Criteria summarized from article:
The 2018 Definition of Periprosthetic Hip and Knee Infection: An Evidence-Based and Validated Criteria
Parvizi J, Tan TL, Goswami K, Higuera C, Valle CD, Chen AF, Shohat N. J Arthroplasty. 33(2018)1309-1314.
This study was performed in order to 1) generate evidence-based weight-adjusted scoring system for defining PJI (hip and knee) and 2) validate it on an external cohort
Abnormal Lab Values (Adapted from Table 2)
| Test | Point Value for Algorithm | |
| Preop Labs | ||
| Serum CRP > 1 mg/dL | 2 | |
| Serum D-dimer > 860 mg/mL | 2 | |
| Serum ESR < 30 mm/h | 1 | |
| Joint Aspirate | ||
| Synovial WBC > 3000 (cells/uL) | 3 | |
| Synovial alpha-defensin (signal to cutoff ratio >1) | 3 | |
| Synovial leukocyte esterase (++) | 3 | |
| Synovial PMN% > 80% | 2 | |
| Synovial CRP > 6.9 mg/L | 1 | |
| Intraop Findings | ||
| Histology (>5 neutrophils per HPF in 5 fields observed of tissue at 400x magnification) | 3 | |
| Purulence | 3 | |
| Single culture positive | 2 |
Algorithm (Fig 1 from article)
If score is inconclusive pre-op, then add in intra-op criteria for an aggregate score. If remains inconclusive can consider further molecular diagnostics such as next-generation sequencing.
Overall sensitivity and specificity of this scoring system was 97.7% and 99.5% respectively.
Patients where these criteria may be inaccurate include: those with adverse local tissue reaction, crystalline deposition arthropathy, inflammatory arthropathy flare, or infections with a slow growing organism (such as P acnes, coag negative staph, etc).
In this study, the infected group were more likely to be male, had undergone revision surgery, TKA more likely than THA, and higher Charlson Comorbidity Index (history of RA, DM, malignancy) “This scoring system is not designed or intended to be used as a guide for which tests should be ordered; rather, it should be used as a tool to diagnose patients when a panel of tests are already available.”