Effects of fossil fuel and total anthropogenic emission removal on public health and climate.

Anthropogenic greenhouse gases and aerosols are associated with climate change and human health risks. We used a global model to estimate the climate and public health outcomes attributable to fossil fuel use, indicating the potential benefits of a phaseout. We show that it can avoid an excess mortality rate of 3.61 (2.96-4.21) million per year from outdoor air pollution worldwide. This could be up to 5.55 (4.52-6.52) million per year by additionally controlling nonfossil anthropogenic sources. Globally, fossil-fuel-related emissions account for about 65% of the excess mortality, and 70% of the climate cooling by anthropogenic aerosols. The chemical influence of air pollution on aeolian dust contributes to the aerosol cooling. Because aerosols affect the hydrologic cycle, removing the anthropogenic emissions in the model increases rainfall by 10-70% over densely populated regions in India and 10-30% over northern China, and by 10-40% over Central America, West Africa, and the drought-prone Sahel, thus contributing to water and food security. Since aerosols mask the anthropogenic rise in global temperature, removing fossil-fuel-generated particles liberates 0.51(±0.03) °C and all pollution particles 0.73(±0.03) °C warming, reaching around 2 °C over North America and Northeast Asia. The steep temperature increase from removing aerosols can be moderated to about 0.36(±0.06) °C globally by the simultaneous reduction of tropospheric ozone and methane. We conclude that a rapid phaseout of fossil-fuel-related emissions and major reductions of other anthropogenic sources are needed to save millions of lives, restore aerosol-perturbed rainfall patterns, and limit global warming to 2 °C.

Mortality-Air Pollution Associations in Low Exposure Environments (MAPLE): Phase 2.

