Septic Revision Research Articles

Hidden costs of first choice alternatives: A financial model of thromboprophylaxis and prosthetic joint infection prophylaxis in total knee arthroplasty

BackgroundAspirin has been shown to be equally or more effective than factor Xa inhibitors for thromboprophylaxis following total knee arthroplasty (TKA). Cefazolin has been proven more effective than vancomycin in preventing prosthetic joint infection (PJI) after TKA. This study aimed to compare costs between different drug combinations for prevention of venous thromboembolism (VTE) and PJI following TKA, focusing on costs associated with PJI management. MethodsWe used published PJI rates for TKA patients treated with aspirin or factor Xa inhibitors for thromboprophylaxis, as well as for those who received prophylactic cefazolin or vancomycin. Unit prices for each drug and labor costs associated with vancomycin administration were obtained from our hospital's pharmacy service. The PJI cost model included the price of 2-stage septic TKA revision and national projections of future TKA volume. ResultsThe least expensive average per-patient cost resulted from the combination of aspirin and cefazolin, equating to $521.19 given a 0.8 % PJI rate. The most expensive average per-patient cost was the combination of a factor Xa inhibitor and vancomycin, equaling $5,714.96 given a 1.8 % PJI rate. This extrapolates to an annual cost burden of $19.5 billion by 2040. ConclusionThe average per-patient cost of using a combination of a factor Xa inhibitor and vancomycin is 711 % greater than the combination of aspirin and cefazolin. In this era of value-based care, aspirin and cefazolin should be considered gold standards for TKA thromboprophylaxis and PJI prophylaxis, as they reduce costs and improve patient outcomes.

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.

Declining Trends in Septic Revision Following Total Knee Arthroplasty From 2010 to 2019: A National Cohort Analysis

Periprosthetic joint infections (PJI) following total knee arthroplasty (TKA) are associated with high patient morbidity, mortality, and healthcare costs. Methods to reduce the burden of PJI have been shown to be efficacious on a small scale. On a national scale, it is unknown whether these methods have reduced PJI rates. A retrospective trend analysis was conducted using a national database. The incidence of 2-year septic revision was observed for the entire cohort and patients who had high-risk co-morbidities from 2010 to 2019. A multivariable logistic regression was performed to compare the odds ratios of 2-year septic revision rates from 2011 to 2019 to the reference year of 2010. Linear regression was used to compare the change throughout this period in the overall and high-risk sub-analysis groups. Among the 860,185 patients, 5,589 underwent septic revision within 2 years. The 2-year septic revision rate decreased from 0.75% in 2010 to 0.69% in 2019 (compounded annual growth rate [CAGR] = -0.94%, P = 0.049). Multivariable logistic regressions demonstrated that the odds of septic revision in 2019 were significantly lower than those in 2010 (OR [odds ratio]: 0.83, 95% CI [confidence interval]: [0.70 to 0.96], P = 0.017). In high-risk patients, the septic revision rate decreased from 1.04 to 0.80% (CAGR = -2.80%, P = 0.004), specifically in those who had a history of psychoses, Medicaid insurance, anemia, heart failure, obesity, liver disease, tobacco use, and drug abuse (P < 0.05 for all). This study demonstrates a national reduction in the 2-year septic revision rate in all TKA patients, including patients considered at high risk for PJI. This suggests current preventative methods may be efficacious on a national scale in TKA. Further research is needed to identify more modalities to reduce the national incidence of this morbid and costly complication.

No shortening of the patellar tendon during two-stage total knee arthroplasty revision using articulating spacers.

