This multi-institutional study of 1,504 revision arthroplasty patients developed a weighted scoring system for diagnosing periprosthetic joint infection. It replaced the expert-opinion-based 2011 MSIS criteria with an evidence-derived, stepwise framework incorporating serum, synovial, and intraoperative markers. The new criteria were externally validated on an independent cohort of 422 patients.
The 2011 MSIS criteria were built on expert consensus, not validated evidence. Three of their six minor criteria were intraoperative findings, making preoperative diagnosis unreliable. Their sensitivity was only 79.3% — meaning about 1 in 5 true PJI cases was missed.
When you evaluate a patient for PJI before revision surgery, apply the 2018 Parvizi scoring system. Calculate the preoperative score from serum CRP, D-dimer, and ESR. If the score is 2-5, aspirate the joint and add synovial markers. A preoperative score ≥6 diagnoses infection before the patient enters the OR.
If the preoperative score remains 2-5 after aspiration, do not dismiss infection. Add intraoperative findings (histology, purulence, culture) to the preoperative score. A combined aggregate ≥6 confirms PJI.
Four scenarios can generate false positives and require clinical caution: adverse local tissue reaction, crystalline arthropathy, inflammatory arthropathy flare, and slow-growing organisms such as Propionibacterium acnes. Patients with a final inconclusive score and negative cultures are a distinct group that may benefit from next-generation sequencing.
This multi-institutional study of 1,504 revision arthroplasty patients developed a weighted scoring system for diagnosing periprosthetic joint infection. It replaced the expert-opinion-based 2011 MSIS criteria with an evidence-derived, stepwise framework incorporating serum, synovial, and intraoperative markers. The new criteria were externally validated on an independent cohort of 422 patients.
The 2011 MSIS criteria were built on expert consensus, not validated evidence. Three of their six minor criteria were intraoperative findings, making preoperative diagnosis unreliable. Their sensitivity was only 79.3% — meaning about 1 in 5 true PJI cases was missed.
When you evaluate a patient for PJI before revision surgery, apply the 2018 Parvizi scoring system. Calculate the preoperative score from serum CRP, D-dimer, and ESR. If the score is 2-5, aspirate the joint and add synovial markers. A preoperative score ≥6 diagnoses infection before the patient enters the OR.
If the preoperative score remains 2-5 after aspiration, do not dismiss infection. Add intraoperative findings (histology, purulence, culture) to the preoperative score. A combined aggregate ≥6 confirms PJI.
Four scenarios can generate false positives and require clinical caution: adverse local tissue reaction, crystalline arthropathy, inflammatory arthropathy flare, and slow-growing organisms such as Propionibacterium acnes. Patients with a final inconclusive score and negative cultures are a distinct group that may benefit from next-generation sequencing.