Quantifying the Burden of Revision Total Joint Arthroplasty for Periprosthetic Infection

A qualitative study of patients' experiences before, during and after surgical treatment for periprosthetic knee joint infection; "I assumed it had to be like that … "

BACKGROUND

Periprosthetic joint infection (PJI) of the knee is associated with extended hospital stay, high doses of antibiotics, lengthy rehabilitation, and pain. Standard treatment is a two-stage procedure comprising two surgeries and two hospitalizations. To facilitate exploration of patients' perspectives, the qualitative study presented here was an adjunct to a Danish randomized controlled trial comparing one-stage and two-stage revision surgery.

AIM

To explore patient experiences, before, during and after hospitalization and surgical treatment with one- or two-stage revision for PJI of the knee.

MATERIAL AND METHODS

Qualitative, semi-structured telephone interviews were conducted with 10 individuals who had undergone either one- or two-stage revision because of PJI. Thematic analysis was employed.

RESULTS

The essence of the findings was that the infection was a transition point in a possible life-changing illness. The three themes representing this comprised: 1) physical, 2) psychological, and 3) social implications. Each theme is further illuminated with subthemes.

CONCLUSIONS

Infection is a transition point in a possible life changing illness. Late diagnosis and delayed treatment are major issues. Individuals suffer from pain, weight loss, fatigue, and reduced mobility as well as dependency on family members, leading to psychological challenges including depression.

IMPLICATIONS FOR CLINICAL PRACTICE

Patients with PJI of the knee could be better informed, educated and involved before and during treatment. Information is needed not only about the physical consequences, but also the psychological and social consequences. More patient involvement and inter-professional and care sector coordination is important when caring for patients with PJI.

Establishment of a Novel Rat Model of Gram-Negative Periprosthetic Joint Infection Using Cementless Hip Hemiarthroplasty

BACKGROUND

Gram-negative periprosthetic joint infections (GN-PJIs) present unique challenges. Our aim was to establish a clinically representative GN-PJI model that recapitulates biofilm formation in vivo. We also hypothesized that biofilm formation on the implant surface would affect its ability to osseointegrate.

METHODS

Three-dimensionally-printed medical-grade titanium hip implants were used to replace the femoral heads of male Sprague-Dawley rats. GN-PJI was induced using 2 bioluminescent Pseudomonas aeruginosa strains: a reference strain (PA14-lux) and a mutant biofilm-defective strain (ΔflgK-lux). Infection was monitored in real time using an in vivo imaging system (IVIS) and magnetic resonance imaging (MRI). Bacterial loads were quantified utilizing the viable colony count. Biofilm formation at the bone-implant interface was visualized using field-emission scanning electron microscopy (FE-SEM). Implant stability, as an outcome, was directly assessed by quantifying osseointegration using microcomputed tomography, and indirectly assessed by identifying gait-pattern changes.

RESULTS

Bioluminescence detected by the IVIS was focused on the hip region and demonstrated localized infection, with greater ability of PA14-lux to persist in the model compared with the ΔflgK-lux strain, which is defective in biofilm formation. This was corroborated by MRI, as PA14-lux induced relatively larger implant-related abscesses. Biofilm formation at the bone-implant interface induced by PA14-lux was visualized using FE-SEM versus defective-biofilm formation by ΔflgK-lux. Quantitatively, the average viable colony count of the sonicated implants, in colony-forming units/mL, was 3.77 × 108 for PA14-lux versus 3.65 × 103 for ΔflgK-lux, with a 95% confidence interval around the difference of 1.45 × 108 to 6.08 × 108 (p = 0.0025). This difference in the ability to persist in the model was reflected significantly on implant osseointegration, with a mean intersection surface of 4.1 × 106 ± 1.99 × 106 μm2 for PA14-lux versus 6.44 × 106 ± 2.53 × 106 μm2 for ΔflgK-lux and 7.08 × 106 ± 1.55 × 106 μm2 for the noninfected control (p = 0.048).

CONCLUSIONS

To our knowledge, this proposed, novel in vivo biofilm-based model is the most clinically representative for GN-PJI to date, since animals can bear weight on the implant, poor osseointegration was associated with biofilm formation, and localized PJI was assessed by various modalities.

CLINICAL RELEVANCE

This model will allow for more reliable testing of novel biofilm-targeting therapeutics.

Is long time to reimplantation a risk factor for reinfection in two-stage revision for periprosthetic infection? A systematic review of the literature

The two-stage revision arthroplasty is a common treatment option for chronic periprosthetic infection (PJI). The time to reimplantation (TTR) reported in the literature varies substantially from a few days to several hundred days. It is hypothesized that longer TTR could be associated with worse infection control after second stage. A systematic literature search was performed according to Preferred Reporting items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, in Pubmed, Cochrane Library and Web of Science Core Collection in clinical studies published until January 2023. Eleven studies investigating TTR as a potential risk factor for reinfection met the inclusion criteria (ten retrospective and one prospective study, published 2012-2022). Study design and outcome measures differed notably. The cutoff points above which TTR was regarded as "long" ranged from 4 to 18 weeks. No study observed a benefit for long TTR. In all studies, similar or even better infection control was observed for short TTR. The optimal TTR, however, is not yet defined. Larger clinical studies with homogeneous patient populations and adjustment for confounding factors are needed.

Cost Drivers in Two-Stage Treatment of Hip Periprosthetic Joint Infection With an Antibiotic Coated Cement Hip Spacer

BACKGROUND

The current gold standard for treating chronic Periprosthetic Joint Infection (PJI) is a 2-stage revision arthroplasty. There has been little investigation into what specific patient and operative factors may be able to predict higher costs of this treatment.

METHODS

An institutional electronic health record database was retrospectively queried for patients who developed a PJI after a total hip arthroplasty, and underwent removal of the prosthesis and implantation of an antibiotic-impregnated articulating hip cement spacer. Patient demographics, surgical variables, hospital readmissions, emergency department visits, and post-operative complications were collected. Total costs were captured through an internal accounting database through 2 years post-operatively. Negative binomial regressions were utilized for multivariable analyses. A total of 55 hips with PJI were available for cost analyses.

RESULTS

A comorbidity index score was associated with a 70% increase (Odds Ratio (OR): 1.7 [1.18-2.5], P = .003) in total costs at 2-years. Illicit drug use was associated with a 70% increase in costs at 1-year post-operatively (OR 1.7 [1.18-2.5], P = .003). Metal-on-poly liners were associated with a 22% decrease in cost at 2-years post-operatively when compared to Cement-on-Bone articulating spacers, and Metal-on-poly -constrained liners accounted for 38% lower costs at 1-year (OR 0.62 [0.44-0.87], P = .004). Use of an intraoperative extended trochanteric osteotomy was associated with a 46 and 61% increase in cost at 1-year (OR 1.46 [1.14-1.89]) and 2-years (OR 1.61 [1.26-2.07], P < .001) post-operatively.

CONCLUSION

Age, comorbidity index score, drug use, and extended trochanteric osteotomy were associated with increased costs of PJI treatment. This may be used to improve reimbursement models and target areas of cost savings.

Is the routine use of local antibiotics in the management of periprosthetic joint infections justified?

Periprosthetic joint infection (PJI) following total hip and total knee arthroplasty continues to be a leading cause of re-operation and revision arthroplasty. Not only is the treatment of PJI notoriously challenging, but success rates are variable. Regardless of the surgical strategy used, successful management of PJI requires a comprehensive surgical debridement focused at eradicating the underlying biofilm followed by appropriate antimicrobial therapy. Although systemic antimicrobial delivery continues to be a cornerstone in the treatment of PJI, many surgeons have started using local antibiotics to deliver higher concentrations of antibiotics directly into the vulnerable joint and adjacent soft tissues, which often have compromised vascularity. Available evidence on the use of topical powder, bone cement, and calcium sulphate carriers for local delivery of antibiotics during the initial treatment of PJI is limited to studies that are extremely heterogeneous. There is currently no level-1 evidence to support routinely using these products. Further, appropriately powered, prospective studies are needed to quantify the safety and efficacy of antibiotic-located calcium-sulphate carriers to justify their added costs. These products should not encourage surgeons to deviate from best practice guidelines, such as those recommended during the International Consensus Meeting on Musculoskeletal Infections.

Can Technology Assistance be Cost Effective in TKA? A Simulation-Based Analysis of a Risk-prioritized, Practice-specific Framework

BACKGROUND

Robotic, navigated, and patient-specific instrumentation (PSI) TKA procedures have been introduced to improve component placement precision and improve implant survivorship and other clinical outcomes. However, the best available evidence has shown that these technologies are ineffective in reducing revision rates in the general TKA patient population. Nonetheless, it seems plausible that these technologies could be an effective and cost-effective means of reducing revision risk in clinical populations that are at an elevated risk of revision because of patient-specific demographics (such as older age at index surgery, elevated BMI, and being a man). Since clinical trials on this topic would need to be very large, a simulation approach could provide insight on which clinical populations would be the most promising for analysis.

QUESTIONS/PURPOSES

We conducted a simulation-based analysis and asked: (1) Given key demographic parameters characterizing a patient population, together with estimates of the precision achievable with selected forms of technology assistance in TKA, can we estimate the expected distributions of anticipated reductions in lifetime revision risk for that population and the associated improvements in quality-adjusted life years (QALYs) that would be expected to result? (2) Are there realistic practice characteristics (such as combinations of local patient demographics and capital and per-procedure costs) for which applying a per-patient risk-prioritized policy for using technology-assisted TKA could be considered cost-effective based on projected cost savings from reductions in revision rates?

