Hospital Costs for Unsuccessful Two-Stage Revisions for Periprosthetic Joint Infection.

BACKGROUND: Although 2-stage exchange arthroplasty is the preferred surgical treatment for periprosthetic joint infection (PJI) in the United States, little is known about the risk of complications between stages, mortality, and the economic burden of unsuccessful 2-stage procedures. METHODS: The 2015-2019 Medicare 100% inpatient sample was used to identify 2-stage PJI revisions in total hip and knee arthroplasty patients using procedural codes. We used the Fine and Gray sub-distribution adaptation of the conventional Kaplan-Meier method to estimate the probability of completing the second stage of the 2-stage PJI infection treatment, accounting for death as a competing risk. Hospital costs were estimated from the hospital charges using "cost-to-charge" ratios from Centers for Medicare and Medicaid Services. RESULTS: A total of 5094 total hip arthroplasty and 13,062 total knee arthroplasty patients had an index revision for PJI during the study period. In the first 12 months following the first-stage explantation, the likelihood of completing a second-stage PJI revision was 43.1% (95% confidence interval [CI] 41.7-44.5) for hips and 47.9% (95% CI 47.0-48.8) for knees. Following explantation, 1-year patient survival rates for hip and knee patients were 87.4% (95% CI 85.8-88.9) and 91.4% (95% CI 90.6-92.2), respectively. The median additional cost for hospitalizations between stages was $23,582 and $20,965 per patient for hips and knees, respectively. Hospital volume, Northeast or Midwest region, and younger age were associated with reduced PJI costs (P < .05). CONCLUSION: Although viewed as the most preferred, the 2-stage revision strategy for PJI had less than a 50% chance of successful completion within the first year, and was associated with high mortality rates and substantial costs for treatment failure.

Corrosion Concerns? Trends in Metal-on-Polyethylene Total Hip Arthroplasty Revision Rates and Comparisons Against Ceramic-on-Polyethylene up to 10 Years of Follow-Up.

BACKGROUND: We compared the revision risk between metal-on-polyethylene (MOP) and ceramic-on-polyethylene (COP) total hip arthroplasty patients and evaluated temporal changes in short-term revision risks for MOP patients. METHODS: Primary MOP (n = 9480) and COP (n = 3620) total hip arthroplasties were evaluated from the Medicare data set (October 2005 to December 2015) for revision risk, with up to 10 years of follow-up using multivariate analysis. Temporal change in the short-term revision risk for MOP was evaluated (log-rank and Wilcoxon tests). RESULTS: Revision incidence was 3.8% for COP and 4.3% for MOP. MOP short-term revision risk did not change over time (P ≥ .844 at 1 year and .627 at 2 years). Dislocation was the most common reason for revision (MOP: 23.5%; COP: 24.8%). Overall adjusted revision risks were not different between MOP and COP up to 10 years of follow-up (P ≥ .181). CONCLUSIONS: Concerns with corrosion for metal heads do not appear to result in significantly elevated revision risk for MOP at up to 10 years. Corrosion does not appear as a primary reason for revision compared to other mechanisms.

Are Ceramic Bearings Becoming Cost-Effective for All Patients Within a 90-Day Bundled Payment Period?

BACKGROUND: We analyzed whether the total hospital cost in a 90-day bundled payment period for ceramic-on-polyethylene (C-PE) and ceramic-on-ceramic (COC) total hip arthroplasty (THA) bearings was changing over time, and whether the cost differential between ceramic bearings and metal-on-polyethylene (M-PE) bearings was approaching the previously published tipping point for cost-effectiveness of US$325. METHODS: A total of 245,077 elderly Medicare patients (65+) who underwent primary THA between 2010 and 2015 were identified from the United States Medicare 100% national administrative hospital claims database. The total inpatient cost, calculated up to 90 days after index discharge, was computed using cost-to-charge ratios, and hospital payment was analyzed. The differential total inpatient cost of C-PE and COC bearings, compared to metal-on-polyethylene (M-PE), was evaluated using parametric and nonparametric models. RESULTS: After adjustment for patient and clinical factors, and the year of surgery, the mean hospital cost up to 90 days for primary THA with C-PE or COC was within ±1% of the cost for primary THA with M-PE bearings (P < .001). From the nonparametric analysis, the median total hospital cost was US$296-US$353 more for C-PE and COC than M-PE. Cost differentials were found to decrease significantly over time (P < .001). CONCLUSION: Patient and clinical factors had a far greater impact on the total cost of inpatient THA surgery than bearing selection, even when including readmission costs up to 90 days after discharge. Our findings indicate that the cost-effectiveness thresholds for ceramic bearings relative to M-PE are changing over time and increasingly achievable for the Medicare population.

