The assessment of neutrophil CD64 count as an early warning marker of joint replacement infection

Predictors for surgical site infection after fasciotomy in patients with acute leg compartment syndrome

BACKGROUND

Surgical site infection (SSI) is one of the most common complications of orthopedic surgery, which can result in fever, pain, and even life-threatening sepsis. This study aimed to determine the predictors of SSI after fasciotomy in patients with acute leg compartment syndrome (ALCS).

METHODS

We collected information on 125 ALCS patients who underwent fasciotomy in two hospitals between November 2013 and January 2021. Patients with SSI were considered as the SSI group and those without SSI as the non-SSI group. Univariate analysis, logistic regression analysis, and receiver operating characteristic (ROC) curve analyses were used to evaluate patient demographics, comorbidities, and admission laboratory examinations.

RESULTS

In our research, the rate of SSI (26 of 125) was 20.8%. Several predictors of SSI were found using univariate analysis, including body mass index (BMI) (p = 0.001), patients with open fractures (p = 0.003), and patients with a history of smoking (p = 0.004). Besides, the levels of neutrophil (p = 0.022), glucose (p = 0.041), globulin (p = 0.010), and total carbon dioxide were higher in the SSI group than in the non-SSI group. According to the results of the logistic regression analysis, patients with open fractures (p = 0.023, OR 3.714), patients with a history of smoking (p = 0.010, OR 4.185), and patients with a higher BMI (p = 0.014, OR 1.209) were related predictors of SSI. Furthermore, ROC curve analysis indicated 24.69 kg/m² as the cut-off value of BMI to predict SSI.

CONCLUSIONS

Our results revealed open fractures, BMI, and smoking history as independent risk factors for SSI following fasciotomy in patients with ALCS and determined the cut-off value of BMI, enabling us to individualize the evaluation of the risk for SSI to implement early targeted treatments.

Distinguishing Sepsis From Infection by Neutrophil Dysfunction: A Promising Role of CXCR2 Surface Level

Sepsis is one of the well-established diseases with specific patterns of neutrophil dysfunctions. Previous studies demonstrated sepsis-related neutrophil dysfunctions in comparison with subjects without infection. Since sepsis and infection are recently recognized as distinctive processes, whether these neutrophil dysfunctions are associated with sepsis or infection are not known. Therefore, we longitudinally compared neutrophil functions, widely-cited as exhibiting sepsis-related changes, between patients with septic shock and infection. The surface level of cluster of differentiation 64 (CD64), C-C motif chemokine receptor 2 (CCR2), C-X-C motif chemokine receptor 2 (CXCR2); apoptosis; and NETosis were measured from peripheral blood neutrophils for seven consecutive days using flow cytometry. The between-group comparisons of neutrophil functions were made both on a day-by-day basis and as linear regression between time and measured neutrophil functions (sepsis status included as model predictors). Our study found that, among neutrophil functions studied, only CXCR2 surface level is associated with sepsis. At disease onset, CXCR2 level decrease, with a dose-response relationship with clinical severity. Its level reverts to resemble infected patients by the end of the week. The relationship between CD64 surface level, CCR2 surface level, NETosis, and sepsis are mediated through the effect of infection. Apoptosis activity between these groups are similar, hence, not sepsis-related.

Incidence and risk factors for surgical site infection following elective foot and ankle surgery: a retrospective study

Background

This study aimed to investigate the incidence of surgical site infection (SSI) in elective foot and ankle surgeries and identify the associated risk factors.

Methods

This was designed as a retrospective study, including patients who underwent elective surgery of foot and ankle between July 2015 and June 2018. Data on demographics, comorbidities, and perioperative parameters were collected from the medical records, the laboratory report, the operation report, and the outpatient follow-up registration database. SSI was defined in accordance with the Center for Disease Control criteria. Univariate and multivariate logistic regression analyses were used to identify the independent risk factors for SSI.

Results

A total of 1201 patients undergoing 1259 elective foot/ankle surgeries were included, of whom 26 (2.1%) had an SSI, representing an incidence rate of 1.3% for superficial SSI and 0.8% for deep SSI, respectively. The results for organism culture showed Pseudomonas aeruginosa in 7 cases, methicillin-resistant Staphylococcus aureus (MRSA) in 6, methicillin-susceptible Staphylococcus aureus (MSSA) in 5, methicillin-resistant coagulase-negative Staphylococci (MRCNS) in 2, Escherichia coli in 2, and Proteus mirabilis in 1 case. Five factors were identified to be independently associated with SSI, including prolonged preoperative stay (OR, 1.21; 95% CI, 1.09 to 1.30), allograft or bone substitute (OR, 3.76; 95% CI, 1.51 to 5.30), elevated FBG level (OR, 1.17; 95% CI, 1.04 to 1.26), lower ALB level (OR, 2.33; 95% CI, 1.19 to 3.05), and abnormal NEUT count (OR, 1.72; 95% CI, 1.27 to 2.12).

Conclusions

SSI following elective foot and ankle surgeries is low, but relatively high in forefoot surgeries, requiring particular attention in clinical practice. Although most not modifiable, these identified factors aid in risk assessment of SSI and accordingly stratifying patients and therefore should be kept in mind.

