Background. Total hip arthroplasty (THA) has become one of the most commonly performed elective procedures. Today, there are nearly 50 000 annual hospitalizations for hip replacement surgery in Canada. This number is projected to increase significantly with the aging population. Periprosthetic joint infection (PJI) is the 3rd leading cause of failure following THA and is reported to occur at an incidence of 1–3%. A two-stage revision THA is the current gold standard treatment and this has a tremendous economic impact on the healthcare system. The purpose of this study is to create an accurate cost estimate of two-stage revision THA and, in turn, evaluate the economic burden of PJI as it compares to primary THA in a Canadian healthcare context. Methods. We conducted a retrospective review of primary THA cases and two-stage revision THA for PJI at our institution. Patients were matched for age and BMI. We recorded all costs associated with each procedure, including: OR time, equipment, length of hospital stay, readmission rates, and any other inpatient resource use. Unit costs were obtained using administrative data from the case costing department at London Health Sciences Centre. Billing fees associated with the procedure were obtained from the Ontario Schedule of Benefits. Descriptive statistics were used to summarize the demographic characteristics of patients, hospital costs and resource use data. Patients with PJI were compared to the matched cohort of primary THA using the t-test (for continuous variables), and the chi-square test (for categorical variables). Results. Fifty consecutive cases of revision THA were matched to 50 patients who underwent uncomplicated primary THA between 2006 and 2014. Periprosthetic infection was associated with a significant increase in hospital stay (26.5 vs. 2.0; t=4.95, p<0.001), clinic visits (9.5 vs. 3.8; T= 6.49, p<0.001), readmission rates (12 vs. 1; X. 2. 11.1, p<0.001) and overall cost ($39 953 vs. $7 460; T=73, p<0.001) in comparison to the primary arthroplasty cohort. Conclusion. Two-stage revision for infected THA is a significant economic burden to the healthcare system. Our data suggests a 5-fold increase in healthcare cost when compared to primary THA. This may be an important consideration when distributing resources among Canadian tertiary care centres

Total hip arthroplasty (THA) has become one of the most commonly performed elective procedures. Today, there are nearly 50 000 annual hospitalisations for hip replacement surgery in Canada. This number is projected to increase significantly with the aging population. Periprosthetic joint infection (PJI) is the 3rd leading cause of failure following THA and is reported to occur at an incidence of 1–3%. A two-stage re-vision THA is the current gold standard treatment and this has a tremendous economic impact on the healthcare system. The purpose of this study is to create an accurate cost estimate of two-stage revision THA and, in turn, evaluate the economic burden of PJI as it compares to primary THA in a Canadian healthcare context. We conducted a retrospective review of primary THA cases and two-stage revision THA for PJI at our institution. Patients were matched for age and BMI. We recorded all costs associated with each procedure, including: OR time, equipment, length of hospital stay, readmission rates, and any other inpatient resource use. Unit costs were obtained using administrative data from the case costing department at London Health Sciences Centre. Billing fees associated with the procedure were obtained from the Ontario Schedule of Benefits. Descriptive statistics were used to summarise the demographic characteristics of patients, hospital costs and resource use data. Patients with PJI were compared to the matched cohort of primary THA using the t-test (for continuous variables), and the chi-square test (for categorical variables). Twenty consecutive cases of revision THA were matched to 20 patients who underwent uncomplicated primary THA between 2006 and 2014. Periprosthetic infection was associated with a significant increase in hospital stay (26.5 vs. 2.0; p<0.001), clinic visits (9.5 vs. 3.8; p<0.001), readmission rates (12 vs. 1; p<0.001) and overall cost ($39 953 vs. $7 460; p<0.001) in comparison to the primary arthroplasty cohort. Two-stage revision for infected THA is a significant economic burden to the healthcare system. Our data suggests a 5-fold increase in healthcare cost when compared to primary THA. This may be an important consideration when distributing resources among Canadian tertiary care centres

