6 Infected 3–5 Possibly infected (“Consider further molecular diagnostics such as next-generation sequencing”) <3 Not infected *	≥1 Positive Criteria
* “PJI may be present if fewer than four of these criteria are met”	* “The presence of PJI is possible even if the above criteria are not met (…)”	* “PJI may be present without meeting these criteria, (…).”	* “Proceed with caution in adverse local tissue reaction, crystal deposition disease, slow growing organisms”
Criteria	Major: 1. Sinus tract communicating with the prosthesis; 2. A pathogen is isolated by culture from at least two separate tissue or fluid samples obtained from the affected prosthetic joint Minor: (a) Elevated ESR (>30 mm/h) and CRP (>10 mg/L) concentration (b) Elevated synovial leukocyte count (c) Elevated PMN% (d) Purulence in the affected joint (e) Isolation of a microorganism in one culture of periprosthetic tissue or fluid (f) Greater than five neutrophils per high-power field in five high-power fields observed from histologic analysis of periprosthetic tissue at ×400 magnification	1 Sinus tract communicating with the prosthesis 2 Purulence without other etiology surrounding the prosthesis 3 Acute inflammation seen on histopathological examination of the periprosthetic tissue 4. ≥2 intraoperative cultures or combination of preoperative aspiration and intraoperative cultures yielding an indis tinguishable organism (the growth of a virulent microorganism (e.g., Staphylococcus aureus) in a single specimen of a tissue biopsy or synovial fluid is also considered as indicative of a PJI)	Major 1. A sinus tract communicating with the joint 2. Two positive periprosthetic cultures with phenotypically identical organisms, Minor: (a) Elevated ESR (>30 mm/h) and CRP (>100 mg/L for acute infections; >10 mg/L for chronic infections) (b) Elevated synovial fluid WBC count (>10,000 cells/mL for acute infections; >3000 cells/mL for chronic infections) or ++ change on leukocyte esterase test strip (c) Elevated PMN% (>90% for acute infections; >80% for chronic infections) (d) Positive histological analysis of periprosthetic tissue (>5 neutrophils per high-power field in five high-power fields observed on periprosthetic tissue at ×400 magnification) (e) A singlepositive culture	Major: 1. Sinus tract with evidence of communication to the joint or visualisation of the prosthesis 2. Two positive growths of the same organism using standard culture methods Minor: (a) Elevated CRP (>100 mg/L for acute infections; >10 mg/L for chronic infections) or D-Dimer (unknown threshold for acute infection; >860 µg/L for chronic infection) (score 2) (b) Elevated ESR (no role for acute infections; >30 mm/h for chronic infections) (score 1) (c) Elevated synovial WBC count (>10,000 cells/mL for acute infections; >3000 cells/mL for chronic infections) OR Leukocyte Esterase (++ for acute and chronic infections) OR Positive alpha-defensin (score 3) (d) Elevated synovial PMN% (>90% for acute infections; >70% for chronic infections) (score 2) (e) Single positive culture (score 2) (f) Positive histology (score 3) (g) Positive intraoperative purulence (score 3)	1. Purulence around the prosthesis or sinus tract 2. Increase synovial fluid leukocyte count (>2000 cells/mL or >70% granulocytes) 3. Positive histopathology 4. Confirmatory microbial growth in synovial fluid, periprosthetic tissue, or sonication culture (“Confirmatory microbial growth in periprosthetic tissue: if positive in ≥1 specimen in highly virulent organisms or ≥2 in low virulent pathogens; sonication culture considered positive if >50 colony-forming units/mL of sonication fluid.”)