INTRODUCTION: Mortality is associated with long-term exposure to fine particulate matter (particulate matter ≤2.5 µm in aerodynamic diameter; PM2.5), although the magnitude and form of these associations remain poorly understood at lower concentrations. Knowledge gaps include the shape of concentration-response curves and the lowest levels of exposure at which increased risks are evident and the occurrence and extent of associations with specific causes of death. Here, we applied improved estimates of exposure to ambient PM2.5 to national population-based cohorts in Canada, including a stacked cohort of 7.1 million people who responded to census year 1991, 1996, or 2001. The characterization of the shape of the concentration-response relationship for nonaccidental mortality and several specific causes of death at low levels of exposure was the focus of the Mortality-Air Pollution Associations in Low Exposure Environments (MAPLE) Phase 1 report. In the Phase 1 report we reported that associations between outdoor PM2.5 concentrations and nonaccidental mortality were attenuated with the addition of ozone (O3) or a measure of gaseous pollutant oxidant capacity (Ox), which was estimated from O3 and nitrogen dioxide (NO2) concentrations. This was motivated by our interests in understanding both the effects air pollutant mixtures may have on mortality and also the role of O3 as a copollutant that shares common sources and precursor emissions with those of PM2.5. In this Phase 2 report, we further explore the sensitivity of these associations with O3 and Ox, evaluate sensitivity to other factors, such as regional variation, and present ambient PM2.5 concentration-response relationships for specific causes of death. METHODS: PM2.5 concentrations were estimated at 1 km2 spatial resolution across North America using remote sensing of aerosol optical depth (AOD) combined with chemical transport model (GEOS-Chem) simulations of the AOD:surface PM2.5 mass concentration relationship, land use information, and ground monitoring. These estimates were informed and further refined with collocated measurements of PM2.5 and AOD, including targeted measurements in areas of low PM2.5 concentrations collected at five locations across Canada. Ground measurements of PM2.5 and total suspended particulate matter (TSP) mass concentrations from 1981 to 1999 were used to backcast remote-sensing-based estimates over that same time period, resulting in modeled annual surfaces from 1981 to 2016.Annual exposures to PM2.5 were then estimated for subjects in several national population-based Canadian cohorts using residential histories derived from annual postal code entries in income tax files. These cohorts included three census-based cohorts: the 1991 Canadian Census Health and Environment Cohort (CanCHEC; 2.5 million respondents), the 1996 CanCHEC (3 million respondents), the 2001 CanCHEC (3 million respondents), and a Stacked CanCHEC where duplicate records of respondents were excluded (Stacked CanCHEC; 7.1 million respondents). The Canadian Community Health Survey (CCHS) mortality cohort (mCCHS), derived from several pooled cycles of the CCHS (540,900 respondents), included additional individual information about health behaviors. Follow-up periods were completed to the end of 2016 for all cohorts. Cox proportional hazard ratios (HRs) were estimated for nonaccidental and other major causes of death using a 10-year moving average exposure and 1-year lag. All models were stratified by age, sex, immigrant status, and where appropriate, census year or survey cycle. Models were further adjusted for income adequacy quintile, visible minority status, Indigenous identity, educational attainment, labor-force status, marital status, occupation, and ecological covariates of community size, airshed, urban form, and four dimensions of the Canadian Marginalization Index (Can-Marg; instability, deprivation, dependency, and ethnic concentration). The mCCHS analyses were also adjusted for individual-level measures of smoking, alcohol consumption, fruit and vegetable consumption, body mass index (BMI), and exercise behavior.In addition to linear models, the shape of the concentration-response function was investigated using restricted cubic splines (RCS). The number of knots were selected by minimizing the Bayesian Information Criterion (BIC). Two additional models were used to examine the association between nonaccidental mortality and PM2.5. The first is the standard threshold model defined by a transformation of concentration equaling zero if the concentration was less than a specific threshold value and concentration minus the threshold value for concentrations above the threshold. The second additional model was an extension of the Shape Constrained Health Impact Function (SCHIF), the eSCHIF, which converts RCS predictions into functions potentially more suitable for use in health impact assessments. Given the RCS parameter estimates and their covariance matrix, 1,000 realizations of the RCS were simulated at concentrations from the minimum to the maximum concentration, by increments of 0.1 µg/m3. An eSCHIF was then fit to each of these RCS realizations. Thus, 1,000 eSCHIF predictions and uncertainty intervals were determined at each concentration within the total range.Sensitivity analyses were conducted to examine associations between PM2.5 and mortality when in the presence of, or stratified by tertile of, O3 or Ox. Additionally, associations between PM2.5 and mortality were assessed for sensitivity to lower concentration thresholds, where person-years below a threshold value were assigned the mean exposure within that group. We also examined the sensitivity of the shape of the nonaccidental mortality-PM2.5 association to removal of person-years at or above 12 µg/m3 (the current U.S. National Ambient Air Quality Standard) and 10 µg/m3 (the current Canadian and former [2005] World Health Organization [WHO] guideline, and current WHO Interim Target-4). Finally, differences in the shapes of PM2.5-mortality associations were assessed across broad geographic regions (airsheds) within Canada. RESULTS: The refined PM2.5 exposure estimates demonstrated improved performance relative to estimates applied previously and in the MAPLE Phase 1 report, with slightly reduced errors, including at lower ranges of concentrations (e.g., for PM2.5 <10 µg/m3).Positive associations between outdoor PM2.5 concentrations and nonaccidental mortality were consistently observed in all cohorts. In the Stacked CanCHEC analyses (1.3 million deaths), each 10-µg/m3 increase in outdoor PM2.5 concentration corresponded to an HR of 1.084 (95% confidence interval [CI]: 1.073 to 1.096) for nonaccidental mortality. For an interquartile range (IQR) increase in PM2.5 mass concentration of 4.16 µg/m3 and for a mean annual nonaccidental death rate of 92.8 per 10,000 persons (over the 1991-2016 period for cohort participants ages 25-90), this HR corresponds to an additional 31.62 deaths per 100,000 people, which is equivalent to an additional 7,848 deaths per year in Canada, based on the 2016 population. In RCS models, mean HR predictions increased from the minimum concentration of 2.5 µg/m3 to 4.5 µg/m3, flattened from 4.5 µg/m3 to 8.0 µg/m3, then increased for concentrations above 8.0 µg/m3. The threshold model results reflected this pattern with -2 log-likelihood values being equal at 2.5 µg/m3 and 8.0 µg/m3. However, mean threshold model predictions monotonically increased over the concentration range with the lower 95% CI equal to one from 2.5 µg/m3 to 8.0 µg/m3. The RCS model was a superior predictor compared with any of the threshold models, including the linear model.In the mCCHS cohort analyses inclusion of behavioral covariates did not substantially change the results for both linear and nonlinear models. We examined the sensitivity of the shape of the nonaccidental mortality-PM2.5 association to removal of person-years at or above the current U.S. and Canadian standards of 12 µg/m3 and 10 µg/m3, respectively. In the full cohort and in both restricted cohorts, a steep increase was observed from the minimum concentration of 2.5 µg/m3 to 5 µg/m3. For the full cohort and the <12 µg/m3 cohort the relationship flattened over the 5 to 9 µg/m3 range and then increased above 9 µg/m3. A similar increase was observed for the <10 µg/m3 cohort followed by a clear decline in the magnitude of predictions over the 5 to 9 µg/m3 range and an increase above 9 µg/m3. Together these results suggest that a positive association exists for concentrations >9 µg/m3 with indications of adverse effects on mortality at concentrations as low as 2.5 µg/m3.Among the other causes of death examined, PM2.5 exposures were consistently associated with an increased hazard of mortality due to ischemic heart disease, respiratory disease, cardiovascular disease, and diabetes across all cohorts. Associations were observed in the Stacked CanCHEC but not in all other cohorts for cerebrovascular disease, pneumonia, and chronic obstructive pulmonary disease (COPD) mortality. No significant associations were observed between mortality and exposure to PM2.5 for heart failure, lung cancer, and kidney failure.In sensitivity analyses, the addition of O3 and Ox attenuated associations between PM2.5 and mortality. When analyses were stratified by tertiles of copollutants, associations between PM2.5 and mortality were only observed in the highest tertile of O3 or Ox. Across broad regions of Canada, linear HR estimates and the shape of the eSCHIF varied substantially, possibly reflecting underlying differences in air pollutant mixtures not characterized by PM2.5 mass concentrations or the included gaseous pollutants. Sensitivity analyses to assess regional variation in population characteristics and access to healthcare indicated that the observed regional differences in concentration-mortality relationships, specifically the flattening of the concentration-mortality relationship over the 5 to 9 µg/m3 range, was not likely related to variation in the makeup of the cohort or its access to healthcare, lending support to the potential role of spatially varying air pollutant mixtures not sufficiently characterized by PM2.5 mass concentrations. CONCLUSIONS: In several large, national Canadian cohorts, including a cohort of 7.1 million unique census respondents, associations were observed between exposure to PM2.5 with nonaccidental mortality and several specific causes of death. Associations with nonaccidental mortality were observed using the eSCHIF methodology at concentrations as low as 2.5 µg/m3, and there was no clear evidence in the observed data of a lower threshold, below which PM2.5 was not associated with nonaccidental mortality.