METHODS

We designed simulations of hypothetical practice-specific clinical scenarios, each characterized by patient volume, patient demographics, and technology-assisted surgical technique, using demographic information drawn from other studies to characterize two contrasting simulated clinical scenarios in which the distributions of factors describing patients undergoing TKA place one population at a comparatively elevated risk of revision (elevated-risk population) and the second at a comparatively reduced risk of revision (lower-risk population). We used results from previous systematic reviews and meta-analyses to estimate the implant precision in coronal plane alignment for patient-specific instrumentation, navigated, and robotic technology. We generated simulated TKA patient populations based on risk estimates from large clinical studies, structured reviews, and meta-analyses and calculated the patient-specific reduction in the revision risk and the change in QALYs attributable to the technology-assisted intervention in each of the two simulated clinical scenarios. We also incorporated a sensitivity analysis, incorporating variations in the effect size of deviations from overall coronal alignment on revision risk and difference in health state utilities acquired through a structured review process. We then simulated the outcomes of 25,000 operations per patient using the precisions associated with the conventional TKA technique, the three technology-assisted techniques, and a hypothetical technology-assisted intervention that could consistently deliver perfectly neutral overall coronal alignment, which is unachievable in practice. A risk-prioritized treatment policy was emulated by ordering the simulated patients from the highest to lowest predicted increase in QALYs, such that simulated patients who would see the greatest increase in the QALYs (and therefore the greatest reduction in lifetime revision risk) were the patients to receive technology-assisted TKA intervention in a practice. We used cost estimates acquired through a structured review process and calculated the net added costs of each of the three technology-assisted techniques as a function of the percent utilization (proportion of patients treated with technology assistance in a practice), factoring in fixed costs, per-procedure variable costs, and savings occurring from the prevention of future revision surgery. Finally, we calculated the incremental cost-effectiveness ratio (ICER) and marginal cost-effectiveness ratio (MCER) for each technology-assisted technique for the two clinical scenarios. We then used a Monte Carlo approach to simulate variations in key patient risk, health state, and economic factors as well as to obtain a distribution of estimates for cost-effectiveness. We considered an intervention to be cost effective if either the ICER or MCER values were below USD/QALY 63,000.

RESULTS

For the lower-risk population, the median reduction in the revision risk was 0.9% (0.4% to 2.2%, extrema from the sensitivity analysis) and 1.8% (0.9% to 4.4%) for PSI and robotic TKA, respectively, and 1.9% (1.0% to 4.6%) for ideal TKA. In contrast, the median reduction in the revision risk in the elevated-risk clinical scenario was 2.0% (1.2% to 3.4%) and 4.6% (2.7% to 8.5%) for PSI and robotic TKA and 5.1% (3.0% to 9.4%) for ideal TKA. Estimated differences in the cumulative gain in QALYs attributable to technology-assisted TKA ranged from 0.6 (0.2 to 1.8) to 4.0 (1.8 to 10.0) QALYs per 100 patients, depending on the intervention type and clinical scenario. For PSI, we found treating 15% of patients in the lower-risk population and 77% in the elevated-risk population could meet the threshold for being considered cost effective. For navigated TKA systems offering high alignment precision, we found the intervention could meet this threshold for practice sizes of at least 300 patients per year and a percent utilization of 27% in the lower-risk population. In the elevated-risk population, cost-effectiveness could be achieved in practice volumes as small as 100 patients per year with a percent utilization of at least 6%, and cost savings could be achieved with a percent utilization of at least 45%. We found that robotic TKA could only meet the threshold for being considered cost-effectiveness in the lower-risk population if yearly patient volumes exceeded 600 and for a limited range of percent utilization (27% to 32%). However, in the elevated-risk patient population, robotic TKA with high alignment precision could potentially be cost effective for practice sizes as small as 100 patients per year and a percent utilization of at least 20% if a risk-prioritized treatment protocol were used.

CONCLUSION

Based on these simulations, a selective-use policy for technology-assisted TKA that prioritizes using technology assistance for those patients at a higher risk of revision based on patient-specific factors could potentially meet the cost-effectiveness threshold in selected circumstances (for example, primarily in elevated-risk populations and larger practice sizes). Whether it does meet that threshold would depend significantly on the surgical precision that can be achieved in practice for a given proposed technology as well as on the true local costs of using the proposed technology. We further recommend that any future randomized trials seeking to demonstrate possible effects of technology assistance on revision risk focus on clinical populations that are at higher risk of revision (such as, patient populations that are relatively younger, have higher BMIs, and higher proportions of men).

CLINICAL RELEVANCE

This study suggests that technology assistance is only likely to prove cost effective in selected circumstances rather than in all clinical populations and practice settings. In general, we project that surgical navigation is most likely to prove cost effective in the widest range of circumstances, that PSI may be cost effective or cost neutral in a moderate range of circumstances, and that robotic surgery is only likely to be cost effective in moderately large practices containing patients who are on average at an intrinsically elevated risk of revision.

Strategies to Mitigate and Treat Orthopaedic Device-Associated Infections

Orthopaedic device implants play a crucial role in restoring functionality to patients suffering from debilitating musculoskeletal diseases or to those who have experienced traumatic injury. However, the surgical implantation of these devices carries a risk of infection, which represents a significant burden for patients and healthcare providers. This review delineates the pathogenesis of orthopaedic implant infections and the challenges that arise due to biofilm formation and the implications for treatment. It focuses on research advancements in the development of next-generation orthopaedic medical devices to mitigate against implant-related infections. Key considerations impacting the development of devices, which must often perform multiple biological and mechanical roles, are delineated. We review technologies designed to exert spatial and temporal control over antimicrobial presentation and the use of antimicrobial surfaces with intrinsic antibacterial activity. A range of measures to control bio-interfacial interactions including approaches that modify implant surface chemistry or topography to reduce the capacity of bacteria to colonise the surface, form biofilms and cause infections at the device interface and surrounding tissues are also reviewed.

Risk factors of reinfection after prosthesis removal and antibiotic bone cement spacer implantation for the treatment of periprosthetic joint infection

BACKGROUND

Prosthesis removal and antibiotic bone cement spacer implantation is a very important link in two-stage revision of periprosthetic joint infection (PJI) after artificial joint replacement, which is key to the smooth progress of second-stage revision surgery. There are few reports on the risk factors of reinfection after prosthesis removal and antibiotic bone cement spacer implantation for PJI. This study aimed to investigate the risk factors of reinfection after prosthesis removal and antibiotic bone cement spacer implantation for the treatment of PJI.

METHODS

Clinical data of 40 patients who underwent prosthesis removal and antibiotic bone cement spacer implantation for PJI after arthroplasty in our hospital from January 2013 to July 2019 were retrospectively analyzed. During the follow-up period of at least 2 years, 21 patients underwent complete two-stage revision after the removal of the antibiotic bone cement spacer, and 19 patients did not receive a new prosthesis due to other factors, such as reinfection or the patient's wishes, record the infection control of patients during the treatment. Reinfection after prosthesis removal and antibiotic bone cement spacer implantation was defined as failure of effective control of infection, symptoms of reinfection, requires increased antibiotic therapy or reoperation. Multivariate Cox proportional hazards model was used to analyze the risk factors associated with reinfection after prosthesis removal and antibiotic bone cement spacer implantation.

RESULTS

Of the 40 patients, nine (22.5%) developed reinfection after prosthesis removal and antibiotic bone cement spacer implantation with a mean follow-up duration of 31 months, and multivariate analysis revealed that history of prior revision surgery (hazard ratio [HR] = 6.317, confidence interval [CI]: 1.495-26.700; p = 0.012) and presence of sinus tract before treatment (HR = 5.117, 95% CI: 1.199-21.828; p = 0.027) were independent risk factors for reinfection after prosthesis removal and antibiotic bone cement spacer implantation.

CONCLUSION

History of prior revision surgery and presence of sinus tract are two independent risk factors for reinfection in patients with PJI treated with prosthesis removal and antibiotic bone cement spacer implantation.

Decreased serum superoxide dismutase concentration has a high value for the diagnosis of periprosthetic joint infection-a single-center, retrospective study

PURPOSE

As the most serious complication of total knee arthroplasty (TKA), periprosthetic joint infection (PJI) often leads to disastrous consequences. An accurate preoperative diagnosis plays a significant role in saving prostheses and optimizing treatment outcomes. Through this retrospective case-control study, we aimed to investigate the potential of superoxide dismutase (SOD) as a novel serum biomarker in the diagnosis of PJI.

METHODS

We conducted a retrospective review of all patients who underwent TKA and received adequate follow-ups in our hospital from June 2015 to December 2021. A total of 50 patients were enrolled in the PJI group based on the 2018 International Consensus Meeting (ICM) criteria. Besides that, we enrolled 100 patients who underwent TKA in the same period and had a good postoperative course in the control group. Patient characteristics, comorbidities, laboratory results (serum, synovial, and microbial), and intraoperative findings (purulence and histopathology) were documented and compared by univariate analysis. Receiver operating characteristic (ROC) analysis was used to determine the sensitivity, specificity, and diagnostic performance.

RESULTS

The median serum SOD level in the PJI and control group was 135.95 ± 24.47 U/ml (IQR, 111.85-158.30 U/ml) and 173.83 ± 13.9 U/ml (IQR,162.83-183.5 U/ml) (p < 0.05), respectively. With the calculated cutoff of SOD at 149.5U/L, the area under the ROC curve (AUC), sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), were 0.919, 0.72, 0.97, 0.923, and 0.874, respectively. In subgroup analysis, the specificity of SOD in diagnosing culture-negative PJI remained extremely high (0.98). Combined diagnosis of serum SOD and C-reactive protein (CRP) made AUC increase to 0.972.

CONCLUSION

Serum SOD showed great potential in the diagnosis of PJI.

Higher reinfection rate after two-stage revision arthroplasty in patients with refractory diabetes mellitus: a retrospective analysis with a minimum ten-year follow up

Background

Treatment protocols for two-stage revision arthroplasty with diabetes mellitus (DM) have not yet been established. The control of glycated hemoglobin (HbA1c) in two-stage revision arthroplasty is still debated. This study aimed to clarify the importance of preoperative HbA1c levels before each stage of revision arthroplasty and to analyze the risk factors for reinfection.

Methods

Five hundred eighty-eight patients suffered from first-time PJI and was treated in our institute from January 1994 to December 2010 were reviewed. The mean follow-up time was 13.8 (range, 10.2–24.8) years. Patients underwent two-stage revision arthroplasty with DM at presentation were included. The endpoint of the study was reinfection of the revision arthroplasty. Demographic, survivorship, and surgical variables were also analyzed.