Definition Source

MSIS 2011 [1]

IDSA 2013 [2]

ICM 2013 [3]

ICM 2018 [4]

Proposed EBJIS 2018 [5]

Scoring system

1 of the 2 Major Criteria
OR
≥4 of 6 Minor Criteria *

≥1 Positive Criteria *

1 of the 2 Major Criteria
OR
≥3 of 5 Minor Criteria *

1 of the 2 Major Criteria
OR
Minor criteria scoring ≥6 Infected
3–5 Possibly infected
(“Consider further molecular diagnostics such as next-generation sequencing”)
<3 Not infected *

≥1 Positive Criteria

* “PJI may be present if fewer than four of these criteria are met”

* “The presence of PJI is possible even if the above criteria are not met (…)”

* “PJI may be present without meeting these criteria, (…).”

* “Proceed with caution in adverse local tissue reaction, crystal deposition disease, slow growing organisms”

Criteria

Major:

1.
Sinus tract communicating with the prosthesis;
2.
A pathogen is isolated by culture from at least two separate tissue or fluid samples obtained from the affected prosthetic joint

Minor:

(a)
Elevated ESR (>30 mm/h) and CRP (>10 mg/L) concentration
(b)
Elevated synovial leukocyte count
(c)
Elevated PMN%
(d)
Purulence in the affected joint
(e)
Isolation of a microorganism in one culture of periprosthetic tissue or fluid
(f)
Greater than five neutrophils per high-power field in five high-power fields observed from histologic analysis of periprosthetic tissue at ×400 magnification

1
Sinus tract communicating with the prosthesis
2
Purulence without other etiology surrounding the prosthesis
3
Acute inflammation seen on histopathological examination of the periprosthetic tissue
4.
≥2 intraoperative cultures or combination of preoperative aspiration and intraoperative cultures yielding an indis tinguishable organism (the growth of a virulent microorganism (e.g., Staphylococcus aureus) in a single specimen of a tissue biopsy or synovial fluid is also considered as indicative of a PJI)

Major

1.
A sinus tract communicating with the joint
2.
Two positive periprosthetic cultures with phenotypically identical organisms,

Minor:

(a)
Elevated ESR (>30 mm/h) and CRP (>100 mg/L for acute infections; >10 mg/L for chronic infections)
(b)
Elevated synovial fluid WBC count (>10,000 cells/mL for acute infections; >3000 cells/mL for chronic infections) or ++ change on leukocyte esterase test strip
(c)
Elevated PMN% (>90% for acute infections; >80% for chronic infections)
(d)
Positive histological analysis of periprosthetic tissue (>5 neutrophils per high-power field in five high-power fields observed on periprosthetic tissue at ×400 magnification)
(e)
A singlepositive culture

Major:

1.
Sinus tract with evidence of communication to the joint or visualisation of the prosthesis
2.
Two positive growths of the same organism using standard culture methods

Minor:

(a)
Elevated CRP (>100 mg/L for acute infections; >10 mg/L for chronic infections) or D-Dimer (unknown threshold for acute infection; >860 µg/L for chronic infection) (score 2)
(b)
Elevated ESR (no role for acute infections; >30 mm/h for chronic infections) (score 1)
(c)
Elevated synovial WBC count (>10,000 cells/mL for acute infections; >3000 cells/mL for chronic infections) OR Leukocyte Esterase (++ for acute and chronic infections) OR Positive alpha-defensin (score 3)
(d)
Elevated synovial PMN% (>90% for acute infections; >70% for chronic infections) (score 2)
(e)
Single positive culture (score 2)
(f)
Positive histology (score 3)
(g)
Positive intraoperative purulence (score 3)

1.
Purulence around the prosthesis or sinus tract
2.
Increase synovial fluid leukocyte count (>2000 cells/mL or >70% granulocytes)
3.
Positive histopathology
4.
Confirmatory microbial growth in synovial fluid, periprosthetic tissue, or sonication culture

(“Confirmatory microbial growth in periprosthetic tissue: if positive in ≥1 specimen in highly virulent organisms or ≥2 in low virulent pathogens; sonication culture considered positive if >50 colony-forming units/mL of sonication fluid.”)