Serum Inflammatory Biomarkers in the Diagnosis of Periprosthetic Joint Infections

Current Concepts in Shoulder Periprosthetic Joint Infections-Are Shoulders the Same as Hips and Knees?

Background/Objectives: The vast amount of research and data on periprosthetic joint infection (PJI) is focussed on infections in hip and knee replacements. This article aims to highlight the special features of PJI in shoulders. Methods: This narrative review is based on the recent and most relevant literature regarding PJI in general, and in shoulders in particular. Results: While the majority of findings for PJI in hips and knees can be transferred to infected shoulder arthroplasties, shoulder PJI represents a unique entity with a different microbial profile and its own diagnostic challenges. Conclusions: As profound evidence for shoulder PJI is lacking, diagnostic and therapeutic algorithms should be transferred from those for PJI in hips and knees. Further research is necessary to determine optimal management of shoulder PJI.

Nomogram to predict periprosthetic joint infection after total hip arthroplasty using laboratory tests

BACKGROUND

Periprosthetic joint infection (PJI) is a catastrophic complication after joint arthroplasty. This study aimed to analyze the relationship between laboratory tests and PJI and establish a nomogram for predicting risks of PJI after total hip arthroplasty (THA).

MATERIALS AND METHODS

The clinical data of patients who underwent THA from January 2015 to December 2020 were retrospectively analyzed. Demographic and relevant clinical information of patients was collected; independent risk factors associated with PJI were determined by univariate and multivariate logistic regression analysis, and receiver operating characteristics (ROC) were drawn to analyze the specificity and sensitivity of each risk factor. Risk factors are included in the nomogram. Calibration curve and decision curve analysis were used to evaluate the predictive accuracy and discriminability of the model.

RESULTS

A total of 589 patients were enrolled in the study, of whom 87 were eventually diagnosed with PJI. Multivariate logistic regression analysis showed that serum C-reactive protein, erythrocyte sedimentation rate, polymorphonuclear neutrophils, D-dimer, and platelet count were independent risk factors for PJI after THA. The ROC curve analysis model of multivariate combined diagnosis had good diagnostic value, sensitivity was 77.01%, and specificity was 75.51%. The calibration curve shows good agreement between the prediction of the line graph and the actual observed results. The decision curve shows that the nomogram has a net clinical benefit.

CONCLUSIONS

The changes in serum C-reactive protein, erythrocyte sedimentation rate, polymorphonuclear neutrophils, D-dimer, and platelet count are related to the occurrence of PJI after hip arthroplasty. The nomogram prediction model established in this study is promising for the screening of PJI after hip arthroplasty.

LEVEL OF EVIDENCE

Level III evidence. Non-randomized controlled cohort/follow-up study.

The diagnostic accuracy of blood C-reactive protein and erythrocyte sedimentation rate in periprosthetic joint infections - A 10-year analysis of 1510 revision hip and knee arthroplasties from a single orthopaedic center

BACKGROUND

Despite the availability of many highly accurate biomarkers and novel criteria, serum C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) are still the basis for diagnosing periprosthetic joint infection (PJI). This study aims to analyze the influence of different demographical and clinical factors on the cut-off values and accuracy of CRP and ESR in diagnosing chronic PJI.

METHODS

A total number of 4757 patients (with ICD-10 codes T84.0 and T84.5) operated on between January 2014 to December 2023 in a single orthopaedic center were screened in terms of the inclusion and exclusion criteria. Finally, 1510 patients (1032 aseptic revisions and 478 periprosthetic joint infections [PJI]) were included in the analysis. The best cut-off values, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for both CRP and ESR for all cohort and for subgroups divided depending on the demographical (gender, joint and BMI) and clinical factors (prosthesis fixation, specific diagnostic criteria, and virulence of the bacteria) were calculated.

RESULTS

For all cohort, the best cut-off value for CRP was 9.6 mg/L with an area under the curve (AUC) of 0.93 and for ESR was 29 mm/h with the AUC of 0.891. For CRP the sensitivity was higher (84.9%) than for ESR (75.1%), with the same values of specificity (90.5% and 90.8%, respectively). According to the specific subgroups, for CRP higher sensitivity was observed for males (89.6%) than for females (82.6%) if lower thresholds were used. Similarly, when the higher cut-off value for CRP was applied, better specificity for high-virulent (94.8%) than for low-virulent pathogens (88.9%) was observed. For ESR, superior sensitivity values were observed if a fistula was observed, for lower BMI thresholds and for infections caused by high-virulent pathogens. Higher optimal threshold and better specificity were observed for knees than for hips, without the appearance of fistula, when minor criteria were used and infection was caused by high-virulent pathogens.

CONCLUSIONS

Our study indicates better sensitivity for CRP than ESR and similar specificity values for diagnosing chronic PJI. If results oscillate close to 10 mg/L for CRP and between 25 and 30 mm/h for ESR we propose to use different cut-off values depending on the demographic and/or clinical factors to increase diagnostic accuracy.

Analysis of clinical indicators and survival prediction in trauma patients

BACKGROUND

Accurate prognostic assessment of critically ill trauma patients in emergency departments is crucial for early intervention and improving survival rates. This study investigates the relationship between blood parameters, disease severity, and patient outcomes.

OBJECTIVE

To explore the relationship between blood parameters and the severity and prognosis of critically ill trauma patients in an emergency trauma center. The goal is to facilitate early diagnosis, implement measures to improve survival rates, and enhance patient outcomes.

METHODS

This retrospective study analyzed the blood parameters of 569 critically ill trauma patients admitted to the trauma center from 2020 to August 2023. The analysis focused on examining the relationship between these parameters and the severity and prognosis of the patients.

RESULTS

Compared to the improved and non-recovered groups, the mortality group had longer times from injury to hospital admission, higher ISS and NEWS scores, lower GCS scores, more acidic blood gas analysis, electrolyte imbalances, and poorer liver and kidney function as well as coagulation indicators.

CONCLUSION

Low pH, high PaCO2, high lactate, high potassium, high NLR, high D-Dimer, high ISS, and high NEWS are independent risk factors. Conversely, high PLT, albumin, and GCS scores are independent protective factors. These indicators can effectively predict the prognosis of trauma patients.

