Can Patient Selection Explain the Obesity Paradox in Orthopaedic Hip Surgery? An Analysis of the ACS-NSQIP Registry

Prior Bariatric Surgery is Associated with Improved Total Hip Arthroplasty Outcomes in Patients Who Have Obesity: A National Cohort Study with 6 Years of Follow-Up

BACKGROUND

Obesity is a risk factor for end-stage hip osteoarthritis (OA). While total hip arthroplasty (THA) is commonly performed to reduce pain and improve function associated with OA, obesity has been associated with an increased risk of complications after THA. Although bariatric surgery may also be utilized to reduce weight, the impact of bariatric surgery on THA outcomes remains inadequately understood.

METHODS

This retrospective cohort analysis utilized multicenter electronic medical record data ranging from 2003 to 2023. Patients who have obesity who underwent THA were stratified based on prior bariatric surgery. The final bariatric cohort comprised 451 patients after propensity score matching. Complication rates and revision risks were compared between cohorts at six, 24, and 72 months. Additional analysis stratified patients by interval between bariatric surgery and THA.

RESULTS

At six-month follow-up, the bariatric cohort had significantly lower risks of surgical site infection (SSI), wound dehiscence, and deep vein thrombosis (DVT). At 24 months, the bariatric cohort had a lower risk of DVT. At 72 month follow-up, the bariatric cohort had reduced rates of revision, mortality, cardiac morbidity, and Clavien-Dindo grade IV complications.

CONCLUSION

Obese patients who underwent bariatric surgery prior to THA experienced reduced medical complications at all time points and reduced rates of revision at 72 months relative to a matched cohort who did not undergo bariatric surgery.

Catastrophic complications following microvascular free tissue transfer: A 10-year review of NSQIP data

INTRODUCTION

There is an absence of literature regarding the risks of catastrophic medical outcomes (CMOs) such as stroke, cardiac arrest, and pulmonary embolism in microvascular free tissue transfer. This study aims to determine the CMO and mortality rates, as well as risk factors, associated with microvascular reconstruction of the head and neck, extremity, and breast.

METHODS

This study uses data from the American College of Surgeons National Surgical Quality Improvement Program. Cases of microvascular free tissue transfer from 2012 to 2021 were analyzed to assess the 30-day rates of CMOs, including death, as well as associated risk factors.

RESULTS

Of the 22,839 included patients, 785 (3.44%) experienced 1043 CMOs, including 99 (0.43%) deaths. Pulmonary complications of prolonged respiratory failure and pulmonary embolism were the most common. Independent risk factors included age, male sex, underweight status, longer operation times, American Society of Anesthesiologists (ASA) class of III or above, wound classification other than clean, and underlying conditions such as diabetes, hypertension, chronic obstructive pulmonary disorder, dyspnea, metastatic cancer, and ventilator dependence. CMOs were associated with an average 10-day delay in hospital discharge. Multivariate regression analysis revealed that head and neck reconstructions were associated with increased risk of CMO (OR 4.96; p < 0.0001).

CONCLUSION

This is the largest study to examine CMOs following microvascular free tissue transfer. Compared to previous literature spanning the period between 2006 and 2011, we observed a decreased rate of CMOs but a slight increase in 30-day mortality. Our data provide updated and comprehensive criteria for risk stratification and patient counseling. The modifiable risk factors reported in our study should be considered in elective, non-urgent cases of microvascular reconstruction.

The obesity paradox exists for perioperative complications and mortality following lower extremity arterial bypass surgery

OBJECTIVE

The obesity paradox refers to a phenomenon by which obese individuals experience lower risk of mortality and even protective associations from chronic disease sequelae when compared with the non-obese and underweight population. Prior literature has demonstrated an obesity paradox after cardiac and other surgical procedures. However, the relationship between body mass index (BMI) and perioperative complications for patients undergoing major open lower extremity arterial revascularization is unclear.

METHODS

We queried the Vascular Quality Initiative for individuals receiving unilateral infrainguinal bypass between 2003 and 2020. We used multivariable logistic regression to assess the relationship of BMI categories (underweight [<18.5 kg/m2], non-obese [18.5-24.9 kg/m2], overweight [25-29.9 kg/m2], Class 1 obesity [30-34.9 kg/m2], Class 2 obesity [35-39.9 kg/m2], and Class 3 obesity [>40 kg/m2]) with 30-day mortality, surgical site infection, and adverse cardiovascular events. We adjusted the models for key patient demographics, comorbidities, and technical and perioperative characteristics.