Surgical techniques in two-stage revision total knee arthroplasty(rTKA) include the use of articulating spacers and static spacers. Shortening of the patellar tendon could be a reason for inferior functional outcomes in two-stage septic rTKA. The aim of this study was to determine if articulating spacers also have negative effects on the extensor mechanism in rTKA. This retrospective study includes 65 consecutive patients (23 women, 42 men, age 71.3 ± 1.2; range, 51.2-88.6 years) undergoing septic two-stage rTKA using an articulating spacer between 2014 and 2021 in a single orthopedic center. For all patients, calibrated true lateral radiographs before total knee arthroplasty (TKA) explantation (T0), directly after TKA explantation (T1), shortly before TKA reimplantation (T2) and 6-8 days after TKA reimplantation (T3) were used to calculate the modified Insall Salvati ratio (mISR). Overall, the mISR decreased significantly immediately after explantation (T0 vs. T1, p = 0.002) from 1.43 ± 0.03 to 1.36 ± 0.03 and remained stable until T2 (1.37 ± 0.02, p = 0.74). Following TKA reimplantation, the mISR increased again to 1.43 ± 0.03 (T3). There were no significant differences between T0 and T3 (p = 0.88). Six out of 65 patients (9%) experienced patellar tendon shortening > 10% at T3. Septic two-stage revision TKA using an articulating spacer does not lead to patellar tendon shortening in the majority of cases. This study suggests that one reason for the improved range of motion after reimplantation may be the use of articulating spacers compared to static spacers.

Comparison of Externally Transferred and Self-Recruited Patients with Hip and Knee Revision Arthroplasty at a Certified Maximum-Care Arthroplasty Center (ACmax).

According to the guidelines of the EndoCert initiative, certified maximum-care arthroplasty centers (ACmax) are obliged to admit patients from certified arthroplasty centers (AC) if these patients need to be transferred to the more specialized ACmax due to difficult replacement and revision procedures as well as after complications in primary care that are beyond the expertise of the smaller centers. This study investigated whether the cohort of transferred patients differed from the patients directly recruited at the ACmax for factors such as severity of diagnosis, comorbidities or outcome. The aim was to determine whether transferred patients increased the resource requirements for the ACmax. A total of 136 patients were included in the retrospective study and analyzed in terms of case severity, length of hospital stays (LOS), Diagnosis-Related Group charges, readmission rate and concomitant diseases. All patients were followed for up to 12 months after the initial hospital stay. There were significant differences between the groups of transferred and self-recruited patients. For example, transferred patients had a higher Patient Clinical Complexity Level (PCCL). Similarly, the increased Case Mix Index (CMI) of transferred patients indicated more intensive care during the inpatient stay. The higher values for the comorbidity indices also supported these results. This had an impact on the LOS and overall costs, too. The differences between the groups were also reflected by adverse events during the one-year follow-up. The higher percentage of patients with septic revisions, whose treatment is especially demanding, among transferred patients aggravated the differences even further. Thus, transferred patients were associated with increased resource requirements for the ACmax. While it serves patients' safety to transfer them to an ACmax with specialized expertise and greater structural quality, the care of transferred patients ties up considerable resources at the ACmax that might only be insufficiently reimbursed by the generalized tariffs.

Low UKA implantation volume, comorbidities, male sex, and implantation of constrained TKA are risk factors for septic revision after knee arthroplasty implantation : A register-based study from the German Arthroplasty Register

Periprosthetic joint infection (PJI) is one of the main causes of revision surgeries after total knee arthroplasty (TKA) and unicondylar knee replacement. Patient- and hospital-related risk factors must be evaluated to prevent PJI. This study identifies influencing factors and differences in infection rates between various types of implant. The basis for the data is the German Arthroplasty Register (EPRD). Septic revisions were calculated with the aid of Kaplan-Meier estimates, with septic revision surgery defined as the primary endpoint. Patients with constrained and unconstrained TKA or UKA were analysed using the Holm multiple log-rank test and the Cox proportional hazard model. The 300,998 cases of knee arthroplasty analysed included 254,144 (84.4%) unconstrained TKA, 9993 (3.3%) constrained TKA and 36,861 (12.3%) UKA, with a maximum follow-up of 7 years. After 1 year, the PJI rate was 0.5% for UKA and 2.8% for TKA, whereas after 7 years it was 4.5% for UKA and 0.9% for TKA (p < 0.0001). In constrained TKA, the PJI rate was significantly increased compared with unconstrained TKA (p < 0.0001). After 1 year, the PJI rate was 2.0% for constrained TKA and 0.8% for unconstrained TKA, as well as 3.1% and 1.4% respectively after 7 years. Implantation of a constrained TKA (HR = 2.55), male sex (HR = 1.84), an increased Elixhauser Comorbidity Index score (HR = 1.18-1.56) and an implantation volume of less than 25 UKA per year (HR = 2.15) were identified as risk factors for revision surgeries; an Elixhauser Comorbidity Index score of0 (HR = 0.80) was identified as a preventive factor. A reduced implantation volume and constrained knee arthroplasty are linked to a higher risk of PJI. Comorbidities (increased Elixhauser Comorbidity Index score), male sex and a low UKA-implantation volume were identified as risk factors for PJI. Patients who fulfil these criteria need specific infection prevention measures. Further analyses are required to investigate the potential influence of prevention and risk factor modification. III.

