Periprosthetic Joint Infection Research Articles

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

BackgroundEarly 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.MethodsA 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.ResultsMultivariate 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.ConclusionThe 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.

Association between malnutrition status and total joint arthroplasty periprosthetic joint infection and surgical site infection: a systematic review meta-analysis

BackgroundMalnutrition is a state resulting from lack of intake or uptake of nutrition. Investigating the association between malnutrition and postoperative complications is essential for enhancing patient outcomes in total joint arthroplasty (TJA). This meta-analysis aimed to investigate the impact of malnutrition on the incidence of surgical site infections (SSIs) and periprosthetic joint infections (PJIs) following TJA.MethodsThe data were searched from databases including PubMed, Embase, Web of Science, and Cochrane Library inception through July 19 2023, without time restrictions. Inclusion criteria focused on studies examining malnutrition as a risk factor for SSIs and PJIs postarthroplasty, providing sufficient data for calculating odds ratios (ORs) and 95% confidence intervals (CIs). Methodological quality was assessed using the Newcastle‒Ottawa Scale, and statistical analyses were executed in Stata version 17.ResultsA total of 1,025 articles were screened, and 9 studies satisfying the predefined inclusion criteria were consequently selected for this meta-analysis. Studies indicated that malnutrition is significant factor to the heightened incidence of both SSIs and PJIs following TJA procedures. Our pooled results yielded aggregated ORs of 2.60 for SSIs and 3.44 for PJIs, with respective 95% CIs of 2.10–3.10 and 2.35–4.53. The heterogeneity of malnutrition as a risk factor for postoperative SSI was I2 = 0.0% (p = 0.592), and for PJI was I2 = 0.0% (p = 0.422). Egger’s linear regression test showed no significant publication bias (p > 0.05).ConclusionsMalnutrition is a significant risk factor for SSIs and potentially PJIs in patients undergoing TJA. Preoperative optimization strategies targeted at malnourished patients are suggested to minimize postoperative complications clinically.

Prevalence of unexpected intraoperative cultures (UPIC) in revision total knee arthroplasty (TKA) and risk of periprosthetic joint infection (PJI).

Prevalence of unexpected positive intraoperative cultures (UPIC) in revision total knee arthroplasty (TKA) is reported to be 8.32% with largely varying findings in individual studies (5.92-62.07%) due to a heterogeneity in preoperative diagnostic work-up and diagnostic criteria for periprosthetic joint infection (PJI). When diagnosed as unsuspected PJI, re-revision rate is reported to be as high as 18.45% compared to 2.94% in patients with UPIC classified as contamination (p = 0.0237). We performed a monocentric retrospective analysis of revision TKA surgery to determine prevalence of UPIC, risk of developing a subsequent PJI and re-revision rate after 24 months compared to those without UPIC. All presumed aseptic total knee revision procedures from 2008 until 2017 were retrospectively reviewed. Single stage femorotibial revisions of TKA with at least 3 intraoperative cultures and a minimum follow-up of 24 months were included, whereas partial revisions or revisions from unicompartimental knee prosthesis to TKA were excluded. Demographic data were collected as well as initial reason for revision, preoperative aspiration results, micro-organism identified and postoperative antibiotics' administration. Primary outcome was survival rate after 24 months with differentiation based on UPIC interpretation: sterile, contamination, unsuspected PJI. Of 256 included cases, 75 (29.3%) were found to have at least 1 UPIC during revision surgery, 72% of whom a single UPIC was found. Thirty-four cases (13.28%) were interpreted as unsuspected PJI and therefore treated with antibiotics. In total, 13 of the 256 patients (5.08%) had to be re-revised during follow-up with 7 PJI (2.73%), none of them developing reinfection defined as PJI with the same microorganism. A statistically significant trend towards earlier failure in the unsuspected PJI group compared to the contaminant group was not observed. However, a higher incidence of re-revisions attributed to septic reasons was noted in the former group. Presence of UPIC in presumed aseptic revision TKA does not correlate with a lower survival rate, but a higher incidence of subsequent PJI was observed in cases interpreted as unsuspected PJI.