Are We Winning or Losing the Battle With Periprosthetic Joint Infection: Trends in Periprosthetic Joint Infection and Mortality Risk for the Medicare Population.

BACKGROUND: Periprosthetic joint infection (PJI) is a potentially deadly complication of total joint arthroplasty. This study was designed to address how the incidence of PJI and outcome of treatment, including mortality, are changing in the population over time. METHODS: Primary total hip arthroplasty (THA) and total knee arthroplasty (TKA) patients with PJI from the 100% Medicare inpatient data set (2005-2015) were identified. Cox proportional hazards regression models for risk of PJI after THA/TKA (accounting for competing risks) or risk of all-cause mortality after PJI were adjusted for patient and clinical factors, with year included as a covariate to test for time trends. RESULTS: The unadjusted 1-year and 5-year risk of PJI was 0.69% and 1.09% for THA and 0.74% and 1.38% for TKA, respectively. After adjustment, PJI risk did not change significantly by year for THA (P = .63) or TKA (P = .96). The unadjusted 1-year and 5-year overall survival after PJI diagnosis was 88.7% and 67.2% for THA and 91.7% and 71.7% for TKA, respectively. After adjustment, the risk of mortality after PJI decreased significantly by year for THA (hazard ratio = 0.97; P < .001) and TKA (hazard ratio = 0.97; P < .001). CONCLUSION: Despite recent clinical focus on preventing PJI, we are unable to detect substantial decline in the risk of PJI over time, although mortality after PJI has declined. Because PJI risk appears not to be changing over time, the incidence of PJI is anticipated to scale up proportionately with the demand for THA and TKA, which is projected to increase substantially in the coming decade.

Does Prior Bariatric Surgery Affect Implant Survivorship and Complications Following Primary Total Hip Arthroplasty/Total Knee Arthroplasty?

BACKGROUND: The purpose of this study is to evaluate the impact of prior bariatric surgery on survivorship, outcome, and complications following primary total hip arthroplasty (THA)/total knee arthroplasty (TKA). METHODS: Using the Medicare 5% part B data from 1999 to 2012, we analyzed patients who underwent primary THA (n = 47,895) and primary TKA (n = 86,609). Patients with prior bariatric surgery before arthroplasty were compared to patients with other common metabolic conditions. Kaplan-Meier risk of revision THA/TKA for those with and without bariatric surgery and each of the metabolic bone conditions was calculated. The risk for infection was also evaluated. Regression analysis was used to determine the relative risk of revision at various time intervals for those with and without each of the metabolic conditions. Analysis was also adjusted for the metabolic conditions, age, gender, socioeconomic status, and Charlson comorbidity index. RESULTS: The prevalence of patients with prior bariatric surgery within 24 months of primary THA/TKA was 0.1%. Benchmarked against other common chronic metabolic conditions, bariatric surgery prior to THA was not associated with an increased risk for revision surgery at all measured intervals but positively correlated with increased risk for developing infections. Conversely, patients undergoing primary TKA following bariatric surgery were at increased risk for revision compared to controls but not at increased risk for infection. CONCLUSION: The impact of bariatric surgery prior to elective THA/TKA remains unclear. These patients remain at increased risk for infections following THA and revisions following TKA.

Cancer mortality and quantitative oil production in the Amazon region of Ecuador, 1990-2010.

PURPOSE: Controversy persists over whether cancer risk is increased in communities surrounding oil fields, especially in the Oriente region of Ecuador. This ecologic study uses quantitative exposure data, updated mortality data, and improved statistical methods to study the impact of oil exploration and production activities on cancer mortality rates in the Oriente. METHODS: Cancer mortality rates in the Oriente in 1990 through 2010 were compared between seven cantons with active oil exploration and production as of 1990 and thirteen cantons with little or no such activities. Poisson regression was used to estimate mortality rate ratios (RRs) adjusted for age and sex. In a two-stage analysis, canton-specific log-RRs were regressed against quantitative estimates of cumulative barrels of oil produced and well-years per canton, adjusting for canton-level demographic and socioeconomic factors. RESULTS: Overall and site-specific cancer mortality rates were comparable between oil-producing and non-oil-producing cantons. For overall cancer mortality in males and females combined, the RR comparing oil-producing to non-oil-producing cantons was 0.85 [95 % confidence interval (CI) 0.72-1.00]. For leukemia mortality, the corresponding RR was 0.80 (95 % CI 0.57-1.13). Results also revealed no excess of mortality from acute non-lymphocytic, myeloid, or childhood leukemia. Standardized mortality ratios were consistent with RRs. Canton-specific RRs showed no pattern in relation to oil production volume or well-years. CONCLUSIONS: Results from this first ecologic study to incorporate quantitative measures of oil exploration and production showed no association between the extent of these activities and cancer mortality, including from cancers associated with benzene exposure.

