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Background: Smoking is an established risk factor for postoperative complications after total hip arthroplasty (THA). It is unknown if the decreasing prevalence of adult smoking in the United States is reflected in the elective THA patient population. We aimed to investigate recent trends in: (1) the prevalence of smoking pre-THA, stratified by patient demographics; and (2) rates of 30-day complications and increased healthcare utilisation post-THA in smokers versus non-smokers. Methods: Patients who underwent primary elective THA (2011–2019) were identified using the National Surgical Quality Improvement Program database. A total of 243,163 cases (Smokers: n = 30,536; Non-smokers: n = 212,627) were included. Trends analyses were performed for smoking prevalence across the study period. Smokers were propensity score-matched (1:1) to a cohort of non-smokers (n = 29,628, each), and rates of 30-day complications, readmission, and non-home discharge were compared. Results: The rate of preoperative smoking significantly decreased from 14.0% in 2011 to 11.6% in 2019 (p -trend = 0.0286). When stratified, a significant decreasing trend in smoking was found for males and all races; within races, American-Indian/Alaska-Native race had the sharpest decline (2011:36.3% vs. 2019:23.2%). No significant change in 30-day complication rates among smokers or non-smokers was observed (p -trend > 0.05), but non-home discharge significantly decreased for both smokers (p -trend = 0.001) and non-smokers (p -trend < 0.001). After matching, higher rates of superficial surgical site infections (SSI) (0.9% vs. 0.5%; p < 0.001), deep SSI (0.5% vs. 0.3%; p < 0.001), wound disruption (0.2% vs. 0.1%; p = 0.006), and readmission (4.2% vs. 3.1%; p = <0.001) were found in smokers versus non-smokers. Conclusions: The present study is encouraging that national efforts to reduce the prevalence of smoking may be successful within the THA population, but there is a persistently elevated risk of postoperative complications in smokers after THA. [ABSTRACT FROM AUTHOR]

Background: Demographic factors have been implicated in THA and TKA outcome disparities. Specifically, patients' racial backgrounds have been reported to influence outcomes after surgery, including length of stay, discharge disposition, and inpatient readmissions. However, in the United States, health-impacting socioeconomic disadvantage is sometimes associated with racial differences in ways that can result in important confounding, thereby raising the question of whether race-associated post-THA/TKA adverse outcomes are an independent function of race or a byproduct of confounding from socioeconomic deprivation, which is potentially addressable. To explore this, we used the Area Deprivation Index (ADI) as a proxy for socioeconomic disadvantage, since it is a socioeconomic parameter that estimates the likely deprivation associated with a patient's home address. Questions/purposes: The goal of this study was to investigate (1) whether race (in this study, Black versus White) was independently associated with adverse outcomes, including prolonged length of stay (LOS > 3 days), nonhome discharge, 90-day readmission, and emergency department (ED) visits while controlling for age, gender, BMI, smoking, Charlson comorbidity index (CCI), and insurance; and (2) whether socioeconomic disadvantage, measured by ADI, substantially mediated any association between race and any of the aforementioned measured outcomes. Methods: Between November 2018 and December 2019, 2638 underwent elective primary THA and 4915 patients underwent elective primary TKA for osteoarthritis at one of seven hospitals within a single academic center. Overall, 12% (742 of 5948) of patients were Black and 88% (5206 of 5948) were White. We included patients with complete demographic data, ADI data, and who were of Black or White race; with these criteria, 11% (293 of 2638) were excluded in the THA group, and 27% (1312 of 4915) of patients were excluded in the TKA group. In this retrospective, comparative study, patient follow-up was obtained using a longitudinally maintained database, leaving 89% (2345 of 2638) and 73% (3603 of 4915) for analysis in the THA and TKA groups, respectively. For both THA and TKA, Black patients had higher ADI scores, slightly higher BMIs, and were more likely to be current smokers at baseline. Furthermore, within the TKA cohort there was a higher proportion of Black women compared with White women. Multivariable regression analysis was utilized to assess associations between race and LOS of 3 or more days, nonhome discharge disposition, 90-day inpatient readmission, and 90-day ED admission, while adjusting for age, gender, BMI, smoking, CCI, and insurance. This was followed by a mediation analysis that explored whether the association between race (the independent variable) and measured outcomes (the dependent variables) could be partially or completely attributable to confounding from the ADI (the mediator, in this model). The mediation effect was measured as a percentage of the total effect of race on the outcomes of interest that was mediated by ADI. Results: In the THA group, after adjusting for age, gender, BMI, smoking, CCI, and insurance, White patients had lower odds of experiencing an LOS of 3 days or more (OR 0.43 [95% confidence interval (CI) 0.31 to 0.59]; p < 0.001) and nonhome discharge (OR 0.39 [95% CI 0.27 to 0.56]; p < 0.001). In mediation analysis, ADI partially explained (or mediated) 37% of the association between race and LOS of 3 days or more (-0.043 [95% CI -0.063 to -0.026]; p < 0.001) and 40% of the association between race and nonhome discharge (0.041 [95% CI 0.024 to 0.059]; p < 0.001). However, a smaller direct association between race and both outcomes was observed (LOS 3 days or more: -0.075 [95% CI -0.13 to -0.024]; p = 0.004; nonhome discharge: 0.060 [95% CI 0.016 to 0.11]; p = 0.004). No association was observed between race and 90-day readmission or ED admission in the THA group. In the TKA group, after adjusting for age, gender, BMI, smoking, CCI, and insurance, White patients had lower odds of experiencing an LOS of 3 days or more (OR 0.41 [95% CI 0.32 to 0.54]; p < 0.001), nonhome discharge (OR 0.44 [95% CI 0.33 to 0.60]; p < 0.001), 90-day readmission (OR 0.54 [95% CI 0.39 to 0.77]; p < 0.001), and 90-day ED admission (OR 0.60 [95% CI 0.45 to 0.79]; p < 0.001). In mediation analysis, ADI mediated 19% of the association between race and LOS of 3 days or more (-0.021 [95% CI -0.035 to -0.007]; p = 0.004) and 38% of the association between race and nonhome discharge (0.029 [95% CI -0.016 to 0.040]; p < 0.001), but there was also a direct association between race and these outcomes (LOS 3 days or more: -0.088 [95% CI -0.13 to -0.049]; p < 0.001; nonhome discharge: 0.046 [95% CI 0.014 to 0.078]; p = 0.006). ADI did not mediate the associations observed between race and 90-day readmission and ED admission in the TKA group. Conclusion: Our findings suggest that socioeconomic disadvantage may be implicated in a substantial proportion of the previously assumed race-driven disparity in healthcare utilization parameters after primary total joint arthroplasty. Orthopaedic surgeons should attempt to identify potentially modifiable socioeconomic disadvantage indicators. This serves as a call to action for the orthopaedic community to consider specific interventions to support patients from vulnerable areas or whose incomes are lower, such as supporting applications for nonemergent medical transportation or referring patients to local care coordination agencies. Future studies should seek to identify which specific resources or approaches improve outcomes after TJA in patients with socioeconomic disadvantage. Level of Evidence: Level III, therapeutic study. [ABSTRACT FROM AUTHOR]