Relationship between soft tissue envelope thickness of the lower extremity and acute periprosthetic joint infection of the knee.

The prevalence of obesity is increasing worldwide and it is known to be associated with many postoperative complications, including infection. Patients' body fat distribution may vary and body mass index (BMI) does not provide sufficient information about adipose tissue thickness of the lower extremities. The aim of this study is to investigate the relationship between thigh diameters and early postoperative prosthesis-related joint infections (PJI) in patients who underwent arthroplasty. The study included 76 patients and 114 knees who were operated on by a single surgeon and underwent total knee arthroplasty (TKA) due to primary knee osteoarthritis between May 2022 and September 2023 in a tertiary reference hospital. Circumference of the thickest part of the operated thigh (cm), preoperative erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels, height, weight, BMI and the presence of early postoperative prosthesis-related joint infections were evaluated. The mean BMI was 32.6 ± 4.2 (kg/m2). Two (2.6%) were normal weight, 14 (18.5%) were overweight, 58 (76.3%) were obese and 2 (2.6%) were morbidly obese. The mean circumference of the thickest part of the thigh was 57.56 ± 6.38 (cm). 6 patients were diagnosed with PJI in the acute phase. The mean circumference of the thickest part of the thigh was statistically significantly greater in the group with acute PJI compared to the group without PJI (p = 0.048). The incidence of acute PJI was found to be significantly higher in patients with larger thigh diameters, whereas no such relationship was observed for BMI. The incorporation of preoperative soft tissue envelope measurements into routine clinical examination may prove beneficial in reducing the risk of PJI.

Incidence of periprosthetic joint infection after primary total knee arthroplasty shows significant variation : a synthesis of meta-analysis and bibliometric analysis

Total Knee Arthroplasty (TKA) is a surgery that is commonly performed on older adults to improve their quality of life. However, the increasing use of knee joint prostheses has led to a rise in the incidence of Prosthetic Joint Infections (PJI) in patients after TKA. Different clinical studies have looked at the occurrence of PJI after TKA in different regions, but they have drawn varying conclusions. To better understand this topic, we conducted a meta-analysis and bibliometric study using data from multiple databases. Our research found that the estimated prevalence of PJI after TKA is approximately 1.08% across different regions, but there is still considerable variation. Additionally, our regression analysis of sub-groups shows significant differences in follow-up periods. Furthermore, our comprehensive bibliometric analysis identifies current research trends, “hotspots” related to TKA-related PJI, influential nations, organizations, and noteworthy publications. Our analysis provides valuable insights to guide future research in this area.

Outpatient parenteral antimicrobial therapy (OPAT) for the management of periprosthetic joint infections in the Republic of Ireland (ROI) from 2013 to 2021

ObjectivesPeriprosthetic joint infection (PJI) is a complication of joint arthroplasty and is seen in 1-2% of cases. Since its initiation in 2013, the national outpatient parenteral antimicrobial therapy (OPAT) program has facilitated the outpatient management of intravenous antimicrobials for PJI. This study aims to describe the clinical epidemiology of patients on OPAT with PJI between 2013 and 2021. MethodsA retrospective analysis of patients discharged on OPAT between January 1, 2013 to August 31, 2021 was performed using data available from the national OPAT program. This study focused on those with a PJI. Data were analyzed using STATA/SE version 17.0. ResultsFrom January 1, 2013 until August 31, 2021, there were 14,749 patients managed through the national OPAT program, 8.35% (1232 of 14,749) of which were PJI. Of these, 53% (653 of 1232) were hip arthroplasty, 22.7% (280 of 1232) were knee arthroplasty, and 24.3% (299 of 1232) were “other.” The mean age was 64.5 years (SD 14.15 years). Of those on OPAT, 66.15% (815 of 1232) were health care–administered OPAT, whereas 33.85% (417 of 1232) were self-administered (S) OPAT (S-OPAT). Patients on S-OPAT were statistically younger (61 vs 66 years old, P <0.001, 95% confidence interval 14.1-63.6). The most common antimicrobial prescribed was daptomycin (35.8%; 441 of 1232), followed by ceftriaxone (21.2%; 262 of 1232). The median duration on the OPAT program was 27 days (interquartile range 14.5-35 days). ConclusionOPAT use in PJI is growing. Cumulatively, it has saved 26,992 hospital bed-days. Although S-OPAT is the preferred strategy and should be considered for all patients, our data demonstrate that health care–administered OPAT is required more frequently in older patients.

