Aims: This study evaluated the definitions developed by the European Bone and Joint Infection Society (EBJIS) 2021, the International Consensus Meeting (ICM) 2018, and the Infectious Diseases Society of America (IDSA) 2013, for the diagnosis of periprosthetic joint infection (PJI). Methods: In this single-centre, retrospective analysis of prospectively collected data, patients with an indicated revision surgery after a total hip or knee arthroplasty were included between 2015 and 2020. A standardized diagnostic workup was performed, identifying the components of the EBJIS, ICM, and IDSA criteria in each patient. Results: Of 206 included patients, 101 (49%) were diagnosed with PJI with the EBJIS definition. IDSA and ICM diagnosed 99 (48%) and 86 (42%) as infected, respectively. A total of 84 cases (41%) had an infection based on all three criteria. In 15 cases (n = 15/206; 7%), PJI was present when applying only the IDSA and EBJIS criteria. No infection was detected by one definition alone. Inconclusive diagnoses occurred more frequently with the ICM criteria (n = 30/206; 15%) compared to EBJIS (likely infections: n = 16/206; 8%) (p = 0.029). A better preoperative performance of the EBJIS definition was seen compared with the ICM and IDSA definitions (p < 0.001). Conclusion: The novel EBJIS definition identified all PJIs diagnosed by any other criteria. Use of the EBJIS definition significantly reduced the number of uncertain diagnoses, allowing easier clinical decision-making. Cite this article: Bone Joint Res 2022;11(9):608–618.

Accurate preoperative diagnosis of periprosthetic joint infections (PJIs) can be very challenging, especially in patients with chronic PJI caused by low-virulence microorganisms. Serum parameters, such as serum C-reactive protein (CRP) or the erythrocyte sedimentation rate (ESR), are—among other diagnostic test methods—widely used to distinguish septic from aseptic failure after total hip or knee arthroplasty and are recommended by the AAOS in the preoperative setting. However, they are systemic parameters, and therefore, unspecific. Nevertheless, they may be the first and occasionally the only preoperative indication, especially when clinical symptoms are lacking. They are easy to obtain, cheap, and are available worldwide. In the last decade, different novel serum biomarkers (percentage of neutrophils, neutrophils to lymphocytes ratio, platelet count to mean platelet volume ratio, fibrinogen, D-Dimer, Il-6, PCT) were investigated to find a more specific and accurate serum parameter in the diagnosis of PJI. This article reviews the diagnostic value of established (serum CRP, ESR, WBC) and ‘novel’ serum inflammatory biomarkers (fibrinogen, D-dimer, interleukin-6 (IL-6), procalcitonin, percentage of neutrophils (%N), neutrophils to lymphocytes ratio (NLR), platelet count to mean platelet volume ratio (PC/mPV)) for the preoperative diagnosis of periprosthetic joint infections.

Purpose: Besides other diagnostic test methods, established serum inflammatory markers such as serum C-reactive protein or leukocyte count are widely used preoperatively to aid in diagnosing periprosthetic joint infections (PJI). Although low accuracies were reported, these parameters are easily accessible and routinely available. Novel biomarkers with promising results in diagnosing PJI (platelet count to mean platelet volume ratio) or other infectious conditions (percentage of neutrophils, neutrophils to lymphocytes ratio) were described. The purpose of this study was to investigate the diagnostic value of established and novel serum inflammatory biomarkers for the diagnosis of PJI so as to compare the results to find the serum inflammatory marker with the best performance. Methods: In 177 patients with a previous total hip (n = 91) or knee (n = 86) arthroplasty and indicated revision surgery, the diagnostic value of the routinely available serum inflammatory markers C-reactive protein (CRP), white blood cell count (WBC), percentage of neutrophils (%N), neutrophils to lymphocytes ratio (NLR), fibrinogen and platelet count to mean platelet volume ratio (PC/mPV) were examined retrospectively via receiver operating characteristic curve analysis (AUC). The curves were compared using the z-test. Results: Sensitivities of serum CRP, WBC, %N, NLR, fibrinogen and PC/mPV were calculated with 68%, 36%, 66%, 63%, 69% and 43%, respectively. Specificities were 87%, 89%, 67%, 73%, 89% and 81%, respectively. Serum CRP (0.78) and fibrinogen (0.79) showed significantly better AUCs compared with serum WBC (0.63), %N (0.67), NLR (0.68) and PC/mPV (0.62) (p < 0.0001). Patients with PJI caused by a low-virulent microorganism (median CRP: 17.6 mg/L) obtained lower CRP levels compared with infections caused by high-virulent microorganisms (median CRP: 49.2 mg/L; p = 0.044). The combination of CRP and fibrinogen showed a better sensitivity (77%) with similar specificity (83%) than one method alone but not at a significant level (CRP (p = 0.200); fibrinogen (p = 0.437)). Conclusion: Serum CRP and fibrinogen showed the best accuracies among these widely available serum inflammatory parameters. However, due to the insufficient performance, these biomarkers can only be recommended as suggestive criteria in diagnosing PJI. The preoperative workup should always be complemented by more specific tests such as synovial fluid analysis.