Neighborhood Socioeconomic Disadvantage is Associated with Increased Healthcare Utilization After Septic and Aseptic Revision Total Hip Arthroplasty

BackgroundA greater Area Deprivation Index (ADI), a tool that gauges socioeconomic disadvantage at the neighborhood level, is associated with worse healthcare outcomes following primary total hip arthroplasty (THA). However, its association with revision THA (rTHA) is unknown. This study aimed to determine the association between ADI and rates of postoperative healthcare resource utilization following rTHA. MethodsA total of 996 patients who underwent rTHA between 2016 and 2022 were enrolled in a prospective study. The primary outcomes assessed were non-home discharge disposition (DD), length of stay (LOS) ≥ 3 days, 90-day emergency department (ED) visits, and 90-day hospital readmissions. The ADI was calculated using the patient’s home address at the time of surgery, with greater ADI indicating greater socioeconomic disadvantage. We evaluated the mediation effect of patient race on ADI and postoperative healthcare utilization using a multivariable logistic regression model. ResultsA higher median ADI was revealed for patients who experienced non -home discharge (P = 0.001), extended LOS (P < 0.001), and ED readmission within 90-days of surgery (P = 0.045). When comparing septic versus aseptic rTHA patients, there were significant differences in healthcare resource utilization but no difference in ADI between the two groups. For aseptic rTHA, ADI significantly mediated the effect of race on both non-home DD and LOS ≥ 3 (41% and 46% mediation, respectively). In septic rTHA, ADI mediated 31.1% of the effect of race on non-home DD, but showed minimal mediation effect on LOS. The mediation effect of ADI on ED admission and hospital readmission was minimal for both groups ConclusionHigher ADI scores are associated with increased healthcare utilization after rTHA, including longer hospital stays and more non-home discharges. The ADI significantly mediates the effect of race on these outcomes, particularly in aseptic rTHA cases, suggesting that neighborhood socioeconomic factors play a crucial role in previously observed racial disparities.

Impact of systemic lupus erythematosus (SLE) on outcomes following aseptic and septic revision total knee arthroplasty: an analysis of the 2005-2018 nationwide inpatient sample.