Results

Eighty-eight patients were identified and grouped by HbA1c level before the first stage surgery: Groups 1 and 2 had HbA1c levels < 7% and ≥ 7%, respectively. Reinfection was identified in 4.55% (2/44) and 18.18% (8/44) of the patients in Groups 1 and 2, respectively. Survivorship analysis revealed correction of the HbA1c before the final stage of revision arthroplasty as an independent factor (p < 0.001). The identified risks for reinfection were HbA1c levels ≥ 7% before final-stage surgery, ≥ 3 stages of revision arthroplasty, and extended-spectrum beta-lactamase (ESBL)-Escherichia coli PJI.

Conclusion

The HbA1c level before the final stage of revision arthroplasty could affect staged revision arthroplasty outcomes. Therefore, the necessity of postponing the elective final-stage revision arthroplasty procedure for HbA1c control should be further investigated in the future.

Immune checkpoint upregulation in periprosthetic joint infection

Periprosthetic joint infections (PJI) induce an immunosuppressive cytokine profile through an unknown mechanism. Immune checkpoints, like programmed cell death 1 (PD-1) and its ligand (PD-L1), initiate innate immunosuppressive pathways essential for self-tolerance. Several malignancies and chronic infections co-opt these pathways to derive a survival advantage. This study evaluates PD-1/PD-L1 expression in periprosthetic tissue from patients undergoing revision hip or knee arthroplasty for a PJI versus an aseptic failure. PD-1/PD-L1 in the global tissue sample and the high-power microscopic field of maximum expression was analyzed prospectively using immunohistochemistry. Fifteen patients with a PJI (45%) and 16 patients with an aseptic failure (52%) were included. PD-1 expression was uniformly low. Maximum PD-L1 expression was upregulated in patients with a PJI (25%, interquartile range [IQR]: 5%-75%) versus an aseptic failure, (8%, IQR: 1%-48%, p = 0.039). In the PJI cohort, maximum PD-L1 expression was higher among patients who developed a recurrent PJI (68%, IQR: 53%-86% vs. 15%, IQR: 5%-70%, p = 0.039). Patients with global PD-L1 over 5% trended toward a near 22-fold increase in the odds of reinfection (odds ratio [OR]: 21.9, 95% confidence interval [CI]: 0.9-523.5, p = 0.057) and patients with maximum PD-L1 over 20% trended toward a 15-fold increase in the odds of reinfection (OR: 15.0, 95% CI: 0.6-348.9, p = 0.092). These results support immune checkpoint upregulation as a mechanism of PJI-induced local immune dysfunction. Future studies should confirm PD-L1 as a risk factor for reinfection in larger cohorts.

The Cost-Effectiveness of Normal-Saline Pulsed Lavage for Infection Prophylaxis in Total Joint Arthroplasty

Background

Prosthetic joint infection (PJI) is a well-described complication after total joint arthroplasty which imposes a substantial burden of morbidity and mortality on the individual, as well as cost to the health-care system. This study used a break-even analysis to investigate the cost-effectiveness of pulsed saline lavage (PSL) for PJI prophylaxis after a primary total knee arthroplasty (TKA) and total hip arthroplasty (THA).

Methods

An established model was used to calculate the minimum cost-effective absolute risk reduction of PSL for infection prophylaxis after a total joint arthroplasty. Baseline infection rates of TKA and THA and the cost of a revision surgery for PJI were derived from the literature while the cost of PSL implementation was obtained from institutional data.

Results

PSL is cost-effective at an initial infection rate of 1.10%, revision costs of $32,132 for TKA PJI, and a protocol cost of $38.28 if it reduces infection rates by 0.12% or prevents infection in 1 out of 839 patients. PSL is cost-effective at an initial infection rate of 1.63% and a revision cost of $39,713 for THA PJI if it reduces infection rates by 0.10% or prevents infection in 1 out of 1037 patients. The absolute risk reduction needed for economic viability did not change with varying baseline infection rates and did not exceed 0.38% for infection treatment costs as low as $10,000 and remained less than 0.47% even if PSL cost was as high as $150.

Conclusions

The use of PSL is a cost-effective protocol for PJI prophylaxis after TKAs and THAs.

The Cost-Effectiveness of Closed Incisional Negative Pressure Wound Therapy for Infection Prevention after Revision Total Knee Arthroplasty

Recent investigations have shown that closed incisional negative pressure wound therapy (ciNPWT) decreases the rate of postoperative wound complications following revision total knee arthroplasty (TKA). In this study, we used a break-even analysis to determine whether ciNPWT is a cost-effective measure for reducing prosthetic joint infection (PJI) after revision TKA. The cost of ciNPWT, cost of treatment for PJI, and baseline infection rates following revision TKA were collected from institutional data and the literature. The absolute risk reduction (ARR) in infection rate necessary for cost-effectiveness was calculated using break-even analysis. Using our institutional cost of ciNPWT ($600), this intervention would be cost-effective if the initial infection rate of revision TKA (9.0%) has an ARR of 0.92%. The ARR needed for cost-effectiveness remained constant across a wide range of initial infection rates and declined as treatment costs increased. The use of ciNPWT for infection prevention following revision TKA is cost-effective at both high and low initial infection rates, across a broad range of treatment costs, and at inflated product expenses.

The Cost-Effectiveness of Extended Oral Antibiotic Prophylaxis for Infection Prevention After Total Joint Arthroplasty in High-Risk Patients

BACKGROUND

Extended oral antibiotic prophylaxis may decrease rates of prosthetic joint infection (PJI) after total joint arthroplasty (TJA) in patients at high risk for infection. However, the cost-effectiveness of this practice is not clear. In this study, we used a break-even economic model to determine the cost-effectiveness of routine extended oral antibiotic prophylaxis for PJI prevention in high-risk TJA patients.

METHODS

Baseline PJI rates in high-risk patients, the cost of revision arthroplasty for PJI, and the costs of extended oral antibiotic prophylaxis regimens were obtained from the literature and institutional purchasing records. These variables were incorporated in a break-even economic model to calculate the absolute risk reduction (ARR) in infection rate necessary for extended oral antibiotic prophylaxis to be cost-effective. ARR was used to determine the number needed to treat (NNT).

RESULTS

Extended oral antibiotic prophylaxis with Cefadroxil in patients at high risk for PJI was cost-effective at an ARR in baseline infection rate of 0.187% (NNT = 535) and 0.151% (NNT = 662) for TKA and THA, respectively. Cost-effectiveness was preserved with varying costs of antibiotic regimens, PJI treatment costs, and infection rates.

CONCLUSION

The use of extended oral antibiotic prophylaxis may reduce PJI rates in patients at high risk for infection following TJA and appears to be cost-effective. However, the current evidence supporting this practice is limited in quality. The use of extended oral antibiotic prophylaxis should be weighed against the possible development of future antimicrobial resistance, which may change the value proposition.

Microbiological Trends and Antibiotic Susceptibility Patterns in Patients with Periprosthetic Joint Infection of the Hip or Knee over 6 Years

We sought to analyze trends of the causative pathogens and their antibiotic susceptibility patterns in patients with periprosthetic joint infections (PJI) of the hip and knee to get better insights and improve treatment. Retrospective evaluation of all consecutive patients with microbiological detection of a causative pathogen at a tertiary endoprothetic referral center between January 2016 and December 2021 in Germany was performed. Overall, 612 different microorganisms could be detected in 493 patients (hip: n = 293; knee: n = 200). Evaluation did not show a change in the relative abundance of pathogens detected, with coagulase-negative staphylococci (n = 275; 44.9%) found frequently, followed by S. aureus (n = 86; 14.1%), Enterococcus species (n = 57; 9.3%), Streptococcus species (n = 48; 7.8%), and Gram-negative bacteria (n = 80; 13.1%). Evaluation of the antibiotic susceptibilities showed increasing rates of oxacillin-resistant coagulase-negative staphylococci (60.4%; 46.8−76.7%) and piperacillin-tazobactam-resistant Gram-negative bacteria (26.5%; 0−57.1%), although statistically not significant. Resistance of Gram-positive bacteria to vancomycin (<1%) and Gram-negative microorganisms to meropenem (1.25%) remained an exception. In summary, coagulase-negative staphylococci, as the most frequent pathogen, displayed a continuously high rate of oxacillin resistance. For the highest antimicrobial coverage in the case of an empiric therapy/unknown pathogen, vancomycin might be chosen. Level of evidence: IV.

Combination of C-reactive protein and fibrinogen is useful for diagnosing periprosthetic joint infection in patients with inflammatory diseases

BACKGROUND

The screening of periprosthetic joint infection (PJI) in patients with inflammatory diseases before revision arthroplasty remains uncertain. Serum C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), plasma fibrinogen (FIB), monocyte/lymphocyte ratio, and neutrophil/lymphocyte ratio (NLR) can help screening PJI, but their values in patients with inflammatory diseases have not been determined.

METHODS

Patients with inflammatory diseases who underwent revision hip or knee arthroplasty at West China Hospital, Sichuan University, from January 2008 to September 2020 were divided into infected and non-infected groups based on the 2013 International Consensus Meeting criteria. Sensitivity and specificity of the tested biomarkers for diagnosing infection were determined based on receiver operating characteristic (ROC) curves, and optimal cutoffs were determined based on the Youden index. The diagnostic ability of these biomarkers was re-assessed after combining them with each other.

RESULTS

A total of 62 patients with inflammatory diseases were studied; of them 30 were infected. The area under the ROC curve was 0.813 for CRP, 0.638 for ESR, 0.795 for FIB, and 0.656 for NLR. The optimal predictive cutoff of CRP was 14.04 mg/L with a sensitivity of 86.2% and a specificity of 68.7%, while FIB had a sensitivity of 72.4% and a specificity of 81.2% with the optimal predictive cutoff of 4.04 g/L. The combinations of CRP with FIB produced a sensitivity of 86.2% and specificity of 78.1%.

CONCLUSION

CRP with a slightly higher predictive cutoff and FIB are useful for screening PJI in patients with inflammatory diseases, and the combination of CRP and FIB may further improve the diagnostic values.