Inflammatory Marker Changes Following Total Knee Arthroplasty for Rheumatoid Arthritis with Vancomycin-Loaded Calcium Sulfate Bone Filling

Rheumatoid arthritis (RA) patients undergoing total knee arthroplasty (TKA) face infection risk. The study evaluates vancomycin-loaded calcium sulfate bone as infection prevention. Patients with RA treated with TKA who had their femoral canal filled using either vancomycin-loaded calcium sulfate bone (experimental group [n = 35]) or the patient's own excised autologous bone (control group [n = 30]) at the Qingdao University Affiliated Hospital, Qingdao, China from January 1, 2017, to March 1, 2023, were retrospectively enrolled in this study. An experienced surgeon used midvastus approach. Surgeries included disinfection, antibiotics, and femoral filling. The age, gender, body mass index (BMI), comorbidities, and intraoperative details were extracted from the patient's medical records. Preoperation and postoperation markers (C-reactive protein [CRP], erythrocyte sedimentation rate [ESR]), pain scale (Visual Analog Scale [VAS]), infection rate, and Knee Society Score (KSS) were collected. Groups matched in age, gender, and BMI. No preoperative inflammatory marker differences were observed. However, compared to the control group, the postoperative inflammatory markers were significantly lower in the experimental group at 1-week postsurgery (CRP: 40.80 ± 23.17 vs. 60.80 ± 43.12 mg/L, p = 0.021; ESR: 72.06 ± 17.52 vs. 83.87 ± 21.52 mm/h, p = 0.012) and at 1-month postsurgery (CRP: 15.63 ± 6.56 vs. 21.17 ± 13.16 mg/L, p = 0.032; ESR: 25.25 ± 20.44 vs. 38.40 ± 25.26 mm/h, p = 0.024). There were no significant differences in the VAS (2.79 ± 0.90 vs. 2.70 ± 0.84 score, p = 0.689) and KSS (64.31 ± 17.88 vs. 66.57 ± 12.36) at 1-month postsurgery. Experimental group: zero infections; control group: only one infection. Administering vancomycin and calcium sulfate during TKA in RA patients reduces postoperative inflammation, but does not significantly affect infection risk; further research may be necessary for validation.

Analysis of Serum and Synovial Inflammatory Markers in Periprosthetic Joint Infections: A Narrative Review

Periprosthetic joint infection (PJI) is considered a rare but devastating complication after total joint arthroplasty (TJA). The problem lies in the fact that there is a paucity of "gold standard" diagnostic tests that make the diagnosis of PJI extremely challenging. Recently, there have been increasing evidence-based guidelines that have been introduced to standardise the approach to a patient with a suspected PJI. Diagnosing a case of PJI traditionally involves initial screening for elevated serum inflammation markers C-reactive protein (CRP) (mg/dL) and erythrocyte sedimentation rate (ESR), and aspiration remains the sole confirmatory investigation. However, several factors would affect the values of the aforementioned markers, such as gender, age, and the presence of inflammatory circumstances. Serum D-dimer that detects fibrinolytic activities during infection has high sensitivity, but the specificity was not persuasive as it would elevate during other conditions, such as venous thromboembolism. Therefore, there is also a need for a simultaneous and secondary marker. There are also several synovial biomarkers, including ESR, CRP, alpha-defensin, and synovial fluid leukocyte count and differential for the detection of PJI. In this narrative review, we want to sum up the serum and inflammatory markers that have been introduced so far for detecting PJI.

Construction and evaluation of a combined diagnostic model for chronic periprosthetic joint infection based on serological tests

BACKGROUND

Early diagnosis of chronic periprosthetic joint infection (CPJI) is crucial for ensuring effective treatment and improving patient outcomes. However, many auxiliary diagnostic tests are challenging to implement on a large scale due to economic and technical constraints, making CPJI diagnosis difficult. This study aims to design and validate a combined diagnostic model based on commonly used serological tests to evaluate its diagnostic value for CPJI and develop a diagnostic nomogram.

METHODS

A retrospective study from January 2019 to February 2024 involving 170 patients undergoing knee and hip arthroplasty revision for CPJI and aseptic loosening (AL) was conducted across two medical centers. These patients were divided into the training set and validation set. Patients were categorized into CPJI and AL groups based on infection status. Serological tests conducted upon admission were collected, and single-factor and multi-factor logistic regression analyses were used to identify independent diagnostic factors for early infection. These factors were integrated to construct a nomogram model. The model's performance was evaluated using the receiver operating characteristic area under the curve (AUC), Hosmer-Lemeshow test, decision curve analysis (DCA), and calibration curve, with external validation conducted on the validation set.

RESULTS

Multivariate logistic regression analysis showed that C-reactive protein (CRP), procalcitonin (PCT), and Platelet count/mean platelet volume ratio (PVR) were independent diagnostic factors for CPJI (p < 0.05). The AUCs for diagnosing CPJI using these individual factors were 0.806, 0.616, and 0.700 (p < 0.05), respectively, while their combined detection achieved an AUC of 0.861 (p < 0.05). The DCA clinical impact curve shows the combined model has good clinical utility when the threshold probability of infection presence is between 0.16 and 0.95. Similar results were obtained in the external validation cohort, with the combined detection having an AUC of 0.893.

CONCLUSION

The combined diagnostic model of CRP, PCT, and PVR significantly improves the The combined diagnostic model of CRP, PCT, and PVR significantly improves the diagnostic performance for CPJI compared to individual serum biomarkers. It exhibits good sensitivity, specificity, and clinical applicability, providing valuable references for CPJI diagnosis.

Manilkara zapota (L.) P. Royen Leaf Mitigates Colitis-Associated Colon Cancer through Anti-inflammatory Modulation in BALB/C Mice

Colitis-associated colon cancer (CAC) arises from prolonged inflammation of the inner colon lining. An alternative approach to treating or preventing CAC involves the use of natural products such as Manilkara zapota (L.) P. Royen or M. zapota, which has been studied for its medicinal and pharmacological properties. Previous research has demonstrated the anticancer effects of M. zapota leaf aqueous extract (MZLAE) on colon cancer cells. However, no animal study has investigated the effects of MZLAE on CAC. Therefore, this study aimed to assess the potential anti-inflammatory effects of MZLAE on CAC in mice. In the present study, CAC was induced using azoxymethane (AOM) and dextran sodium sulphate (DSS). The mice were randomly assigned into five groups: (a) normal, (b) AOM/DSS, (c) AOM/DSS + 50 mg/kg MZLAE, (d) AOM/DSS + 100 mg/kg MZLAE, and (e) AOM/DSS + 200 mg/kg MZLAE. Various parameters including disease activity index (DAI), colon length and weight, reactive oxygen species (ROS), superoxide, superoxide dismutase (SOD), histopathological assessment, and proinflammatory cytokines expression were analysed. The results indicated that MZLAE improved DAI scores, colon length, colon histological dysplasia and inflammation scores, and SOD level, while also reducing ROS production and expression of proinflammatory cytokines (tumour necrosis factor-alpha (TNF- α) and interleukin 6 (IL-6)). In conclusion, this study suggests that MZLAE may serve as a promising source of antioxidants and anti-inflammatory agents for alleviating CAC.