The number of arthroplasties being undertaken is expected to grow year on year, and periprosthetic joint infections will be an increasing socioeconomic burden. The challenge to prevent and eradicate these infections has resulted in the emergence of several new strategies, which are discussed in this review. Cite this article: Bone Joint J 2015;97-B:1162–9

Report of a case of migrating periprosthetic infection from a hip replacement to a contralateral knee joint undergoing a total knee replacement. We present a 74-year old female patient who underwent a total hip arthroplasty of the left hip after a subcapital fracture of the femur. Four months after the index procedure the patient presented with signs and symptoms of infection of the operated joint. Staph aureus and Enterococcus faecalis were recognized as the infecting bacteria. The implants were removed, cement spacers were placed and a total hip arthroplasty was performed again after three months. Unfortunately, infection ensued again and the patient underwent three more procedures until the joint was considered clean and t he hip remained flail without implants. The patient elected to undergo a total knee arthroplasty due to severe osteoarthritis of right knee. Intraoperatively tissue samples were taken and sent for cultures which identified Enterococcus faecalis present in the knee joint. Enterococcus migrated from the infected hip to nonoperated knee joint. Intravenous antibiotics were administered for three weeks but the knee presented with infection of the arthroplasty ten months after its insertion. The implants were removed the joint was debrided and cement spacers were inserted. The patient decided not to proceed with another procedure and she remains with the cement spacers in her knee. Rare report of migrating periprosthetic infection. Nosocomial enterococci acquired resistance cannot be ruled out. Unique characteristics in enterococci antibiotic resistance and biofilm formation

Background. Additive manufacturing (AM) has created many new avenues for material and manufacturing innovation. In orthopaedics, metal additive manufacturing is now widely used for production of joint replacements, spinal fusion devices, and cranial maxillofacial reconstruction. Plastic additive manufacturing on the other hand, has mostly been utilized for pre-surgical planning models and surgical cutting guides. The addition of pharmaceuticals to additively manufactured plastics is novel, particularly when done at the raw material level. The purpose of this study was to prove the concept of antibiotic elution from additively manufactured polymeric articles and demonstrate feasibility of application in orthopaedics. Methods. Using patented processes, three heat-stable antibiotics commonly used in orthopaedics were combined with six biocompatible polymers (2 bioresorbable) into filament and powder base materials for fused deposition modeling (FDM) and selective laser sintering (SLS) AM processes. Raw materials of 1%, 2%, and 5% antibiotic concentrations (by mass) were produced as well as a blend of all three antibiotics each at 1% concentration. Thin disks of 25 mm diameter were manufactured of each polymer with each antibiotic at all concentrations. Disks were applied to the center of circular petri dishes inoculated with a bacterium as per a standard zone of inhibition, or Kirby-Bauer disk diffusion tests. After 72 hours incubation, the zone of inhibited bacterial growth was measured. Periprosthetic joint infection (PJI) of the knee was selected as the proof-of-concept application in orthopaedics. A series of tibial inserts mimicking those of a common TKR system were manufactured via SLS using a bioresorbable base material (Figure 1). Three prototype inserts were tested on a knee wear simulator for 333,000 cycles following ISO 14242–1:2014 to approximate 2–4 months of in vivo use between surgeries of a 2-stage procedure for PJI. Gravimetric measurement and visual damage assessment was performed. Results. Bacterial growth was inhibited to a mean diameter of 32.3 mm (FDM) and 42.2 mm (SLS) for nearly all combinations of polymers and concentrations of antibiotics. Prototype tibial inserts experienced an average of 200 mg of wear during testing and demonstrated no evidence of cracking, delamination or significant deformation (Figure 2). Conclusion. Bench-level testing of these novel antibiotic-eluting polymers demonstrates feasibility for their application in orthopaedic medicine. In particular, treatment of stubborn PJI with potential for increased and sustained antibiotic elution, patient-specific cocktailing, and maintenance of knee joint structure and function compared to existing PJI products and practices. Subsequent testing for these novel polymers will determine static and dynamic (wear-induced) antibiotic elution rates. For any figures or tables, please contact the authors directly

