Chronic Periprosthetic Joint Infection Research Articles

Dual Surgical Setup Associated with Reduced Infection Recurrence for Hip and Knee Arthroplasty After Two-Stage Exchange.

Two-stage exchange (TSE) is the gold standard for the treatment of chronic periprosthetic joint infection (PJI) after total joint arthroplasty of the hip and knee in the United States. Failure of treatment can have devastating consequences for the patient, including poor functional outcomes, multiple further surgeries, and increased mortality. Several factors associated with infection recurrence have previously been identified in the literature. The purpose of this study was to evaluate whether the use of a dual surgical setup was associated with reduced risk of recurrence after TSE for PJI. A retrospective study was conducted between January 2000 and December 2021 to isolate patients who underwent TSE after total joint arthroplasty of the hip and knee. Failure was defined as infection recurrence requiring surgical intervention. Demographic factors (age, sex, body mass index, smoking status, American Society of Anesthesiologists status), preoperative comorbidities (hypertension, cardiac disease, diabetes status, depression diagnosis, pulmonary disease), operating surgeon, single versus dual setup, hospital setting, use of long-term antibiotics postoperatively after TSE, aspiration data, and infecting organism were compared between cohorts using multivariate regression analysis. A total of 134 patients were identified who underwent TSE after diagnosis of PJI. The mean follow-up was 67.84 (range, 13 to 236) months. Dual setup (odds ratio, 0.13; confidence interval, 0.02 to 0.52; P = 0.0122) was found to be an independent predictive variable associated with a lower risk of infection recurrence. Utilization of a dual surgical setup is a low-cost modifiable risk factor associated with a lower risk of recurrence of after TSE of the hip and knee for PJI.

Two-Stage Treatment of Chronic Periprosthetic Knee Infections With the Use of Gentamicin-Articulated Spacers: Success Rate and Predictors of Failure at the Minimum Seven-Year Follow-Up.

The purpose of this study was to assess the survivorship rates of 2-stage treatment with gentamicin-impregnated polymethylmethacrylate articulated knee spacer in patients with chronic periprosthetic joint infection and to identify risk factors associated with failure. We conducted a retrospective study among 73 patients with chronic periprosthetic joint infection after primary total knee replacement with articulated polymethylmethacrylate gentamicin-impregnated spacers (Subiton, Medical Labs, Ind Argentina), performed in a single institution with a minimum follow-up of 7years. Clinical and functional assessment was performed with Knee Society Score and Western and Ontario McMaster Universities Osteoarthritis Index. A univariate and multivariate analysis was performed to identify the variables that influenced the success and failure rates. We included 73 patients. There were 53 (71.3%) monomicrobial, 11 (15%) polymicrobial, and 10 (13.7%) negative cultures infections. The success and failure rates were 90.5% (n= 66) and 9.5% (n= 7), respectively. Multivariate analysis identified that age (odds ratio= 1.77; P= .039), greater erythrocyte sedimentation rate values prior to the first stage (odds ratio= 1.04; P= .006), and polymicrobial infections (odds ratio= 7.32; P= .0003) were independent variables associated with failure. Two-stage revision with polymethylmethacrylate gentamicin-impregnated knee spacers is an effective strategy for the treatment of chronic periprosthetic joint infection after total knee arthroplasty. Age, higher erythrocyte sedimentation rate values prior first stage, and polymicrobial infections were independent risk factors for treatment failure.

Should We Use Rifampicin in Periprosthetic Joint Infections Caused by Staphylococci When the Implant Has Been Exchanged? A Multicenter Observational Cohort Study.