Isolation and Antibiofilm Activity of Bacteriophages against Cutibacterium acnes from Patients with Periprosthetic Joint Infection

Isolation and Antibiofilm Activity of Bacteriophages against Cutibacterium acnes from Patients with Periprosthetic Joint Infection

Body Mass Index and the Risk of Postoperative Complications After Total Knee Arthroplasty.

Given the growing prevalence of obesity, it is crucial to understand the effect of obesity on complications after total knee arthroplasty (TKA). This study aims to assess the relationship between body mass index (BMI) and postoperative periprosthetic joint infection (PJI), medical complications, and surgical complications after TKA. The Premier Healthcare Database was used to identify all primary elective TKAs between 2016 and 2021. The primary outcome was risk of PJI within 90 days of surgery. Using logistic regression, restricted cubic splines were generated to assess the relationship between BMI as a continuous variable and PJI risk. Bootstrap simulation was then done to identify a BMI inflection point on the final restricted cubic spline model past which the risk of PJI increased. The relationship between BMI and composite 90-day medical and surgical complications was also assessed. A direct relationship was observed between increasing BMI and increasing risk of PJI with a BMI changepoint of 31 kg/m2 identified as being associated with increased risk. Above a BMI of 31 kg/m2, there was an average relative risk increase of PJI of 13.6% for every unit BMI. This relative risk per unit BMI increased from 5.8% for BMI 31 to 39 to 11.5% between BMI 40 and 49 kg/m2, and 21.3% for BMIs ≥50 kg/m2. Similarly, a direct relationship was also found between increasing BMI and both medical and surgical complications with BMI changepoints of 34 and 32 kg/m2 identified, respectively. Obese patients with a BMI >31 kg/m2 were at increased risk of PJI. Although the relative risk increase was small per unit BMI above 31 kg/m2, the cumulative increase in risk may be marked for patients with higher BMIs. These data should be used to inform discussions that involve shared decision making between patients and surgeons who weigh the risks and benefits of surgery.

Conventional single articulation constrained liners in revision hip arthroplasty: risk factors for failure and their combinations.

Constrained liners (CLs) have been used in revision total hip arthroplasty (rTHA) with varying results. Relatively few studies have identified specific risk factors for failure. This study aimed to assess implant survivorship and complication rates, identify risk factors for constraint-related complications, and assess the effect of multiple factors present in a single case. We conducted a retrospective analysis of 101 rTHAs for various aseptic indications and as second-stage procedures for periprosthetic joint infection (PJI) utilising 2 models of conventional single-articulation CLs. We excluded 8 cases in which the liners were removed early due to PJI and assessed the risk factors for constraint-related complications in the remaining 93 cases. The mean follow-up duration for complication-free cases was 6.5 years (range 4.7-10.5 years). The incidences of dislocation of a prosthetic head and loosening of the acetabular component were 19.8% and 5.0%, respectively. We also observed 8 cases where the locking ring of the liner was dislodged without dislocation (1 case required re-revision). The presence of factors related to impingement (cup retention, smaller internal diameter CLs, signs of probable impingement from the femoral side) was associated with higher rates of constraint-related complications. The presence of factors related to soft-tissue stabilisers did not increase the rate of complications. The simultaneous presence of multiple impingement-related risk factors resulted in worse outcomes. CLs may be less effective for treating or preventing instability related to impingement. CLs should be used with caution or avoided when multiple impingement-related risk factors are present.

Atypical Periprosthetic Joint Infection Post-Total Knee Arthroplasty: A Case of Actinomyces europaeus

Atypical Periprosthetic Joint Infection Post-Total Knee Arthroplasty: A Case of Actinomyces europaeus

Efficacy and safety of intra-articular-only meropenem after one-stage revision for treating Escherichia coli-induced periprosthetic joint infection in a rat model.