Systemic lupus erythematosus (SLE) can adversely affect surgical outcomes, and the impact on revision total knee arthroplasty (TKA) outcomes is unclear. This study aimed to explore the impact of SLE on in-patient outcomes of revision TKA. The Nationwide Inpatient Sample (NIS) database from 2005 to 2018 was searched for patients aged ≥ 18years old who received revision TKA. Patients with and without SLE were propensity score matched (PSM) at a 1:4 ratio. Associations between SLE and in-hospital outcomes were examined using regression analyses. The study included 133,054 patients, with 794 having SLE. After 1:4 PSM, data of 3,970 patients were analyzed (SLE, 794; non-SLE, 3,176). Multivariate-adjusted analyses revealed that SLE patients had a significantly higher risk of postoperative complications (adjusted odds ratio [aOR] = 1.23, 95% confidence interval [CI]: 1.05-1.44, p = 0.011), non-routine discharge (aOR = 1.22, 95% CI: 1.02-1.46, p = 0.028), major blood loss (aOR = 1.19), respiratory failure/mechanical ventilation (aOR = 1.79), acute kidney injury (AKI) (aOR = 1.47), and wound dehiscence (aOR = 2.09). SLE patients also had a longer length of hospital stay (aBeta = 0.31) and greater total hospital costs (aBeta = 6.35) compared to non-SLE patients. Among those with aseptic failure, SLE patients had a significantly higher risk of postoperative complications (aOR = 1.23) and non-routine discharge (aOR = 1.36). SLE is independently associated with worse in-hospital outcomes in patients undergoing revision TKA. This study highlights the importance of heightened vigilance and tailored perioperative management for patients undergoing major surgeries in the background of SLE. Key Points • SLE significantly increases the risk of non-routine discharge, major blood loss, respiratory failure, acute kidney injury, and wound dehiscence, in patients undergoing aseptic and septic revision TKA. • Patients with SLE experience longer hospital stays and higher hospital costs compared to those without SLE. • The study's findings highlight the necessity for healthcare providers to consider the presence of SLE as a critical factor in preoperative planning and postoperative care to improve outcomes in revision TKA patients.

Antibiotic-loaded bone cement is associated with a reduction of the risk of revision of total knee arthroplasty: Analysis of the Catalan Arthroplasty Register.

The purpose of this study was to analyse the impact on peri-prosthetic joint infection (PJI) rate and prosthetic survival using antibiotic-loaded bone cement (ALBC) versus plain cement during total knee arthroplasty (TKA). A retrospective cohort study was conducted. The main data source was the Catalan Arthroplasty Register (RACat). TKAs with surgery date between 1 January 2011 and 31 December 2020 were analysed and followed up until 31 December 2023. The main variable of interest was the type of cement (ALBC vs. plain cement), and several endpoints (septic revision, aseptic revision, and all-cause revision) were considered. The analysed outcomes were revision rates, survival rates and risk factors' hazard ratios (HR). A total of 22,781 TKAs were analysed, 13,125 (57.6%) of them with plain cement and 9656 (42.4%) with ALBC. The septic revision rate was lower in the ALBC group after 3 months of follow-up (0.52% vs. 0.78%, p value = 0.04). Prosthetic survival with respect to the aseptic revision endpoint was also higher for the ALBC group during the whole follow-up period (~158 months). Regarding risk factors for infection, ALBC showed a protective effect, HR: 0.53 (0.44, 0.63), while sex (being male) and the analysed comorbidities increased the risk. ALBC is associated with a reduction in both the septic revision and the aseptic revision rate after TKA, and thus with higher prosthetic survival. Level III, Therapeutic, retrospective.

Low implantation volume, comorbidities, male sexand implantation of constrained TKA identified as risk factors for septic revision in knee arthroplasty:A register-based study from the German Arthroplasty Registry.

Periprosthetic joint infection (PJI) is a major cause of revision surgery after total knee arthroplasty (TKA) and unicondylar knee arthroplasty (UKA). Patient- and hospital-related risk factors need to be assessed to prevent PJI. This study identifies influential factors and differences in infection rates between different implant types. Data were obtained from the German Arthroplasty Registry. Septic revisions were calculated using Kaplan-Meier estimates with septic revision surgery as the primary endpoint. Patients with constrained and unconstrained TKA or UKA were analysed using Holm's multiple log-rank test and Cox's proportional hazards ratio. The 300,998 cases of knee arthroplasty analysed included 254,144 (84.4%) unconstrained TKA, 9993 (3.3%) constrained TKA and 36,861 (12.3%) UKA with a maximum follow-up of 7 years. At 1 year, the PJI rate was 0.5% for UKA and 2.8% for TKA, whereas at 7 years, the PJI rate was 4.5% for UKA and 0.9% for TKA (p < 0.0001). The PJI rate significantly increased for constrained TKA compared to unconstrained TKA (p < 0.0001). The PJI rate was 2.0% for constrained TKA and 0.8% for unconstrained TKA at 1 year and 3.1% and 1.4% at 7 years. Implantation of a constrained TKA (hazard ratio [HR] = 2.55), male sex (HR = 1.84), increased Elixhauser score (HR = 1.18-1.56) and implant volume of less than 25 UKA per year (HR = 2.15) were identified as risk factors for revision surgery; an Elixhauser score of 0 (HR = 0.80) was found to be a preventive factor. Reduced implant volume and constrained knee arthroplasty are associated with a higher risk of PJI. Comorbidities (elevated Elixhauser score), male sex and low UKA implant volume have been identified as risk factors for PJI. Patients who meet these criteria require specific measures to prevent infection. Further research is required on the potential impact of prevention and risk factor modification. Level III.

