Economic Considerations

Exploring surgical techniques, patient management approaches, and trends in healthcare along with other important factors that contribute to the economics of total joint arthroplasty.



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Readmisison due to infection following total hip and total knee procedures

Nadine Zawadzki, et al

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  • Readmisison due to infection following total hip and total knee procedures
    Nadine Zawadzki, et al
    Policymakers have expanded readmissions penalty programs to include elective arthroplasties, but little is known about the risk factors for readmissions following these procedures. We hypothesized that infections after total hip arthroplasty (THA) and total knee arthroplasty (TKA) lead to excess readmissions and increased costs. This study aims to evaluate the proportion of readmissions due to infections following THA and TKA.Healthcare Cost andB5:G5 Utilization Project-State Inpatient Databases were used for the study. Procedure codes “8151” and “8154” were used to identify inpatient discharges with THA and TKA in Florida (FL) 2009 to 2013, Massachusetts (MA) 2010 to 2012, and California (CA) 2009 to 2011. Readmission was measured by a Centers for Medicare and Medicaid Services (CMS) validated algorithm. Infections were identified by ICD-9-CM codes: 99859, 99666, 6826, 0389, 486, 4821, 00845, 5990, 48242, 04111, 04112, 04119, 0417, 99591, and 99592. Descriptive analysis was performed.In CA, 4.29% of patients were readmitted with 33.02% of the total readmissions for infection. In FL, 4.7% of patients were readmitted with 33.39% of the readmissions for infection. In MA, 3.92% of patients were readmitted with 35.2% of readmissions for infection. Of the total number of readmissions due to infection, methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible Staphylococcus aureus (MSSA) together accounted for 14.88% in CA, 13.38% in FL, and 13.11% in MA.The rate of infection is similar across all 3 states and is a leading cause for readmission following THA and TKA. Programs to reduce the likelihood of MRSA or MSSA infection would reduce readmissions due to infection.

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  • The Epidemiology of Revision Total Knee Arthroplasty in the United States
    Kevin J. Bozic., Steven M. Kurtz ., Edmund Lau ., Kevin Ong ., Vanessa Chiu ., Thomas P. Vail ., Harry E. Rubash ., Daniel J. Berry
    Understanding the cause of failure and type of revision total knee arthroplasty (TKA) procedures performed in the United States is essential in guiding research, implant design, and clinical decision making in TKA. We assessed the causes of failure and specific types of revision TKA procedures performed in the United States using newly implemented ICD-9-CM diagnosis and procedure codes related to revision TKA data from the Nationwide Inpatient Sample (NIS) database. Clinical, demographic, and economic data were reviewed and analyzed from 60,355 revision TKA procedures performed in the United States between October 1, 2005 and December 31, 2006. The most common causes of revision TKA were infection (25.2%) and implant loosening (16.1%), and the most common type of revision TKA procedure reported was all component revision (35.2%). Revision TKA procedures were most commonly performed in large, urban, nonteaching hospitals in Medicare patients ages 65 to 74. The average length of hospital stay (LOS) for all revision TKA procedures was 5.1 days, and the average total charges were $49,360. However, average LOS, average charges, and procedure frequencies varied considerably by census region, hospital type, and procedure performed.

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  • Determinants of Direct Medical Costs in Primary and Revision Total Knee Arthroplasty
    Maradit Kremers H., Visscher SL., Moriarty JP., Reinalda MS., Kremers WK., Naessens JM., Lewallen DG.
    BACKGROUND: TKA procedures are increasing rapidly, with substantial cost implications. Determining cost drivers in TKA is essential for care improvement and informing future payment models.
    QUESTIONS/PURPOSES: We determined the components of hospitalization and 90-day costs in primary and revision TKA and the role of demographics, operative indications, comorbidities, and complications as potential determinants of costs.
    METHODS: We studied 6475 primary and 1654 revision TKA procedures performed between January 1, 2000, and September 31, 2008, at a single center. Direct medical costs were measured by using standardized, inflation-adjusted costs for services and procedures billed during the 90-day period. We used linear regression models to determine the cost impact associated with individual patient characteristics.
    RESULTS: The largest proportion of costs in both primary and revision TKA, respectively, were for room and board (28% and 23%), operating room (22% and 17%), and prostheses (13% and 24%). Prosthesis costs were almost threefold higher in revision TKA than in primary TKA. Revision TKA procedures for infections and bone and/or prosthesis fractures were approximately 25% more costly than revisions for instability and loosening. Several common comorbidities were associated with higher costs. Patients with vascular and infectious complications had longer hospital stays and at least 80% higher 90-day costs as compared to patients without complications.
    CONCLUSIONS: High prosthesis costs in revision TKA represent a factor potentially amenable to cost containment efforts. Increased costs associated with demographic factors and comorbidities may put providers at financial risk and may jeopardize healthcare access for those patients in greatest need.