The optimum type of antibiotics and their administration route for treating Gram-negative (GN) periprosthetic joint infection (PJI) remain controversial. This study aimed to determine the GN bacterial species and antibacterial resistance rates related to clinical GN-PJI, and to determine the efficacy and safety of intra-articular (IA) antibiotic injection after one-stage revision in a GN pathogen-induced PJI rat model of total knee arthroplasty. A total of 36 consecutive PJI patients who had been infected with GN bacteria between February 2015 and December 2021 were retrospectively recruited in order to analyze the GN bacterial species involvement and antibacterial resistance rates. Antibiotic susceptibility assays of the GN bacterial species were performed to screen for the most sensitive antibiotic, which was then used to treat the most common GN pathogen-induced PJI rat model. The rats were randomized either to a PJI control group or to three meropenem groups (intraperitoneal (IP), IA, and IP + IA groups). After two weeks of treatment, infection control level, the side effects, and the volume of antibiotic use were evaluated. Escherichia coli was the most common pathogen in GN-PJI, and meropenem was the most sensitive antibiotic. Serum inflammatory markers, weightbearing activity, and Rissing score were significantly improved by meropenem, especially in the IA and IP + IA groups ( p < 0.05). Meropenem in the IA group eradicated E. coli from soft-tissue, bone, and prosthetic surfaces, with the same effect as in the IP + IA group. Radiological results revealed that IA and IP + IA meropenem were effective at relieving bone damage. Haematoxylin and eosin staining also showed that IA and IP + IA meropenem improved synovial inflammation and bone destruction. No pathological changes in the main organs or abnormal serum markers were observed in any of the meropenem-treated rats. The IA group required the lowest amount of meropenem, followed by the IP and IP + IA groups. IA-only meropenem with a two-week treatment course was effective and safe for PJI control following one-stage revision in a rat model, with less meropenem use.

Unexpected positive cultures in aseptic revision hip and knee arthroplasty.

The outcomes of patients with unexpected positive cultures (UPCs) during revision total hip arthroplasty (THA) and total knee arthroplasty (TKA) remain unknown. The objectives of this study were to establish the prevalence and infection-free implant survival in UPCs during presumed aseptic single-stage revision THA and TKA at mid-term follow-up. This study included 297 patients undergoing presumed aseptic single-stage revision THA or TKA at a single treatment centre. All patients with at least three UPCs obtained during revision surgery were treated with minimum three months of oral antibiotics following revision surgery. The prevalence of UPCs and causative microorganisms, the recurrence of periprosthetic joint infections (PJIs), and the infection-free implant survival were established at minimum five years' follow-up (5.1 to 12.3). Of the 297 patients undergoing aseptic revisions, 37 (12.5%) had at least three UPCs obtained during surgery. The UPC cohort included 23 males (62.2%) and 14 females (37.8%), with a mean age of 71.2 years (47 to 82). Comorbidities included smoking (56.8%), hypertension (48.6%), diabetes mellitus (27.0%), and chronic renal impairment (13.5%). The causative microorganisms included Staphylococcus epidermidis (49.6%), Bacillus species (18.9%), Micrococcus species (16.2%), and Cutibacterium acnes (16.2%). None of the study patients with UPCs developed further PJIs or required further surgical intervention during follow-up. The prevalence of UPCs during presumed aseptic revision THA and TKA was 12.5%. The most common causative microorganisms were of low virulence, and included S. epidermidis, Bacillus species, Micrococcus species, and C. acnes. Microorganism-specific antibiotic treatment for minimum three months' duration of UPCs in presumed aseptic revision arthroplasty was associated with excellent infection-free implant survival at mid-term follow-up.

Unbalanced metaphyseal fixation is associated with an increased aseptic loosening of revision total knee arthroplasty at mean 4-year follow-up.