Previous studies demonstrated the efficacy of a rifampicin-based regimen in the treatment of acute staphylococcal periprosthetic joint infections (PJIs) treated with surgical debridement. However, evidence is lacking to support the use of rifampicin in cases where the implant is exchanged during revision. We included all consecutive cases of staphylococcal PJIs treated from January 2013 to December 2018 with revision surgery in this international, retrospective, multicenter observational cohort study. PJI was defined according to the European Bone and Joint Infection Society diagnostic criteria. A relapse or reinfection during follow-up, the need for antibiotic suppressive therapy, the need for implant removal, and PJI-related death were defined as clinical failure. Cases without reimplantation or with follow-up <12 months were excluded. A total of 375 cases were included in the final analysis, including 124 1-stage exchanges (33.1%) and 251 2-stage exchanges (66.9%). Of those, 101 cases failed (26.9%). There was no statistically significant difference in failure of patients receiving rifampicin (22.5%, 42/187) and those not receiving rifampicin (31.4%, 59/188; P = .051). A subanalysis of chronic PJIs treated by 2-stage exchange arthroplasty demonstrated a lower failure rate in cases treated with rifampicin (15%) compared with the no-rifampicin group (35.5%; P = .005). In this subgroup, the use of rifampicin and an antibiotic holiday of >2 weeks were independent predictors of clinical success (odds ratio [OR], 0.36; 95% CI, 0.15-0.88; and OR, 0.19; 95% CI, 0.04-0.90; respectively). Combination treatment with rifampicin increases treatment success in patients with chronic staphylococcal PJI treated with 2-stage exchange arthroplasty.

The Diagnostic Utility of Fast Tests for Detecting C-Reactive Protein in Synovial Fluid in Periprosthetic Joint Infections.

Despite the fact that many synovial fluid biomarkers have found application in the routine diagnosis of periprosthetic joint infection (PJI), this process still remains a challenge for orthopaedic surgeons. To simplify this process, fast point-of-care (POC) tests can be used during ambulatory visits and in operating room conditions. However, before such tests can be routinely used in clinical practice, they require validation. The purpose of the present study was to evaluate the diagnostic accuracy of different fast POC tests for detecting C-reactive protein (CRP) in synovial fluid for the diagnosis of PJI. Synovial fluid samples were collected from 120 consecutive patients who underwent revision total joint arthroplasty (TJA). The patients were divided into 2 groups. The first group included 76 patients who underwent revision for reasons other than infection (the aseptic revision TJA [arTJA] group), and the second group included 44 patients who underwent revision because of periprosthetic joint infection (PJI). The diagnosis of infection was made according to the International Consensus Meeting (ICM) 2018 criteria. All patients were operatively treated at a single orthopaedic center from January 2022 to February 2023. Four fast CRP tests with different cutoff values (1 and 3 mg/L, ≥8 mg/L, ≥10 mg/L [cassette], ≥10 mg/L [strip]) were used off-label for synovial fluid testing. Tests were performed on the same synovial fluid samples, and the results of these tests were compared with those obtained with the laboratory method. The cassette test with a minimum cutoff value of ≥8 mg/L demonstrated the best accuracy for the diagnosis of chronic PJI, with a sensitivity and specificity of 90.9% and 90.8%, respectively. For the cassette test with a cutoff value of >3 mg/L, the sensitivity and specificity were 68.2% and 77.6%, respectively. For the tests with a minimum cutoff value of ≥10 mg/L, the sensitivity and specificity were 77.3% and 94.7%, respectively, for the cassette test and 77.3% and 96.1%, respectively, for the strip test. The laboratory method with the statistically calculated threshold (2.7 mg/L) revealed the highest AUC (area under the receiver operating characteristic curve) value (0.95), with 90.9% sensitivity and 94.7% specificity. The cassette POC test with the minimum cutoff value of ≥8 mg/L had very good accuracy for the diagnosis of chronic PJI. This test had comparable sensitivity and slightly lower specificity in comparison with the laboratory method with the calculated threshold of 2.7 mg/L. Diagnostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Incidence, associated factors, and outcomes of acute kidney injury following placement of antibiotic bone cement spacers in two-stage exchange for periprosthetic joint infection: a comprehensive study.