Purpose:. Two-stage revision is the gold standard treatment for chronic periprosthetic infection of the hip or knee. Implantation of a functional antibiotic spacer allows patients the option of two stage revision or living with the spacer in place. Some patients may be satisfied with the activity level that they attain with the functional antibiotic spacer and may avoid the morbidity of a second surgery. Methods:. We retrospectively examined the outcomes of 30 joints in 27 patients treated for chronic periprosthetic infection of the hip or knee at a mean follow-up of 27 months (range 11–46 months). Comparing the patients treated with two-stage revision to those patients living with a functional antibiotic spacer, we used University of California Los Angeles activity scores, modified Harris hip scores, and patient satisfaction measures to answer two main questions: (1) Is there a significant difference in activity level? (2) Is there a significant difference in patient satisfaction? Patient satisfaction was measured on a 1–100 scale with 100 being completely satisfied. Results:. There were no statistically significant differences in the American Society of Anesthesiologists scores between the groups—mean 2.69 in the two-stage group and mean 3.00 in the spacer group (p value 0.255). Statistically significant differences were found between the groups for University of California Los Angeles activity scores—mean 5.3 in the two-stage group and mean 2.8 in the spacer group (p value 0.027). There were no statistically significant differences in modified Harris hip scores—mean 55.6 in the two-stage group and mean 41.6 in the spacer group (p value 0.34). In the subgroup analysis of the modified Harris hip score questions, there was a statistically significant difference in the need for support when ambulating—mean 4.21 in the two-stage group and mean 2.45 in the spacer group (p value 0.024)—and in the distance that can be walked—mean 6.15 in the two-stage group and mean 2.0 in the spacer group (p value 0.005). No statistically significant differences were found in patient satisfaction measures—mean 70.0 in the two-stage group and mean 76.6 in the spacer group (p value 0.65)—though the mean satisfaction measure was higher in the spacer group. Conclusion:. Patients living with a functional antibiotic spacer are less active than patients undergoing a two-stage revision for chronic periprosthetic infection of the hip or knee. Specifically, patients living with a functional antibiotic spacer need more support when ambulating and ambulate shorter distances than patients, who undergo two-stage revision surgery. Despite the decreased activity level, patients living with a functional antibiotic spacer are just as satisfied with the outcome of their joint as those patients treated with a two-stage revision. Patients with modest activity goals may be satisfied to live with a functional antibiotic spacer and to avoid a second surgery

Introduction:. Periprosthetic joint infection (PJI) is a devastating diagnosis that carries a significant rate of associated mortality and places a large burden on health care systems. Treatment protocols often include combined intravenous antibiotics and staged revision surgery with locally-delivered antibiotics via PMMA cement spacers and/or beads. One disadvantage of PMMA is the need for later removal. Antibiotic releasing Calcium Sulphate beads (CaSO. 4. ) have had promising results in revision joint surgery and are absorbable, making later removal unnecessary. We report on use in a tertiary referral centre in the UK and present our initial findings. Methods & Results:. CaSO. 4. beads containing 1 gram of Vancomycin and 240 mg of tobramycin per 10 cc was implanted in 12 patients between August 2012 and December 2012, all having undergone revision joint surgery for PJI. Of these patients; 7 were men and 5 women, mean age was 57 years (range 39–72) with a mean ASA grade of 2 (1–4). Indications were infected Total Hip Replacement (n = 7), infected Total Knee Replacement (n = 4) and infected metal on metal hip resurfacing (n = 1). Three procedures were emergencies, with the remainder being semi-elective procedures. One patient had single-stage revision THR. At latest follow up 10 patients had made a full recovery, with normal function and inflammatory markers. Two patients were awaiting a second stage revision procedure. Mean follow up was 2 months (1–4). Conclusion:. Implantable calcium sulphate beads are a new therapeutic agent for use in periprosthetic infection, with improved drug eluting properties and total absorption radiographically within two to three weeks. This study is the first to report its use in the UK, with encouraging data supporting its use in revision arthroplasty surgery