The total number of total knee arthroplasty performed is rising, and the number of revisions is rising accordingly. Periprosthetic joint infection emerged in recent years as a leading cause of total knee revisions. Bone loss is a real challenge when facing septic knee revisions since radical debridement is crucial to overcome infection. Many devices have already demonstrated to reliably address bone loss and guarantee enhanced fixation. However, the role of balancing metaphyseal fixation and its interplay with the level of constraint has not been elucidated yet. An institutional arthroplasty registry was retrospectively reviewed looking for patients who underwent two-stage revision of the knee and metaphyseal cones implantation. Patients were divided into two groups based on the presence of cones only on one side (femoral or tibial, Group U) or both femoral and tibial side (Group B). Failure, aseptic loosening, and revision rates were compared between groups, as were values of patient-reported outcome measure. Kaplan-Meier analysis was used to assess survival of implants. A total of 65 patients were included in the analysis and were evaluated at a mean final follow-up of 4years (range, 2-7). Mean age was 67 (range, 43-81) years. Mean BMI was 27.4 (range, 20-37) kg/m2. The overall mean KSS, OKS, ROM significantly increased from baseline values to last follow-up (p < 0.001). Kaplan-Meier analysis demonstrated that patients included in Group U had a significantly lower rate of implant survival compared to those included in Group B. Patients undergoing revision total knee arthroplasty for periprosthetic infection present considerable rates of complication and failure. Management of bone loss represents a concern for the surgeon, who must achieve a stable fixation. Our study demonstrated that implants characterized by an unbalanced metaphyseal fixation are at higher risk of aseptic loosening and consequent revision, especially when coupled with hinged inserts.

Perioperative Glycemic Variability Influences Infection Rates Differently Following Revision Hip and Knee Arthroplasty

IntroductionRecent investigations have determined that abnormal postoperative glycemia following primary total joint arthroplasty is associated with adverse events. Our study aimed to determine if hyperglycemia and glycemic variability following aseptic revision total joint arthroplasty (rTJA) were associated with periprosthetic joint infection (PJI) within two years postoperatively. MethodsA retrospective review was performed of 2,208 patients within a single institution undergoing aseptic rTJA from 2012 to 2019. Postoperative glucose values were recorded. Glycemic variability was measured via three parameters: coefficient of variation (%CV), mean amplitude of glycemic excursions (MAGE), and J-index. Logistic regression analyses were performed to examine associations with PJI at 90-day, 1-, and 2-year follow-up. ResultsIn revision hips, all glycemic measures were not associated with PJI at any timepoint in logistic regression analyses, except for MAGE, which predicted PJI at one year (P = 0.045); body mass index (BMI) was the only factor associated with PJI at all timepoints in all models. In revision knees, all glycemic measures were not associated with PJI at any timepoint in logistic regression analyses; however, PJI rates differed between diabetics and non-diabetics at all time-points (P < 0.05). ConclusionsOur findings illustrate that decreasing preoperative BMI and postoperative glycemic variability may be critical in reducing PJI rates in revision hips. Furthermore, patients who have diabetes should be counseled that they remain at higher risk of PJI regardless of perioperative glucose control after revision knee surgery.

Tranexamic Acid as a Preventive Strategy Against Periprosthetic Joint Infection in Aseptic Revision Arthroplasty: A Comprehensive Review

Tranexamic Acid as a Preventive Strategy Against Periprosthetic Joint Infection in Aseptic Revision Arthroplasty: A Comprehensive Review

Synovial vancomycin and meropenem concentrations in periprosthetic joint infection treated by single-stage revision combined with intra-articular infusion.