Evaluation of synovial fluid neutrophil CD64 index as a screening biomarker of prosthetic joint infection

AIMS

Prosthetic joint infection (PJI) remains a major clinical challenge. Neutrophil CD64 index, Fc-gamma receptor 1 (FcγR1), plays an important role in mediating inflammation of bacterial infections and therefore could be a valuable biomarker for PJI. The aim of this study is to compare the neutrophil CD64 index in synovial and blood diagnostic ability with the standard clinical tests for discrimination PJI and aseptic implant failure.

METHODS

A total of 50 patients undergoing revision hip and knee arthroplasty were enrolled into a prospective study. According to Musculoskeletal Infection Society (MSIS) criteria, 25 patients were classified as infected and 25 as not infected. In all patients, neutrophil CD64 index and percentage of polymorphonuclear neutrophils (PMN%) in synovial fluid, serum CRP, ESR, and serum CD64 index levels were measured preoperatively. Receiver operating characteristic (ROC) curves and the area under the curve (AUC) were analyzed for each biomarker.

RESULTS

Serum CD64 index showed no significant difference between the two groups (p = 0.091). Synovial fluid CD64 index and PMN% discriminated good differentiation between groups of PJI and aseptic failure with AUC of 0.946 (95% confidence interval (CI) 0.842 to 0.990) and 0.938 (95% CI 0.832 to 0.987) separately. The optimal threshold value of synovial CD64 index for the diagnosis of PJI was 0.85, with a sensitivity of 92.00%, a specificity of 96.00%, and diagnostic odds ratio (DOR) of 227.11.

CONCLUSION

The present study demonstrates that CD64 index in synovial fluid could be a promising laboratory marker for screening PJI. The cut-off values of 0.85 for synovial CD64 index has the potential to distinguish aseptic failure from PJI. Cite this article: Bone Joint J 2020;102-B(4):463-469.

Utility of CD64 on Neutrophils in Orthopedic Infection

Background

Musculoskeletal infections are often seen in the daily practice of orthopedics. Several markers [white blood cell (WBC), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), procalcitonin (PCT)] have been used for diagnosing these infections. However, these markers may be elevated due to surgery or trauma, and may not be infection-related. These markers also show drug-dependent dynamics during infection that differ from its usual dynamics. Such situations make diagnosis of infections difficult, and Cluster of Differentiation 64 (CD64) has been brought to attention. This study aimed to clarify the utility of CD64 on neutrophils by comparing it with conventional infection markers (CRP, PCT) in musculoskeletal infection.

Methods

Forty-four patients who were suspected of having musculoskeletal infection between May 2010 and November 2013 in our hospital were enrolled in this study. Patients were divided into subgroups according to their culture results, antibiotics administration, measurement timing, and if they were immunocompromised. The measurements of the infection markers were compared between each group. In addition, the positive rates of each infection marker were compared between groups.

Results

There was no difference in the infection marker measurements between several groups. There was no statistically significant difference between groups for the positive rates of CD64, CRP, and PCT.

Conclusion

We evaluated the utility of CD64 on neutrophils in musculoskeletal infection. CD64 showed the utility that was equivalent to conventional infection markers in diagnoses of various musculoskeletal infections.

Procalcitonin and α-Defensin for Diagnosis of Periprosthetic Joint Infections

BACKGROUND

Current methods to diagnose periprosthetic joint infection (PJI) before revision surgery have limited diagnostic accuracy. This meta-analysis was performed to estimate the accuracy of procalcitonin (PCT) and α-defensin for the diagnosis of PJI.

METHODS

Articles on the diagnostic value of PCT or α-defensin for PJI diagnosis were searched in the PubMed database. Sensitivity, specificity, diagnostic odds ratio, the area under the curve of summary receiver operating characteristic curves (AUC), the positive likelihood ratio, and the negative likelihood ratio were calculated to evaluate the diagnostic ability of PCT and the α-defensin test for the diagnosis of PJI.

RESULTS

The pooled sensitivities for detecting PJI using PCT and α-defensin were 0.53 (95% confidence interval [CI], 0.24-0.80) and 0.96 (95% CI, 0.85-0.99), respectively. The pooled specificities for detecting PJI using PCT and α-defensin were 0.92 (95% CI, 0.45-0.99) and 0.95 (95% CI, 0.89-0.98), respectively. The pooled diagnostic odds ratios for detecting PJI using PCT and α-defensin were 13 (95% CI, 3-70) and 496 (95% CI, 71-3456), respectively. The pooled AUCs for PCT and α-defensin were 0.76 (95% CI, 0.72-0.80) and 0.99 (95% CI, 0.97-0.99), respectively. The positive likelihood ratio and the negative likelihood ratio of PCT were 6.8 (95% CI, 1.0-48.1) and 0.51 (95% CI, 0.31-0.84), respectively, whereas those of α-defensin were 19.6 (95% CI, 8.2-46.8) and 0.04 (95% CI, 0.01-0.17), respectively.

CONCLUSION

Synovial fluid α-defensin has a great potential to diagnose PJI.

Identification of periprosthetic joint infection after total hip arthroplasty

Although total hip arthroplasty (THA) is accepted as one of the most successful surgical procedures in orthopaedic surgery, periprosthetic joint infection after THA continues to be one of the most devastating complications. However, accurate preoperative identification of periprosthetic joint infection in patients presenting with joint pain or radiographic periprosthetic lucencies is often difficult, even after a comprehensive work-up. The purpose of this article is to review the diagnostic options available to improve the management and results of this potentially catastrophic complication.