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  • The Increasing Financial Burden of Knee Revision Surgery in the United States
    Carlos Lavernia, MD*; David J. Lee, PhD†; and Victor Hugo Hernandez, MD
    The popularity of total knee arthroplasty combined with the aging US population indicates a dramatic increase in revision TKA procedures. Our objective was to project revision surgery costs in the United States, and to estimate the financial burden for hospitals historically under-reimbursed for these complex surgical procedures. Inflation adjusted charge data derived from a series of knee revision surgeries performed by a single surgeon practice (CJL) (n = 100) were applied to population projections of the number of revision surgeries expected for the Medicare population from 2005-2030. The average charge of TKA revision surgery was 73,696 dollars, (Cost was 36,848 dollars) with substantially higher costs for patients undergoing surgery because of deep joint infection, patients receiving a three component exchange, and patients receiving hinged or constrained condylar knee implants. The number of revision procedures is expected to increase from 37,544 in 2005 to 56,918 in 2030. Projected hospital costs for these procedures may exceed 2 billion dollars by 2030. The number of revision knee surgeries may increase by 66% in the next 25 years. Reimbursement rates will not cover hospital costs for this procedure despite recent increases in Medicare payments for revision arthroplasty.

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  • Outpatient Total Knee Arthroplasty Is Associated with Higher Risk of Perioperative Complications
    Armin Arshi, MD, Natalie L. Leong, MD, Anthony D’Oro, BS, Christopher Wang, BS, Zorica Buser, PhD, Jeffrey C. Wang, MD, Kristofer J. Jones, MD, Frank A. Petrigliano, MD, and Nelson F. SooHoo, MD
    BACKGROUND: As concerns regarding health-care expenditure in the U.S. remain at the national forefront, outpatient arthroplasty is an appealing option for carefully selected patient populations. The purpose of this study was to determine the nationwide trends and complication rates associated with outpatient total knee arthroplasty (TKA) in comparison with standard inpatient TKA.
    METHODS: We performed a retrospective review of the Humana subset of the PearlDiver Patient Record Database to identify patients who had undergone TKA (Current Procedural Terminology [CPT] code 27447) as either outpatients or inpatients from 2007 to 2015. The incidence of perioperative medical and surgical complications was determined by querying for relevant International Classification of Diseases, Ninth Revision (ICD-9) and CPT codes. Multivariate logistic regression analysis adjusted for age, sex, and Charlson Comorbidity Index (CCI) was used to calculate odds ratios (ORs) of complications among outpatients relative to inpatients treated with TKA.
    RESULTS: Cohorts of 4,391 patients who underwent outpatient TKA and 128,951 patients who underwent inpatient TKA were identified. The median age was in the 70 to 74-year age group in both cohorts. The incidence of outpatient TKA increased across the study period (R = 0.60, p = 0.015). After adjustment for age, sex, and CCI, outpatient TKAs were found to more likely be followed by tibial and/or femoral component revision due to a noninfectious cause (OR = 1.22, 95% confidence interval [CI] = 1.01 to 1.47; p = 0.039), explantation of the prosthesis (OR = 1.35, CI = 1.07 to 1.72; p = 0.013), irrigation and debridement (OR = 1.50, CI = 1.28 to 1.77; p < 0.001), and stiffness requiring manipulation under anesthesia (OR = 1.28, CI = 1.17 to 1.40; p < 0.001) within 1 year. Outpatient TKA was also more frequently associated with postoperative deep vein thrombosis (OR = 1.42, CI = 1.25 to 1.63; p < 0.001) and acute renal failure (OR = 1.13, CI = 1.01 to 1.25; p = 0.026).
    CONCLUSIONS: With the potential to minimize arthroplasty costs among healthy patients, outpatient TKA is an increasingly popular option. Nationwide data from a private insurance database demonstrated a higher risk of perioperative surgical and medical complications including component failure, surgical site infection, knee stiffness, and deep vein thrombosis.