RESULTS

From 2003 to 2020, 60,588 arterial bypass procedures met inclusion criteria for analysis. Upon multivariable logistic regression with the non-obese category as the reference group, odds of 30-day mortality were significantly decreased among the overweight (odds ratio [OR], 0.64; 95% confidence interval [CI], 0.53-0.78), Class 1 obese (OR, 0.65; 95% CI, 0.52-0.81), Class 2 obese (OR, 0.66; 95% CI, 0.48-0.90), and Class 3 obese (OR, 0.61; 95% CI, 0.39-0.97) patient categories. Conversely, odds of 30-day mortality were increased in the underweight patient group (OR, 1.58; 95% CI, 1.16-2.13). Furthermore, a BMI-dependent positive association was present, with odds of surgical site infections with patients in Class 3 obesity having the highest odds (OR, 2.10; 95% CI, 1.60-2.76). Finally, among the adverse cardiovascular event outcomes assessed, only myocardial infarction (MI) demonstrated decreased odds among overweight (OR, 0.82; 95% CI, 0.71-0.96), Class 1 obese (OR, 0.78; 95% CI, 0.65-0.93), and Class 2 obese (OR, 0.66; 95% CI, 0.51-0.86) patient populations. Odds of MI among the underweight and Class 3 obesity groups were not significant.

CONCLUSIONS

The obesity paradox is evident in patients undergoing lower extremity bypass procedures, particularly with odds of 30-day mortality and MI. Our findings suggest that having higher BMI (overweight and Class 1-3 obesity) is not associated with increased mortality and should not be interpreted as a contraindication for lower extremity arterial bypass surgery. However, these patients should be under vigilant surveillance for surgical site infections. Finally, patients that are underweight have a significantly increased odds of 30-day mortality and may be more suitable candidates for endovascular therapy.

30-day to 10-year mortality rates following total hip arthroplasty: a meta-analysis of the last decade (2011-2021)

BACKGROUND

Mortality after total hip arthroplasty (THA) is a rare but devastating complication. This meta-analysis aimed to: (1) determine the mortality rates at 30 days, 90 days, 1 year, 5 years and 10 years after THA; (2) identify risk factors and causes of mortality after THA.

METHODS

Pubmed, MEDLINE, Cochrane, EBSCO Host, and Google Scholar databases were queried for studies reporting mortality rates after primary elective, unilateral THA. Inverse-proportion models were constructed to quantify the incidence of all-cause mortality at 30 days, 90 days, 1 year, 5 years and 10 years after THA. Random-effects multiple regression was performed to investigate the potential effect modifiers of age (at time of THA), body mass index, and gender.

RESULTS

A total of 53 studies (3,297,363 patients) were included. The overall mortality rate was 3.9%. The 30-day mortality was 0.49% (95% CI; 0.23-0.84). Mortality at 90 days was 0.47% (95% CI, 0.38-0.57). Mortality increased exponentially between 90 days and 5 years, with a 1-year mortality rate of 1.90% (95% CI, 1.22-2.73) and a 5-year mortality rate of 9.85% (95% CI, 5.53-15.22). At 10-year follow-up, the mortality rate was 16.43% (95% CI, 1.17-22.48). Increasing comorbidity indices, socioeconomic disadvantage, age, anaemia, and smoking were found to be risk factors for mortality. The most commonly reported causes of death were ischaemic heart disease, malignancy, and pulmonary disease.

CONCLUSIONS

All-cause mortality remains low after contemporary THA. However, 1 out of 10 patients and 1 out of 6 patients were deceased after 5 years and 10 years of THA, respectively. As expected, age, but not BMI or gender, was significantly associated with mortality.