Background. The diagnosis of Periprosthetic Joint Infection (PJI) is a considerable challenge in total joint arthroplasty. The mainstay for diagnosis of PJI is a combination of serological markers, including C-reactive protein (CRP), along with joint aspirate for white cell count, differential and culture. The aim of this study was to examine the use of synovial fluid CRP in the diagnosis of PJI. Material & Methods. Synovial fluid samples were collected prospectively from patients undergoing primary and revision knee arthroplasty. Samples were assessed for CRP, cell count and differential. Three groups were analyzed; those undergoing primary knee arthroplasty, aseptic knee arthroplasties and infected arthroplasties. Demographic data, along with associated medical co-morbidities, were collected,. Statistical analysis was performed. Synovial fluid CRP was correlated with serum CRP values. Sensitivity and specificity were calculated. Results. 50 synovial fluid samples were collected from 50 patients. Synovial fluid CRP was 0.3 +/− 0.4 in native knees, 0.2 +/− 0.5 in aseptic knee arthroplasties, 4.3+/−4.1 in patients with infected knee arthroplasties. Synovial fluid CRP was significantly higher in septic total knee arthroplasties by comparison to both aseptic total knees (p< 0.001) and native knees (p=0.006). The specificity was 100% and the sensitivity was 89% at a CRP of 1. Conclusion. While this is preliminary data, synovial fluid CRP was found to be significantly elevated in patients with infected total knee arthroplasties. This test is easily performed under routine hospital laboratory conditions without specific, expensive assays. We believe synovial CRP assay holds great promise as a new, potentially low-cost, diagnostic marker for PJI

BACKGROUND. Periprosthetic infection is the most challenging complication following total knee arthroplasty (TKA). Poor oral hygiene has been assumed as an important risk factor for TKA infection. We aimed to investigate whether the improvement of oral hygiene through dental scaling could reduce the risk of TKA infection. METHODS. A nested case control study was conducted and enrollees in the National Health Insurance Research Database (NHIRD) aged above 40 years who had received total knee arthroplasty (TKA) between 1999–2002 were included as the TKA cohort. The cases were patients who underwent resection arthroplasty for infected TKA, and each case was matched by 4 controls from the TKA cohort by gender, using incidence density sampling method. The frequency of dental scaling before the index date was analyzed and compared between the case and the control groups. Multiple conditional logistic regression was used to assess the frequency of dental scaling and the risk of TKA infection. RESULTS. The percentages of patients who ever received dental scaling before the end of follow-up were higher in the control group than that in the TKA infection group. As compared with patients never received dental scaling, there was a trend that patients who received dental scaling once within 2 years, may have 9% lower risk in TKA infection (adjusted odds ratio, 0.91; 95% confidence interval, 0.76–1.08). Moreover, the risk of TKA infection can be reduced significantly in patients who had dental scaling at least once per year, with an odds ratio of 0.71 (95% confidence interval, 0.53–0.95). CONCLUSIONS. Improvement of oral hygiene by more frequent and regular dental scaling (at least once per year) may reduce the risk of TKA infection. TKA Patients should be advised to check their oral hygiene regularly

Introduction. Serum erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), and synovial fluid white blood cell (WBC) count and differential are effective in diagnosing periprosthetic joint infection (PPJI); however their utility in patients with inflammatory arthritis is unknown. The purpose of this study is to determine the utility of these tests in patients with inflammatory arthritis. Methods. 934 Consecutive revision hip and knee arthroplasties were prospectively evaluated for PPJI. 202 Cases were excluded due to acute post-operative or hematogenous infection. 690 Patients had non-inflammatory and 42 had inflammatory arthritis. Receiver operating characteristic (ROC) curves were used to establish optimal ESR, CRP, WBC, and % neutrophil values for diagnosis of PPJI, and the area under the curve (AUC) was calculated to determine the overall accuracy. Results. The optimal thresholds for predicting PPJI were ESR 30mm/hr, CRP 17mg/L, WBC 2667, and differential 75% neutrophils in inflammatory arthritis, and ESR 32mm/hr, CRP 15mg/L, WBC 4000, and 78% neutrophils in non-inflammatory arthritis. The efficacy of these tests was similar in both populations (AUC for inflammatory ESR=86.2%, CRP=86.2%, WBC=93.8, 93.6% neutrophils; AUC for non-inflammatory ESR=85.2%, CRP=90.2%, WBC=94.5, 95% neutrophils); there was no significant difference between groups (ESR p = 0.861, CRP p= 0.549, WBC p=0.8315, % neutrophils p=0.7021). The rate of PPJI was significantly higher in patients with inflammatory (33.3%) than non-inflammatory (18.8%) arthritis (p-value=0.013). Conclusions. These results suggest that the ESR and CRP are useful in diagnosing PPJI in patients with inflammatory as well as non-inflammatory arthritis with similar optimal cut-off values