Serum albumin-to-globulin ratio and CRP-to-albumin ratio did not outperform serum CRP in diagnosing periprosthetic joint infections

Aims

Serum inflammatory parameters are widely used to aid in diagnosing a periprosthetic joint infection (PJI). Due to their limited performances in the literature, novel and more accurate biomarkers are needed. Serum albumin-to-globulin ratio (AGR) and serum CRP-to-albumin ratio (CAR) have previously been proposed as potential new parameters, but results were mixed. The aim of this study was to assess the diagnostic accuracy of AGR and CAR in diagnosing PJI and to compare them to the established and widely used marker CRP.

Methods

From 2015 to 2022, a consecutive series of 275 cases of revision total hip (n = 129) and knee arthroplasty (n = 146) were included in this retrospective cohort study. Based on the 2021 European Bone and Joint Infection Society (EBJIS) definition, 144 arthroplasties were classified as septic. Using receiver operating characteristic curve (ROC) analysis, the ideal thresholds and diagnostic performances were calculated. The areas under the curve (AUCs) were compared using the z-test.

Results

AGR, CAR, and CRP were associated with PJI (p < 0.001). Sensitivities were 62.5% (95% CI 54.3 to 70.0), 73.6% (95% CI 65.8 to 80.1), and 71.5% (95% CI 63.6 to 78.3), respectively. Specificities were calculated with 84.7% (95% CI 77.5 to 89.9), 86.3% (95% CI 79.2 to 91.2), and 87.8% (95% CI 80.9 to 92.4), respectively. The AUC of CRP (0.797 (95% CI 0.750 to 0.843)) was significantly higher than the AUC of AGR (0.736 (95% CI 0.686 to 0.786), p < 0.001), and similar to AUC of CAR (0.799 (95% CI 0.753 to 0.846), p = 0.832). Decreased sensitivities were observed in PJIs caused by low-virulence organisms (AGR: 60%, CAR: 78%) compared to high-virulence pathogens (AGR: 80%, p = 0.042; CAR: 88%, p = 0.158). Higher sensitivities were seen in acute haematogenous (AGR: 83%, CAR: 96%) compared to chronic PJIs (AGR: 54%, p = 0.001; CAR: 65%, p < 0.001).

Conclusion

Serum AGR and CAR showed limited diagnostic accuracy (especially in low-grade and chronic infections) and did not outperform the established marker CRP in our study. Hence, neither parameter can be recommended as an additional tool for diagnosing PJI.

An overview of the current diagnostic approach to Periprosthetic Joint Infections

The diagnosis of periprosthetic joint infections (PJI) presents a formidable challenge to orthopaedic surgeons due to its complex and diverse manifestations. Accurate diagnosis is of utmost importance, as even mild pain following joint replacement surgery may indicate PJI in the absence of a definitive gold standard diagnostic test. Numerous diagnostic modalities have been suggested in the literature, and international societies have continually updated diagnostic criteria for this debilitating complication. This review article aims to comprehensively examine the latest evidence-based approaches for diagnosing PJI. Through a thorough analysis of current literature, we explore promising diagnostic strategies that have demonstrated effectiveness in identifying PJI. These strategies encompass the utilization of laboratory markers, such as erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), alongside imaging techniques such as magnetic resonance imaging (MRI) and leukocyte scintigraphy. Additionally, we highlight the importance of synovial fluid analysis, including the potential role of alpha-defensin as a biomarker, and examine evolving international diagnostic criteria to standardize and improve diagnostic accuracy.

Effects of serum inflammatory factors, health index and disease activity scores on ankylosing spondylitis patients with sleep disorder

BACKGROUND

Patients with ankylosing spondylitis (AS) frequently suffer from comorbid sleep disorders, exacerbating the burden of the disease and affecting their quality of life.

AIM

To investigate the clinical significance of serum inflammatory factors, health index and disease activity scores in patients with AS complicated by sleep disorders.

METHODS

A total of 106 AS patients with comorbid sleep disorders were included in the study. The patients were grouped into the desirable and undesirable prognosis groups in accordance with their clinical outcomes. The serum levels of inflammatory factors, including C-reactive protein, erythrocyte sedimentation rate, interleukin (IL)-6, tumour necrosis factor-α and IL-1β, were measured. Disease activity scores, such as the Bath AS functional index, Bath AS disease activity index, Bath AS metrology index and AS disease activity score, were assessed. The health index was obtained through the Short Form-36 questionnaire.

RESULTS

The study found significant associations amongst serum inflammatory factors, health index and disease activity scores in AS patients with comorbid sleep disorders. Positive correlations were found between serum inflammatory factors and disease activity scores, indicating the influence of heightened systemic inflammation on disease severity and functional impairment. Conversely, negative correlations were found between disease activity scores and health index parameters, highlighting the effect of disease activity on various aspects of health-related quality of life. Logistic regression analysis further confirmed the predictive value of these factors on patient outcomes, underscoring their potential utility in risk assessment and prognostication.

CONCLUSION

The findings demonstrate the intricate interplay amongst disease activity, systemic inflammation and patient-reported health outcomes in AS patients complicated by sleep disorders. The results emphasise the need for comprehensive care strategies that address the diverse needs and challenges faced by these patients and underscore the potential relevance of serum inflammatory factors, health index and disease activity scores as prognostic markers in this patient population.

Diagnostic Test Performances for Identifying Periprosthetic Joint Infection in Hip Hemiarthroplasty

INTRODUCTION

Periprosthetic joint infection (PJI) is a devastating complication of hip hemiarthroplasty (HHA) that is not well-represented in the literature. Therefore, this study aimed to evaluate diagnostic markers for identifying PJI in patients after HHA and compare them with the most recent 2018 International Consensus Meeting on Musculoskeletal Infection criteria.