Mortality-Air Pollution Associations in Low-Exposure Environments (MAPLE): Phase 1.

INTRODUCTION: Fine particulate matter (particulate matter ≤2.5 µm in aerodynamic diameter, or PM2.5) is associated with mortality, but the lower range of relevant concentrations is unknown. Novel satellite-derived estimates of outdoor PM2.5 concentrations were applied to several large population-based cohorts, and the shape of the relationship with nonaccidental mortality was characterized, with emphasis on the low concentrations (<12 µg/m3) observed throughout Canada. METHODS: Annual satellite-derived estimates of outdoor PM2.5 concentrations were developed at 1-km2 spatial resolution across Canada for 2000-2016 and backcasted to 1981 using remote sensing, chemical transport models, and ground monitoring data. Targeted ground-based measurements were conducted to measure the relationship between columnar aerosol optical depth (AOD) and ground-level PM2.5. Both existing and targeted ground-based measurements were analyzed to develop improved exposure data sets for subsequent epidemiological analyses.Residential histories derived from annual tax records were used to estimate PM2.5 exposures for subjects whose ages ranged from 25 to 90 years. About 8.5 million were from three Canadian Census Health and Environment Cohort (CanCHEC) analytic files and another 540,900 were Canadian Community Health Survey (CCHS) participants. Mortality was linked through the year 2016. Hazard ratios (HR) were estimated with Cox Proportional Hazard models using a 3-year moving average exposure with a 1-year lag, with the year of follow-up as the time axis. All models were stratified by 5-year age groups, sex, and immigrant status. Covariates were based on directed acyclical graphs (DAG), and included contextual variables (airshed, community size, neighborhood dependence, neighborhood deprivation, ethnic concentration, neighborhood instability, and urban form). A second model was examined including the DAG-based covariates as well as all subject-level risk factors (income, education, marital status, indigenous identity, employment status, occupational class, and visible minority status) available in each cohort. Additional subject-level behavioral covariates (fruit and vegetable consumption, leisure exercise frequency, alcohol consumption, smoking, and body mass index [BMI]) were included in the CCHS analysis.Sensitivity analyses evaluated adjustment for covariates and gaseous copollutants (nitrogen dioxide [NO2] and ozone [O3]), as well as exposure time windows and spatial scales. Estimates were evaluated across strata of age, sex, and immigrant status. The shape of the PM2.5-mortality association was examined by first fitting restricted cubic splines (RCS) with a large number of knots and then fitting the shape-constrained health impact function (SCHIF) to the RCS predictions and their standard errors (SE). This method provides graphical results indicating the RCS predictions, as a nonparametric means of characterizing the concentration-response relationship in detail and the resulting mean SCHIF and accompanying uncertainty as a parametric summary.Sensitivity analyses were conducted in the CCHS cohort to evaluate the potential influence of unmeasured covariates on air pollution risk estimates. Specifically, survival models with all available risk factors were fit and compared with models that omitted covariates not available in the CanCHEC cohorts. In addition, the PM2.5 risk estimate in the CanCHEC cohort was indirectly adjusted for multiple individual-level risk factors by estimating the association between PM2.5 and these covariates within the CCHS. RESULTS: Satellite-derived PM2.5 estimates were low and highly correlated with ground monitors. HR estimates (per 10-µg/m3 increase in PM2.5) were similar for the 1991 (1.041, 95% confidence interval [CI]: 1.016-1.066) and 1996 (1.041, 1.024-1.059) CanCHEC cohorts with a larger estimate observed for the 2001 cohort (1.084, 1.060-1.108). The pooled cohort HR estimate was 1.053 (1.041-1.065). In the CCHS an analogous model indicated a HR of 1.13 (95% CI: 1.06-1.21), which was reduced slightly with the addition of behavioral covariates (1.11, 1.04-1.18). In each of the CanCHEC cohorts, the RCS increased rapidly over lower concentrations, slightly declining between the 25th and 75th percentiles and then increasing beyond the 75th percentile. The steepness of the increase in the RCS over lower concentrations diminished as the cohort start date increased. The SCHIFs displayed a supralinear association in each of the three CanCHEC cohorts and in the CCHS cohort.In sensitivity analyses conducted with the 2001 CanCHEC, longer moving averages (1, 3, and 8 years) and smaller spatial scales (1 km2 vs. 10 km2) of exposure assignment resulted in larger associations between PM2.5 and mortality. In both the CCHS and CanCHEC analyses, the relationship between nonaccidental mortality and PM2.5 was attenuated when O3 or a weighted measure of oxidant gases was included in models. In the CCHS analysis, but not in CanCHEC, PM2.5 HRs were also attenuated by the inclusion of NO2. Application of the indirect adjustment and comparisons within the CCHS analysis suggests that missing data on behavioral risk factors for mortality had little impact on the magnitude of PM2.5-mortality associations. While immigrants displayed improved overall survival compared with those born in Canada, their sensitivity to PM2.5 was similar to or larger than that for nonimmigrants, with differences between immigrants and nonimmigrants decreasing in the more recent cohorts. CONCLUSIONS: In several large population-based cohorts exposed to low levels of air pollution, consistent associations were observed between PM2.5 and nonaccidental mortality for concentrations as low as 5 µg/m3. This relationship was supralinear with no apparent threshold or sublinear association.