Two-stage exchange with placement of antibiotic cement spacer (ACS) is the gold standard for the treatment of chronic periprosthetic joint infection (PJI), but it could cause a high prevalence of acute kidney injury (AKI). However, the results of the current evidence on this topic are too mixed to effectively guide clinical practice. We retrospectively identified 340 chronic PJI patients who underwent the first-stage exchange with placement of ACS. The Kidney Disease Improving Global Outcomes guideline was used to define postoperative AKI. Multivariate logistic analysis was performed to determine the potential factors associated with AKI. Furthermore, a systematic review and meta-analysis on this topic were conducted to summarize the knowledge in the current literature further. In our cohort, the incidence of AKI following first-stage exchange was 12.1%. Older age (per 10 years, OR= 1.509) and preoperative hypoalbuminemia (OR= 3.593) were independent predictors for postoperative AKI. Eight AKI patients progressed to chronic kidney disease after 90 days. A meta-analysis including a total of 2525 PJI patients showed the incidence of AKI was 16.6%, and AKI requiring acute dialysis was 1.4%. Besides, host characteristics, poor baseline liver function, factors contributing to acute renal blood flow injury, and the use of nephrotoxic drugs may be associated with the development of AKI. However, only a few studies supported an association between antibiotic dose and AKI. AKI occurs in approximately one out of every six PJI patients undergoing first-stage exchange. The pathogenesis of AKI is multifactorial, with hypoalbuminemia could be an overlooked associated factor. Although the need for acute dialysis is uncommon, the fact that some AKI patients will develop CKD still needs to be taken into consideration.

The role of culture-negative infection among infectious complications after total knee arthroplasty

Introduction Diagnosis of chronic periprosthetic joint infection (PJI) is difficult with the clinical signs of periprosthetic inflammation showing no growth of microorganism in the biomaterial. The frequency of culture-negative infection can reach 42.1 %. The objective of the study was to analyze outcomes of two-stage treatment of chronic PJI of the knee joint depending on the etiology of the infectious process.Material and methods A retrospective analysis of outcomes was produced for 103 patients: group I (n=30) showing no growth of microorganisms and group II (n = 73) demonstrating positive growth of pathogens. Knee PJI was diagnosed according to the 2018 ICM criteria. A favorable outcome suggested absence of recurrence for at least two years after reimplantation of endoprosthesis, arthrodesis, “life with a spacer” without signs of infection.Results Culture-negative infection was detected in 29.1 % (n = 30). Patients in the group were 1.5 times more likely to receive antibiotic therapy prior to admission and had average levels of CRP, ESR and articular leukocyte count being 1.5-2 times less than those in group II. Staphylococci (69.8 %) including MRSE (75 %) was the leading pathogen in group II. Recurrence of infection was 3.4 % in group I and 16.9 % in group II (p = 0.0928), the two-stage treatment was successful in 96.7 % and 74 %, respectively (p = 0.0064).Discussion Causes for the lack of growth of microorganisms in biological materials included previous antibiotic therapy, wound drainage, violations of the rules for sampling of biological material, absence of media for the growth of atypical microorganisms and the ability of microorganisms to form biofilms on implant surfaces. An emergency histological examination of the affected tissues was practical during surgery in doubtful situations for adequate surgical approach. The results of a meta-analysis (2023) showed that the replacement of an infected endoprosthesis was more effective for the treatment of a culture-negative infection compared to debridement and preservation of implant.Conclusion The culture-negative infection group in our series showed better success rate of a two-stage treatment of PJI using implant replacement and broad-spectrum empiric antibiotic therapy at a two-year follow-up period. The negative microbiological result in the group could be caused by antibacterial drugs administered prior to diagnosis of PJI.

The Influence of Patient Sex on Outcomes Following One-Stage and Two-Stage Revision for Periprosthetic Joint Infection in Total Joint Arthroplasty.