Introduction

Radiation cross-linking of ultrahigh molecular weight polyethylene (UHMWPE) has reduced the in vivo wear and osteolysis associated with bearing surface wear (1), significantly reducing revisions associated with this complication (2). Currently, one of the major and most morbid complications of joint arthroplasty is peri-prosthetic infection (3). In this presentation, we will present the guiding principles in using the UHMWPE bearing surface as a delivery device for therapeutic agents and specifically antibiotics. We will also demonstrate efficacy in a clinically relevant intra-articular model.

Introduction

Accurate diagnosis of peri-prosthetic joint infection is critical to allow adequate treatment. Currently, the criteria of the Musculo-Skeletal Infection Society (MSIS) serve as a validated reference tool. More recently, these criteria have been modified for better accuracy. The goal of this study was to compare retrospectively the diagnostic accuracy of these two different tools in cases of known peri-prosthetic hip or knee infection or in aseptic cases and to analyze one additional criterion: presence of an early loosening (prior to 2 years after implantation).

Background. Increasing evidence suggests a link between the bearing surface used in total hip arthroplasty (THA) and the occurrence of infection. It is postulated that polyethylene has immunomodulatory effects and may influence bacterial function and survival, thereby impacting the development of periprosthetic joint infection (PJI). This study aimed to investigate the association between polyethylene type and revision surgery for PJI in THA using data from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR). We hypothesized that the use of XLPE would demonstrate a statistically significant reduction in revision rates due to PJI compared to N-XLPE. Methods. Data from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) spanning September 1, 1999, to December 31, 2021, were used to compare the infection revision rates between THA using N-XLPE and XLPE. We calculated the Cumulative Percentage Revision rate (CPR) and Hazard Ratio (HR) while controlling for factors like age, sex, body mass index (BMI), American Society of Anesthesiologists’ (ASA) grade, and head size. Results. From the total 361,083 primary THAs, 26,827 used N-XLPE and 334,256 used XLPE. Excluding data from the first 6 months post-surgery, 220 revisions occurred in the N-XLPE group and 1,055 in the XLPE group for PJI. The HR for infection revision was significantly higher in N-XLPE compared to XLPE, at 1.64 (95% CI, 1.41–1.90, p<0.001). Conclusions. This analysis provides evidence of an association between N-XLPE and revision for infection in THA. We suspect that polyethylene wear particles contribute to the susceptibility of THA to PJI, resulting in a significantly higher risk of revision for infection in N-XLPE hips compared to those with XLPE. Level of Evidence. Therapeutic Level III