This prospective study compared bifocal acute shortening and relengthening (ASR) with bone transport (BT) in a consecutive series of complex tibial infected non-unions and osteomyelitis, for the reconstruction of segmental defects created at the surgical resection of the infection. Patients with an infected tibial segmental defect (>2 cm) were eligible for inclusion. Patients were allocated to ASR or BT, using a standardized protocol, depending on defect size, the condition of soft tissues and the state of the fibula (intact or divided). We recorded the Weber–Cech classification, previous operations, external fixation time, external fixation index (EFI), follow-up duration, time to union, ASAMI bone and functional scores and complications. A total of 47 patients (ASR: 20 patients, BT: 27 patients) with a median follow-up of 37.9 months (range 16–128) were included. In the ASR group, the mean bone defect size measured 4.0 cm, and the mean frame time was 8.8 months. In the BT group, the mean bone defect size measured 5.9cm, and the mean frame time was 10.3 months. There was no statistically significant difference in the EFI between ASR and BT (2.0 and 1.8 months/cm, respectively) (p = 0.223). A total of 3/20 patients of the ASR and 15/27 of the BT group needed further unplanned surgery during Ilizarov treatment (p = 0.006). Docking site surgery was significantly more frequent in BT; 66.7%, versus ASL; 5.0% (p < 0.0001). The infection eradication rate was 100% in both groups at final follow-up. Final ASAMI functional rating scores and bone scores were similar in both groups. Segmental resection with the Ilizarov method is effective and safe for reconstruction of infected tibial defects, allowing the eradication of infection and high union rates. However, BT demonstrated a higher rate of unplanned surgeries, especially docking site revisions. Acute shortening and relengthening does not reduce the fixator index. Both techniques deliver good functional outcome after completion of treatment.

Purpose The aim of this study was to evaluate the pre-operative performance of an automated multiplex PCR (mPCR) system in patients with suspected periprosthetic joint infection (PJI). Methods Under sterile conditions, synovial fluid samples from patients with a suspected PJI were collected pre-operatively. One hundred eighty microliter of the aspirate was used for analysis in the mPCR. The remaining joint fluid was sent for microbiological analysis. PJI was diagnosed by using the Musculoskeletal Infection Society (MSIS) criteria. Total percentage agreement and Cohen’s kappa coefficient were calculated to measure overall agreement. Results Overall, 90 patients with a suspected PJI were included. Using MSIS criteria, 38 (42%) patients were classified as septic. Total percent agreement between mPCR and synovial fluid culture was 86% with a Cohen’s kappa of 0.68. The mPCR and synovial fluid culture showed sensitivities of 71% and 84%, respectively. Combined evaluation provided an even higher sensitivity of 92%. While Cutibacterium spp. were detected five times by mPCR, it could only be cultured once. A higher detection rate of CoNS by mPCR (n = 7) compared to conventional culture (n = 5) was also demonstrated. In comparison to synovial fluid culture, the mPCR missed Staphylococcus aureus five times. Conclusion With a moderate agreement between synovial fluid mPCR and culture, the mPCR system could be a useful adjunct in diagnosing a PJI pre-operatively. Due to faster availability of results and a higher detection rate of low-virulent microorganisms, it can complement conventional culture.

It has been shown that the outcome of a DAIR (debridement, antimicrobial therapy, and implant retention) procedure depends on multiple factors (e.g. infection type, host factors, clinical presentation, condition of surrounding soft tissue, causing pathogen, surgical technique, antimicrobial therapy); therefore, adequate patient selection is key for DAIR success. In this position paper, we discuss the most relevant factors influencing the outcome and define indications, contraindications, and risk factors for a DAIR procedure based on the most robust and most recently published data. Furthermore, we discuss the surgical technique in combination with systemic antimicrobial therapy in patients undergoing a DAIR procedure. This position paper may help reduce reinfection rates as well as the physical, psychological, and economic burden associated with periprosthetic joint infection (PJI). We believe that a reasonable outcome can be achieved with careful patient selection, a dedicated multidisciplinary team, and an appropriate surgical technique and antimicrobial therapy.