30-Days to 10-Years Mortality Rates following Total Knee Arthroplasty: A Systematic Review and Meta-Analysis of the Last Decade (2011-2021)

Mortality data following primary total knee arthroplasty (TKA) beyond 1-year postoperative time period is sparse. This systematic review and meta-analysis aimed to: (1) estimate contemporary mortality rates at 30 days, 90 days, 1 year, 5 years, and 10 years following primary TKA; and (2) identify risk factors and causes of mortality following TKA. PubMed, MEDLINE, Cochrane, EBSCO host, and Google Scholar databases were queried from January 1, 2011 to October 30, 2021 for all studies reporting mortality rates following primary TKA. A meta-analysis of proportions was conducted using a random-effects model to ascertain pooled mortality rates (95% confidence interval [CI]). Meta-regression was utilized to account for confounding effects on mortality rates due to the study's country of origin, median date of study data, average patient age, and patient gender ratios, with a level of significance maintained at p-value <0.05. A total of 44 articles were included in quantitative synthesis. The pooled 30-day mortality rate was 0.14% (95% CI:0.05-0.22%; n = 1,817,647). The pooled 90-day mortality rate was 0.35% (95% CI:0.0.28-0.43%; n = 1,641,974). The pooled 1-year mortality rate was 1.1% (95% CI:0.71-1.49%; n = 1,178,698). The pooled 5-year mortality rate was 5.38% (95% CI:4.35-6.42%; n = 597,041). The pooled 10-year mortality rate was 10.18% (95% CI:7.78-12.64%; n = 815,901). Our 30-day mortality rate was lower than previously reported. The most common causes of death at all time points were due to cardiac disease, cerebrovascular disease, and malignancy. Obesity demonstrated mixed effects on long-term mortality rates. Overall mortality rates of TKA remain low worldwide at all time points and immediate postoperative mortality rates continue to fall. Compared to symptomatic knee osteoarthritic patients reported in the literature, TKA patients qualitatively exhibited lower mortality rates, which may support the value of TKA in improving quality of life without associated excess mortality. Future long-term mortality studies should be conducted to account for geographical variability in mortality rates and further elucidate modifiable risk factors associated with mortality among TKA patients.

Body Mass Index (BMI) Cutoffs and Racial, Ethnic, Sex, or Age Disparities in Patients Treated With Total Ankle Arthroplasty

Background

The rising prevalence of obesity among American adults has disproportionately affected Black adults and women. Furthermore, body mass index (BMI) has historically been used as a relative contraindication to many total joint arthroplasty (TJA) procedures, including total ankle arthroplasty. The purpose of this study was to investigate potential disparities in patient eligibility for total ankle arthroplasty based on race, ethnicity, sex, and age by applying commonly used BMI cutoffs to the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database.

Methods

Patients in the ACS-NSQIP database who underwent TAA from 2011 to 2020 were retrospectively reviewed in a cross-sectional analysis. BMI cutoffs of <50, <45, <40, and <35 were then applied. The eligibility rate for TAA was examined for each BMI cutoff, and findings were stratified by race, ethnicity, sex, and age. Independent t tests, chi-squared tests, and Fisher exact tests were performed to compare differences at an α = 0.05.

Results

A total of 1215 of 1865 TAA patients (65.1%) were included after applying the exclusion criteria. Black patients had disproportionately lower rates of eligibility at the most stringent BMI cutoff of <35 (P = .004). Hispanic patients had generally lower rates of eligibility across all BMI cutoffs. In contrast, Asian American and Pacific Islander patients had higher rates of eligibility at the BMI cutoffs of <35 (P = .033) and <40 (P = .039), and White non-Hispanic patients had higher rates of eligibility across all BMI cutoffs. Females had lower eligibility rates across all BMI cutoffs. Ineligible patients were also younger compared to eligible patients across all BMI cutoffs.

Conclusion

Stringent BMI cutoffs may disproportionately disqualify Black, female, and younger patients from receiving total ankle arthroplasty.

Level of Evidence

Level III, retrospective cross-sectional study.

The association between obesity and postoperative outcomes in a broad surgical population: A 7-year American College of Surgeons National Surgical Quality Improvement analysis

BACKGROUND

The number of obese surgical patients continues to grow, and yet obesity's association with surgical outcomes is not totally clear. This study examined the association between obesity and surgical outcomes across a broad surgical population using a very large sample size.

METHODS

This was an analysis of the 2012 to 2018 American College of Surgeons National Surgical Quality Improvement database, including all patients from 9 surgical specialties (general, gynecology, neurosurgery, orthopedics, otolaryngology, plastics, thoracic, urology, and vascular). Preoperative characteristics and postoperative outcomes were compared by body mass index class (normal weight 18.5-24.9 kg/m², overweight 25.0-29.9, obese class I 30.0-34.9, obese II 35.0-39.9, obese III ≥40). Adjusted odds ratios were computed for adverse outcomes by body mass index class.