METHODS

A total of 98 patients (64 PJIs, 65.3%) were analyzed. Patients were identified by relevant Current Procedural Terminology and International Classification of Diseases-9/10 codes from 2000 to 2021 across a single healthcare system. Preoperative or intraoperative synovial fluid nucleated cell (NC) count, synovial polymorphonuclear (PMN) percentage, serum erythrocyte sedimentation rate (ESR), serum C-reactive protein (CRP), and serum white blood cell count were compared with Student t -test between aseptic and septic cohorts. Diagnostic utility and laboratory cutoff values were determined using receiver-operating characteristic curves and Youden index, respectively.

RESULTS

Mean values were significantly higher in the septic cohort for synovial NC count (120,992.2 versus 1,498.0 cells/μL, P < 0.001), synovial PMN percentage (91.3% versus 56.2%, P < 0.001), serum ESR (75.6 versus 36.3 mm/hr, P < 0.001), serum CRP (20.2 versus 125.8 mg/L, P < 0.001), and serum white blood cell count (8.5 versus 11.5 cells/μL, P < 0.001). Synovial NC count, synovial PMN percentage, and serum CRP had excellent PJI discriminatory ability with an area under the curve of 0.99, 0.90, and 0.93, respectively. Optimal cutoffs were 2,700 cells/μL for synovial NC count (100% sensitivity and 94% specificity), 81.0% for synovial PMN percentage (96% sensitivity and 89% specificity), 52.0 mm/hr for serum ESR (75% sensitivity and 80% specificity), and 40.0 mg/L for serum CRP (85% sensitivity and 92% specificity).

CONCLUSION

Our findings support the continued use of routine serum and synovial fluid tests for diagnosing PJI in HHA patients. Optimal cutoff values for both synovial fluid biomarkers were very close in alignment with the 2018 International Consensus Meeting criteria.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Different biomarker ratios in peripheral blood have limited value in diagnosing periprosthetic joint infection after total joint arthroplasty: a single-center, retrospective study

BACKGROUND

Periprosthetic joint infection (PJI) is a severe complication that can occur after total joint arthroplasty (TJA). The timely and accurate diagnosis of PJI is the key to treatment. This study investigated the diagnostic value of platelet to lymphocyte ratio (PLR), platelet count to mean platelet volume ratio (PVR), neutrophil to lymphocyte ratio (NLR) and monocyte to lymphocyte ratio (MLR) in PJI after total knee arthroplasty (TKA) and total hip arthroplasty (THA).

METHODS

We performed a retrospective analysis of the patients who underwent revision hip or knee arthroplasty at our Institute between June 2015 and June 2020. Of the 187 patients reviewed, 168 were included in the study. According to the diagnostic criteria of the Musculoskeletal Infection Society (MSIS), 58 patients were in the PJI group, and 110 patients were in the aseptic loosening (AL) group. We recorded and compared the preoperative peripheral blood white blood cell (WBC) count, platelet count (PLT), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), PLR, PVR, NLR, and MLR in both groups. The diagnostic performance of the WBC, PLT, PLR, PVR, NLR, and MLR individually and in combination with the ESR and CRP for PJI diagnosis was evaluated by receiver operating characteristic (ROC) curves, and the sensitivity, specificity, positive predictive value, and negative predictive value were calculated.

RESULTS

Compared to those in the AL group, the mean WBC, PLT, ESR, CRP, PLR, PVR, NLR, and MLR in the peripheral blood of the PJI group were significantly greater (P < 0.05). The analysis of the ROC curve revealed that the ESR, CRP, PLR, PVR, NLR, and MLR in peripheral blood had moderate effectiveness in diagnosing PJI, with area under the curve (AUC) values of 0.760 (95% CI: 0.688-0.823), 0.758 (95% CI: 0.687-0.821), 0.714 (95% CI: 0.639-0.781), 0.709 (95% CI: 0.634-0.777), 0.723 (95% CI: 0.649-0.789), and 0.728 (95% CI: 0.654-0.793), respectively. Conversely, the WBC and PLT counts demonstrated poor diagnostic value for PJI, with AUC values of 0.578 (95% CI: 0.499-0.653) and 0.694 (95% CI: 0.619-0.763), respectively. The results of the prediction model calculations revealed that the combined AUC of the WBC, PLT, ESR, CRP, PLR, PVR, NLR, and MLR was the highest at 0.853 (95% CI, 0.790-0.909), indicating good value in the diagnosis of PJI, with a sensitivity of 82.8% and a specificity of 72.7%. Moreover, the novel composite of parameters improved the accuracy and reliability in diagnosing PJI compared to the traditional biomarkers ESR and CRP (P = 0.015).

CONCLUSION

Our study suggested that the diagnostic value of the peripheral blood biomarkers PLR, PVR, NLR, and MLR for diagnosing PJI is limited and not superior to that of the ESR or CRP. However, when the WBC, PLT, ESR, CRP, PLR, PVR, NLR, and MLR are combined, the diagnostic performance of PJI in TJA patients can be improved.

Diagnostics in Late Periprosthetic Infections-Challenges and Solutions

The rising number of arthroplasties is combined with a rising number of periprosthetic joint infections, which leads to life-concerning consequences for the patients, including extended antibiotic treatment, further surgery and increased mortality. The heterogeneity of the symptoms and inflammatory response of the patients due to, e.g., age and comorbidities and the absence of a single diagnostic test with 100% accuracy make it very challenging to choose the right parameters to confirm or deny a periprosthetic joint infection and to establish a standardized definition. In recent years, additional diagnostic possibilities have emerged primarily through the increasing availability of new diagnostic methods, such as genetic techniques. The aim of the review is to provide an overview of the current state of knowledge about the various tests, including the latest developments. The combination of different tests increases the accuracy of the diagnosis. Each physician or clinical department must select the tests from the available methods that can be best implemented for them in organizational and technical terms. Serological parameters and the cultivation of the samples from aspiration or biopsy should be combined with additional synovial tests to create an accurate figure for the failure of the prosthesis, while imaging procedures are used to obtain additional information for the planned therapeutic procedure.

AZU1: a new promising marker for infection in orthopedic and trauma patients?