An ensemble of J HH , J CH , and J CC values was measured in aqueous solutions of methyl α- and β-d-idohexopyranosides containing selective 13 C-enrichment at various carbons. By comparing these J-couplings to those reported previously in the α- and β-d-idohexopyranoses, methyl glycosidation was found to affect ring conformational equilibria, with the percentages of 4 C 1 forms based on 3 J HH analysis as follows: α-d-idopyranose, ∼18%; methyl α-d-idopyranoside, ∼42%; methyl β-d-idopyranoside, ∼74%; β-d-idopyranose, 82%. J CH and J CC values were analyzed with assistance from theoretical values obtained from density functional theory (DFT) calculations. Linearized plots of the percentages of 4 C 1 against limiting J CH and J CC values in the chair forms were used to (a) determine the compatibility of the experimental J CH and J CC values with 4 C 1 / 1 C 4 ratios determined from J HH analysis and (b) determine the sensitivity of specific J CH and J CC values to ring conformation. Ring conformational equilibria for methyl idohexopyranosides differ significantly from those predicted from recent molecular dynamics (MD) simulations, indicating that equilibria determined by MD for ring configurations with energetically flat pseudorotational itineraries may not be quantitative. J-couplings in methyl α-l-[6- 13 C]idopyranosiduronic acid and methyl α-d-[6- 13 C]glucopyranosiduronic acid were measured as a function of solution pH. The ring conformational equilibrium is pH-dependent in the iduronic acid.

Density functional theory (DFT) is a powerful computational tool to enable structural interpretations of NMR spin-spin coupling constants ( J-couplings) in saccharides, including the abundant (1)H-(1)H ( JHH), (13)C-(1)H ( JCH), and (13)C-(13)C ( JCC) values that exist for coupling pathways comprised of 1-4 bonds. The multiple hydroxyl groups in saccharides, with their attendant lone-pair orbitals, exert significant effects on J-couplings that can be difficult to decipher and quantify without input from theory. Oxygen substituent effects are configurational and conformational in origin (e.g., axial/equatorial orientation of an OH group in an aldopyranosyl ring; C-O bond conformation involving an exocyclic OH group). DFT studies shed light on these effects, and if conducted properly, yield quantitative relationships between a specific J-coupling and one or more conformational elements in the target molecule. These relationships assist studies of saccharide structure and conformation in solution, which are often challenged by the presence of conformational averaging. Redundant J-couplings, defined as an ensemble of J-couplings sensitive to the same conformational element, are particularly helpful when the element is flexible in solution (i.e., samples multiple conformational states on the NMR time scale), provided that algorithms are available to convert redundant J-values into meaningful conformational models. If the latter conversion is achievable, the data can serve as a means of testing, validating, and refining theoretical methods like molecular dynamics (MD) simulations, which are currently relied upon heavily to assign conformational models of saccharides in solution despite a paucity of experimental data needed to independently validate the method.