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  • Antibiotic cement was associated with half the risk of re-revision in 1,154 aseptic revision total knee arthroplasties
    Stefano A Bini., Priscilla H Chan., Maria CS Inacio., Elizabeth W Paxton., and Monti Khatod
    Background and purpose Aseptic revisions comprise 80% of revision total knee arthroplasties (TKAs). We determined the incidence of re-revision TKA, the reasons for re-revision, and risk factors associated with these procedures. Patients and methods We conducted a retrospective cohort study of 1,154 patients who underwent aseptic revision TKA between 2002 and 2013 and were followed prospectively by a total joint replacement registry in the USA. Revision was defined as any operation in which an implanted component was replaced. Patient-, surgeon-, and procedure-related risk factors were evaluated. Survival analyses were conducted.
    Results There were 114 re-revisions (10%) with a median time to reoperation of 3.6 years (interquartile range (IQR): 2.6–5.2). The infection rate was 2.9% (34/1,154) and accounted for 30% of re-revisions (34 of 114). In adjusted models, use of antibiotic-loaded cement was associated with a 50% lower risk of all-cause re-revision surgery (hazard ratio (HR) = 0.5, 95% CI: 0.3–0.9), age with a 20% lower risk for every 10-year increase (HR = 0.8, CI: 0.7–1.0), body mass index (BMI) with a 20% lower risk for every 5-unit increase (HR = 0.8, CI: 0.7–1.0), and a surgeon’s greater cumulative experience (≥ 20 cases vs. < 20 cases) with a 3 times higher risk of re-revision (HR = 2.8, CI: 1.5–5).
    Interpretation Revised TKAs were at high risk of subsequent failure. The use of antibiotic-loaded cement, higher age, and higher BMI were associated with lower risk of further revision whereas a higher degree of surgeon experience was associated with higher risk.

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  • Risk Calculators Predict Failures of Knee and Hip Arthroplasties: Findings from a Large Health Maintenance Organization
    Elizabeth W. Paxton., Maria C. S. Inacio., Monti Khatod., Eric Yue., Tadashi Funahashi., Thomas Barber

    Background
    Considering the cost and risk associated with revision Total knee arthroplasty (TKAs) and Total hip arthroplasty (THAs), steps to prevent these operations will help patients and reduce healthcare costs. Revision risk calculators for patients may reduce revision surgery by supporting clinical decision-making at the point of care.

    Questions/purposes
    We sought to develop a TKA and THA revision risk calculator using data from a large health-maintenance organization’s arthroplasty registry and determine the best set of predictors for the revision risk calculator.

    Methods
    Revision risk calculators for THAs and TKAs were developed using a patient cohort from a total joint replacement registry and data from a large US integrated healthcare system. The cohort included all patients who had primary procedures performed in our healthcare system between April 2001 and July 2008 and were followed until January 2014 (TKAs, n = 41,750; THAs, n = 22,721), During the study period, 9% of patients (TKA = 3066/34,686; THA=1898/20,285) were lost to followup and 7% died (TKA= 2350/41,750; THA=1419/20,285). The outcome of interest was revision surgery and was defined as replacement of any component for any reason within 5 years postoperatively. Candidate predictors for the revision risk calculator were limited to preoperative patient demographics, comorbidities, and procedure diagnoses. Logistic regression models were used to identify predictors and the Hosmer-Lemeshow goodness-of-fit test and c-statistic were used to choose final models for the revision risk calculator.