Early and reliable detection of infection is vital for successful treatment. Serum markers such as C-reactive protein (CRP) and procalcitonin (PCT) are known to increase with a time lag. Azurocidin 1 (AZU1) has emerged as a promising marker for septic patients, but its diagnostic value in orthopedic and trauma patients remains unexplored. Between July 2020 and August 2023, all patients necessitating inpatient treatment for periprosthetic joint infection (PJI), peri-implant infection (II), soft tissue infection, chronic osteomyelitis, septic arthrodesis, bone non-union with and without infection were enrolled. Patients undergoing elective total joint arthroplasty (TJA) served as the control group. Blood samples were collected and analyzed for CRP, white blood cell count (WBC), PCT, and AZU1. Based on the inclusion and exclusion criteria 222 patients were included in the study (trauma = 38, soft tissue infection = 75, TJA = 33, PJI/II = 39, others = 37). While sensitivity and specificity were comparably high for AZU1 (0.734/0.833), CRP and PCT had higher specificity (0.542/1 and 0.431/1, respectively), and WBC a slightly higher sensitivity (0.814/0.455) for septic conditions. Taken together, the area under the curve (AUC) showed the highest accuracy for AZU1 (0.790), followed by CRP (0.776), WBC (0.641), and PCT (0.656). The Youden-Index was 0.57 for AZU1, 0.54 for CRP, 0.27 for WBC, and 0.43 for PCT. Elevated AZU1 levels effectively distinguished patients with a healthy condition from those suffering from infection. However, there is evidence suggesting that trauma may influence the release of AZU1. Additional research is needed to validate the diagnostic value of this new biomarker and further explore its potential clinical applications.

Is large unstained cell percentage (%LUC) a novel diagnostic marker for periprosthetic joint infections?

BACKROUND

Periprosthetic joint infection (PJI) is a very important complication that occurs after total joint replacement. Diagnosing PJI is at least as difficult as this disease. There is no biomarker that alone can diagnose PJI.

OBJECTIVE

This study aimed to evaluate the effectiveness of large unstained cell percentage (%LUC) in diagnosing PJI and deciding on re-implantation in two stage septic exchange arthroplasty.

METHODS

Patients who underwent revision arthroplasty between 2019 and 2023 were screened retrospectively. These patients were grouped as those who underwent two-stage septic exchange and those who underwent aseptic exchange. Prosthesis removal from the patients who underwent two-stage septic exchange, before spacer application, and on the 3rd post-operative day after spacer application, Blood parameters were collected at the 1st month and before the second stage after the spacer application, and before the revision surgery from the patients who underwent aseptic exchange. White blood cell, neutrophil percentage, %LUC, albumin, sedim and CRP values were checked and recorded one by one from all patients.

RESULTS

The data of a total of 233 patients, including 133 patients in the two stage septic exchange group and 100 patients in the aseptic exchange group, were included in the study. When the predictive value of %LUC in PJI was accepted as cut-off 1.75, the sensitivity was 69.2% and the specificity was 73%. The change in %LUC over time in patients who underwent two-stage septic exchange was statistically significant (p= 0.0001). A positive correlation was found between the value of .%LUC after spacer application and the value of CRP before prosthesis protrusion/spacer application surgery, and the Spearman correlation coefficient was found to be 0.005.

CONCLUSION

%LUC value can be a promising biomarker for the diagnosis of PJI by considering both sensitivity and specificity rates. Apart from this, it is an easily accessible and effective biomarker for re-implantation decision making and evaluation of response to treatment, especially in two-stage septic exchange surgeries.

Efficacy of DAIR in managing Candida parapsilosis-infected total knee arthroplasty with five-year follow-up: A case report and review of literature

RATIONALE

Fungal periprosthetic joint infections (fPJIs) are relatively uncommon, accounting for approximately 1% of all PJIs. Revision surgery is typically recommended for fungal infections; however, the physical and financial impact on patients is significant. In this report, we present a case of fPJI successfully treated with debridement, antibiotics, and implant retention (DAIR) with a favorable outcome over a 5-year period.

PATIENT CONCERN

A 56-year-old male patient presented with a non-healing surgical incision 1 week after undergoing primary total knee arthroplasty on the right side.

DIAGNOSIS

Microbiological culture of the wound effusion identified Candida parapsilosis. Postoperatively, the patient exhibited a significant decrease in serum albumin levels and poor glycemic control. Both C-reactive protein and erythrocyte sedimentation rate were elevated.

INTERVENTIONS

A comprehensive DAIR procedure was performed, along with continuous closed irrigation using fluconazole for 1 week. The patient received intravenous voriconazole for 4 weeks, followed by oral fluconazole for an additional 3 months.

OUTCOMES

At 1- and 5-year follow-up appointments, the patient C-reactive protein and erythrocyte sedimentation rate levels were within normal limits, and there was no evidence of swelling, erythema, or tenderness in the right knee joint, indicating no signs of infection.

LESSONS

DAIR is an effective treatment for early fPJIs, and continuous closed irrigation may provide specific advantages. The patient nutritional status plays a crucial role in the management of periprosthetic infections.

Ratiometric Fluorescence and Afterglow Lifetime Dual-Channel Nanoprobe for Simultaneous Imaging of HOCl and Temperature in Arthritis

Arthritis is a joint disorder that potentially causes permanent joint damage and eventual disability without effective treatment. Clinical detection methods, including in vitro blood tests and anatomical imaging, still have limitations in achieving real-time in situ early detection of arthritis. In this work, a dual-channel luminescence nanoprobe (AGNPs-Cy7) is reported, which combines a cyanine dye and a photochemical reaction-based afterglow system for real-time in vivo imaging of arthritis. AGNPs-Cy7 simultaneously detect hypochlorous acid (HOCl) and temperature, two important indicators associated with the early development of arthritis, by monitoring the respective changes in independent ratiometric fluorescence and afterglow lifetime signals. The anti-interference properties of both the ratiometric fluorescence signal and afterglow lifetime signal enhance sensing accuracy compared to the single luminescence intensity. The developed probe successfully reveals the simultaneous increase in HOCl concentration and temperature in an arthritis mouse model.