A patient's perception of their hospital stay influences the functional outcome and satisfaction of total knee arthroplasty.

INTRODUCTION: To assess whether patient satisfaction with their hospital stay influences the early outcome of total knee arthroplasty (TKA). METHODS: During a 5-year period patients undergoing primary TKA at the study centre had prospective outcome data recorded (n = 2264). The Oxford knee score (OKS) and the short form (SF)-12 were recorded pre-operatively and 1 year post-operatively when satisfaction with their TKA was also assessed. Patient satisfaction with their hospital stay was also evaluated and their reasons for it were qualitatively documented. RESULTS: Decreasing level of satisfaction with their hospital stay was associated with a significantly worse post-operative OKS (p < 0.001) and SF-12 score (p < 0.001). Multivariable regression analysis confirmed that the patient's perceived level of satisfaction with their hospital stay was an independent predictor of change in the OKS (p < 0.001) and SF-12 score (p < 0.006) after adjusting for confounding variables. Patient satisfaction with their TKA was significantly influenced by their hospital experience, decreasing from 96% in those with an excellent experience to 42% in those with a poor experience. Food, staff/care, and the hospital environment were the most frequent reasons of why patients rated their hospital experience as fair or poor. CONCLUSION: A patient's perception of their inpatient hospital experience after surgery is an important modifiable predictor of early functional outcome and satisfaction with TKA.

Post-operative Oxford knee score can be used to indicate whether patient expectations have been achieved after primary total knee arthroplasty.

PURPOSE: The aim of this study was to identify threshold values in the post-operative Oxford knee score (OKS) and change in the score for achievement of specific patient expectations and satisfaction, and whether failure to meet specific patient expectations influenced the rate of satisfaction after total knee arthroplasty (TKA). METHODS: Prospectively complied data for 322 primary TKA were used. Patient demographics, and pre- and post-operative (1 year) OKS, and expectation fulfilment were collected. Patient satisfaction was also assessed 1 year post-operatively. RESULTS: Patient pre-operative expectations varied in prevalence and differed according to gender, age, and severity of knee symptoms according the OKS. Fulfilment of patient expectations was variable and was dependent upon the specific expectation; the majority of patients achieved their expectation of pain relief and improved ability to walk (>70%), however, few fulfilled their expectation to kneel or squat (<25%). The threshold according to the post-operative OKS at which these expectations were achieved varied by more than ten points, ranging from ≥31 for pain relief to ≥42 for kneeling. Failure to fulfil patient expectations, for 15 of the 17 assessed, significantly increased the risk of dissatisfaction at 1 year (p < 0.05). CONCLUSION: The post-operative OKS can be used to predict the point at which the greatest proportion of patient expectations is achieved. Some expectations, however, are rarely fulfilled after a TKA and patients should be made aware of this pre-operatively which may improve their satisfaction post-operatively. LEVEL OF EVIDENCE: Retrospective comparative study, Level III.

Mega prosthetic distal femoral arthroplasty for non-tumour indications: does the indication affect the functional outcome and survivorship?