RESULTS

A total of 5,572,019 patients were included; 44.6% were obese. Median operative times were marginally higher for obese patients (89 vs 83 minutes, P < .001). Compared to normal weight patients, overweight and obese patients in classes I, II, and III all had higher adjusted odds of developing infection, venous thromboembolism, and renal complications, but they did not exhibit elevated odds of other postoperative complications (mortality, overall morbidity, pulmonary, urinary tract infection, cardiac, bleeding, stroke, unplanned readmission, or discharge not home (except for class III patients).

CONCLUSION

Obesity was associated with increased odds of postoperative infection, venous thromboembolism, and renal but not the other American College of Surgeons National Surgical Quality Improvement complications. Obese patients need to be carefully managed for these complications.

A systematic review and meta-analysis of the effect of obesity on patients undergoing lower extremity revascularization

OBJECTIVE

In the present review, we assessed the effect of obesity on clinical outcomes for patients with peripheral arterial disease who had undergone endovascular or open lower extremity revascularization surgery.

METHODS

A systematic search strategy of MEDLINE, EMBASE, CINAHL, Web of Science, and Cochrane Library was conducted. The included studies had compared obese and nonobese cohorts with peripheral arterial disease who had undergone endovascular or open lower extremity revascularization. The outcomes included mortality, major adverse cardiovascular events, major adverse limb events, surgical site infections, endovascular access site complications, and perioperative complications.

RESULTS

Eight studies were included with 171,648 patients. The obese patients (body mass index ≥30 kg/m²) were more likely to be women, to have diabetes, and to have more cardiovascular comorbidities despite being younger. No association was found between obesity and peripheral arterial disease severity. Obesity was associated with an overall 22% decreased mortality risk after lower extremity revascularization (risk ratio [RR], 0.78; 95% confidence interval [CI], 0.71-0.85; P < .001; I² = 0%; GRADE (grading of recommendations assessment, development, evaluation), very low quality). A subgroup analysis by intervention type showed similar findings (endovascular: RR, 0.79; 95% CI, 0.71-0.87; P < .001; I² = 0%; open: RR, 0.70; 95% CI, 0.51-0.95; P = .024; I² = 43%). Obesity was associated with a 14% decreased risk of major adverse cardiovascular events for open surgery only (RR, 0.86; 95% CI, 0.76-0.98; P = .021; I² = 0%; GRADE, very low quality). Obesity was associated with an increased risk of surgical site infections pooled across intervention types (RR, 1.69; 95% CI, 1.34-2.14; P < .001; I² = 78%; GRADE, very low quality). No association was found between obesity and major adverse limb events (RR, 1.02; 95% CI, 0.93-1.11; P = .73; I² = 15%; GRADE, very low quality) or endovascular access site complications (RR, 1.11; 95% CI, 0.76-1.63; P = .58; I² = 86%; GRADE, very low quality). Pooled perioperative complications did not differ between the obese and nonobese cohorts (RR, 1.04; 95% CI, 0.84-1.28; P = .73; I² = 92%; GRADE, very low quality).

CONCLUSIONS

Obesity was associated with reduced mortality risk with both endovascular and open surgery, although a reduction in major adverse cardiovascular events was only observed with open surgery. In addition, obese patients had an increased risk of surgical site infections. Obesity was not associated with major adverse limb events, endovascular access site complications, or perioperative complications. The GRADE quality of evidence was very low. The findings from the present review suggest a survival advantage for obese patients with peripheral arterial disease. Future studies could focus on prospectively investigating the effect of obesity on peripheral arterial disease outcomes. A nuanced evaluation of body mass index as a preoperative risk factor is warranted.

Obesity paradox among patients undergoing total knee arthroplasty: a retrospective cohort study

BACKGROUND

Obesity has been recognized as the risk factor for postoperative complication for surgical patients. However, recent studies have showed protective effect of obesity in surgical and non-surgical patients. Our study is to examine the association of body mass index(BMI) with early postoperative complications in patients undergoing total knee arthroplasty.