TRIAL REGISTRATION

ChiCTR.org.cn, ChiCTR2000039989.

Prevention of Orthopedic Prosthetic Infections Using Evidence-Based Surgical Site Infection Care Bundles: A Narrative Review

Background: The number of primary/revision total joint replacements (TJR) are expected to increase substantially with an aging population and increasing prevalence of comorbid conditions. The 30-day re-admission rate, in all orthopedic specialties, is 5.4% (range, 4.8%-6.0%). A recent publication has documented that the surgical site infection (SSI) infection rate associated with revision total knee (rTKR, 15.6%) and revision total hip (rTHR, 8.6%) arthroplasties are four to seven times the rate of the primary procedures (2.1%-2.2%). These orthopedic infections prolong hospital stays, double re-admissions, and increase healthcare costs by a factor of 300%. Methods: A search of PubMed/MEDLINE, EMBASE and the Cochrane Library publications, which reported the infection risk after TKR and THR, was undertaken (January 1, 1995 to December 31, 2021). The search also included documentation of evidence-based practices that lead to improved post-operative outcomes. Results: The evidence-based approach to reducing the risk of SSI was grouped into pre-operative, peri-operative, and post-operative periods. Surgical care bundles have existed within other surgical disciplines for more than 20 years, although their use is relatively new in peri-operative orthopedic surgical care. Pre-admission chlorhexidine gluconate (CHG) showers/cleansing, staphylococcal decolonization, maintenance of normothermia, wound irrigation, antimicrobial suture wound closure, and post-operative wound care has been shown to improve clinical outcome in randomized controlled studies and meta-analyses. Conclusions: Evidence-based infection prevention care bundles have improved clinical outcomes in all surgical disciplines. The significant post-operative morbidity, mortality, and healthcare cost, associated with SSIs after TJR can be reduced by introduction of evidence-based pre-operative, intra-operative, and post-operative interventions.

[Preoperative screening for risk factors]

The demographic change and continuously improving healthcare lead to increasing numbers of older, comorbid patients in elective orthopedic surgery. Perioperative risk assessment is crucial for patient counseling and preoperative planning. Risk factors, such as heart failure, chronic obstructive pulmonary disease, peripheral arterial occlusive disease, anemia, malnutrition, obesity, smoking and insufficiently controlled diabetes mellitus are common in patients undergoing elective orthopedic surgery. A thorough and early screening not only enables the individual assessment of the risk profile but in an elective setting also enables the chance for modification of certain risk factors in order to reduce the individual perioperative risk. Meanwhile, recommendations regarding risk stratification and adjustment of modifiable risk factors are included in national guidelines on the indications for elective total hip arthroplasty.

Methodological Challenges in Predicting Periprosthetic Joint Infection Treatment Outcomes: A Narrative Review

The management of periprosthetic joint infection (PJI) generally requires both surgical intervention and targeted antimicrobial therapy. Decisions regarding surgical management–whether it be irrigation and debridement, one-stage revision, or two-stage revision–must take into consideration an array of factors. These include the timing and duration of symptoms, clinical characteristics of the patient, and antimicrobial susceptibilities of the microorganism(s) involved. Moreover, decisions relating to surgical management must consider clinical factors associated with the health of the patient, alongside the patient's preferences. These decisions are further complicated by concerns beyond mere eradication of the infection, such as the level of improvement in quality of life related to management strategies. To better understand the probability of successful surgical treatment of a PJI, several predictive tools have been developed over the past decade. This narrative review provides an overview of available clinical prediction models that aim to guide treatment decisions for patients with periprosthetic joint infection, and highlights key challenges to reliably implementing these tools in clinical practice.

Microbiological Profiles of Patients with Periprosthetic Joint Infection of the Hip or Knee

Periprosthetic joint infections (PJI) are one of the most devastating consequences after total joint arthroplasty. We sought to analyze the causative pathogens of patients with PJI to get better insights and improve treatment. We performed a retrospective study of all patients with PJI of the hip and knee with microbiological detection of a causative pathogen at a tertiary endoprothetic referral center between January 2016 and March 2021. A total of 432 cases with PJI (hip: n = 250; knee: n = 182) were included. The most common causative pathogen were coagulase-negative staphylococci (n = 240; 44.2%), of which Staphylococcus epidermidis (n = 144; 26.7%) was the most frequently detected, followed by S. aureus (n = 77; 14.3%) and enterococci (n = 49; 9%). Gram-negative pathogens and fungi could be detected in 21% (n = 136) and 2.4% (n = 13) of all cases. Overall, 60% of all coagulase-negative staphylococci were oxacillin-resistant, while none of these displayed to be vancomycin-resistant. In summary, the majority of pathogens in cases of PJI could be identified as coagulase-negative staphylococci. For empirical therapy vancomycin might provide the highest antimicrobial coverage in case of an unknown pathogen.

Vancomycin Containing PDLLA and PLGA/β-TCP Inhibit Biofilm Formation but Do Not Stimulate Osteogenic Transformation of Human Mesenchymal Stem Cells

Aims

Chronic osteomyelitis, including implant-related prosthetic joint infection, is extremely difficult to cure. We develop vancomycin containing release systems from poly(d,l-lactide) (PDLLA) and poly(d,l-lactide-co-glycolide) (PLGA) composites with beta-tricalcium phosphate (β-TCP) to treat methicillin-resistant Staphylococcus aureus osteomyelitis. We ask whether vancomycin containing PDLLA/β-TCP and PLGA/β-TCP composites will prevent early biofilm formation, allow cell proliferation and osteogenic differentiation, and stimulate osteogenic signaling molecules in the absence of an osteogenic medium.

Methods

Composites were produced and characterized with scanning electron microscopy. In vitro vancomycin release was assessed for 6 weeks. Biofilm prevention was calculated by crystal violet staining. Human bone marrow-derived mesenchymal stem cells (hBM-MSCs) and osteosarcoma cell (SaOS-2) proliferation and differentiation were assessed with water soluble tetrazolium salt and alkaline phosphatase (ALP) staining. Real-time quantitative polymerase chain reaction defined osteogenic signaling molecules for hBM-MSCs.

Results

Totally, 3.1 ± 0.2 mg and 3.4 ± 0.4 mg vancomycin released from PDLLA/β-TCP and the PLGA/β-TCP composites, respectively, and inhibited early biofilm formation. hBM-MSCs and SaOS-2 cells proliferated on the composites and stimulated ALP activity of cells. Runt-related transcription factor 2 (RUNX2) and SRY-Box transcription Factor 9 (SOX9) expressions were, however, lower with composites when compared with control.

Conclusion

Vancomycin containing PDLLA/β-TCP and PLGA/β-TCP composites inhibited early biofilm formation and proliferated and differentiated hBM-MSCs and SaOS-2 cells, but osteogenesis-related RUNX2 and SOX9 transcription factors were not strongly expressed in the absence of an osteogenic medium for 14 days.

Use of antibiotic-cement coated locking plates in the setting of periprosthetic infection and infected nonunion

INTRODUCTION

In the setting of periprosthetic total hip and knee arthroplasty (THA/TKA) infection, plating of the femur may be necessary for fracture fixation, prophylactic fixation of the femur, poor bone quality, or infected femoral shaft nonunion. The purpose of this study was to investigate infection control rates and fracture healing in patients receiving antibiotic cement coated plates in the setting of infected nonunion and periprosthetic infections.

METHODS

We retrospectively reviewed a series of ten patients who had an antibiotic coated plate placed in the setting of periprosthetic infection or infected nonunion with a minimum follow-up of six months. 80 g of Simplex bone cement (Stryker, Mahwah, NJ) were mixed with 4 g of powdered vancomycin and 4.8 g of powdered tobramycin and applied to a dynamic compression plate with locking screw guides in every hole. The antibiotic loaded cement was allowed to harden before implantation. Outcome measures were designed to assess for fracture healing defined as three out of four cortices united on radiographs along with bearing full weight without pain and evidence of infection control defined as normalized erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) in the absence of antibiotic treatment with no clinical signs of infection.

RESULTS

Ten patients were treated with an antibiotic cement coated plate in the settings of infectious nonunion and periprosthetic infection and followed for an average of three years (mean 21.4 months, seven months to 61 months). Eight patients (80%) went on to successful control of infection after initial procedure. Two patients developed chronic drainage and had a second antibiotic spacer with antibiotic cement coated plate placed before the infection was controlled. All patients obtained successful control of infection at latest follow-up showing no clinical signs of infection, normalized laboratory markers, and negative culture results. There were no reported mechanical failures of the implant, fractures of the femur, or soft tissue complications.

CONCLUSION

An antibiotic cement coated plating technique is a viable option for periprosthetic THA and TKA infections requiring plating of the femur or in patients with an infected nonunion.

Systematic Review and Meta-Analysis of Intrawound Vancomycin in Total Hip and Total Knee Arthroplasty: A Continued Call for a Prospective Randomized Trial

BACKGROUND

Periprosthetic joint injection (PJI) is a rare, but life-altering complication of total joint arthroplasty (TJA). Though intrawound vancomycin powder (IVP) has been studied in other orthopedic subspecialties, its efficacy and safety in TJA has not been established.

METHODS

PubMed and MEDLINE databases were used to identify studies utilizing IVP in primary and revision total hip (THA) and knee arthroplasty (TKA). Postoperative PJI data were pooled using random effect models with results reported as odds ratios (ORs) and 95% confidence intervals (CIs). Studies were weighted by the inverse variance of their effect estimates.

RESULTS

Overall, 16 of the 1871 studies identified were pooled for final analysis, yielding 33,731 patients totally. Of these, 17 164 received IVP. In aggregate, patients who received IVP had a decreased rate of PJI (OR 0.46, P < .05). Separately, TKA and THA patients who received IVP had lower rates of PJI (OR 0.41, P < .05 and OR 0.45, P < .05, respectively). Aggregate analysis of primary TKA and THA patients also revealed a decreased PJI rate (OR 0.44, P < .05). Pooled revision TKA and THA patients had a similar decrease in PJI rates (OR 0.30, P < .05). Although no publication bias was appreciated, these findings are limited by the low-quality evidence available.