PURPOSE: To report the functional outcome, implant survival, and patient mortality after mega prosthetic distal femoral arthroplasty according to the surgical indication. METHODS: A prospective database was compiled for 45 consecutive patients undergoing distal femoral arthroplasty, of which 26 had fractures of the distal femur (group 1) and 19 underwent revision of a total knee arthroplasty (group 2). There were 17 males and 28 females with a median age of 74.5 years. Short form (SF)-12 scores were recorded pre-operatively (before the fracture or revision) and 1 year post-operatively, at which point a Toronto Extremity Salvage Score (TESS) was also obtained. Length of hospital stay and return to place of domicile was obtained from the hospital database. Mortality status was obtained from the General Register Office for Scotland. No patient was lost to follow-up. RESULTS: The 1-year physical (52.4) and mental (63.4) components of the SF-12 score and the TESS (70.5 %) did not significantly differ between the groups (n.s.). The fracture group, however, had a longer length of stay (8 vs. 19 days, p = 0.001) and were also less likely to return to their original domicile (odds ratio 9.5, p = 0.02). The overall implant survival rate was 85 % at 5 years, which was worse for the fracture group (80 vs. 90 %, n.s.). The 5-year mortality rate for the revision group was 17 %, whereas the fracture group demonstrated a greater mortality rate of 43 % (n.s.). CONCLUSION: The functional outcome, revision rate, and mortality of patients undergoing distal femoral arthroplasty for non-tumour reasons are not influenced by indication, but patients undergoing surgery for fractures of the distal femur have a longer length of stay and are less likely to return home. Distal femoral arthroplasty should be considered as a management option for non-tumour salvage procedures of the distal femur. LEVEL OF EVIDENCE: Retrospective comparative study, Level III.

Results of the Oxford Phase 3 mobile bearing medial unicompartmental knee arthroplasty from an independent center: 467 knees at a mean 6-year follow-up: analysis of predictors of failure.

A retrospective review of 467 Oxford UKAs was performed in 387 patients. Thirty-eight knees (8.1%) were revised to TKA at a mean of 49 months, most commonly for lateral compartment OA (47%). The 5-year cumulative survival using revision to TKA was 98.5%. Revisions required short stems in 26% and augments in 21% of cases. The mobile bearing dislocation rate was 0.64%. Correction of ≥3-5° from the preoperative alignment in a valgus direction was predictive of revision to TKA (P<.0001). Multivariate analysis revealed female gender (P=.002) also was associated with an increased risk of revision. Careful attention to the degree of mechanical axis correction with an overall maintained varus alignment may reduce revision rates for mobile bearing UKA.

Computer-assisted total knee arthroplasty is currently of no proven clinical benefit: a systematic review.

BACKGROUND: Navigated total knee arthroplasty (TKA) may improve coronal alignment outliers; however, it is unclear whether navigated TKA improves the long-term clinical results of TKA. QUESTIONS/PURPOSES: Does the literature contain evidence of better long-term function and lower revision rates with navigated TKA compared with conventional TKA? METHODS: A systematic literature review was conducted of navigated TKA reviewing articles related to coronal alignment, clinical knee and function scores, cost, patient satisfaction, component rotation, anteroposterior and mediolateral stability, complications, and longer-term reports. RESULTS: Coronal plane alignment is improved with navigated TKA with fewer radiographic outliers. We found limited evidence of improvements in any other variable, and function was not improved. The duration of surgery is increased and there are unique complications related to navigated TKA. The long-term benefits of additional increase in accuracy of alignment are not supported by any current evidence. CONCLUSIONS: The findings in reports of navigated TKA should be interpreted with caution. There are few short- and medium- and no long-term studies demonstrating improved clinical outcomes using navigated TKA. Despite substantial research, contradictory findings coupled with reservations about the cost and efficacy of the technology have contributed to the failure of computer navigation to become the accepted standard in TKA. Longer-term studies demonstrating improved function, lower revision rates, and acceptable costs are required before navigated TKA may be widely adopted. In the future, with improvements in study design, methodology, imaging, navigation technology, newer functional outcome tools, and longer-term followup studies, we suspect that navigated TKA may demonstrate yet unrecognized benefits.

Patient satisfaction after total knee arthroplasty is affected by their general physical well-being.

PURPOSE: We hypothesise that patients with a worse post-operative generic physical health, and those with a subclinical improvement, will have a greater rate of dissatisfaction with their total knee arthroplasty (TKA) despite improvement in their knee function. METHODS: Prospectively complied data for 2,330 primary TKA were used. Patient demographics, comorbidity, and pre- and post-operative (1 year) Oxford knee scores (OKS) and Short Form (SF-) 12 scores were collected. Patient satisfaction was also assessed 1 year post-operatively. The satisfaction rate of patients with a poor post-operative SF-12 physical component summary (PCS score) (≤40 points) and those with a subclinical improvement (<4 points) in the score were compared to those with a score of more than 40 and a clinically significant improvement, respectively. RESULTS: More than half of the patients (n = 1,220) had a poor post-operative SF-12 PCS, and a third (n = 722) had a subclinical improvement in their general physical health after TKA. These patients were more likely to be older in age, suffer with concomitant back pain, and pain in other joints, and have a significantly worse pre-operative mental well-being score (SF-12) and OKS (all p < 0.04 on regression analysis). Both groups had a clinically significant improvement in their OKS post-operatively (p < 0.001), but it was 10 and 8 points less, respectively, than those patients with a SF-12 PCS of more than 40, and a clinical significant improvement in their PCS score (p < 0.001). Logistic regression analysis demonstrated that patients who had a poor post-operative SF-12 PCS (odds ratio 7.9, p < 0.001) and those with a subclinical improvement in their general physical health (odds ratio 5.1, p < 0.001) after TKA were significantly less likely to be satisfied. CONCLUSION: Despite benefitting from a significant improvement in their OKS after TKA, patients with a poor post-operative SF-12 PCS and those with a subclinical improvement in their general physical well-being are significantly less likely to be satisfied at 1 year.