Periprosthetic Joint Infections of the Knee-Comparison of Different Treatment Algorithms.

Background: Periprosthetic joint infection (PJI) following total knee arthroplasty is a serious complication lacking evidence-based diagnostic and treatment protocols, particularly in ruling out persisting infection before reimplantation. Methods: This retrospective analysis assessed the mid-term outcomes of 66 patients undergoing septic two-stage knee revision surgeries from 2007 to 2013, diagnosed as per the Musculoskeletal Infection Society criteria. After implant removal and antibiotic treatment, reimplantation decisions were based on either joint aspiration, blood counts, and clinical examination (group A) or an open biopsy (group B). Both groups underwent meticulous debridement and spacer exchange during the interim period. Results: Late re-infection occurred in 12.1% of all patients. In group A, 13.8% experienced late re-infection, with 14.3% in subgroup A1 and 13.3% in subgroup A2. In group B, 10% had a late re-infection. No significant difference in re-infection or complication rates was found between the groups. Conclusions: The study did not demonstrate the superiority of group B's approach of open biopsy over group A's joint aspiration, clinical examination, and blood counts in preventing re-infection or reducing complications.

Effect of Multiantibiotic-Loaded Bone Cement on the Treatment of Periprosthetic Joint Infections of Hip and Knee Arthroplasties-A Single-Center Retrospective Study.

Two-stage septic revision is the prevailing method for addressing late periprosthetic infections. Using at least dual-antibiotic-impregnated bone cement leads to synergistic effects with a more efficient elution of individual antibiotics. Recent data on the success rates of multiantibiotic cement spacers in two-stage revisions are rare. We conducted a retrospective follow-up single-center study involving 250 patients with late periprosthetic hip infections and 95 patients with prosthetic knee infections who underwent septic two-stage prosthesis revision surgery between 2017 and 2021. In accordance with the antibiotic susceptibility profile of the microorganisms, a specific mixture of antibiotics within the cement spacer was used, complemented by systemic antibiotic treatment. All patients underwent preoperative assessments and subsequent evaluations at 3, 6, 9, 12, 18, and 24 months post operation and at the most recent follow-up. During the observation period, the survival rate after two-step septic revision was 90.7%. Although survival rates tended to be slightly lower for difficult-to-treat (DTT) microorganism, there was no difference between the pathogen groups (easy-to-treat (ETT) pathogens, methicillin-resistant staphylococci (MRS), and difficult-to-treat (DTT) pathogens). Furthermore, there were no differences between monomicrobial and polymicrobial infections. No difference in the survival rate was observed between patients with dual-antibiotic-loaded bone cement without an additional admixture (Copal® G+C and Copal® G+V) and patients with an additional admixture of antibiotics to proprietary cement. Employing multiple antibiotics within spacer cement, tailored to pathogen susceptibility, appears to provide reproducibly favorable success rates, even in instances of infections with DTT pathogens and polymicrobial infections.

Re-revision and mortality rate following revision total hip arthroplasty for infection.