CONCLUSION

While IVP may reduce the risk of PJI in primary and revision TJA, its widespread use cannot be recommended until higher-quality data, such as that obtained from randomized control trials, are available. This study underscores the continued need for more rigorous studies before general adoption of this practice by arthroplasty surgeons.

The Temporal Impact of Prosthesis Implantation and Semi-Quantitative Criteria on the Diagnostic Efficacy of Triple-Phase Bone Scanning for Periprosthetic Joint Infection

Objective

To evaluate the diagnostic efficacy of triple‐phase bone scanning and the temporal impact of prosthesis implantation on the diagnostic efficacy of triple‐phase bone scanning for periprosthetic joint infection (PJI).

Methods

Patients who were admitted to our hospital for joint pain and dysfunction after total joint arthroplasty between 2014 and 2020 were retrospectively included. Triple‐phase bone scanning was performed, and the blood pool images were evaluated to obtain the semi‐quantitative criteria. The patients were then grouped into six groups according to the time interval from index primary arthroplasty to triple‐phase bone scanning. We examined whether there were significant differences in sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy between the groups.

Results

Overall, 66 patients who underwent total hip arthroplasty (THA) and 74 patients who underwent total knee arthroplasty (TKA) were analyzed. No significant differences were observed between visual analysis and semi‐quantitative measurement in terms of sensitivity, specificity, PPV, NPV, and accuracy. For patients with a time interval from prosthesis implantation to bone scanning of >1 year, visual analysis had a higher PPV (100%) in patients who underwent THA and the use of semi‐quantitative criteria had a higher NPV (85.7%) in patients who underwent TKA.

Conclusion

The semi‐quantitative criteria showed no advantages in the diagnosis of PJI. In addition, triple‐phase bone scanning demonstrated good clinical diagnostic efficacy when the time interval from prosthesis implantation to bone scanning was >1 year.

Scientometric Analysis of the Top 50 Most-Cited Joint Arthroplasty Papers: Traditional vs Altmetric Measures

Background

Material and methods

Results

Conclusion

Factors Associated With the Incidence and Timing of Total Knee Arthroplasty Infection

BACKGROUND

Periprosthetic joint infection (PJI) following total knee arthroplasty remains a challenging clinical problem. This study examined variables related to the incidence and timing of PJI.

METHODS

We retrospectively reviewed 8462 primary total knee arthroplasties performed at our institution between 2006 and 2018 for PJI. The mean follow-up is 3.7 years. Eighty-seven variables including patient-reported diagnoses, demographics, and medications were collected. Time to infection, bacterial organism, success of infection treatment, and variables associated with infection are reported.

RESULTS

PJI occurred in 105 (1.24%) cases. The incidence of infection in the first year was 0.72% and represented 58% of all infections. Multivariate Cox regression revealed males (hazard ratio [HR] = 2.85, 95% confidence interval [CI], 1.69-4.79) and patients with major depression or anxiety (HR = 2.11, 95% CI, 1.21-3.67) were more likely to develop an infection in the first year. After the first year, patients with a history of cellulitis (HR = 3.97, 95% CI, 1.91-8.27) and those taking antiepileptic medications (HR = 3.61, 95% CI, 1.73-7.52) were more likely to develop an infection. Culture-negative infections were more common after one year than before (23% vs 8%, P = .04). Debridement, antibiotics, and implant retention was used in 79% (48/61) of infections in the first year and 55% (24/44) after one year with success rates of 51% and 70%, respectively (P = .16).

CONCLUSION

The majority of infections occur during the first year after surgery. Importantly, patient variables associated with infection are different among infections that occur before and after one year. A multicenter study with a much larger number of infections may allow analysis of more time intervals after surgery.

Mark Coventry Award: Efficacy of Saline Wash Plus Antibiotics Doped Polyvinyl Alcohol (PVA) Composite (PVA-VAN/TOB-P) in a Mouse Pouch Infection Model

BACKGROUND

The efficacy of saline irrigation for treatment of periprosthetic infection (PJI) is limited by the presence of contaminated medical devices. This study evaluated treatment efficacy of locally placed polyvinyl alcohol (PVA)/bioceramic composite doped with vancomycin (PVA-VAN-P) or vancomycin and tobramycin (PVA-VAN/TOB-P) after saline irrigation in a mouse pouch infection model.

METHODS

Sutures were implanted into air pouches of BALB/cJ mice, then inoculated with Staphylococcus aureus. Mice were randomized into 6 groups (n = 6 each): (1) no bacteria; (2) bacteria without saline wash; (3) saline wash only; (4) saline wash + PVA-P; (5) saline wash + PVA-VAN-P, and (6) saline wash + PVA-VAN/TOB-P. After 7 days, pouches were washed with saline alone or with additional injection of 0.2 mL of the composites. Sacrifice occurred 14 days after the washout. Histology was performed on the pouch tissues and bacteria cultures on the washout fluid.

RESULTS

Bacterial culture (optical density) showed that infection persisted after saline irrigation (0.10 ± 0.14) but was effectively eradicated by the addition of PVA-VAN-P (0.05 ± 0.09) and PVA-VAN/TOB-P (0.002 ± 0.003, P < .05). These effects were confirmed by histology. Importantly, no residues of the PVA-P were detected in either the pouch washouts or pouch tissues.

CONCLUSION

PJI is common and problematic, and few innovations have changed clinical practice and/or outcome. Our data confirmed that the effect of saline irrigation was very limited in the presence of contaminated sutures. PVA-VAN/TOB-P was biodegradable, biocompatible, and effective in eradicating bacterial retention after saline irrigation. Application of PVA-VAN/TOB-P after saline irrigation could be an option for treatment of PJI and should be evaluated in future PJI animal models.

Recent Antibiotic Treatment Impacts Serum and Synovial Laboratory Values in Early Periprosthetic Joint Infection Workup

BACKGROUND

Accurately detecting early postoperative periprosthetic joint infection (PJI) following total hip arthroplasty (THA) and total knee arthroplasty (TKA) remains challenging. The purpose of our study was to determine the impact of antibiotics given prior to laboratory evaluation on the reliability of serologic and synovial fluid tests to identify PJI in the early postoperative period.

METHODS

We identified 49,861 primary total hip arthroplasties and total knee arthroplasties performed between 2000 and 2019. Among these patients, 21 hips and 28 knees that underwent arthrocentesis within 12 weeks of their arthroplasty were identified as infected. Patients who had received antibiotics within 2 weeks prior to laboratory evaluation were compared to those who had not. Median values of C-reactive protein, erythrocyte sedimentation rate, synovial white blood cell (WBC) count, synovial neutrophil percentage, and synovial absolute neutrophil count were compared between groups. The false negative rate for detecting PJI using laboratory values was compared using published cutoffs for PJI in the early postoperative period.

RESULTS

Median values of C-reactive protein (105 vs 22 mg/L; P = .006), synovial WBC count (57,591 vs 4,473 cells/μL; P = .003), synovial neutrophil percentage (94% vs 76%; P = .004), and synovial absolute neutrophil count (50,748 vs 2,804 cells/μL; P < .001) were significantly lower in patients who received antibiotics compared to those who did not. False negative rates for detecting PJI were significantly higher for synovial WBC and synovial neutrophil percentage in patients treated with antibiotics compared to untreated patients.

CONCLUSION

False negative rates for detecting early PJI when using published cutoffs were markedly higher in antibiotic-treated patients compared to untreated patients for synovial WBC count and synovial neutrophil percentage.

LEVEL OF EVIDENCE

Level IV retrospective review.

Epidemiology of Revision Total Knee Arthroplasty in the United States, 2012 to 2019

Background

As primary total knee arthroplasty volume continues to increase, so will the number of revision total knee arthroplasty (rTKA) procedures. The purpose of this study is to provide an updated perspective on the incidence, indications, and financial burden of rTKA in the United States.

Material and methods

This was a retrospective epidemiologic analysis using the National Inpatient Sample. International Classification of Diseases ninth and tenth revision codes were used to identify patients who underwent rTKA and create cohorts based on rTKA indications from 2012 to 2019. National and regional trends for length of stay, cost, and discharge location were evaluated.

Results

A total of 505,160 rTKA procedures were identified. The annual number of rTKA procedures increased by 29.6% over the study period (56,490 to 73,205). The top 3 indications for rTKA were aseptic loosening (23.1%), periprosthetic joint infection (PJI) (20.4%), and instability (11.0%). Over the study period, the proportion of patients discharged to skilled nursing facility decreased from 31.7% to 24.1% (P < .001). Hospital length of stay decreased from 4.0 days in 2012 to 3.8 days in 2019 (P < .001). Hospital costs increased by $1300 from $25,730 to $27,077 (P < .001). The proportion of rTKA cases performed at urban academic centers increased (52.1% to 74.3%, P < .001) while that at urban nonacademic centers decreased (39.0% to 19.2%, P < .001).

Conclusion

The top 3 indications for rTKA were aseptic loosening, PJI, and instability, with PJI becoming the most common indication in 2019. These cases are increasingly being performed at urban academic centers and away from urban nonacademic centers.

Level of Evidence

3 (Retrospective cohort study).

Predictors of Staphylococcus Aureus Nasal Colonization in Joint Arthroplasty Patients

Early identification and treatment of Staphylococcus aureus (S. aureus) nasal colonization can reduce the risk of prosthetic joint infection. The purpose of this study was to evaluate patient-specific predictors for S. aureus nasal colonization in total joint arthroplasty patients to aid in preoperative screening protocols. A total of 2,147 arthroplasty patients who were preoperatively screened for S. aureus nasal colonization were retrospectively reviewed. Factors analyzed consisted of procedure type, primary diagnosis, gender, ethnicity, body mass index, the presence of chronic obstructive pulmonary disease, obstructive sleep apnea, hypertension, diabetes mellitus, use of immunosuppression medication, smoking history, and chronic kidney disease. Univariate and multivariate analyses were performed with significance p < 0.05 and 95% confidence intervals. Overall, 3.7% (79) of our cohort tested positive for methicillin-resistant Staphylococcus aureus (MRSA), and 23.2% (493) tested positive for methicillin-sensitive Staphylococcus aureus (MSSA). Independent predictors for MRSA colonization were of Hispanic ethnicity (p = 0.001, odds ratio [OR] 13.98, confidence interval [CI] 2.97-65.76), immunosuppression medication use (p = 0.006, OR 2.82, CI 1.35-5.87), and revision total hip arthroplasty (THA) procedure (p < 0.001, OR 7.51, CI 2.58-21.89). Independent predictors for MSSA colonization were body mass index (BMI) >35 (p = 0.002, OR 1.57, CI 1.19-2.1). Variables were found to be protective against MSSA colonization including female gender (p = 0.012, OR 0.76, CI 0.61-0.94), age 60 to 69 (p = 0.025, OR 0.75, CI 0.58-0.96), and age 70 to 79 (p = 0.002, OR 0.63, CI 0.47-0.84). Age, Hispanic ethnicity, gender, revision THA, use of immunosuppression medication, and elevated BMI were independent risk factors for S. aureus nasal colonization.