Prophylactic antibiotics do not affect cultures in the treatment of an infected TKA: a prospective trial.

UNLABELLED: Prophylactic antibiotics are frequently withheld until cultures are obtained in revision total knee arthroplasty (TKA). We undertook a prospective study to determine whether prophylactic preoperative intravenous antibiotics would affect the results of cultures obtained intraoperatively. We enrolled 25 patients with 26 infected TKAs, a known preoperative infecting organism, and no recent antibiotic therapy. Reaspiration of the infected TKA was performed after anesthesia and sterile preparation. Intravenous antibiotic prophylaxis was then administered and the tourniquet inflated. Intraoperative culture swabs and tissue were obtained at arthrotomy. The timing of events was recorded. Pre- and postantibiotic culture data were analyzed to determine the effect of intravenous preoperative prophylactic antibiotics on cultures obtained intraoperatively. Infections were acute postoperative (four), chronic (19), and acute hematogenous (three). The most common infecting organism was cloxacillin-sensitive Staphylococcus aureus (nine knees [35%]). Preoperative prophylactic antibiotics did not affect the results of intraoperative cultures and we therefore believe should not be withheld before surgery for an infected TKA when an organism has been identified on aspiration preoperatively, and there has been no recent (4 weeks) antimicrobial therapy. LEVEL OF EVIDENCE: Level II, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.

Sagittal alignment of the cemented femoral component in revision total knee arthroplasty influences the anterior and posterior condylar offset: Stem length does not affect these variables.

BACKGROUND: The position of the femoral component can influence knee kinematics by altering the posterior (PCO) and anterior condylar offset (ACO). The primary aim of this study was to assess whether the length of the cemented stem influences the sagittal position of the femoral component after revision total knee arthroplasty (rTKA). The secondary aim was to determine the influence of the sagittal position on PCO and ACO. METHODS: There were 172 consecutive patients over a seven-year period that underwent rTKA with a cemented semi-constrained prosthesis. The 172 patients were separated into two groups: 115 with short stems (50 mm) and 57 with longer stems (100 or 150 mm). Using rotationally acceptable lateral radiographs, the degree of flexion(+)/extension(-) of the femoral components, PCO, and ACO were measured. RESULTS: There was no significant difference (p > 0.25) between the two groups for sagittal position, PCO, or ACO. The average flexion of the femoral component with short stems was 2.2 ±â€¯4.1° and 2.2 ±â€¯3.4° for long stems (difference = 0.0, 95% confidence intervals (CI) -1.3 to 1.2). The average PCO ratio was 1.02 ±â€¯0.15 for short stems and 0.99 ±â€¯0.17 for long stems (difference = 0.03, 95% CI -0.02 to 0.08). The average ACO ratio was at 0.07 ±â€¯0.08 for short stems and 0.08 ±â€¯0.08 for long stems (difference = 0.01, 95% CI -0.01 to 0.04). There was a significant correlation between sagittal alignment of the femoral component and PCO (flexion increased PCO, r = 0.39, p < 0.0001) and ACO (flexion decreased ACO, r = -0.34, p < 0.0001). CONCLUSIONS: Cemented stem length does not influence the position of femoral component in the sagittal axis, PCO, or ACO. Surgical technique and sizing of the femoral component may be more predictive.

DDT residues: distribution of concentrations in Emerita analoga (stimpson) along coastal California.

The total concentrations (tDDT) of DDT [1,1,1-trichloro-2,2-bis(pchlorophenyl)ethane], DDD [1,1-dichloro-2,2-bis(p-chlorophenyl)ethanel, and DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene] in Emerita analoga from 19 California beaches reflect tDDT contamination nearby. Animals near the Los Angeles County sewer outfall contain over 45 times as much tDDT as animals near major agricultural drainage areas. Sediments near the outfall probably contain over 100 metric tons of tDDT-a reservoir for input into marine organisms. The effluent from a plant that manufactures DDT is a probable source.

Three-dimensional structure of the adenovirus major coat protein hexon.