Although females have a higher rate of primary total joint arthroplasty (TJA), males have a higher rate of revision. The literature lacks studies examining the relationship between sex and outcomes following single and two-stage exchange for periprosthetic joint infection (PJI). The purpose of this study was to examine if differences exist in outcomes following revision for chronic PJI between sexes. A retrospective review was performed on all patients with an MSIS confirmed PJI who underwent a single or two-stage exchange at our institution from January 2010 to January 2021. Patient demographics, comorbidity characteristics, and outcomes were collected and compared between males and females. The primary outcome variable was disease-free survival at 1 year following definitive revision. Multivariable logistic regression analysis was performed to determine risk factors for failure. Of the 470 patients meeting final eligibility criteria, 250 were male and 226 were female (2 males and 4 females had a joint infection of either the contralateral side or a different joint and were treated as separate records). Of the patients in the cohort, 80% of the males (200/250) and 80% of the females (181/226) were found to be disease-free at 1-year follow-up (p > 0.99). Multivariable logistic regression analysis showed that nicotine use and diabetes, but not sex, were significant predictors of failure. Our study did not find a relationship between sex and outcome of revision for PJI. Further research is required to determine whether differences exist between males and females in the expression of PJI and outcomes following treatment.

Neutrophil to Lymphocyte Ratio and Periprosthetic Joint Infection: A Systematic Review and Meta-Analysis

BackgroundThe neutrophil-to-lymphocyte ratio (NLR) has shown promising results as a diagnostic tool for periprosthetic joint infection (PJI) after total joint arthroplasty. We conducted a systematic review and meta-analysis to determine the utility of NLR in the diagnosis of PJI. MethodsWe searched PubMed, Scopus, and Web of Science from inception up to 2022 and evaluated the quality of the included literature. ResultsBased on the 12 eligible studies, NLR levels were significantly higher in patients who had PJI compared to those who had aseptic loosening (standard mean difference (SMD) = 1.05, 95% Confidence Interval (CI) = 0.71 to 1.40, P < .001). In the subgroup analysis according to type of PJI, NLR levels were significantly higher in patients who had either acute (SMD = 1.04, 95% CI = 0.05 to 2.03, P < .001) or chronic PJI (SMD = 1.08, 95% CI = 0.55 to 1.61, P < .001), compared to those who had aseptic loosening. According to type of arthroplasty, NLR levels were significantly higher in patients who had either total knee arthroplasty (SMD = 1.81, 95% CI = 1.48 to 2.13, P < .001) or total hip arthroplasty (SMD = 1.76, 95% CI = 1.54 to 1.98, P < .001) compared to aseptic loosening. The pooled sensitivity of the 12 studies was 0.73 (95% CI, 0.65 to 0.79), and the pooled specificity was 0.75 (95% CI, 0.71 to 0.78). The pooled positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio of NLR were 2.94 (95% CI = 2.44 to 3.54), 0.35 (95% CI = 0.27 to 0.46), and 8.26 (95% CI = 5.42 to 12.58), respectively. ConclusionIn summary, this meta-analysis indicates that NLR is a reliable marker in the diagnosis of PJI.

High infection control rate after systematic one-stage procedure for shoulder arthroplasty chronic infection.

The twostage revision procedure is the gold standard surgical technique in chronic shoulder periprosthetic joint infection (PJI). Series of onestage revision have been published with similar outcomes but with preoperative selection of patients. The aim of this work was to report the outcomes (infection eradication, functional, and radiographic) after systematic onestage revision, without preoperative selection of patients, in chronic shoulder PJI. This was a retrospective monocentric study including 40 patients (14 women and 26 men) with a diagnosis of periprosthetic joint infection after a shoulder arthroplasty. A onestage shoulder prosthesis revision was performed in all patients, for a PJI evolving for more than three weeks, without preoperative patient selection. The primary endpoint was the absence of signs of persistent infection at a minimum follow-up of two years. Secondary endpoints were clinical and radiological outcomes. At the last follow-up, 36/40 patients had no recurrence of infection after the onestage revision, i.e., 90% of our series. In 45% (18/40) of the cases, the microbial organism was not known at the time of the onestage revision. Cutibacterium acnes was the most frequent pathogen, found in 67.5% (27/40) of the patients. The infection was polymicrobial in 40% (16/40) of the cases. At last follow-up, mean absolute Constant score was 48.4% (16-93) and weighted score was 65.5% (22-100), and satisfaction was evaluated by the patients as excellent or good in 75% (30/40). About 20% (8/40) of the patients had a postoperative complication. A onestage revision procedure, combined with appropriate antibiotic therapy, made it possible to eradicate the PJI in 90% of the shoulders in our series with satisfactory functional outcomes.