This study compares the re-revision rate and mortality following septic and aseptic revision hip arthroplasty (rTHA) in registry data, and compares the outcomes to previously reported data. This is an observational cohort study using data from the German Arthroplasty Registry (EPRD). A total of 17,842 rTHAs were included, and the rates and cumulative incidence of hip re-revision and mortality following septic and aseptic rTHA were analyzed with seven-year follow-up. The Kaplan-Meier estimates were used to determine the re-revision rate and cumulative probability of mortality following rTHA. The re-revision rate within one year after septic rTHA was 30%, and after seven years was 34%. The cumulative mortality within the first year after septic rTHA was 14%, and within seven years was 40%. After multiple previous hip revisions, the re-revision rate rose to over 40% in septic rTHA. The first six months were identified as the most critical period for the re-revision for septic rTHA. The risk re-revision and reinfection after septic rTHA was almost four times higher, as recorded in the ERPD, when compared to previous meta-analysis. We conclude that it is currently not possible to assume the data from single studies and meta-analysis reflects the outcomes in the 'real world'. Data presented in meta-analyses and from specialist single-centre studies do not reflect the generality of outcomes as recorded in the ERPD. The highest re-revision rates and mortality are seen in the first six months postoperatively. The optimization of perioperative care through the development of a network of high-volume specialist hospitals is likely to lead to improved outcomes for patients undergoing rTHA, especially if associated with infection.

Investigation of the pathogen-specific antibody response in periprosthetic joint infection.

Periprosthetic joint infections (PJIs) are a very demanding complication of arthroplasty. Diagnosis of PJI and pathogen identification pose considerable challenges in clinical practice. We hypothesized that the pathogen-specific immune response to PJI reflects the infection process, provides clinically relevant information on disease course, and has the potential to further optimize antimicrobial therapy. We conducted a prospective matched cohort pilot study with 13 patients undergoing two-stage septic revision arthroplasty (PJI patients) between 06/2020 and 06/2021, as well as 11 control patients undergoing one-stage aseptic revision arthroplasty (Non-PJI patients). Pre-, intra- and postoperative serum samples were collected at standardized time points. We developed a custom Luminex®-based quantitative bead-based suspension array (Infection Array; IA), and used it for simultaneous measurement of antibody specificities against 32 pathogens commonly associated with PJI in 267 serum samples. The IA was able to trace the dynamics of the pathogen-specific humoral immune response in all patients against PJI-related pathogens, prominently coagulase-negative staphylococci and streptococci. Pathogen-specific serum antibody titers declined in 62% of PJI patients over the course of treatment, while no changes in antibody titers were observed in 82% of Non-PJI patients during this study. Our serological data strongly suggested that antibody signatures reflect an immune response to microbial invasion. Our results provide insights into the pathophysiology of PJI and information on the individual disease courses. The IA is therefore a promising and novel serological tool of high resolution for monitoring the immunoproteomic footprints of infectious pathogens in the course of PJI.

The economic impact of two-stage knee arthroplasty revisions: a projection for a specialized health center in Türkiye

Objectives: The increase in the number of arthroplasty surgeries worldwide also leads to an increase in revision surgeries. This study examines the costs of primary and revision arthroplasty treatments in a tertiary university hospital's orthopedics and traumatology clinic. It also explores the impact of revision surgeries on the healthcare system. Methods: Seventy-six patients who had total knee arthroplasty at a university hospital between 01.01.2017 and 30.09.2022 were included in the study. The patients were divided into three groups: primary (n=25), aseptic reasons one-stage revision (n=27), and septic reasons two-stage revisions (n=24). For each patient included in the study, detailed documents regarding medical supplies, anesthesia, operating room, intensive care, consultation, medicine/serum, medical treatment, laboratory, blood and blood products, microbiology, radiology, food, bed, and attendant fees were provided separately by the hospital purchasing and statistics departments. Results: When comparing the costs of primary, one-stage revision, and two-stage revision surgeries, the average costs were 5689 Turkish Lira (₺), 8294.97 ₺, and 40919.67 ₺, respectively. In patients with septic reasons, the group that underwent two-stage revisions had significantly higher costs than the aseptic group in terms of surgery time, hospital stay duration, medication, treatment, surgery, anesthesia, intensive care, laboratory tests, imaging, blood center services, consultations, visits, meal expenses, and invoiced amount (P&amp;lt;0.001). Conclusion: Preventing and treating periprosthetic infections is costly and challenging. We need more research to develop effective protocols and reduce costs. As the number of patients undergoing knee arthroplasty is expected to rise, healthcare systems must ensure the sustainability of public financial resources, especially in public university hospitals.