Aims. The aim of this study was to analyze the prevalence of culture-negative periprosthetic joint infections (PJIs) when adequate methods of culture are used, and to evaluate the outcome in patients who were treated with antibiotics for a culture-negative PJI compared with those in whom antibiotics were withheld. Methods. A multicentre observational study was undertaken: 1,553 acute and 1,556 chronic PJIs, diagnosed between 2013 and 2018, were retrospectively analyzed. Culture-negative PJIs were diagnosed according to the Muskuloskeletal Infection Society (MSIS), International Consensus Meeting (ICM), and European Bone and Joint Society (EBJIS) definitions. The primary outcome was recurrent infection, and the secondary outcome was removal of the prosthetic components for any indication, both during a follow-up period of two years. Results. None of the acute PJIs and 70 of the chronic PJIs (4.7%) were culture-negative; a total of 36 culture-negative PJIs (51%) were treated with antibiotics, particularly those with histological signs of infection. After two years of follow-up, no recurrent infections occurred in patients in whom antibiotics were withheld. The requirement for removal of the components for any indication during follow-up was not significantly different in those who received antibiotics compared with those in whom antibiotics were withheld (7.1% vs 2.9%; p = 0.431). Conclusion. When adequate methods of culture are used, the incidence of culture-negative PJIs is low. In patients with culture-negative PJI, antibiotic treatment can probably be withheld if there are no histological signs of infection. In all other patients, diagnostic efforts should be made to identify the causative microorganism by means of serology or molecular techniques. Cite this article: Bone Joint J 2022;104-B(1):183–188

Aim. Diagnosing periprosthetic joint infection after total joint arthroplasty is often challenging. The alpha defensin test has been recently reported as a promising diagnostic test for periprosthetic joint infection. The goal of this study was to determine the diagnostic accuracy of alpha defensin testing. Method. One hundred and eighty-three synovial alpha defensin and synovial fluid C-reactive protein (CRP) tests performed in 183 patients undergoing evaluation for periprosthetic joint infection were reviewed. Results were compared with the Musculoskeletal Infection Society (MSIS) criteria for periprosthetic joint infection. Results. Alpha defensin tests were performed prior to surgical treatment for infection, and 37 of these patients who had these tests were diagnosed by MSIS criteria as having infections. Among this group, the alpha defensin test had a sensitivity of 81.1% (95% confidence interval [CI], 64.8% to 92.0%) and a specificity of 95.9% (95% CI, 91.3% to 98.5%). There were 6 false-positive results, 4 of which were associated with metallosis. There were 7 false negatives, all of which were associated with either draining sinuses (n = 3) or low-virulence organisms (n = 4). A combined analysis of alpha defensin and synovial fluid CRP tests was performed in which a positive result was represented by a positive alpha defensin test and a positive synovial fluid CRP test (n = 28). Among this group, the sensitivity was calculated to be 73.0% (95% CI, 55.9% to 86.2%) and the specificity was calculated to be 99.3% (95% CI, 96.2% to 99.9%). An additional combined analysis was performed where a positive result was represented by a positive alpha defensin test or positive synovial fluid CRP test (n = 64). Among this group, the sensitivity was calculated tobe91.9%(95%CI, 78.1%to98.3%) andthe specificitywas calculated tobe79.5%(95%CI, 72.0%to85.7%). Conclusions. Alpha defensin in combination with synovial fluid CRP demonstrates very high sensitivity for diagnosing periprosthetic joint infection, but may yield false-positive results in the presence of metallosis or false-negative results in the presence of low-virulence organisms. When both alpha defensin and synovial fluid CRP tests are positive, there is a very high specificity for diagnosing periprosthetic joint infection

Aims. Despite numerous studies on periprosthetic joint infections (PJI), there are no robust data on the risk factors and timing of metachronous infections. This study was performed to answer the following questions: 1) Is there any difference of manifestation time of metachronous PJIs between different localizations of multiple artificial joints? 2) Can we identify any specific risk factor for metachronous PJIs for different localizations of multiple artificial joints?. Methods. Between January 2010 and December 2018, 661 patients with more than one prosthetic joint at the time of PJI surgical treatment were recruited. Seventy-one developed metachronous PJI after a mean time interval of 101.4 months (range 37.5 to 161.5 months). The remaining patients were chosen as control group. The diagnosis of the PJI, including the metachronous PJI, was made according to the Muscoloskeletal Infection Society (MSIS) criteria. The metachronous infections were divided in group 1: metachronous infections in the same extremity (e.g. right hip and right knee); group 2: metachronous infections of the other extremity (e.g. right knee and left hip); group 3: metachronous infections of the lower extremity and upper extremity (e.g. right knee and left shoulder). Results. We identified 32 PJI cases in group 1, 38 in group 2 and 1 in group 3. Diabetes mellitus was found higher in the metachronous infections (p<0.05). Rate of same side infection was significantly higher compared to contralateral and upper and lower infection (p<0.05). Time interval of metachrononous infection development was faster in same-side infections. Same bacteria sample rate between primary PJI and metachronous PJI in same side infections (21/32) was significantly higher than in the contralateral PJI group (13/38, p<0.05). Conclusions. The current study underlined that the risk of metachronous infections are relatively high, particularly in the cases of prostheses on the same side