Two-stage revision in periprosthetic joint infection of the hip using a new intraoperatively molded articulating spacer design

PurposeThe treatment of periprosthetic joint infection (PJI) after total hip arthroplasty (THA) is still under debate. Two-stage exchange arthroplasty is the most common surgical procedure performed. This study analyzed a new functional articulating hip spacer called "Spaceflex" regarding the mechanical-related complications, the recurrent/persistent infection during the interval period, the overall infection-free survivorship after reimplantation, the overall complication/reoperation after reimplantation and the evaluation of patient-reported outcome measures (PROMs) at three intervals of time: before the first stage, during the interval period, and at the final follow-up after reimplantation. MethodsA consecutive series of 56 patients with chronic hip PJI undergoing two-stage prosthetic revision using a new intraoperatively molded articulating hip spacer design implanted by the same experienced surgeons was examined from January 2017 to December 2021. The demographic and clinical characteristics of the included patients were analyzed. Specifically, PROMs before the first stage, during the interval period, and at the final follow-up after reimplantation and complications reported during the interval period and after reimplantation were examined. ResultsThe new functional articulating hip spacer was characterized by a low mechanical complication rate (5.8%) and an overall two-stage procedure success rate of 90.6% at the last follow-up. PROMs improved with the spacer during the interval period and at the final follow-up. Furthermore, the reinfection rate was in line with other case series with different spacer designs. Finally, low postoperative complication rates after reimplantation have been demonstrated. ConclusionsTwo-stage revision performed with a modular articulating spacer allows patients to preserve satisfactory functional and quality-of-life outcomes in the postoperative period, with a low risk of mechanical complications and without increasing the reinfection rate.

Joint fluid interleukin-6 combined with the neutral polymorphonuclear leukocyte ratio (PMN%) as a diagnostic index for chronic periprosthesis infection after arthroplasty

BackgroundThe diagnosis of periprosthetic joint infection (PJI) remains a challenge in clinical practice. Many novel serum and joint fluid biomarkers have important implications for the diagnosis of PJI. The presented study evaluated the value of joint fluid interleukin-6 (IL-6) combined with the neutral polymorphonuclear leukocyte (PMN%) ratio for chronic PJI diagnosis after arthroplasty.Materials and methodsSixty patients with chronic PJI or aseptic failure who underwent hip or knee revision from January 2018 to January 2020 in our department were included in this retrospective study. According to the 2013 MSIS diagnostic criteria, the 60 patients were divided into a PJI group and a non-PJI group (30 patients per group). We collected the joint fluid before surgery and determined the level of IL-6 and the PMN% by ELISA, and the differences between the two groups were compared. The diagnostic efficacy of joint fluid IL-6 combined with PMN% in chronic PJI was analyzed using a receiver operating characteristic curve (ROC curve).ResultsThe diagnosis of PJI using joint fluid IL-6 combined with PMN% presented an area under the curve of 0.983, which was more accurate than the areas under the curve for diagnosis using IL-6 and PMN% individually (0.901 and 0.914, respectively). The optimal threshold values for IL-6 and PMN% were 662.50 pg/ml and 51.09%, respectively. Their sensitivity and specificity were 96.67% and 93.33%, respectively. The accuracy of the diagnosis of PJI was 95.00%.ConclusionsJoint fluid IL-6 combined with PMN% can be used as an auxiliary method to detect chronic infection around the prosthesis after hip/knee arthroplasty.Level of evidencePatients who underwent hip/knee revision at the First Hospital of Chongqing Medical University for periprosthetic infection or aseptic failure of the prosthesis after hip/knee arthroplasty from January 2018 to January 2020 were included.Trial registration This study was approved by the ethics committee of the First Hospital of Chongqing Medical University on September 26, 2018 (local ethics committee number: 20187101) and registered with the China Clinical Trials Registry (registration number: ChiCTR1800020440) with an approval date of December 29, 2018.