Synovial fluid NMR-based metabolomics in septic and aseptic revision total knee arthroplasty: Implications on diagnosis and treatment.

Periprosthetic joint infection (PJI) is one of the most challenging complications following total knee arthroplasty. Despite its importance, there is a paucity of reports in the literature regarding its pathogenesis. Recently, cellular metabolic reprogramming has been shown to play an important role in the progression and outcome of infectious diseases. Therefore, the aim of this study was to evaluate the metabolites composition of the synovial fluid from patients with PJI or aseptic failure of total knee arthroplasties. The synovial fluids from 21 patients scheduled for revision total knee arthroplasty (11 with the diagnosis of PJI and 10 with aseptic failures) were analyzed using 1D 1H NMR spectroscopy. Univariate and multivariate statistical analyzes were used to identify metabolites that were differentially abundant between those groups. A total of 28 metabolites were identified and five of them found to be differentially abundant between infected and non-infected synovial fluids. Lactate, acetate and 3-hydroxybutyrate were found to be in a higher concentration, and glucose and creatine were found reduced in the synovial fluid from PJI patients. Synovial fluid from patients with PJI exhibit a distinct metabolic profile, possibly reflecting metabolic adaptation that occurs in the infected periprosthetic microenvironment. Further research and studies are warranted to gain a broader insight into the metabolic pathways engaged by both pathogen and immune cells in the context of a PJI.

Evaluating the Clinical Relevance of Routine Sonication for Periprosthetic Hip or Knee Joint Infection Diagnosis.

Periprosthetic joint infection (PJI) is a serious complication after joint arthroplasty. PJI screening and conventional cultures may be inconclusive. Sonication fluid culturing stands out as a valuable adjunct technique for PJI diagnosis. This study aims to determine the clinical relevance of routine sonication for all (a)septic revisions. All patients who underwent (partial) hip or knee revision arthroplasty between 2012 and 2021 were retrospectively reviewed. We formed three groups based on the European Bone and Joint Society PJI criteria: infection confirmed, likely, and unlikely. We analyzed clinical, laboratory, and radiological screening. Sensitivity and specificity were calculated for synovial fluid (preoperative), tissue, and sonication fluid cultures. We determined the clinical relevance of sonication as the percentage of patients for whom sonication confirmed PJI; 429 patients who underwent (partial) revision of hip or knee arthroplasty were included. Sensitivity and specificity were 69% and 99% for synovial fluid cultures, 76% and 92% for tissue cultures, and 80% and 89% for sonication fluid cultures, respectively. Sonication fluid cultures improved tissue culture sensitivity and specificity to 83% and 99%, respectively. In 11% of PJIs, sonication fluid cultures were decisive for diagnosis. This is applicable to acute and chronic infections. Sonication fluid cultures enhanced the sensitivity and specificity of PJI diagnostics. In 11% of PJI cases, causative pathogens were confirmed by sonication fluid culture results. Sonication fluid culture should be performed in all revision arthroplasties.

How Useful Is Preoperative Aspiration before Revision of Unicompartmental Knee Prostheses Because of Osteoarthritis in the Other Compartments?

Periprosthetic joint infections (PJIs) of unicompartmental knee arthroplasties (UKAs) can lead to secondary osteoarthritis of the other compartments. The objective of this study was to identify the frequency of PJIs in cases of UKA with progressed secondary osteoarthritis and the result of septic one-stage revision in these cases to verify the value of preoperative aspiration in cases of secondary osteoarthritis of UKA. We retrospectively reviewed 97 patients with a unicompartmental arthroplasty who underwent revision surgery to a total knee arthroplasty (TKA) between January 2013 and March 2021 because of subsequent osteoarthritis. Preoperative aspiration and sample collection during the revision surgery were employed to identify potential periprosthetic joint infections (PJIs). The post-revision period was monitored for septic complications over an average duration of 55.7 ± 25.2 months (24-113). PJIs were identified in 5.2% of cases through preoperative aspiration. In all instances of PJIs, a one-stage septic revision was performed, and notably, none of these cases experienced septic complications during the follow-up period. Preoperative aspiration is essential in order to exclude the presence of a PJI before performing revision surgery of UKA due to secondary osteoarthritis.