National revision burden for lumbar total disc replacement in the United States: epidemiologic and economic perspectives.

STUDY DESIGN: Retrospective cohort study using a nationally representative inpatient database. OBJECTIVE: To quantify the national revision burden for lumbar total disc replacements (TDRs) in the United States following Food and Drug Administration approval, for comparison with lumbar fusion and other common orthopedic procedures, including hip and knee replacement. SUMMARY OF BACKGROUND DATA: Previous studies of revision lumbar TDR surgery have been based on IDE studies. The epidemiology and costs of TDR revision surgery from a national perspective have not yet been reported. METHODS: The Nationwide Inpatient Sample was used to identify primary and revision TDR and anterior fusion procedures in 2005 and 2006. Surgeries were identified in the Nationwide Inpatient Sample using ICD9-CM codes. The prevalence of TDR and fusion surgery was calculated as a function of age, gender, race, census region, primary payer class, and type of hospital. Average length of stay and total hospitalization costs were also computed for each type of procedure. RESULTS: During the study period, there was a national total of 7172 TDR and 62,731 anterior fusion surgeries, including both primary and revisions. Overall, TDR patients were younger and had less comorbidity than fusion surgery patients. The average revision burden for lumbar TDR and anterior fusion was 11.2% and 5.8%, respectively. The average length of stay for primary lumbar TDR was significantly shorter compared to revision TDR, primary anterior fusion, and revision anterior fusion (P < 0.0001). Both the primary and the revision surgery using the TDR surgery involved significantly lower total hospital costs relative to anterior fusion surgery (P < 0.0001). Including revision, the average costs per TDR procedure were lower than anterior and posterior lumbar fusion. CONCLUSION: Although the revision burden for TDR was significantly higher than fusion surgery, the TDR revision burden fell within the revision burden range of hip and knee replacement, which are generally considered successful and cost-effective procedures. Economically, the higher revision burden for TDRs was offset by lower costs for both the primary as well as the revision procedures relative to fusion.

Cancer mortality and oil production in the Amazon Region of Ecuador, 1990-2005.

OBJECTIVES: To compare cancer mortality rates in Amazon cantons (counties) with and without long-term oil exploration and extraction activities. METHODS: Mortality (1990 through 2005) and population census (1990 and 2001) data for cantons in the provinces of the northern Amazon Region (Napo, Orellana, Sucumbios, and Pastaza), as well as the province with the capital city of Quito (Pichincha province) were obtained from the National Statistical Office of Ecuador, Instituto Nacional del Estadistica y Censos (INEC). Age- and sex-adjusted mortality rate ratios (RR) and 95% confidence intervals (CI) were estimated to evaluate total and cause-specific mortality in the study regions. RESULTS: Among Amazon cantons with long-term oil extraction, activities there was no evidence of increased rates of death from all causes (RR = 0.98; 95% CI = 0.95-1.01) or from overall cancer (RR = 0.82; 95% CI = 0.73-0.92), and relative risk estimates were also lower for most individual site-specific cancer deaths. Mortality rates in the Amazon provinces overall were significantly lower than those observed in Pichincha for all causes (RR = 0.82; 95% CI = 0.81-0.83), overall cancer (RR = 0.46; 95% CI = 0.43-0.49), and for all site-specific cancers. CONCLUSIONS: In regions with incomplete cancer registration, mortality data are one of the few sources of information for epidemiologic assessments. However, epidemiologic assessments in this region of Ecuador are limited by underreporting, exposure and disease misclassification, and study design limitations. Recognizing these limitations, our analyses of national mortality data of the Amazon Region in Ecuador does not provide evidence for an excess cancer risk in regions of the Amazon with long-term oil production. These findings were not consistent or supportive of earlier studies in this region that suggested increased cancer risks.