The Change of Serum Interleukin-6 Fails to Identify Subsequent Periprosthetic Joint Infection in Patients Who Have Two-Stage Revision for Periprosthetic Joint Infection

BackgroundThe diagnosis of persistent infection prior to second-stage reimplantation in 2-stage exchanges for periprosthetic joint infection (PJI) can be challenging as there is no optimal diagnostic tool. This study investigates the usefulness of pre-reimplantation serum C-reactive protein (CRP) and interleukin-6 (IL-6) and its change between both stages to identify patients who have subsequent PJI. MethodsThere were 125 patients who underwent planned 2-stage exchange for chronic knee or hip PJI from a single center retrospectively identified. Patients were included if preoperative CRP and IL-6 were available for both stages. Subsequent PJI was defined as 2 positive microbiological cultures at reimplantation or subsequent surgery or death due to PJI during follow-up. ResultsPrior to reimplantation, the median serum CRP (total knee arthroplasties [TKAs]: 1.0 versus 0.5 mg/dL, P = .028; total hip arthroplasties [THAs]: 1.3 versus 0.5 mg/dL, P = .015) and median IL-6 (TKA: 8.0 versus 6.0 pg/mL, P = .052; THA: 7.0 versus 6.0 pg/mL, P = .239) were higher in patients who had subsequent PJI. The IL-6 and CRP values showed moderate sensitivity (TKA/CRP: 66.7%; THA/CRP: 58.8%; TKA/IL-6: 46.7%; THA/IL-6: 35.3%) and good specificity (TKA/CRP: 66.7%; THA/CRP: 81.0%; TKA/IL-6: 86.3%; THA/IL-6: 83.3%). The change in CRP and IL-6 between the stages did not differ between the groups, respectively. ConclusionsSerum CRP and IL-6 show low to moderate sensitivity and good specificity in the diagnosis of subsequent PJI prior to reimplantation, which questions their usefulness as a rule-out test. Furthermore, the change in between stages does not appear to identify subsequent PJI.

Immunological markers of arthroplasty failure

Periprosthetic joint infection still remains a clinical challenge since accurate definition of this condition and reliable laboratory markers have not been established yet. This study aimed to evaluate the benefit of some lymphocyte and monocyte subset determination in patients with periprosthetic joint infection and non-infectious arthroplasty failure. Thirty-four patients with chronic periprosthetic joint infection, 12 patients with non-infectious arthroplasty and 30 healthy persons were included in the study. The counts of CD3+, CD3+CD4+, CD3+CD8+, CD19+, CD3-CD16+CD56+, CD3+HLA-DR+, CD4+CD45RACD45RО+, CD4+CD45RA+ CD45RО- and CD14+ HLA-DR+ subsets in peripheral blood were assessed by flow cytometry. The assessment of the intensity of antigen expression was carried out according to mean fluorescence intensity. A significant increase in CD3+CD4+ subsets (p &lt; 0,01) and a significant decrease in CD3-CD16+CD56+ subsets (p &lt; 0,005) were revealed in patients with periprosthetic joint infection compared to the healthy controls. The content of CD19+ lymphocytes in these patients was significantly higher than in aseptic ones (p &lt; 0,005); the latter group was also characterized by more pronounced increase in the number of activated T lymphocytes (CD3+HLA-DR+) compared to controls (p &lt; 0,001). Patients with periprosthetic joint infection showed decreased “naïve” T lymphocytes (CD4+CD45RA+CD45RO-) count compared to aseptic ones (p &lt; 0,05), and both groups showed a decrease counts compared to controls (p &lt; 0,001). On the contrary, memory T lymphocyte (CD4+CD45RACD45RO+) count was significantly increased in both compared groups (p &lt; 0,05). Patients with periprosthetic joint infection compared with other two groups demonstrated a significant decrease in the number of activated monocytes (CD14+HLA-DR+) and pronounced decrease in the expression intensity of this marker on cell membrane (p &lt; 0,05 and p &lt; 0,001, respectively). Thus, evaluation of lymphocyte and monocyte subsets, including expression of cell activation antigens could be useful as additional laboratory test in combination with other conventional methods for differentiation between periprosthetic joint infection and aseptic arthroplasty failure.