The three-dimensional crystal structure of the adenovirus major coat protein is presented. Adenovirus type 2 hexon, at 967 residues, is now the longest polypeptide whose structure has been determined crystallographically. Taken with our model for hexon packing, which positions the 240 trimeric hexons in the capsid, the structure defines 60% of the protein within the 150 X 10(6) dalton virion. The assembly provides the first details of a DNA-containing animal virus that is 20 times larger than the spherical RNA viruses previously described. Unexpectedly, the hexon subunit contains two similar beta-barrels whose topology is identical to those of the spherical RNA viruses, but whose architectural role in adenovirus is very different. The hexon structure reveals several distinctive features related to its function as a stable protective coat, and shows that the type-specific immunological determinants are restricted to the virion surface.

Minimal incision surgery as a risk factor for early failure of total knee arthroplasty.

A consecutive series of revision total knee arthroplasty (TKA) performed at 3 centers by 5 surgeons for a 3-year period was reviewed. Revisions performed for infection and rerevisions were excluded. Review of clinical and radiographic data determined incision type, sex, age, time to revision, and primary diagnosis at time of revision. Two-hundred thirty-seven first-time revision TKAs were performed, of which 44 (18.6%) had been a minimal incision surgery (MIS) primary TKA and 193 (81.4%) had been a standard primary TKA. Patients with MIS were younger (62.1 vs 66.2 years, P = .02). Most striking was the difference in time to revision, which was significantly shorter for the MIS group (14.8 vs 80 months, P < .001). Minimal incision surgery TKA accounted for a substantial percentage of revision TKA in recent years at these centers. The high prevalence of MIS failures occurring within 24 months is disturbing and warrants further investigation.

The effects of wildfire severity and pyrodiversity on bat occupancy and diversity in fire-suppressed forests.

Wildfire is an important ecological process that influences species' occurrence and biodiversity generally. Its effect on bats is understudied, creating challenges for habitat management and species conservation as threats to the taxa worsen globally and within fire-prone ecosystems. We conducted acoustic surveys of wildfire areas during 2014-2017 in conifer forests of California's Sierra Nevada Mountains. We tested effects of burn severity and its variation, or pyrodiversity, on occupancy and diversity for the 17-species bat community while accounting for imperfect detection. Occupancy rates increased with severity for at least 6 species and with pyrodiversity for at least 3. Two other species responded negatively to pyrodiversity. Individual species models predicted maximum occupancy rates across burn severity levels but only one species occurred most often in undisturbed areas. Species richness increased from approximately 8 species in unburned forests to 11 in pyrodiverse areas with moderate- to high-severity. Greater accessibility of foraging habitats, as well as increased habitat heterogeneity may explain positive responses to wildfire. Many bat species appear well adapted to wildfire, while a century of fire suppression and forest densification likely reduced habitat quality for the community generally. Relative to other taxa, bats may be somewhat resilient to increases in fire severity and size; trends which are expected to continue with accelerating climate change.

Communication regarding routine childhood vaccination.

Vaccine hesitancy is an emerging problem in South Africa (SA), which threatens to erode the country's immunisation achievements. Communication interventions may be an effective strategy for addressing vaccine hesitancy. We highlight a Cochrane review of qualitative evidence that explored parents' views and experiences of communication regarding childhood vaccinations, and provide implications for practice that are relevant to the SA context. The findings suggest that healthcare providers (HCPs) play a central role in childhood vaccination attitudes and decision-making. Therefore, capacitating HCPs to promote vaccination with confidence is key to effective communication to address vaccine hesitancy in SA.

Early functional outcomes after condylar-stabilizing (deep-dish) versus standard bearing surface for cruciate-retaining total knee arthroplasty.

AIMS: The primary study aim was to compare early knee-specific function of patients undergoing cemented total knee arthroplasty (TKA) with either a cruciate-retaining (CR) polyethylene insert or a highly congruent condylar-stabilizing (CS) insert. Secondary aims were to compare general health and satisfaction between the groups. METHODS: A total of 418 consecutive primary TKAs were identified retrospectively. Demographics and preoperative and 1-year postoperative patient-reported outcome measures (PROMs) were collected prospectively. PROMs consisted of Oxford Knee Scores, EuroQol-5 Dimensions scores, and Short Form-12 scores. RESULTS: A total of 54 (12.9%) patients received a CS insert and 364 patients received a CR TKA. The CS group had a significantly (odds ratio (OR) 2.9; p = 0.002) greater proportion of females (77.8% versus 54.9%). The only significant difference in postoperative PROMs was a higher Short Form-12 physical component score in the CR group (difference 3.1; 95% confidence interval (CI) 0.1 to 6.1; p = 0.04). Linear regression analysis demonstrated no significant difference for all postoperative PROMs (p > 0.25). There was no significant difference in satisfaction rate (OR 0.94; 95% CI 0.42 to 2.12; p = 0.56) or pain visual analogue score (difference 6.1; 95% CI -1.9 to 14.0; p = 0.14) between the groups. CONCLUSION: More congruent CS inserts have equivalent PROMs and patient satisfaction at 1 year compared with less congruent CR inserts. These represent an option for surgeons undertaking TKA where increased congruency is desired.