Periprosthetic Joint Infection Diagnosis: A Narrative Review

Replacement of native joints aims to restore patients' quality of life by relieving pain and improving joint function. While periprosthetic joint infection (PJI) affects a small percentage of patients, with an estimated incidence of 1-9% following primary total joint replacement, this postoperative complication necessitates a lengthy hospitalisation, extended antibiotic treatment and further surgery. It is highlighted that establishing the correct diagnosis of periprosthetic infections is critical in order for clinicians to avoid unnecessary treatments in patients with aseptic failure. Of note, the PJI diagnosis could not purely rely upon clinical manifestations given the fact that heterogeneity in host factors (e.g., age and comorbidities), variability in infection period, difference in anatomical location of the involved joint and discrepancies in pathogenicity/virulence of the causative organisms may confound the clinical picture. Furthermore, intra-operative contamination is considered to be the main culprit that can result in early or delayed infection, with the hematogenous spread being the most prevalent mode. To elaborate, early and hematogenous infections often start suddenly, whereas chronic late infections are induced by less virulent bacteria and tend to manifest in a more quiescent manner. Last but not least, viruses and fungal microorganisms exert a role in PJI pathogenesis.

Novel diagnostic markers for periprosthetic joint infection: a systematic review

Background

Identifying novel biomarkers that are both specific and sensitive to periprosthetic joint infection (PJI) has the potential to improve diagnostic accuracy and ultimately enhance patient outcomes. Therefore, the aim of this systematic review is to identify and evaluate the effectiveness of novel biomarkers for the diagnosis of PJI.

Methods

We searched the MEDLINE, EMBASE, PubMed, and Cochrane Library databases from January 1, 2018, to September 30, 2022, using the search terms "periprosthetic joint infection," "prosthetic joint infection," or "periprosthetic infection" as the diagnosis of interest and the target index, combined with the term "marker." We excluded articles that mentioned established biomarkers such as CRP, ESR, Interleukin 6, Alpha defensin, PCT (procalcitonin), and LC (leucocyte cell count). We used the MSIS, ICM, or EBJS criteria for PJI as the reference standard during quality assessment.

Results

We collected 19 studies that analyzed fourteen different novel biomarkers. Proteins were the most commonly analyzed biomarkers (nine studies), followed by molecules (three studies), exosomes (two studies), DNA (two studies), interleukins (one study), and lysosomes (one study). Calprotectin was a frequently analyzed and promising marker. In the scenario where the threshold was set at ≥50-mg/mL, the calprotectin point-of-care (POC) performance showed a high sensitivity of 98.1% and a specificity of 95.7%.

Conclusion

None of the analyzed biomarkers demonstrated outstanding performance compared to the established parameters used for standardized treatment based on established PJI definitions. Further studies are needed to determine the benefit and usefulness of implementing new biomarkers in diagnostic PJI settings.

Diagnosis of Periprosthetic Joint Infection: The Utility of Biomarkers in 2023

Periprosthetic joint infection (PJI) is a rare yet devastating complication following total joint arthroplasty (TJA). Early and accurate diagnosis of PJI is paramount in order to maximize the chances of successful treatment. However, we are yet to identify a single "gold standard" test for the diagnosis of PJI. As a result, the diagnosis of PJI is often challenging. Currently, the 2018 ICM definition of PJI is the only validated diagnostic criteria available. This article will review the importance of serum and synovial biomarkers in the diagnosis of PJI. In addition, it will provide a brief overview of the emerging modalities for the identification of infections in this setting.

Emerging Technologies in Diagnosing Periprosthetic Joint Infections

Periprosthetic joint infection (PJI) is a well-known serious complication following joint replacement surgeries and is responsible for high failure rates of implanted devices. Any delay in the diagnosis can compromise treatment success, putting a huge burden on the patients' wellness and healthcare systems. Diagnosing PJIs is quite complex as there is still no gold standard test to reach the definitive diagnosis in a timely manner. A number of laboratory tests and radiological imaging inventions have evolved in the past few years, requiring consistent updates of the available guidelines to keep up with the latest advances in the field. This article highlights the recent advances in diagnosing PJIs and discusses their validity for use in clinical practice.

The Challenge of Periprosthetic Joint Infection Diagnosis: From Current Methods to Emerging Biomarkers

Due to the increase in the life span and mobility at older ages, the number of implanted prosthetic joints is constantly increasing. However, the number of periprosthetic joint infections (PJIs), one of the most severe complications after total joint arthroplasty, also shows an increasing trend. PJI has an incidence of 1-2% in the case of primary arthroplasties and up to 4% in the case of revision operations. The development of efficient protocols for managing periprosthetic infections can lead to the establishment of preventive measures and effective diagnostic methods based on the results obtained after the laboratory tests. In this review, we will briefly present the current methods used in PJI diagnosis and the current and emerging synovial biomarkers used for the prognosis, prophylaxis, and early diagnosis of periprosthetic infections. We will discuss treatment failure that may result from patient factors, microbiological factors, or factors related to errors during diagnosis.

Long Pentraxin 3 as a New Biomarker for Diagnosis of Hip and Knee Periprosthetic Joint Infections

BACKGROUND

Preoperative diagnosis of periprosthetic joint infections (PJIs) poses an unmet clinical challenge. The long pentraxin PTX3 is a component of the innate immune system involved in infection immunity. This study evaluated the potential of synovial and plasmatic PTX3 in the diagnosis of hip and knee PJIs.

METHODS

Consecutive total hip and knee arthroplasty (THA/TKA) revisions were prospectively included and classified as septic or aseptic according to the European Bone and Joint Infection Society (EBJIS) and Musculoskeletal Infection Society (MSIS) criteria. The concentration of PTX3 in plasma and synovial fluid samples was measured with ELISA. The AUC, threshold value, sensitivity, specificity, and positive and negative likelihood ratios were calculated using the ROC (receiver operating characteristic) curve method.

RESULTS

The study population included 128 patients (94 THAs; 34 TKAs). The AUC of the synovial PTX3 based on EBJIS criteria was 0.85 (p < 0.0001), with a sensitivity of 81.13% and a specificity of 93.33%. The AUC based on MSIS criteria was 0.95 (p < 0.001), with a sensitivity of 91.43% and a specificity of 89.25%. Plasmatic PTX3 failed to discriminate infected from non-infected patients.

CONCLUSIONS

Synovial PTX3 demonstrated an excellent diagnostic potential in hip and knee PJIs, with a very high specificity irrespective of the diagnostic criteria for PJI.