    Results
    The best predictors for the TKA revision risk calculator were age (odds ratio [OR], 0.96; 95% CI, 0.95–0.97; p < 0.001), sex (OR, 0.84; 95% CI, 0.75–0.95; p = 0.004), square-root BMI (OR, 1.05; 95% CI, 0.99–1.11; p = 0.140), diabetes (OR, 1.32; 95% CI, 1.17–1.48; p < 0.001), osteoarthritis (OR, 1.16; 95% CI, 0.84–1.62; p = 0.368), posttraumatic arthritis (OR, 1.66; 95% CI, 1.07–2.56; p = 0.022), and osteonecrosis (OR, 2.54; 95% CI, 1.31–4.92; p = 0.006). The best predictors for the THA revision risk calculator were sex (OR, 1.24; 95% CI, 1.05–1.46; p = 0.010), age (OR, 0.98; 95% CI, 0.98–0.99; p < 0.001), square-root BMI (OR, 1.07; 95% CI, 1.00–1.15; p = 0.066), and osteoarthritis (OR, 0.85; 95% CI, 0.66–1.09; p = 0.190).

    Conclusions
    Study model parameters can be used to create web-based calculators. Surgeons can enter personalized patient data in the risk calculators for identification of risk of revision which can be used for clinical decision making at the point of care. Future prospective studies will be needed to validate these calculators and to refine them with time.

    Level of Evidence
    Level III, prognostic study.

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  • Are There Modifiable Risk Factors for Hospital Readmission After Total Hip Arthroplasty in a US Healthcare System?
    Elizabeth W. Paxton., Maria C. S. Inacio., Jasvinder A. Singh., Rebecca Love., Stefano A. Bini., Robert S. Namba
    BACKGROUND: Although total hip arthroplasty (THA) is a successful procedure, 4% to 11% of patients who undergo THA are readmitted to the hospital. Prior studies have reported rates and risk factors of THA readmission but have been limited to single-center samples, administrative claims data, or Medicare patients. As a result, hospital readmission risk factors for a large proportion of patients undergoing THA are not fully understood.
    QUESTIONS/PURPOSES: (1) What is the incidence of hospital readmissions after primary THA and the reasons for readmission? (2) What are the risk factors for hospital readmissions in a large, integrated healthcare system using current perioperative care protocols?
    METHODS: The Kaiser Permanente (KP) Total Joint Replacement Registry (TJRR) was used to identify all patients with primary unilateral THAs registered between January 1, 2009, and December 31, 2011. The KPTJRR’s voluntary participation is 95%. A logistic regression model was used to study the relationship of risk factors (including patient, clinical, and system-related) and the likelihood of 30-day readmission. Readmissions were identified using electronic health and claims records to capture readmissions within and outside the system. Odds ratio (OR) and 95% confidence intervals (CIs) were calculated. Of the 12,030 patients undergoing primary THAs included in the study, 59% (n = 7093) were women and average patient age was 66.5 years (± 10.7).
    RESULTS: There were 436 (3.6%) patients with hospital readmissions within 30 days of the index procedure. The most common reasons for readmission were infection and inflammatory reaction resulting from internal joint prosthetic (International Classification of Diseases, 9(th) Revision, Clinical Modification [ICD-9-CM] 996.66, 7.0%); other postoperative infection (ICD-9-CM 998:59, 5.5%); unspecified septicemia (ICD-9-CM 038.9, 4.9%); and dislocation of a prosthetic joint (ICD-9-CM 996.42, 4.7%). In adjusted models, the following factors were associated with an increased likelihood of 30-day readmission: medical complications (OR, 2.80; 95% CI, 1.59-4.93); discharge to facilities other than home (OR, 1.89; 95% CI, 1.39-2.58); length of stay of 5 or more days (OR, 1.80; 95% CI, 1.22-2.65) versus 3 days; morbid obesity (OR, 1.74; 95% CI, 1.25-2.43); surgeries performed by high-volume surgeons compared with medium volume (OR, 1.53; 95% CI, 1.14-2.08); procedures at lower-volume (OR, 1.41; 95% CI, 1.07-1.85) and medium-volume hospitals (OR, 1.81; 95% CI, 1.20-2.72) compared with high-volume ones; sex (men: OR, 1.51; 95% CI, 1.18-1.92); obesity (OR, 1.32; 95% CI, 1.02-1.72); race (black: OR, 1.26; 95% CI, 1.02-1.57); increasing age (OR, 1.03; 95% CI, 1.01-1.04); and certain comorbidities (pulmonary circulation disease, chronic pulmonary disease, hypothyroidism, and psychoses).
    CONCLUSIONS: The 30-day hospital readmission rate after primary THA was 3.6%. Modifiable factors, including obesity, comorbidities, medical complications, and system-related factors (hospital), have the potential to be addressed by improving the health of patients before this elective procedure, patient and family education and planning, and with the development of high-volume centers of excellence. Nonmodifiable factors such as age, sex, and race can be used to establish patient and family expectations regarding risk of readmission after THA. Contrary to other studies and the finding of increased hospital volume associated with lower risk of readmission, higher volume surgeons had a higher risk of patient readmission, which may be attributable to the referral patterns in our organization.