MATERIALS AND METHODS

All patients who had primary total knee arthroplasty between January 2014 and December 2019 were included. Medical records were retrospectively reviewed and BMI was categorized as underweight(BMI < 18.5), normal weight(18.5 < BMI < 24.9), overweight I(25 < BMI < 27.4), overweight II(27.5 < BMI < 29.9), obese I(30 < BMI < 34.9) and obese II(BMI ≥ 35). The association between BMI and occurrence of early postoperative complications was examined and logistic regression was used to calculate relationship between BMI and early postoperative complications.

RESULTS

A total of 2969 patients were included in our analysis. The overall complication rate in patients undergoing total knee arthroplasty was 14.8%, with the highest complication being 22.2% in the underweight group, the second highest in the normal weight group(17.5%), the lowest in the overweight I(13.8%) and obese I(12.0%) group and then higher again in obese II group(16.7%). In multivariable analyses, overweight I (OR 0.737, 95% CI 0.559-0.972, P = 0.031) and obese I (OR 0.631, 95% CI 0.449-0.885, P = 0.008) were associated with lower risk of early postoperative complications after total knee arthroplasty.

CONCLUSION

In this retrospective study, overweight and obese patients had a lower risk of early postoperative complications after total knee arthroplasty. Further studies are necessary to confirm and investigate the mechanism of obesity paradox in this surgical population.

TRIAL REGISTRATION

This study had been registrated in www.chictr.org.cn on 25/10/2021 and the registration ID was ChiCTR2100052408.

Are Body Mass Index Cutoffs Creating Racial, Ethnic, and Gender Disparities in Eligibility for Primary Total Hip and Knee Arthroplasty?

BACKGROUND

Unabated increases in the prevalence of obesity among American adults have disproportionately affected women, Black persons, and Hispanic persons. The purpose of this study was to evaluate for disparity in rates of patient eligibility for primary total hip arthroplasty (THA) and total knee arthroplasty (TKA) based on race and ethnicity and gender by applying commonly used body mass index (BMI) eligibility criteria to two large national databases.

METHODS

We retrospectively reviewed data from the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database for the years 2015-2019 for primary THA and TKA and the National Health and Nutrition Examination Survey (NHANES) from 2011-2018. Designations of race and ethnicity were standardized between cohorts. BMI cutoffs of <50 kg/m², <45 kg/m², <40 kg/m², and <35 kg/m² were then applied. Rates of eligibility for surgery were examined for each respective BMI cutoff and stratified by age, race and ethnicity, and gender.

RESULTS

143,973 NSQIP THA patients, 242,518 NSQIP TKA patients, and 13,255 NHANES participants were analyzed. Female patients were more likely to be ineligible for surgery across all cohorts for all modeled BMI cutoffs (P < .001 for all). Black patients had relatively lower rates of eligibility across all cohorts for all modeled BMI cutoffs (P < .0001 for all). Hispanic patients had disproportionately lower rates of eligibility only at a BMI cutoff of <35 kg/m².

CONCLUSION

Using BMI cutoffs alone to determine the eligibility for primary THA and TKA may disproportionally exclude women, Black persons, and Hispanic persons. These data raise concerns regarding further disparity and restriction of arthroplasty care to vulnerable populations that are already marginalized.

LEVEL OF EVIDENCE

Retrospective Cohort Study, Level III.

What is the Impact of Body Mass Index Cutoffs on Total Knee Arthroplasty Complications?

BACKGROUND

Body mass index (BMI) cutoffs are commonly used to decide whether to offer obese patients elective total knee arthroplasty (TKA). However, weight loss goals may be unachievable for many patients who are consequentially denied complication-free surgery. The purpose of this study was to assess the impact of different BMI cutoffs on the rates of complication-free surgery after TKA.

METHODS

Patients undergoing elective, primary TKA from 2015 to 2018 were identified in the American College of Surgeons National Surgical Quality Improvement Program database using Common Procedural Terminology code 27447. The BMI and rates of any thirty-day complication were collected. BMI cutoffs of 30, 35, 40, 45, and 50 kg/m² were applied to model the incidence of complications if TKA would have been allowed or denied based on the BMI.