We aimed to determine the concentrations of synovial vancomycin and meropenem in patients treated by single-stage revision combined with intra-articular infusion following periprosthetic joint infection (PJI), thereby validating this drug delivery approach. We included 14 patients with PJI as noted in their medical records between November 2021 and August 2022, comprising eight hip and seven knee joint infections, with one patient experiencing bilateral knee infections. The patients underwent single-stage revision surgery, followed by intra-articular infusion of vancomycin and meropenem (50,000 µg/ml). Synovial fluid samples were collected to assess antibiotic concentrations using high-performance liquid chromatography. The peak concentrations of vancomycin and meropenem in the joint cavity were observed at one hour post-injection, with mean values of 14,933.9 µg/ml (SD 10,176.3) and 5,819.1 µg/ml (SD 6,029.8), respectively. The trough concentrations at 24 hours were 5,495.0 µg/ml (SD 2,360.5) for vancomycin and 186.4 µg/ml (SD 254.3) for meropenem. The half-life of vancomycin was 6 hours, while that of meropenem ranged between 2 and 3.5 hours. No significant adverse events related to the antibiotic administration were observed. This method can achieve sustained high antibiotic concentrations within the joint space, exceeding the reported minimum biofilm eradication concentration. Our study highlights the remarkable effectiveness of intra-articular antibiotic infusion in delivering high intra-articular concentrations of antibiotics. The method provided sustained high antibiotic concentrations within the joint cavity, and no severe side-effects were observed. These findings offer evidence to improve clinical treatment strategies. However, further validation is required through studies with larger sample sizes and higher levels of evidence.

Obesity and Primary Total Knee Arthroplasty: The Absolute versus Relative Risk of Periprosthetic Joint Infection at 15 Years

When indicating patients for primary total knee arthroplasty (TKA), surgeons and patients must understand the absolute and relative risks of periprosthetic joint infection (PJI) to make an informed decision. We sought to evaluate the long-term risk of PJI following primary TKA stratified by body mass index (BMI) and PJI-related risk factors. We identified 25,160 primary TKAs performed from 2000 to 2021 at a single institution. Patients were stratified as having 0, 1, or ≥ 2 PJI risk factors (diabetes, chronic kidney disease, non-primary osteoarthritis, immunosuppression, or active smoking) and into BMI categories. The 15-year cumulative risk of PJI was evaluated by BMI and PJI risk factors. For the entire cohort, the 15-year absolute risk of PJI was 3%. For patients who did not have PJI risk factors, the absolute risk of PJI at 15 years was 3% in normal weight, 4% in class III obesity, and 4% in class IV obesity. Patients who had class III obesity had a 3-times higher relative risk of PJI when compared to normal-weight patients (P = 0.01). Among patients who had ≥ 2 PJI risk factors, the absolute risk of PJI at 15 years was 5% in normal weight and 6% in patients who have class III obesity. Healthy patients who had class III obesity had a 3-times increased risk of PJI relative to healthy, normal-weight patients; however, the absolute risk of PJI at 15 years after primary TKA was 4% in this group. Surgeons and patients must consider both a 3-times increased relative risk of PJI and a 4% absolute risk of PJI at 15 years after primary TKA when considering surgery in otherwise healthy patients who have BMI ≥ 40.

Estimation of two-year hospital costs of hip and knee periprosthetic joint infection treatments using activity-based costing.

Our aim was to estimate the total costs of all hospitalizations for treating periprosthetic joint infection (PJI) by main management strategy within 24 months post-diagnosis using activity-based costing. Additionally, we investigated the influence of individual PJI treatment pathways on hospital costs within the first 24 months. Using admission and procedure data from a prospective observational cohort in Australia and New Zealand, Australian Refined Diagnosis Related Groups were assigned to each admitted patient episode of care for activity-based costing estimates of 273 hip PJI patients and 377 knee PJI patients. Costs were aggregated at 24 months post-diagnosis, and are presented in Australian dollars. The mean cost per hip and knee PJI patient was $64,585 (SD $53,550). Single-stage revision mean costs were $67,029 (SD $47,116) and $80,063 (SD $42,438) for hip and knee, respectively. Two-stage revision costs were $113,226 (SD $66,724) and $122,425 (SD $60,874) for hip and knee, respectively. Debridement, antibiotics, and implant retention in hips and knees mean costs were $53,537 (SD$ 39,342) and $48,463 (SD $33,179), respectively. Suppressive antibiotic therapy without surgical management mean costs were $20,296 (SD $8,875) for hip patients and $16,481 (SD $6,712) for knee patients. Hip patients had 16 different treatment pathways and knee patients had 18 treatment pathways. Additional treatment, episodes of care, and length of stay contributed to substantially increased costs up to a maximum of $369,948. Treating PJI incurs a substantial cost burden, which is substantially influenced by management strategy. With an annual PJI incidence of 3,900, the cost burden would be in excess of $250 million to the Australian healthcare system. Treatment pathways with additional surgery, more episodes of care, and a longer length of stay substantially increase the associated hospital costs. Prospectively monitoring individual patient treatment pathways beyond initial management is important when quantifying PJI treatment cost. Our study highlights the importance of optimizing initial surgical treatment, and informs treating hospitals of the resources required to provide care for PJI patients.