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  • Rheumatoid arthritis is associated with higher 90-day Hospital Readmission Rates Compared to Osteoarthritis after Hip or Knee arthroplasty: A cohort study
    Jasvinder A. Singh., Maria C.S. Inacio., Robert S. Namba., and Elizabeth W. Paxton
    OBJECTIVE: To examine whether an underlying diagnosis of rheumatoid arthritis (RA) or osteoarthritis (OA) impacts the 90-day readmission rates after total hip arthroplasty (THA) or total knee arthroplasty (TKA).
    METHODS: We analyzed prospectively collected data from an integrated health care system, Total Joint Replacement Registry, of adults with RA or OA undergoing unilateral primary THA or TKA during 2009-2011. Adjusted logistic regression models for 90-day readmission were fit. Odds ratios with 95% confidence intervals (95% CIs) were calculated. Study year was an effect modifier for the outcome; therefore separate analyses were conducted for each of the 3 study years.
    RESULTS: Of the 34,311 patients, 496 had RA and 33,815 had OA. Comparisons of RA and OA patients, respectively, were 73% and 61% women, 45% and 70% white, and patients had a mean age of 61 versus 67 years (P < 0.001). Crude 90-day readmission rates for RA and OA were 8.5% and 6.7%, respectively. The adjusted odds of 90-day readmission increased from year to year for RA compared to OA patients, from 0.89 (95% CI 0.46-1.71) in 2009 to 1.34 (95% CI 0.69-2.61) in 2010, and to 1.74 (95% CI 1.16-2.60) in 2011. The 2 most common readmission reasons were joint prosthesis infection (10.2%) and septicemia (10.2%) in RA and joint prosthesis infection (5.7%) and other postoperative infection (5.1%) in OA.
    CONCLUSION: RA is a risk factor for 90-day readmission after primary THA or TKA. An increasing risk of readmissions noted in RA in 2011 is concerning and indicates that further studies should examine the reasons for this increasing trend.

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  • Preoperative Patient Profile in Total Hip and Knee Arthroplasty: Predictive of Increased Medicare Payments in a Bundled Payment Model
    Karas V., Kildow Beau J., Baumgartner B., Green C., Attarian D., Bolognesi, M., Seyler T.
    OBJECTIVE: To examine whether an underlying diagnosis of rheumatoid arthritis (RA) or osteoarthritis (OA) impacts the 90-day readmission rates after total hip arthroplasty (THA) or total knee arthroplasty (TKA).
    METHODS: We analyzed prospectively collected data from an integrated health care system, Total Joint Replacement Registry, of adults with RA or OA undergoing unilateral primary THA or TKA during 2009-2011. Adjusted logistic regression models for 90-day readmission were fit. Odds ratios with 95% confidence intervals (95% CIs) were calculated. Study year was an effect modifier for the outcome; therefore separate analyses were conducted for each of the 3 study years.
    RESULTS: Of the 34,311 patients, 496 had RA and 33,815 had OA. Comparisons of RA and OA patients, respectively, were 73% and 61% women, 45% and 70% white, and patients had a mean age of 61 versus 67 years (P < 0.001). Crude 90-day readmission rates for RA and OA were 8.5% and 6.7%, respectively. The adjusted odds of 90-day readmission increased from year to year for RA compared to OA patients, from 0.89 (95% CI 0.46-1.71) in 2009 to 1.34 (95% CI 0.69-2.61) in 2010, and to 1.74 (95% CI 1.16-2.60) in 2011. The 2 most common readmission reasons were joint prosthesis infection (10.2%) and septicemia (10.2%) in RA and joint prosthesis infection (5.7%) and other postoperative infection (5.1%) in OA.
    CONCLUSION: RA is a risk factor for 90-day readmission after primary THA or TKA. An increasing risk of readmissions noted in RA in 2011 is concerning and indicates that further studies should examine the reasons for this increasing trend.