Serum CD64 as a Marker for Chronic Periprosthetic Joint Infection.

Serum cluster of differentiation 64 (CD64) has emerged as a diagnostic test for musculoskeletal infections. The purpose of this study was to evaluate the utility of serum CD64 in diagnosing periprosthetic joint infections (PJIs) compared to conventional markers like white blood count (WBC), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and interleukin-6 (IL-6). A prospective case-control study on patients undergoing revision hip or knee arthroplasty surgery >6weeks after their index surgery was performed at a single institution. Whole blood samples were drawn within 24 hours prior to revision surgery for white blood count, ESR, CRP, IL-6, and CD64. Intraoperative cultures were obtained during the revision, and PJI was defined using the major criteria from the 2018 Musculoskeletal Infection Society criteria. Two-sample Wilcoxon rank-sum test and Fisher's exact test were used to determine if there were significant differences in serum laboratory values between patients with and without infection. The sensitivity, specificity, positive predictive value (PPV), negative predictive value, and accuracy of each test were calculated. With an average age of 67 years, 39 patients with 15 revision THAs and 24 TKAs, were included. 19 patients (48.7%) were determined to have PJI. Patients with PJI had significantly higher CD64 (P=.036), CRP (P= .016), and ESR (P= .045). CD64 had the highest specificity (100%) and PPV (100%), moderate accuracy (69.2%), but low sensitivity (37.0%) and negative predictive value (62.5%). Given the high specificity, PPV, and accuracy, CD64 may be an excellent confirmatory test to help diagnose PJI.

Low accuracy in preoperative tissue biopsies for diagnosing chronic periprosthetic joint infection: an observational retrospective single-centre study.

Diagnosing periprosthetic joint infection (PJI) can be challenging. The ability to distinguish between septic and aseptic failure of a joint prosthesis is crucial for treatment strategy optimisation and prognosis prediction. Preoperative tissue cultures are included in many diagnostic algorithms; however, studies report different degrees of concordance (63%-85%) with intraoperative cultures. This study aimed to investigate the diagnostic performance of tissue biopsies in the preoperative diagnostic process with the 2018 International Consensus Meeting criteria as a reference and to describe the concordance between microbiological findings in pre- and intraoperative biopsies. This observational retrospective study included 44 patients requiring revision surgery of a total hip or knee arthroplasty, where the diagnostic workup included biopsies of periprosthetic tissue. The accuracy of preoperative biopsies was calculated, and concordance between microbiological findings in pre- and intraoperative biopsies was described. The accuracy was 59%, with a sensitivity of 50% and specificity of 79%. Full concordance between microbiological findings in pre- and intraoperative biopsies was found in 64% of the cases. An open biopsy of periprosthetic tissue cannot reliably confirm or exclude PJI, and, therefore, should not be performed.

Bacterial Burden, Not Local Immune Response, Differs Between Acute and Chronic Peri-Prosthetic Joint Infections.

Background: Conducting gram stains in peri-prosthetic joint infections (PJI) is known to have poor sensitivity. However, the aims of this study were to use gram stain results of acute and chronic PJI to determine differences with respect to bacterial burden and levels of local innate immunologic response. Patients and Methods: Patients with acute and chronic PJI from January 1, 2016 and December 31, 2020 were identified by use of Current Procedural Terminology codes. Manual review of medical records for infecting organisms and gram stain results for stained bacteria and for local tissue inflammation (amount of polymorphonuclear leukocytes seen on high powered microscopic fields) were recorded. Statistical comparisons between acute (n = 70) and chronic (n = 134) PJI were analyzed with respect to gram stain sensitivity and amount of local tissue inflammation. Results: The ability to identify stained bacteria was statistically significantly higher in the acute cohort (61.4%) than the chronic cohort (9.7%; p < 0.0001). Interestingly, the amount of local inflammation was similar for acute and chronic PJI except in the subgroup analysis with chronic polymicrobial (p = 0.0229) and chronic culture negative (p = 0.0001) PJI. Conclusions: This study shows that both acute and chronic PJI had similar levels of local inflammation seen on gram stains, despite higher bacterial burdens in acute infections. This suggests that innate immune responses, and thus likelihood of infection eradication, is not solely dependent on bacterial burden. These findings should spearhead further research evaluating the different immunologic responses that occur in acute and chronic PJI to improve diagnostics, therapeutics, and infection-free implant survival.