Background. The identification of novel biomarker which is highly specific and sensitive for periprosthetic joint (PJI) have the potential to improve diagnostic accuracy and ultimately improve patient outcomes. Thus, the aim of this systemic review is to identify and evaluate novel biomarkers for the preoperative diagnostics of PJI. Methods. MEDLINE, EMBASE, PubMed and Cochrane Library databases identified from 1. st. of January 2018 to 30. th. of September. 2022. We used “periprosthetic joint infection” OR “prosthetic joint infection” OR “periprosthetic infection” as the diagnosis of interest and the target index applied AND “marker”. To focus on novel biomarkers already used biomarkers of the established PJI diagnostic criteria of MSIS, ICM and EBJIS were not included in the analysis. These three criteria were considered the reference standard during quality assessment. Results. A total of 19 studies were included. In these, fourteen different novel biomarkers were analyzed. Fifteen studies (79%) had prospective designs and the other four (22%) were retrospective studies. Six studies (33%) included only periprosthetic knee infections and thirteen (67%) included periprosthetic knee and hip infections. Proteins were analyzed in most cases (nine studies), followed by molecules (three studies), exosome (two studies) as well as DNA (two studies), interleukin (one study) and lysosome (one study). One novel and promising marker that had been frequently analyzed is calprotectin. Conclusion. No marker demonstrated higher sensitivity and specificity than already known parameters used for standardized treatment based on established PJI definitions. Further studies are needed to elucidate the benefit and usefulness of implementing new biomarkers in diagnostic PJI settings

Background. The diagnosis of periprosthetic joint infection (PJI) remains a challenge in clinical practice and the analysis of synovial fluid (SF) is a useful diagnostic tool. Recently, two synovial biomarkers (leukocyte esterase (LE) strip test, alpha-defensin (AD)) have been introduced into the MSIS (MusculoSkeletal Infection Society) algorithm for the diagnosis of PJI. AD, although promising with high sensitivity and specificity, remains expensive. Calprotectin is another protein released upon activation of articular neutrophils. The determination of calprotectin and joint CRP is feasible in a routine laboratory practice with low cost. Purpose. Our objective was to evaluate different synovial biomarkers (calprotectin, LE, CRP) for the diagnosis of PJI. Methods. In this monocentric study, we collected SF from hip, knee, ankle and shoulder joints of 42 patients who underwent revision or puncture for diagnostic purposes. Exclusion criteria included a joint surgery in the previous 3 months and a diagnosis of a systemic inflammatory disease. PJI was diagnosed in a multidisciplinary consultation meeting (RCP) of the Reference Centers for Osteoarticular Infections of the Great West (CRIOGO). SF was analysed for LE, CRP and calprotectin. The cut-off values used were 50 mg/L for calprotectin, 8.8 mg/L for CRP and 125 WBC/µL for LE. The overall sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for these different synovial markers. Results. Of the 42 patients included, 28 were considered as infected and 14 uninfected. The statistical parameters are presented in Table 1. Conclusion. The present study shows that the synovial calprotectin assay has an excellent sensitivity and a 100% NPV for the diagnosis of PJI, suggesting that a result < 50 mg/L could exclude PJI. This promising study suggests that calprotectin should be included with synovial CRP in a new decision algorithm for the diagnosis of PJI. For any tables or figures, please contact the authors directly

