| Study | Definition | +ve | -ve |
|---|---|---|---|
| ASEPSIS 1986 [11] | A scoring method for post operative wound infections for use in clinical trials A score of 1 to 5 is given for each of the following parameters dependent on the proportion of wound affected: 1-serous exudate 2-erythema 3-purulent exudate 4-separation of deep tissues Additional points are then given for: 1-antibiotic use 2-drainage of pus under local anaesthetic 3-debridement of wound under general anesthetic 4-serous discharge 5-erythema 6-purulent exudate 7-separation of deep tissues 8-isolation of bacteria 9-inpatient stay more than 14 days Score Meaning 0 to10 No infection Normal healing 11 to 20 Disturbance of healing 21 to 30 Minor infection 31 to 40 Moderate infection ≥ 41 Severe infection |
Recognized by NICE as a valid measure for assessment of surgical site infection | Score is time consuming to carry out in daily clinical practice |
| SPLIF 2010 [5] | Classification according to etiology, location and duration Diagnosis: Presence of a fistula close to the prosthesis confirms infection until proven otherwise Post operative signs suggestive of infection: 1- unusually strong pain or its recurrence after a symptom free period 2- purulent discharge from a surgical wound 3- disunion, necrosis or scar inflammation 4- general signs of fever 5- radiological appearance of loosening Biological signs: White cell count (WCC) is not a good positive or negative predictor of infection Normal Erythrocyte Sedimentation rate (ESR) and C-reactive protein (CRP) do not exclude infection CRP should be used for monitoring of infection Suspect infection with ESR >30mm and CRP >13.5mg/l Imaging modalities: CT, MRI, US and nuclear medicine imaging suggestive of infection |
Includes physical signs Provides biological parameters Describes imaging techniques for diagnosis |
Specificity and sensitivity of biological parameters not given High level of clinical suspicion may lead to over diagnosis of PJI |
| AAOS 2010 [12] | High probability of infection: One or more symptom AND at least one or more of the following: Risk factors (supported by evidence or expert opinion), physical exam findings (e.g. warmth, effusion, redness, swelling or a sinus tract associated with the joint) or radiological evidence of implant loosening/osteolysis Low probability of infection: Pain or joint stiffness only and no risk factors, physical examination findings or radiological evidence of implant loosening /osteolysis Algorithm provided for clinical tests: If ESR and CRP raised joint aspiration is recommended If joint aspiration provides positive differential cell count and positive culture – infection is likely If only one of the above is positive repeat aspiration and if positive infection is likely If second aspiration is negative and surgery is planned frozen section is recommended |
Applicable to hip and knee surgery only Risk factors included Physical signs included Useful algorithm |
Amount of samples for aspirate/culture may miss diagnosing some PJIs |
| IDSA 2012 [4] | Definite: 1) Sinus tract communicating with the prosthesis 2) There is purulence around the prosthesis without any other known cause Highly suggestive: 1) Acute inflammation on histopathologic examination of periprosthetic tissue at the time of surgical debridement OR prosthesis removed is highly suggestive of PJI as defined by the attending pathologist 2) >2 Intra-operative cultures yielding same organism, OR combined aspiration and culture 3) Cultures grow a virulent microorganism from tissue or synovial fluid samples Additional information - PJI can be present if the given criteria are not met. All available information should be taken into account when diagnosing PJI - Intra-operative diagnosis is reliable when interpreted by a skilled pathologist |
Clear information stipulates that at least 3 or optimally 5 periprosthetic samples OR explanted prosthesis should be submitted for anaerobic and aerobic cultures Antibiotics should be withheld for 2 weeks prior to cultures being taken if possible |
In the absence of a skilled pathologist PJI may be missed |
| MSIS 2011 [15] | Major criteria: 1) There is a sinus tract communicating with the prosthesis; or 2) A pathogen is isolated by culture from 2 or more separate tissue or fluid samples obtained from the affected prosthetic joint; or Minor criteria: 3) When 4 of the following 6 criteria exist: a. Elevated ESR and CRP b. Elevated synovial WCC c. Elevated synovial polymorphonuclear percentage (PMN%) d. Presence of purulence in the affected joint e. Isolation of a microorganism in one culture of periprosthetic tissue or fluid, or f. Greater than 5 neutrophils per high-power field in 5 high-power fields observed from histologic analysis of periprosthetic tissue at ×400 magnification Additional Information Please note that a PJI may be present if less than 4 of these criteria are met |
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| International consensus group 2014 [16] |
Major criteria: 1) A sinus tract communicating with the joint; or 2) 2 positive phenotypically identical organisms on cultures taken in periprosthetic sampling; or Minor Criteria: 3) when 3 of the following 5 criteria exist: a. Elevated ESR & CRP b. Elevated synovial fluid WCC OR ++ change on leucocyte esterase test strip c. Elevated synovial fluid PMN% d. A single positive culture e. Positive histological analysis of periprosthetic tissue |
Accompanying declaration states infection may be present when these criteria are not met Further stipulation of values of the minor criteria is given according to acuteness or chronicity of infection |
|
| CDC 2015 [7] | Major Criteria: 1) A sinus tract communicating with the joint; or 2) 2 positive periprosthetic tissue or fluid cultures with matching organisms; or Minor Criteria: 3) when 3 of the following 5 criteria exist: a. CRP >100mg/L AND ESR >30mm/hr b. Synovial fluid WCC >10,000 cells/μL OR ++ change on leucocyte esterase strip test of synovial fluid c. Elevated synovial fluid PMN percentage (>90%) d. A single positive periprosthetic tissue or fluid culture e. Positive histological analysis of periprosthetic tissue (more than 5 PMNs per high power field) Additional Information Further details given about: 1) Definition of matching organism 2) Positive cultures of hardware from a hip or knee can be used to meet criterion 2 3) Definition of sinus given |
Specific for hip and knee replacement only |