Proximal Femur Fractures in the Elderly-A Novel Modality to Predict Mortality: The Neutrophil-to-Lymphocyte Ratio

Background: The assessment and identification of elderly patients with proximal femur fractures (PFF) who are at high risk of postoperative mortality may influence the treatment decision-making process. The purpose of this study was to determine whether the neutrophil-to-lymphocyte ratio (NLR) could be used to predict postoperative mortality in the elderly population. Methods: A four-year retrospective cohort study of electronic medical records was conducted at a single tertiary care hospital between 2015 and 2018. Data from 1551 patients aged 65 years and older who underwent surgical treatment for PFF were collected and analyzed. The data included complete blood counts at admission, demographic information, underlying illnesses, type of surgery, and postoperative mortality and complications during the first year of follow-up. A survival analysis model was utilized. Results: The mean age was 90.76 ± 1.88 years, 1066 (68.7%) women. Forty-four (2.8%) patients experienced postoperative infection. A higher NLR0 was independently associated with higher all-cause mortality rates in patients who underwent surgical treatment for PFF (p = 0.041). Moreover, the mean NLR0 value was higher when the death occurred earlier after surgery (p < 0.001). Conclusions: When combined with other clinical and laboratory findings, NLR0 levels may serve as a potentially valuable, inexpensive, and reliable prognostic biomarker to improve risk stratification for elderly patients who are candidates for PFF surgery. Furthermore, with additional research, we could potentially develop a treatment algorithm to identify patients at high risk of postoperative mortality.

Serum acute-phase protein concentrations following uncomplicated total hip arthroplasty in dogs

OBJECTIVES

To establish preoperative and postoperative serum C reactive protein (CRP) and serum amyloid A (SAA) levels in dogs undergoing uncomplicated total hip arthroplasty (THA).

STUDY DESIGN

Prospective clinical trial.

ANIMALS

Eighteen client-owned dogs.

METHODS

Dogs undergoing THA were recruited. Serum CRP and SAA levels were measured in all dogs the day prior to surgery, and 3 and 6 months following surgery. All dogs received a physical examination and underwent radiography at each visit, and dogs with complications were excluded from the study. For continuous numeric data, histograms were generated and evaluated for normality. A 1-way repeated measures ANOVA was performed to find differences between time points.

RESULTS

No complications were encountered in any of the recruited dogs. Median age was 30 months (12-66), and the median bodyweight was 27.3 kg (22.3-40.2). Mean CRP concentrations in the preoperative, 3-month, and 6-month periods were 3.8 mg/L ± 4.4, 0.8 mg/L ± 1.9, and 1.4 mg/L ± 1.4, respectively. The mean SAA concentrations in the preoperative, 3-month, and 6-month periods were 13.9 mg/L ± 8.8, 14.1 mg/L ± 12.6, and 18.4 mg/L ± 15.1, respectively. There were no differences for each parameter between time points.

CONCLUSION

C-reactive protein and SAA levels were consistent with levels previously established for noninflammatory and normal conditions in dogs.

CLINICAL SIGNIFICANCE

Postoperative CRP and SAA concentrations were low by 3 months following uncomplicated THA.

Elevated body temperature and leukocyte count are associated with elevated creatine kinase after seizures

Objective

To evaluate the independent risk factors for elevated creatine kinase (hyperCKemia) after seizures.

Methods

Data included in this retrospective study were obtained from two hospitals from July 1, 2017, to March 31, 2022. Clinical and laboratory data were acquired from the emergency department or within 24 h after patient admission. Variables that exhibited statistical differences (P < 0.05) were selected for further analysis. Associations between body temperature (BT), leukocyte count (LEU), percentage of neutrophils (NEU), and C-reactive protein (CRP) and creatine kinase (CK) levels were assessed using binary logistic regression analysis.

Results

One hundred twenty-three patients who exhibited seizures were included in the study, and 39 (31.7%) patients exhibited hyperCKemia based on a CK level that was >1.5 times the upper limit of the normal range for CK. No statistical differences were observed among the patient characteristics, seizure-related parameters, or electrolyte levels. However, BT, LEU, NEU, and CRP were elevated in patients with hyperCKemia compared to patients with normal CK levels. Specifically, a BT ≥ 37.5 °C (fever) and LEU >9.5×10⁹/L (elevated LEU) exhibited positive correlations with hyperCKemia, and presented an adjusted OR of 8.87 (95% CI: 2.11-37.24, P = 0.003) and 3.01 (95% CI: 1.12-8.05, P = 0.029), respectively.

Conclusion

In this study, hyperCKemia occurred in 31.7% of patients after seizures. Fever and elevated LEU were independent risk factors for seizure-related hyperCKemia. Earlier recognition of risks for seizure-related hyperCKemia would be beneficial in taking prophylactic measures.

Role of Biomarkers in Periprosthetic Joint Infections

Periprosthetic joint infection (PJI) is one of the most serious complications after joint arthroplasty. The incidence rate of PJI after total joint replacement is 1-3%. Although there are different guidelines and diagnostic criteria used to diagnose PJI, diagnosing PJI is a highly difficult process for orthopedists. The current Musculoskeletal Infection Society (MSIS) criteria are widely used for the diagnosis of PJI. These criteria include results from blood/synovial fluid tests, physical examination, and histological and microbiological analyses of intra-operative samples. However, there is currently no blood or synovial test that can definitively diagnose PJI. To make a more effective diagnosis of PJI, a large number of studies have explored and continue to investigate biomarkers. This review aims to provide general information about serum and synovial markers used for the diagnosis of PJI that may be used to create a database to guide researchers in new studies.

Decreased serum superoxide dismutase concentration has a high value for the diagnosis of periprosthetic joint infection-a single-center, retrospective study

PURPOSE

As the most serious complication of total knee arthroplasty (TKA), periprosthetic joint infection (PJI) often leads to disastrous consequences. An accurate preoperative diagnosis plays a significant role in saving prostheses and optimizing treatment outcomes. Through this retrospective case-control study, we aimed to investigate the potential of superoxide dismutase (SOD) as a novel serum biomarker in the diagnosis of PJI.

METHODS

We conducted a retrospective review of all patients who underwent TKA and received adequate follow-ups in our hospital from June 2015 to December 2021. A total of 50 patients were enrolled in the PJI group based on the 2018 International Consensus Meeting (ICM) criteria. Besides that, we enrolled 100 patients who underwent TKA in the same period and had a good postoperative course in the control group. Patient characteristics, comorbidities, laboratory results (serum, synovial, and microbial), and intraoperative findings (purulence and histopathology) were documented and compared by univariate analysis. Receiver operating characteristic (ROC) analysis was used to determine the sensitivity, specificity, and diagnostic performance.