What's New in Musculoskeletal Infection.

What's New in Musculoskeletal Infection.

Handmade spacers for two-stage exchange at the hip.

Two-stage exchange with implantation of atemporary spacer is the gold standard treatment for chronic periprosthetic joint infection of the hip. This article describes asimple and safe technique for handmade spacers at the hip. Periprosthetic joint infection of the hip. Septic arthritis of the native joint. Known allergy against components of polymethylmethacrylate bone cements. Inadequate compliance for two-stage exchange. Patient unfit to undergo two-stage exchange. Bony defect situation at the acetabulum impeding stable reduction of the spacer. Bone loss at the femur jeopardizing stable fixation of the stem. Soft tissue damage with need for plastic temporary vacuum-assisted wound closure (VAC) therapy. Tailoring bone cement with antibiotics. Preparation of ametal endoskeleton. Molding of spacer stem and head by hand. Customizing spacer off-sets to bony anatomy and soft tissue tension. Implantation assuring rotational stability at the femur with abone cement collar. Confirmation of correct position by intraoperative radiography. Restricted weight-bearing. Range of motion as possible. Reimplantation after successful treatment of infection.

Handmade articulating spacer for two-stage exchange at the knee.

Two-stage exchange with implantation of atemporary spacer is considered gold standard treatment for chronic periprosthetic joint infection of the knee. This article describes asimple and safe technique for handmade articulating spacers at the knee. Chronic or relapsing periprosthetic joint infection of the knee. Known allergy against components of polymethylmethacrylate (PMMA) bone cements or admixed antibiotics. Inadequate compliance for two-stage exchange. Patient not able to undergo two-stage exchange. Bony defect situation at the tibia or femur leading to collateral ligament insufficiency. Soft tissue damage with need for plastic temporary vacuum-assisted wound closure (VAC) therapy. Removal of the prosthesis, thorough debridement of necrotic and granulation tissue, tailoring bone cement with antibiotics. Preparation of atibial and femoral stem. Customizing the tibial and femoral articulating spacer components to bony anatomy and soft tissue tension. Confirmation of correct position by intraoperative radiography. Protection of the spacer with an external brace. Restricted weight-bearing. Passive range of motion as possible. Intravenous-followed by oral antibiotics. Reimplantation after successful treatment of infection.

Temporary arthrodesis through static spacer implantation in two-stage treatment of periprosthetic joint infections of the knee.

Treatment of chronic periprosthetic joint infection of the knee requires the removal of the implant and thorough debridement, with reimplantation in asecond stage surgery. Intramedullary spacers can be helpful during the interval between explantation and reimplantation and provide atemporary arthrodesis which fixes the knee in extension preserving leg length and administers local antibiotic therapy. Periprosthetic joint infection of the knee with large bony defects and severe infection of the native joint with advanced destruction/infiltration of the cartilage and bone and/or ligament insufficiency. Suspected antibiotic resistance of the microbiological pathogen to local antibiotic drugs, incompliant patient, and known allergy to bone cement or antibiotic. After implant removal, suitable metal rods are coated with antibiotic-loaded bone cement and inserted into the cleaned intramedullary canals of femur and tibia. Rods are joined at the joint line with aconnector and joint space is filled with more bone cement to achieve temporary and very stable arthrodesis. Partial weight-bearing and no flexion/extension while spacer is in place; second stage reimplantation as soon as infection is controlled. Complications related to the spacer were rare (5.3%). Reimplantation of an implant was possible in 95 of 113patients (84%), of those, 23 (20%) received an arthrodesis. Of the 95patients that were reimplanted, 14 showed signs of recurrent infection. Mean time to last follow-up was 15.6months post reimplantation. Mean knee pain was 2.9/10; overall function was good; 6patients had an extension lag; mean total range of motion was 88°.