Prior Intra-articular Corticosteroid Injection Within 3 Months May Increase the Risk of Deep Infection in Subsequent Joint Arthroplasty: A Meta-analysis

BACKGROUND

Intra-articular injections containing a corticosteroid are used frequently, and periprosthetic joint infection is a serious complication after total joint arthroplasty. There is debate regarding whether intra-articular corticosteroid injections before arthroplasty increase periprosthetic joint infection after surgery.

QUESTIONS/PURPOSES

(1) Does a previous intra-articular corticosteroid injection increase the odds of infection after subsequent hip or knee arthroplasty? (2) Does this risk vary based on how soon before the arthroplasty (such as less than 3 months before surgery) the injection is administered?

METHODS

Using the PubMed, Embase, Cochrane Library, and Web of Science databases from inception to July 2021, we searched for comparative studies in English on patients who received intra-articular corticosteroid injections before arthroplasty and that tracked the frequency of infection after arthroplasty. We extracted data on the risk of infection after subsequent joint arthroplasty. The keywords included "corticosteroid," "steroid," "arthroplasty," "knee replacement," and "hip replacement." Eleven retrospective, comparative studies from four countries were included, of which 10 reported the specific diagnosis criteria and one did not. These articles included data on 173,465 arthroplasties in the hip or knee, as well as of 73,049 injections and 100,416 control patients. The methodologic quality of the included studies was evaluated according to the Newcastle-Ottawa Quality Assessment Scale; the articles' scores ranged from 6 to 7 (the score itself spans 0 to 9, with higher scores representing better study quality). We found no evidence of publication bias based on the Egger test, and tests of heterogeneity generally found heterogeneity, so a random-effects model was used of our meta-analyses. A meta-analysis was performed with Review Manager 5.3 software and Stata version 12.0 software.

RESULTS

Overall, there were no differences in the odds of periprosthetic joint infection between the injection group and the control group among patients who received any kind of injection (odds ratio 1.22 [95% CI 0.95 to 1.58]; p = 0.12). However, in a subgroup analysis, there was a higher OR for postoperative PJI in patients with an intra-articular corticosteroid injection in the knee or hip within 3 months (OR 1.39 [95% CI 1.04 to 1.87]; p = 0.03). There were no differences in the infection risk in patients who had injections between 3 and 6 months before arthroplasty (OR 1.19 [95% CI 0.95 to 1.48]; p = 0.13) or between 6 and 12 months before arthroplasty.

CONCLUSION

The current evidence suggests ipsilateral intra-articular corticosteroid injections within 3 months before arthroplasty were associated with an increased risk of periprosthetic joint infection during subsequent joint arthroplasty. We recommend against performing total joint arthroplasty on a patient who has received an intra-articular corticosteroid injection within 3 months. Further high-quality studies on this topic from registries, national databases, or insurance company data are still required to confirm and extend our findings.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Potential Blood Biomarkers for Diagnosing Periprosthetic Joint Infection: A Single-Center, Retrospective Study

Background: Blood biomarkers are first-line tools for identifying periprosthetic joint infection (PJI). C-reactive protein (CRP) is currently recognized as the standard biomarker for PJI diagnosis. Other recently reported novel biomarkers, including plasma fibrinogen, platelet count, monocyte/lymphocyte ratio (MLR), neutrophil/lymphocyte ratio (NLR), and platelet count/lymphocyte ratio (PLR), have also shown promise in diagnosing PJI. This study aimed to evaluate whether these biomarkers were superior to CRP for identifying PJI. Methods: Patients who underwent revision hip or knee arthroplasty at our hospital from January 2008 to September 2020 were included consecutively and divided into infected and non-infected groups according to the 2013 International Consensus Meeting Criteria. Blood samples were collected preoperatively, and erythrocyte sedimentation rate (ESR), CRP, interleukin-6, fibrinogen, platelet count, MLR, NLR, and PLR were analyzed. The diagnostic values of the tested biomarkers and their combinations were compared with CRP based on the area under the receiver operating characteristic curve (AUC) using the z-test. Classification trees were constructed to explore more accurate combinations of the tested markers for identifying PJI. Results: A total of 543 patients were included, of whom 245 had PJI. Among the tested biomarkers, CRP with a cutoff of 7.39 mg/L showed the highest AUC, which gave a sensitivity of 79.1% and specificity of 86.0%. The AUCs of pairwise combinations of tested markers including CRP also were inferior to CRP itself, as were combinations derived from classification trees. Conclusions: Preoperative serum CRP with a low cutoff may be the best reliable blood biomarker for identifying PJI, and those traditional or novel available blood biomarkers could not further improve the diagnostic ability on the basis of CRP.

Serum calprotectin: a potential biomarker to diagnose chronic prosthetic joint infection after total hip or knee arthroplasty

The preoperative detection of prosthetic joint infection (PJI) prior to revision of total hip or knee arthroplasty is still a challenge. Serum Calprotectin (CP) is a heterodimer of two calcium-binding proteins present in the cytoplasm of neutrophils that is released in inflammatory processes and infections. The objective of this study is to determine the reliability of serum CP in the diagnosis of chronic PJI. 81 patients (40 women, 41 men) that presented a potential indication for revision arthroplasty of the hip (THA; n = 18) or knee (TKA, n = 63) at a single institution were prospectively evaluated. The joints were diagnosed as chronically infected or aseptic based on the musculoskeletal infection society (MSIS) criteria of 2018. Receiver operating characteristics and the Youden's index were used to define an ideal cutoff value. The median serum CP level was significantly higher in the group with chronic PJI (15,120 vs. 4980 ng/ml; p < 0.001) compared to the aseptic cases. The calculated optimal cut-off value was 9910 ng/ml (AUC 0.899, 95% CI 0.830-0.968) with a specificity of 91% and sensitivity of 81%. The present investigation suggests that serum CP has a high specificity and good sensitivity to diagnose chronic PJI after TJA of the knee or hip.

Addressing the Needs of the Rapidly Aging Society through the Development of Multifunctional Bioactive Coatings for Orthopedic Applications

The unprecedented aging of the world's population will boost the need for orthopedic implants and expose their current limitations to a greater extent due to the medical complexity of elderly patients and longer indwelling times of the implanted materials. Biocompatible metals with multifunctional bioactive coatings promise to provide the means for the controlled and tailorable release of different medications for patient-specific treatment while prolonging the material's lifespan and thus improving the surgical outcome. The objective of this work is to provide a review of several groups of biocompatible materials that might be utilized as constituents for the development of multifunctional bioactive coatings on metal materials with a focus on antimicrobial, pain-relieving, and anticoagulant properties. Moreover, the review presents a summary of medications used in clinical settings, the disadvantages of the commercially available products, and insight into the latest development strategies. For a more successful translation of such research into clinical practice, extensive knowledge of the chemical interactions between the components and a detailed understanding of the properties and mechanisms of biological matter are required. Moreover, the cost-efficiency of the surface treatment should be considered in the development process.

Does Surgical Approach for Total Hip Arthroplasty Impact Infection Risk in the Obese Patient? A Systematic Review

This systematic review evaluated the combined effects of obesity and surgical approach on periprosthetic joint infection (PJI) rates after total hip arthroplasty (THA). Wound complication and PJI rates were elevated among patients with body mass index (BMI) of 30 kg/m2 or greater and 35 kg/m2 or greater, respectively, with the direct anterior approach (DAA). A BMI of 30 kg/m2 or greater also increased the risk of PJI with the posterior approach. Patients with BMI of 30 kg/m2 or greater undergoing anterolateral approach THA did not have increased risk of PJI. Patients with elevated BMI (≥30 kg/m2) are at risk for PJI, regardless of approach. Patients undergoing DAA THA who have BMI of 35 kg/m2 or greater may have an increased risk of PJI compared with those undergoing THA with other approaches. [Orthopedics. 2022;45(2):e67-e72.].

Avoidance of intramedullary violation in computer-assisted total knee arthroplasty lowers the incidence of periprosthetic joint infection compared with conventional total knee arthroplasty: A propensity score matching analysis of 5342 cases

BACKGROUND

Conventional total knee arthroplasty (CONV-TKA) inevitably perturbs femoral medullary canal, disturbs medullary micro-architecture and increases blood loss and inflammatory responses. We hypothesized that avoidance of intramedullary violation may lower the incidence of periprosthetic joint infection (PJI). The aim of this study was to verify whether computer-assisted total knee arthroplasty (CAS-TKA) lowers the incidence of PJI as compared with CONV-TKA.

METHODS

A propensity score matching study of 5342 patients who underwent CAS-TKA (n = 1085) or CONV-TKA (n = 4257) for primary osteoarthritis of the knee from 2007 to 2015 in our institute was performed. Patients who underwent CAS-TKA were matched to those who received CONV-TKA at a 1:2 ratio according to demographics and comorbidities. PJI was defined according to the Musculoskeletal Infection Society diagnostic criteria from the 2013 International Consensus Meeting.