Patellofemoral arthroplasty versus total knee arthroplasty for patients with patellofemoral osteoarthritis: equal function and satisfaction but higher revision rate for partial arthroplasty at a minimum eight years' follow-up.

AIMS: The primary aim of this study was to compare the knee-specific functional outcome of patellofemoral arthroplasty with total knee arthroplasty (TKA) in the management of patients with patellofemoral osteoarthritis. PATIENTS AND METHODS: A total of 54 consecutive Avon patellofemoral arthroplasties were identified and propensity-score-matched to a group of 54 patients undergoing a TKA with patellar resurfacing for patellofemoral osteoarthritis. The Oxford Knee Score (OKS), the 12-Item Short-Form Health Survey (SF-12), and patient satisfaction were collected at a mean follow up of 9.2 years (8 to 15). Survival was defined by revision or intention to revise. RESULTS: There was no significant difference in the mean OKS (p > 0.60) or SF-12 scores (p > 0.28) between the groups. There was a lower rate of satisfaction at the final follow-up for the TKA group (78% vs 87%) but this was not statistically significant (odds ratio 0.56, p = 0.21). Length of stay was significantly shorter (p = 0.008) for the Avon group (difference 1.8 days, 95% confidence interval (CI) 0.4 to 3.2). The ten-year survival for the Avon group was 92.3% (95% CI 87.1 to 97.5) and for the TKA group was 100% (95% CI 93.8 to 100). This difference was not statistically significant (log-rank test, p = 0.10). CONCLUSION: Patients undergoing an Avon patellofemoral arthroplasty have a shorter length of stay, and a functional outcome and rate of satisfaction that is equal to that of TKA. The benefits of the Avon arthroplasty need to be balanced against the increased rate of revision when compared with TKA.

A panel study in congestive heart failure to estimate the short-term effects from personal factors and environmental conditions on oxygen saturation and pulse rate.

OBJECTIVES: Recent studies suggest that persons with congestive heart failure (CHF) may be at higher risk for short-term effects of air pollution. This daily diary panel study in Montreal, Quebec, was carried out to determine whether oxygen saturation and pulse rate were associated with selected personal factors, weather conditions and air pollution. METHODS: Thirty-one subjects with CHF participated in this study in 2002 and 2003. Over a 2-month period, the investigators measured their oxygen saturation, pulse rate, weight and temperature each morning and recorded these and other data in a daily diary. Air pollution and weather conditions were obtained from fixed-site monitoring stations. The study made use of mixed regression models, adjusting for within-subject serial correlation and temporal trends, to determine the association between oxygen saturation and pulse rate and personal and environmental variables. Depending on the model, we accounted for the effects of a variety of personal variables (eg, body temperature, salt consumption) as well as nitrogen dioxide (NO2), ozone, maximum temperature and change in barometric pressure at 8:00 from the previous day. RESULTS: In multivariable analyses, the study found that oxygen saturation was reduced when subjects reported that they were ill, consumed salt, or drank liquids on the previous day and had higher body temperatures on the concurrent day (only the latter was statistically significant). Relative humidity and decreased atmospheric pressure from the previous day were associated with oxygen saturation. In univariate analyses, there was negative associations with concentrations of fine particulates, ozone, and sulphur dioxide (SO2), but only SO2 was significant after adjustment for the effects of weather. For pulse rate, no associations were found for the personal variables and in univariate analyses the study found positive associations with NO(2), fine particulates (aerodynamic diameter of 2.5 microm or under, PM(2.5)), SO2, and maximum temperature, although only the latter two were significant after adjustment for environmental effects. CONCLUSIONS: The findings from the present investigation suggest that personal and environmental conditions affect intermediate physiological parameters that may affect the health of CHF patients.

Diagnosis of infected total knee: findings of a multicenter database.

UNLABELLED: Although total knee arthroplasty (TKA) is an effective and successful procedure, the outcome is occasionally compromised by complications including periprosthetic joint infection (PJI). Accurate and early diagnosis is the first step in effectively managing patients with PJI. At the present time, diagnosis remains dependent on clinical judgment and reliance on standard clinical tests including serologic tests, analysis of aspirated joint fluid, and interpretation of intraoperative tissue and fluid test results. Although reports regarding sensitivity and specificity of all diagnostic tests in the literature are abundant, the interpretation of the available data has been hampered by the low sample size of these studies. In view of the scope of this important problem and the limitations of previous reports, a large database was assembled of all revision TKA performed at three academic referral centers in order to determine the current status of diagnosis of the infected TKA utilizing commonly available tests. Intraoperative cultures should not be used as a gold standard for PJI owing to high percentages of false-negative and false-positive cases. When combined with clinical judgment, total white cell count and percentage of neutrophils in the synovial fluid more accurately reflects PJI and when combined with hematologic exams safely excludes or confirms infection. LEVEL OF EVIDENCE: Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.