Aim. Serum parameters continue to be a focus of research in diagnosing periprosthetic joint infections (PJI). Several workgroups have recently proposed serum Albumin-Globulin-Ratio (AGR) as a potential new biomarker. Due to controversies in the literature, its usability in clinical practice remains uncertain. The aim of this study was to assess the value of serum AGR in diagnosing PJI preoperatively, especially in comparison with the well-established marker C-reactive Protein (CRP). Method. From January 2015 to June 2022, patients with indicated revision hip (rTHA) and knee (rTKA) arthroplasty were included in this retrospective cohort study of prospectively collected data. A standardized diagnostic workup was performed using the 2021 European Bone and Joint Infection Society (EBJIS) definition of PJI, excluding CRP. Diagnostic accuracies of serum AGR and CRP were calculated by receiver operating characteristic curve (ROC) analysis. A z-test was used to compare the area under the curves (AUC). Results. A total of 275 patients with rTHA and rTKA were included, 144 joints (52.4%) were identified as septic. Decreased AGR and elevated CRP were strongly associated with PJI, optimal diagnostic thresholds were calculated with 1.253 and 9.4 mg/L, respectively. Sensitivities were 62.5% (95%-confidence interval: 54.3–70.0) and 73.6% (65.8–80.1), and specificities 84.7% (77.5–89.9) and 87.8% (80.9–92.4), respectively. CRP showed a significantly higher AUC than AGR (0.807 (0.761–0.853) and 0.736 (0.686–0.786); p<0.0001). Subgroup analysis of acute versus chronic infections yielded significantly higher diagnostic accuracies in acute PJI for both parameters (p<0.0001). Similar results were observed when focusing on the causative microorganism; a better diagnostic performance was observed in high-virulence PJI compared to low-virulence PJI (p≤0.005). Furthermore, higher AUCs were calculated in knee PJI compared with hip PJI, with a significant difference for AGR (p=0.043). Conclusions. Due to its limited diagnostic accuracy, serum AGR cannot be recommended as an additional marker for diagnosing PJI. Serum parameters are generally unspecific and can be influenced by comorbidities and other foci of infection. Additionally, parameters may remain within normal levels in low-grade PJI. Evaluating AGR, further possible pitfalls must be considered, for example an increased latency until bottom values are reached and the impact of malnutrition

Aim. As the populations of patients who have multiple prosthetic joints increase these years, the fate of a single joint periprosthetic joint infection in these patients is still unknown. Risk factors leading to a subsequent infection in another prosthetic joint are unclear. Our goal is to identify the risk factors of developing a subsequent infection in another prosthetic joint and describe the organism profile to the second prosthetic infection. Method. We performed a retrospective cohort study of all PJI cases underwent surgical intervention at our institute, a tertiary care referral center over 11 years, during January 2006 to December 2016. We identified 96 patients with periprosthetic joint infection who had another prosthetic joint in place at the time of presentation. The comorbidity, number of prosthetic joints, date and type of each arthroplasty, times of recurrent infection at each prosthetic joint with subsequent debridement or 2-stage resection arthroplasty, organisms from every infection episode, the outcome of each periprosthetic joint infection in these patients were analyzed. Results. During January 2006 to May 2017, we retrospective collected 294 PJI cases (159 hips, 135 knees) in our institute. Patients with single prosthetic joint were excluded and finally 96 patients were included. Of the 96 patients, 19 (19.79%) developed a periprosthetic joint infection in a second joint. The type of organism was the same as the first infection in 12 (63.16%) of 19 patients. The time to developing a second infection averaged 2.16 years (range, 0–9.3 years). The risk factors leading to a subsequent infection in another prosthetic joint are albumin level (< 3.5 mg/dl), long-term steroid usage (> 5mg/day, > 3 months), history of necrotizing fasciitis, history of invasive dental procedure (> Grade IV procedure), 3-stage resection arthroplasty or more, and PJI caused by vacomycin-resistent enterococcus (VRE). Conclusions. A PJI might predispose patients to subsequent PJI in another prosthesis. Patients and surgeons must be aware of the risk factors contribute to this devastating complication. Most organisms in the second PJI are identical to the first one, and we believe the bacteremia may be the pathogenesis, but need further proved. The preventive policy may be needed in the future for this population who has multiple prosthetic joints