Asymptomatic Elevated Inflammatory Markers: Is There a Risk for Infection or Revision in Primary Total Knee Arthroplasty?

BackgroundTotal knee arthroplasty (TKA) is the treatment of choice for advanced knee osteoarthritis. Long-term studies report high patient satisfaction, while complications such as periprosthetic joint infection (PJI) can be devastating. Knowledge regarding risk factors for PJI is critical to minimize and ideally avoid complications. The purpose of this study was to investigate the risk of PJI and revision in patients who had preoperative asymptomatic high C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) levels in primary TKAs. MethodsPatients undergoing primary TKA between 2010 and 2022 were eligible. Inclusion criteria were patients who had preoperative complete biochemical parameters and a minimum follow-up of 12 months. Patients who died during the first year, and those who had a history of inflammatory arthritis, autoimmune disease, renal pathologies or septic arthritis, were excluded. Patients who had elevated blood CRP and ESR levels taken within 48 hours before surgery underwent a thorough medical examination with a focus on infection symptoms. After screening and consultation, residual elevated CRP and ESR levels were classified as asymptomatic. After exclusions, 1,528 patients were included. The mean age was 66 years (range, 35 to 92) and the mean follow-up time was 6.4 years (range, 1.6 to 12.3). ResultsThe rate of revision within one year after surgery was 1.6%, whereas the rate of revision in the first five years was 3.8%. The PJI rates for the 1st and 5th postoperative years were 1.7 and 2.9% respectively. Regression analysis did not show any of the potential variables to be a risk factor for revision or PJI. ConclusionAsymptomatic elevated acute-phase reactants are not a risk factor for periprosthetic joint infection or aseptic revision. At a mean follow-up of 6.4 years, overall survival was 96.7%, with only 2.2% of patients revised due to a PJI.

Unexpected positive cultures in conversion hip and knee arthroplasty.

Total hip and knee arthroplasty in patients with previous history of periarticular surgery, such as osteosynthesis, can be surprisingly complex. This type of procedure is known as conversion arthroplasty (cTHA or cTKA) and has a higher risk of complications. The rates of unexpected positive cultures (UPC) and the risk of periprosthetic joint infection (PJI) compared to primary arthroplasty is unclear. The main purpose of this study was to evaluate rates of Unexpected Positive Cultures (UPC) in a series of conversion arthroplasty patients. The main questions to answer are: 1. Are the patients with conversion arthroplasties more susceptible to UPC than other causes of revision arthroplasties? 2. Are the conversion patients with UPC more susceptible to developing PJI? This was a retrospective review of patients submitted to cTHA and cTKA from January 2012 to September 2018. Patients with history of previous infection or with missing intraoperative cultures were excluded. The UPC was defined as a single positive culture obtained during a procedure previously considered aseptic and PJI was defined according to the 2018 ICM criteria. After excluding 141 cases, 205 patients were analyzed, 160 hips and 45 knees. Nine (4.4%) UPC were identified, five (3.1%) in the hip group and four (8,9%) in the knee group. Staphylococcal species were the most common isolated bacteria (n = 7, 77.7%). During the study period, four (1,9%) patients were diagnosed with PJI. Only one case had an UPC and a different germ was identified during revision arthroplasty workup. While UPC are more prevalent in conversion knee arthroplasties compared to conversion hip arthroplasties, the rates are similar to those observed in revision arthroplasty for other indications. Importantly, the presence of a UPC in conversion arthroplasty does not appear to elevate the risk of subsequent periprosthetic joint infection, provided a thorough PJI workup has been conducted preoperatively. Therefore, in such cases, UPCs may be safely disregarded.