RESULTS

After controlling potential risk factors, the use of CAS-TKA resulted in a lower incidence of PJI as compared with CONV-TKA [adjusted hazard ratio (HR), 0.42; 95% confidence interval (CI), 0.18-0.99]. The same trend in PJI reduction was observed with the usage of CAS-TKA under sensitivity testing [HR, 0.33; 95% CI, 0.12-0.95]. The cumulative incidence of PJI was lower in the CAS-TKA group than the CONV-TKA group (log-rank test, p = 0.013).

CONCLUSION

Avoidance of intramedullary violation during TKA may play a pivotal role in lowering the incidence of PJI. The use of CAS-TKA can reduce the incidence of PJI, with a better survival rate in terms of being free of PJI, as compared with CONV-TKA.

[Risk management in orthopedic surgery : Stratification and adjustment of patient-individual risk factors]

Preoperative identification of patients at risk of postoperative complications enables better patient education and surgical planning for the orthopedic surgeon. In addition to demographic and intervention-specific factors, a variety of instruments are available for individual risk assessment. The concept of frailty seems to be promising to identify patients at risk. Modifiable risk factors such as malnutrition, anemia, obesity, smoking, and insufficiently controlled diabetes mellitus are common in elective orthopedic patients. With the use of screening protocols, modifiable risk factors can be identified and optimized preoperatively in order to reduce the individual risk of complications. Recommendations regarding preoperative risk stratification and modification prior to elective hip replacement have meanwhile been incorporated in national guidelines.

The fate of positive intraoperative cultures following conversion total hip arthroplasty

INTRODUCTION

The objectives of this study are to report the rates of positive intraoperative cultures obtained during conversion total hip arthroplasty (THA) according to index surgery, and to describe the natural history of treatment for a consecutive series of patients with unexpected positive intraoperative cultures during conversion THA.

METHODS

We reviewed all patients at 2 institutions undergoing conversion THA from prior open reduction and internal fixation (ORIF) of acetabular and hip fractures or hemiarthroplasty for displaced femoral neck fractures from 2011 to 2018. Intraoperative cultures were taken in 105 patients. Positive intraoperative cultures during conversion were recorded and managed with an infectious diseases consult. The outcomes including PJI at 90 days and 1 year follow-up were documented.

RESULTS

Overall, 19 of 105 patients (18%) undergoing conversion THA had positive intraoperative cultures, with the highest rates in the hemiarthroplasty 7/16 (44%) and acetabular ORIF 9/48 (19%) groups. All 19 patients were initially treated conservatively: 8 received IV antibiotics, 10 received no additional therapy, and 1 received oral antibiotics. 4/9 acetabular fracture conversions developed PJI at 1 year, with 3 requiring multiple irrigation and debridement/polyethylene exchanges to control the infection while the 4th patient required 2-stage exchange. There were no 1-year PJI from any of the other index procedures after conversion. All 7 hemiarthroplasty patients with positive cultures were treated to resolution with 4-8 weeks IV antibiotics alone.

CONCLUSIONS

Patients undergoing conversion THA from prior hip or acetabular fracture have a high rate of positive intraoperative cultures. As such, all patients undergoing conversion THA from prior hip or acetabular fracture fixation should undergo thorough diagnostic workup prior to surgery, and have intraoperative cultures obtained during surgery if infection remains suspicious. Further work should be performed to develop MSIS criteria for preoperative management of patients undergoing conversion THA.

Extended Trochanteric Osteotomy with Intermediate Resection Arthroplasty Is Safe for Use in Two-Stage Revision Total Hip Arthroplasty for Infection

Background: This study sought to compare the results of two-stage revision total hip arthroplasty (THA) for periprosthetic infection (PJI) in patients with and without the use of an extended trochanteric osteotomy (ETO) for removal of a well-fixed femoral stem or cement. Methods: Thirty-two patients who had undergone an ETO as part of a two-stage revision without spacer placement were matched 1:2 with a cohort of sixty-four patients of the same sex and age who had stem removal without any osteotomy. Clinical outcomes including interim revision, reinfection and aseptic failure rates were evaluated. Modified Harris hip scores (mHHS) were calculated. Minimum follow-up was two years. Results: Patients undergoing ETO had a significantly lower rate of interim re-debridement compared to non-ETO patients (0% vs. 14.1%, p = 0.026). Reinfection following reimplantation was similar in both groups (12.5% in ETO patients vs. 9.4% in non-ETO patients, p = 0.365). Revision for aseptic reason was necessary in 12.5% in the ETO group and 14.1% in the non-ETO group (p = 0.833). Periprosthetic femoral fractures were seen in three patients (3.1%), of which all occurred in non-ETO patients. Dislocation was the most common complication, which was equally distributed in both groups (12.5%). The mean mHHS was 37.7 in the ETO group and 37.3 in the non-ETO group, and these scores improved significantly in both groups following reimplantation (p < 0.01). Conclusion: ETO without the use of spacer is a safe and effective method to manage patients with well-fixed femoral stems and for thorough cement removal in two-stage revision THA for PJI. While it might reduce the rate of repeated debridement in the interim period, the use of ETO appears to lead to similar reinfection rates following reimplantation.

Assessment of risk factors for early-onset deep surgical site infection following primary total hip arthroplasty for osteoarthritis

The aim of this study was to determine the incidence, annual trend, and perioperative outcomes and identify risk factors of early-onset (≤90 d) deep surgical site infection (SSI) following primary total hip arthroplasty (THA) for osteoarthritis. We performed a retrospective study using prospectively collected patient-level data from January 2013 to March 2020. The diagnosis of deep SSI was based on the published Centre for Disease Control/National Healthcare Safety Network (CDC/NHSN) definition. The Mann–Kendall trend test was used to detect monotonic trends. Secondary outcomes were 90 d mortality and 90 d readmission. A total of 22 685 patients underwent primary THA for osteoarthritis. A total of 46 patients had a confirmed deep SSI within 90 d of surgery representing a cumulative incidence of 0.2 %. The annual infection rate decreased over the 7-year study period (p=0.026). Risk analysis was performed on 15 466 patients. Risk factors associated with early-onset deep SSI included a BMI > 30 kg m-2 (odds ratio (OR) 3.42 [95 % CI 1.75–7.20]; p<0.001), chronic renal disease (OR, 3.52 [95 % CI 1.17–8.59]; p=0.011), and cardiac illness (OR, 2.47 [1.30–4.69]; p=0.005), as classified by the Canadian Institute for Health Information. Early-onset deep SSI was not associated with 90 d mortality (p=0.167) but was associated with an increased chance of 90 d readmission (p<0.001). This study establishes a reliable baseline infection rate for early-onset deep SSI after THA for osteoarthritis through the use of a robust methodological process. Several risk factors for early-onset deep SSI are potentially modifiable, and therefore targeted preoperative interventions of patients with these risk factors is encouraged.

Detection of Surgical Wrap Defects in the Operating Room Setting

Surgical site infection is a challenging complication that places a significant burden on the patient and the health care system. Emphasis is being placed on the prevention and treatment of surgical site infections. We evaluated the accuracy of identifying surgical wrap defects based on defect size, location, and operating room staff experience. Forty sterilization wraps were divided into 4 separate groups based on the size of the puncture defects created. Defects measuring 1.2 mm, 3.7 mm, and 6.8 mm were compared with a control group of surgical wraps with no defects. Defects were randomly placed on an inner or outer line with circumference of 7 cm or 14 cm, respectively. Twenty operating room staff of varying levels of experience evaluated each wrap for defects. The detection rates for the 1.2-mm, 3.7-mm, and 6.8-mm wraps and the wraps with no defects were 3%, 73%, 80%, and 99%, respectively. A significant difference was seen between the detection rates for the small defects vs all other size defects. No significant difference was seen in detection rate based on the location of defects. The detection rate was higher among staff members with greater than 1 year of experience vs those with less than 1 year of experience. Sterilization wrap defects of all sizes went undetected at very high rates. Small defects of 1.2 mm, which have been shown to allow bacterial contamination, were missed 97% of the time. Operating room staff with more experience detected more defects than those with less than 1 year of experience. Wrap defects may be a source of bacterial contamination that may frequently go unnoticed. [Orthopedics. 2021;44(6):735-e738.].

Predicting the Exception-CRP and Primary Hip Arthroplasty

BACKGROUND

While primary hip arthroplasty is the most common operative procedure in orthopedic surgery, a periprosthetic joint infection is its most severe complication. Early detection and prediction are crucial. In this study, we aimed to determine the value of postoperative C-reactive protein (CRP) and develop a formula to predict this rare, but devastating complication.

METHODS

We retrospectively evaluated 708 patients with primary hip arthroplasty. CRP, white blood cell count (WBC), and several patient characteristics were assessed for 20 days following the operative procedure.

RESULTS

Eight patients suffered an early acute periprosthetic infection. The maximum CRP predicted an infection with a sensitivity and specificity of 75% and 56.9%, respectively, while a binary logistic regression reached values of 75% and 80%. A multinominal logistic regression, however, was able to predict an early infection with a sensitivity and specificity of 87.5% and 78.9%. With a one-phase decay, 71.6% of the postoperative CRP-variance could be predicted.

CONCLUSION

To predict early acute periprosthetic joint infection after primary hip arthroplasty, a multinominal logistic regression is the most promising approach. Including five parameters, an early infection can be predicted on day 5 after the operative procedure with 87.5% sensitivity, while it can be excluded with 78.9% specificity.

Debridement, Antibiotics, and Implant Retention in Periprosthetic Joint Infection: What Predicts Success or Failure?

BACKGROUND

Debridement, antibiotics and implant retention (DAIR) is the treatment of choice for acute postoperative and acute hematogenous periprosthetic joint infection (PJI). There is limited literature on predictive prognostic factors for DAIR. We aim to report the outcomes of DAIR and investigate the predictive prognostic factors.

METHODS

We retrospectively reviewed 106 DAIRs. Failure was defined as requiring removal of TKA implants. Predictive factors that may influence success of DAIR treatment such as age, gender, body mass index, ethnicity, American Society of Anesthesiologists score, comorbidities, preoperative erythrocyte sedimentation rate (ESR) and C-reactive protein, symptom duration, time between total knee arthroplasty and DAIR, cultures, rifampicin use, polyethylene liner change, and antibiotic duration were analyzed.