Aseptic Revision Total Hip Arthroplasty Through an Anterior Approach: Survivorship and Risk Factors for Re-Revision

BackgroundThe utilization of anterior-based approaches for total hip arthroplasty (THA) is increasing. Literature on the outcomes of revision THA (rTHA) through an anterior approach, however, is sparse. This study reports the survivorship and risk factors for re-revision in patients undergoing aseptic rTHA through an anterior approach. MethodsThis was a single-institution, retrospective cohort analysis of patients who underwent aseptic rTHA through an anterior approach (direct anterior, anterior-based muscle sparing) from January 2017 to December 2021, regardless of the original surgical approach. Exclusion criteria were age <18 years, conversion THA, and septic revisions. Patient demographics, complications, and postoperative outcomes were collected. Kaplan–Meier curves were used to measure survivorship while Cox regression analyses were used to identify risk factors for re-revision of THA. ResultsWe identified 251 total anterior rTHAs, of which 155 were aseptic anterior revisions. There were 111 patients (111 rTHAs; 63 anterior-based muscle sparing and 48 direct anterior) who met criteria and had a mean follow-up of 4.2 years (range, 2.1 to 6.9). There were a total of 54 (49%) anterior-based index approaches and 57 (51%) posterior index approaches. The most common indications for rTHA were femoral loosening (n = 25, 22.5%), followed by instability (n = 16, 14.4%) and wear or osteolysis (n = 16, 14.4%). At 2 years, the survivorship from reoperation and re-revision was 89% (95% confidence interval: 84 to 95) and 91% (95% confidence interval: 86 to 96), respectively. Reoperation occurred in 14 patients (12.6%) at a mean time of 7.8 months (range, 0.5 to 28.6). Re-revision occurred in 12 patients (10.8%) at a mean time of 7.3 months (range, 0.5 to 28.6). Instability was the most common reason for re-revision (4.5%). Neither index approach type, revision approach type, nor any patient-specific risk factors were identified as predictors of re-revision or reoperation in multivariable regression analysis. ConclusionsThis study demonstrates an acceptable rate of re-revision when aseptic rTHA is performed through an anterior approach, with the most common reason for aseptic re-revision being instability.

Outcomes of rotating versus pure hinge knee arthroplasty in the setting of one-stage exchange for periprosthetic joint infection.

Rotating or pure hinge knee prostheses are often used in case of periprosthetic joint infection (PJI). Five-year survival data of rotating hinge implants ranging from 52 to 90%, whereas pure hinge data are sparse. This study describes the results of both hinge knee prostheses after one-stage septic exchange. One hundred sixty-seven one-stage septic exchanges of a primary unconstrained total knee arthroplasty (TKA) to a cemented hinge prosthesis (117 rotating and 50 pure hinge TKAs) performed between 2008 and 2017 were retrospectively reviewed. Exclusion criteria were stem extensions or augments used in primary TKA, history of extensor mechanism reconstruction, and a follow-up less than twoyears after surgery. Rates of reinfection, mechanical failures, and all-cause revision-free survival data were documented. At fiveyears, the all-cause revision-free survival was 77% (95% CI 69 to 82). Thirty-one patients (19%) had further revision for aseptic reasons. In the rotating hinge group, the mechanical failure rate was more than twice as high as in the pure hinge group (13% vs 6%), significantly influenced by higher body weight. At a mean follow-up of 6.7years, 21 (13%) patients had a reinfection and underwent a further surgery. Reinfection rates did not differ between the two groups. The use of hinge TKA in the revision of PJI shows favourable fiveyear infection-free and all-cause revision-free survival rates of 91% and 77%, respectively. Our study showed poorer results of the rotating hinge design. These results may help surgeons to choose proper implants in case of septic knee revision.