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  • The Increasing Financial Burden of Knee Revision Surgery in the United States
    C Lavernia MD, DJ Lee PhD, VH Hernandez MD
    The popularity of total knee arthroplasty combined with the aging US population indicates a dramatic increase in revision TKA procedures. Our objective was to project revision surgery costs in the United States, and to estimate the financial burden for hospitals historically under-reimbursed for these complex surgical procedures. Inflation adjusted charge data derived from a series of knee revision surgeries performed by a single surgeon practice (CJL) (n = 100) were applied to population projections of the number of revision surgeries expected for the Medicare population from 2005-2030. The average charge of TKA revision surgery was 73,696 dollars, (Cost was 36,848 dollars) with substantially higher costs for patients undergoing surgery because of deep joint infection, patients receiving a three component exchange, and patients receiving hinged or constrained condylar knee implants. The number of revision procedures is expected to increase from 37,544 in 2005 to 56,918 in 2030. Projected hospital costs for these procedures may exceed 2 billion dollars by 2030. The number of revision knee surgeries may increase by 66% in the next 25 years. Reimbursement rates will not cover hospital costs for this procedure despite recent increases in Medicare payments for revision arthroplasty.

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  • Is the Commercial Antibiotic-Loaded Bone Cement Useful in Prophylactic and Cost Saving After Knee and Hip Joint Arthroplasty? The Transatlantic Paradox.
    P Sanz-Ruiz, PhD MD, JA Matas-Diez, MD, M Sanchez-Somolinos, MD, M Villanueva-Martinez PhD, MD, J Vaquero-Martin PhD, MD
    BACKGROUND: The use of antibiotic-loaded bone cement (ALBC) has proven to be effective in preventing periprosthetic infection (PPI) after total hip (THA) and knee arthroplasty (TKA). However, the economic benefit of using ALBC routinely remains controversial.
    METHODS: A total of 2518 patients subjected to THA, partial hip arthroplasty, and TKA between 2009 and 2012 were identified in our prospectively collected registry. Two groups were defined: before (2009-2010) and after the introduction of ALBC (2011-2012). The risks of PPI associated with each type of surgery in each group were determined and compared. Patients subjected to THA without cemented implants were used as controls, and possible bias associated with changes in infection rate during the study period and other variables were controlled. The costs of the use of ALBC were calculated, along with the savings per case of PPI avoided. The minimum follow-up for discarding PPI was 2 years.
    RESULTS: Following the introduction of ALBC, a global decrease of 57% was observed in the risk of PPI (P = .001). By type of surgery, the decrease was 60.6% in the case of TKA (P = .019) and 72.6% in the case of cemented hip arthroplasty (partial and total; P = .009). No decrease in infection rate was noted in uncemented hip arthroplasty (P = .42). The total saving associated with the use of ALBC was €1,123,846 (€992 per patient): €440,412 after TKA (€801 per patient) and €686,644 after cemented hip arthroplasty (€2672 per patient).
    CONCLUSION: The use of ALBC has been found to be effective in preventing PPI after TKA and hip arthroplasty, with a favorable cost-efficiency profile using standardized cost and infection rates in our setting.

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