RESULTS

The median serum SOD level in the PJI and control group was 135.95 ± 24.47 U/ml (IQR, 111.85-158.30 U/ml) and 173.83 ± 13.9 U/ml (IQR,162.83-183.5 U/ml) (p < 0.05), respectively. With the calculated cutoff of SOD at 149.5U/L, the area under the ROC curve (AUC), sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), were 0.919, 0.72, 0.97, 0.923, and 0.874, respectively. In subgroup analysis, the specificity of SOD in diagnosing culture-negative PJI remained extremely high (0.98). Combined diagnosis of serum SOD and C-reactive protein (CRP) made AUC increase to 0.972.

CONCLUSION

Serum SOD showed great potential in the diagnosis of PJI.

Inflammatory Biomarkers as Prognostic Factors of Acute Deep Vein Thrombosis Following the Total Knee Arthroplasty

Background and objectives: Deep vein thrombosis (DVT) is one of the most serious post-operative complications in the case of total knee arthroplasty (TKA). This study aims to verify the predictive role of inflammatory biomarkers [monocyte-to-lymphocyte ratio (MLR), neutrophil-to-lymphocyte ratio (NLR), platelets-to-lymphocyte ratio (PLR), systemic inflammatory index (SII), systemic inflammation response index (SIRI), and aggregate index of systemic inflammation (AISI)] in acute DVT following TKA. Materials and methods: The present study was designed as an observational, analytical, retrospective cohort study and included all patients over 18 years of age with surgical indications for TKA, admitted to the Department of Orthopedics, Regina Maria Health Network, Targu Mures, Romania, and the Department of Orthopedics, Humanitas MedLife Hospital, Cluj-Napoca, Romania between January 2017 and July 2022. The primary endpoint was the risk of acute DVT following the TKA, and the secondary endpoint was the length of hospital stay, and the outcomes were stratified for the baseline’s optimal MLR, NLR, PLR, SII, SIRI, and AISI cut-off value. Results: DVT patients were associated with higher age (p = 0.01), higher incidence of cardiac disease [arterial hypertension (p = 0.02), atrial fibrillation (p = 0.01)], malignancy (p = 0.005), as well as risk factors [smoking (p = 0.03) and obesity (p = 0.02)]. Multivariate analysis showed a high baseline value for all hematological ratios: MLR (OR: 11.06; p < 0.001), NLR (OR: 10.15; p < 0.001), PLR (OR: 12.31; p < 0.001), SII (OR: 18.87; p < 0.001), SIRI (OR: 10.86; p < 0.001), and AISI (OR: 14.05; p < 0.001) was an independent predictor of DVT after TKA for all recruited patients. Moreover, age above 70 (OR: 2.96; p = 0.007), AH (OR: 2.93; p = 0.02), AF (OR: 2.71; p = 0.01), malignancy (OR: 3.98; p = 0.002), obesity (OR: 2.34; p = 0.04), and tobacco (OR: 2.30; p = 0.04) were all independent predictors of DVT risk. Conclusions: Higher pre-operative hematological ratios MLR, NLR, PLR, SII, SIRI, and AISI values determined before operations strongly predict acute DVT following TKA. Moreover, age over 70, malignancy, cardiovascular disease, and risk factors such as obesity and tobacco were predictive risk factors for acute DVT.

Masquelet technique with radical debridement and alternative fixation in treatment of infected bone nonunion

Background

Infected bone nonunion is the toughest problem in fracture-related infection, leading to high disability and recurrence. The aim of this study was to evaluate the effectiveness of the Masquelet technique with radical debridement and alternative fixation in the management of infected bone nonunion.

Patients and Methods

A retrospective study of prospectively collected data in two trauma centers was performed from 2016 to 2020. Patients diagnosed as infected bone nonunion were included in this study. The initial implant was removed and all patients received a two-stage Masquelet procedure with radical debridement and alternative fixation. The disappearance of inflammatory manifestations and regression of infection indicators (such as interleukin-6 (IL-6), C-reactive protein, white blood cell count) to the normal range were regarded as radical debridement. The alternative fixation depended on local soft tissue conditions. Results were evaluated according to clinical and radiographic assessment and patient satisfaction.

Results

A total of 23 patients were included in our study. Six of them received internal fixation, while the other 17 received external fixation. Of the 23 cases, 21 were successfully reconstructed without infection recurrence, except 2 reinfected cases. Mean full weight bearing time was 6.6 months follow-up post last surgery. Out of the 23, 20 cases had satisfactory functional outcomes without additional bone or soft tissue comorbidities. Discrepancies in leg length and joint stiffness were observed in three cases and marked as unsatisfied results.

Conclusions

Infected bone nonunion can be successfully managed using the Masquelet technique under radical debridement combined with an alternative fixation method.

A New Graphic Type Differentiation of Cell Account Determination for Distinguishing Acute Periprosthetic Joint Infection from Hemarthrosis

Aims: This study evaluates the value of a new graphic representation of cell count data of synovial fluid in the diagnosis of acute periprosthetic joint infection (PJI). Methods: A total of 75 patients with revisions of 48 primary total knee and 27 hip arthroplasties within the first six weeks after surgery were analyzed with cultivation of the synovial fluid and determination of its cell count as well as microbiological and histological analyses of the periprosthetic tissue obtained during the revision surgery using the ICM classification. The synovial fluid was additionally analyzed for graphic representation of the measured cells using LMNE-matrices. Results: A total of 38 patients (50.7%) had an infection. The following types of LMNE matrices could be differentiated: the indeterminate type (IV) in 14.7%, the infection type (II) in 5.3%, the hematoma type (V) in 33.3%, and the mixed type (VI; infection and hematoma) in 46.7%. Differentiation of LMNE types into infection (types II and VI) and non-infection (types IV and V) resulted in a sensitivity of 100%, a specificity of 97.3%, and a positive likelihood ratio of 37.0. The cell count measurement showed a sensitivity of 78.9%, a specificity of 89.2%, and a positive likelihood ratio of 7.3 at a cut-off of 10,000 cells. The percentage of polymorphonuclear leukocytes showed a sensitivity of 34.2%, a specificity of 100%, and a positive likelihood ratio of >200 at a cut-off of 90%. Conclusion: The graphic representation of the cell count analysis of synovial aspirates is a new and helpful method for differentiating between genuine early periprosthetic infections and postoperative hemarthrosis.