RESULTS

The success rate of DAIR was 69.8% (74/106 patients). For successes, mean time from DAIR-to-mortality was longer than failures (61.6 ± 42.7 vs 9.75 ± 9.60 months, P = .0150). Methicillin-susceptible Staphylococcus aureus PJI (odds ratio [OR] 3.64, confidence interval [CI] 1.30-10.2, P = .0140) was a significant predictor for failure of DAIR. Higher preoperative ESR correlated to failure (OR 1.02, CI 1.01-1.04, P = .008). In successes, mean ESR was 75.4 (66.1-84.6), whereas mean ESR in failures was 116 (88.3-143) (P = .011). An ESR > 107.5 predicted failure with a sensitivity of 51.5 and specificity of 85.2. ESR > 107.5 correlated to failure (OR 6.60, CI 2.29-19.0, P < .001). Repeat DAIRs were strongly correlated to failure (OR 5.27, CI 1.99-13.9, P < .01).

CONCLUSION

DAIR failure is associated with earlier time to mortality. Repeat DAIRs, elevated ESR > 107.5, and S aureus PJI are associated with treatment failure and 2-stage revision is recommended.

Bacterial DNA screening to characterize surgical site infection risk in orthopaedic patients

Purpose

To provide an initial characterization of relevant bacterial DNA profiles for patients undergoing closed-fracture fixation or total joint arthroplasties.

Patients and methods

Swabs were collected and analyzed using Polymerase Chain Reaction from adult patients undergoing closed-fracture fixation or total shoulder, knee, or hip arthroplasties.

Results

Bacterial DNA profiles varied across the different orthopaedic patient populations, and produced uncharacteristic profile shifts with direct relevance to each clinical infection.

Conclusion

Findings provide a foundational dataset regarding bacterial colonization of relevant anatomic sites that can act as sources of surgical site infections for patients.

Cost of septic and aseptic revision total knee arthroplasty: a systematic review

BACKGROUND

The increasing incidence of primary total knee arthroplasty (TKA) has led to an increase in both the incidence and the cost burden of revision TKA procedures. This study aimed to review the literature on the cost of revision TKA for septic and aseptic causes and to identify the major cost components contributing to the cost burden.

METHODS

We searched MEDLINE (OvidSp), Embase, Web of Science, Cochrane Library, EconLit, and Google Scholar to identify relevant studies. Selection, data extraction and assessment of the risk of bias and cost transparency within the studies were conducted by two independent reviewers, after which the cost data were analysed narratively for 1- or 2-stage septic revision without re-revision; 2-stage septic revision with re-revision; and aseptic revision with and without re-revision, respectively. The major cost components identified in the respective studies were also reported.

RESULTS

The direct medical cost from the healthcare provider perspective for high-income countries for 2-stage septic revision with re-revision ranged from US$66,629 to US$81,938, which can be about 2.5 times the cost of 1- or 2-stage septic revision without re-revision, (range: US$24,027 - US$38,109), which can be about double the cost of aseptic revision without re-revision (range: US$13,910 - US$29,213). The major cost components were the perioperative cost (33%), prosthesis cost (28%), and hospital ward stay cost (22%).

CONCLUSIONS

Septic TKA revision with re-revision for periprosthetic joint infection (PJI) increases the cost burden of revision TKA by 4 times when compared to aseptic single-stage revision and by 2.5 times when compared to septic TKA revision that does not undergo re-revision. Cost reductions can be achieved by reducing the number of primary TKA that develop PJI, avoidance of re-revisions for PJI, and reduction in the length of stay after revision.

TRIAL REGISTRATION

PROSPERO; CRD42020171988 .

Periprosthetic joint infection after primary TKA in the medicare population: How frequently are patients revised at a different hospital?

BACKGROUND

Periprosthetic infection (PJI) after total knee arthroplasty (TKA) places a significant burden on hospitals. We sought to describe the proportion of patients undergoing revision for PJI at a different hospital within one year of primary TKA and whether patient characteristics or hospital volume were associated with this change.

METHODS

Medicare data from 2005 to 2014 was retrospectively reviewed using PearlDiver. All patients over 64 years undergoing revision for PJI within one year of primary TKA were stratified by the revision occurring within 90 days. Hospitals were grouped by annual TKA volume as Low (<50), Medium (51-100), High (101-200), and Very High (>200). Associations of patient characteristics and hospital volume with revision at a different hospital were assessed using Chi-squared tests and Somers' D.

RESULTS

Of 8,337 patients undergoing revision within 90 days of TKA, 1,370 (16%) were revised at a different hospital. Changing hospitals was associated with having primary TKA at a lower volume hospital (24% for low, 15% medium, 12% high, and 12% very high; P < 0.001). Of 7,608 patients undergoing revision between 91 and 365 days, 1,110 (15%) were revised at a different hospital. Changing hospitals was associated with having primary TKA at a lower volume hospital (26% for low, 14% medium, 10% high, and 9% very high; P < 0.001). Changing hospitals was not associated with sex or age.

CONCLUSION

Patients frequently undergo revision for PJI at a different hospital, even within 90 days of TKA. Further research is needed to understand these implications of this care pathway shift.

Complications in the treatment of periprosthetic joint infection of the hip: when do they occur?

Prosthetic joint infection (PJI) is a devastating complication after total hip arthroplasty (THA). The common treatment in the USA is a two-stage exchange which can be associated with significant morbidity and mortality. The purpose of this study was to analyze complications in the treatment course of patients undergoing two-stage exchange for PJI THA and determine when they occur. Methods: We analyzed all patients that underwent two-stage exchange arthroplasty for treatment of PJI after THA from January 2005 to January 2018 at a single institution. Complications were categorized as medical or surgical and divided into interstage and post-reimplantation. Minimum follow-up was 1 year. Success was based on the MusculoSkeletal Infection Society (MSIS) definition. Results: 205 hips (203 patients) underwent first stage of planned two-stage exchange. The median age was 68 (interquartile range (IQR) 18). There were 97 males and 106 females. Overall, 73/205 (38 %) patients had at least one complication during treatment: 13.5 % (25/185) of patients experienced a medical complication and 28.1 % (52/185) a surgical complication; 2.4 % died within 1 year of surgery, and 4.9 % (15/203) had mortality at a median of 2.5 years (IQR 4.9); 27 % of patients had complications during the interstage period, most commonly being recurrence of infection requiring additional surgery (63 %); and 14 % of patients experienced a complication following reimplantation, most commonly persistence or recurrence of infection (59 %). While 92 % of patients that initiated treatment were ultimately reimplanted, only 69 % were infection free at 1 year and required no additional treatment. Conclusions: While two-stage exchanges for PJI in THA have been reported as successful, there are few reports of the complications during the process. In our series, significant numbers of patients experienced complications, often during the interstage period, highlighting the morbidity of this method of treatment.

A break-even analysis of tranexamic acid for prevention of periprosthetic joint infection following total hip and knee arthroplasty

Purpose

Despite the commonplace use of tranexamic acid in total joint arthroplasty, much of the current data regarding its cost-effectiveness examines savings directly related to its hemostatic properties, without considering its protective effect against periprosthetic joint infections. Using break-even economic modeling, we calculated the cost-effectiveness of routine tranexamic acid administration for infection prevention in total joint arthroplasty.

Materials and methods

The cost of intraoperative intravenous tranexamic acid, the cost of revision arthroplasty for periprosthetic joint infections, and the baseline rates of periprosthetic joint infections in patients who did not receive intraoperative tranexamic acid were obtained from the literature and institutional purchasing records. Break-even economic modeling incorporating these variables was performed to determine the absolute risk reduction in infection rate to make routine intraoperative tranexamic acid use economically justified. The number needed to treat was calculated from the absolute risk reduction.

Results

Routine use of intraoperative tranexamic acid is economically justified if it prevents at least 1 infection out of 3125 total joint arthroplasties (absolute risk reduction = 0.032%). Cost-effectiveness was maintained with varying costs of tranexamic acid, infection rates, and periprosthetic joint infection costs.

Conclusion

The routine use of intraoperative tranexamic acid is a highly cost-effective practice for infection prevention in primary and revision total joint arthroplasty. The use of tranexamic acid is warranted across a wide range of costs of tranexamic acid, initial infection rates, and costs of periprosthetic joint infection treatment.

Development and validation of case-finding algorithms to identify prosthetic joint infections after total knee arthroplasty in Veterans Health Administration data

PURPOSE

To determine the positive predictive values (PPVs) of ICD-9, ICD-10, and current procedural terminology (CPT)-based diagnostic coding algorithms to identify prosthetic joint infection (PJI) following knee arthroplasty (TKA) within the United States Veterans Health Administration.

METHODS

We identified patients with: (1) hospital discharge ICD-9 or ICD-10 diagnosis of PJI, (2) ICD-9, ICD-10, or CPT procedure code for TKA prior to PJI diagnosis, (3) CPT code for knee X-ray within ±90 days of the PJI diagnosis, and (4) at least 1 CPT code for arthrocentesis, arthrotomy, blood culture, or microbiologic procedure within ±90 days of the PJI diagnosis date. Separate samples of patients identified with the ICD-9 and ICD-10-based PJI diagnoses were obtained, stratified by TKA procedure volume at each medical center. Medical records of sampled patients were reviewed by infectious disease clinicians to adjudicate PJI events. The PPV (95% confidence interval [CI]) for the ICD-9 and ICD-10 PJI algorithms were calculated.

RESULTS

Among a sample of 80 patients meeting the ICD-9 PJI algorithm, 60 (PPV 75.0%, [CI 64.1%-84.0%]) had confirmed PJI. Among 80 patients who met the ICD-10 PJI algorithm, 68 (PPV 85.0%, [CI 75.3%-92.0%]) had a confirmed diagnosis.

CONCLUSIONS

An algorithm consisting of an ICD-9 or ICD-10 PJI diagnosis following a TKA code combined with CPT codes for a knee X-ray and either a relevant surgical procedure or microbiologic culture yielded a PPV of 75.0% (ICD-9) and 85.0% (ICD-10), for confirmed PJI events and could be considered for use in future pharmacoepidemiologic studies.