RESULTS

A total of 314,719 patients underwent TKA, and 46,386 (14.7%) had a BMI ≥40 kg/m². With a BMI cutoff of 40 kg/m², 268,333 (85.3%) patients would have undergone TKA. A total of 282,552 (94.8%) would experience complication-free surgery, and 17.3% of all complications would be prevented. TKA would proceed for 309,479 (98.3%) patients at a BMI cutoff of 50 kg/m². A total of 293,108 (94.7%) would not experience a complication, and 2.8% of complications would be prevented. A BMI cutoff of 35 kg/m² would prevent 36.6% of all complications while allowing 94.8% of complication-free surgeries to proceed.

CONCLUSION

Lower BMI cutoffs can reduce complications, but will limit access to complication-free TKA for many patients. These data do not indicate TKA should be performed without consideration of risks from obesity; however, a holistic assessment and shared decision-making may be more valuable when deciding on appropriate goal weight reduction.

Racial Differences in Orthopedic Trauma Surgery

Racial discrepancies among patients in the United States undergoing orthopedic trauma surgery have not been investigated. Issues relating to socioeconomic status and access to care have played a role in the health outcomes of racial groups. In orthopedic surgery, recent joint arthroplasty literature has shown significant racial differences in the use of elective joint arthroplasty. Furthermore, studies also suggest increased rates of early complication in racial minority groups. In general, little information exists on the postoperative outcomes of racial minority groups in orthopedic surgery. We retrospectively queried the National Surgical Quality Improvement Program database to identify patients undergoing orthopedic trauma surgery between 2008 and 2016. Patients of all ages who underwent orthopedic trauma surgery were identified using Current Procedural Terminology codes. Patients classified as either Black or White were included in the study. Demographic data, comorbidities, and basic surgical data were compared between the groups. Adverse outcomes in the initial 30 days postoperative were also examined. Higher frequencies of deep wound infection (0.5% vs 0.3%, P=.002) were noted among Black patients, with decreased mortality (0.3% vs 0.6%, P=.004) and postoperative transfusion (2.7% vs 3.8%, P<.001) rates, compared with White patients. Clear differences exist in the demographic, surgical, and outcome data between Black and White patients undergoing orthopedic trauma surgery. More epidemiological studies are required to further investigate racial differences in orthopedic trauma surgery. [Orthopedics. 2022;45(2):71-76.].

Effect of childhood obesity on admissions for respiratory disease

AIM

The purpose of this study was to assess for an association between higher body mass index and disease severity, morbidity and mortality in children admitted for an acute respiratory distress and failure.

METHODS

A single-institution retrospective cross-sectional study performed in the United States evaluating paediatric patients, 2-20 years of age, admitted for diagnoses related to acute respiratory distress and acute respiratory failure. Main outcomes include disease severity as assessed using the respiratory component of the Paediatric Early Warning Score (PEWS) with adjustment for altered mental status (Resp-PEWS + AMS), hospital or intensive care length of stay (LOS) and death.

RESULTS

Children with obesity made up 42/334 (13%) of the cohort. There was no significant difference in Resp-PEWS + AMS between obese and non-obese cohorts (mean of 0.93, {standard deviation 1.11} vs. 1.13 {1.35}, range 0-6, rank sum p = 0.46). There was no significant difference in overall hospital LOS or intensive care LOS. Multivariate analysis including diagnosis as a control variable did not change the results.

CONCLUSION

We found that body habitus was not an independent factor for illness severity or clinical outcomes.

Impact of body mass index on surgical outcomes and complications in adult spinal deformity

BACKGROUND

Several studies have reported that overweightness and obesity are associated with higher complication rates in lumbar spine surgery. However, little is known about the effect of obesity on postoperative complications in adult spinal deformity (ASD) surgery, especially in the elderly. This study aimed to examine the effect of body mass index (BMI) on surgical outcomes and postoperative complications in elderly ASD patients undergoing surgical correction in Japan.

METHODS

We conducted a retrospective, multicenter, observational study of 234 consecutive patients diagnosed with ASD who underwent corrective surgery. Patients were divided into two groups according to BMI, BMI <25 (153 patients, mean age 71.9 years) and BMI ≥ 25 (overweight/obese, 81 patients, mean age 73.3 years). Radiographic results and perioperative complications were compared between the two groups.

RESULTS

Surgical complications occurred in approximately 20% of patients in each group; complications did not significantly differ between the two groups. A greater proportion of patients in the BMI ≥ 25 group experienced mechanical failure and DJK, although the difference was not significant. Preoperative mean lumbar lordosis (LL), pelvic incidence (PI) minus LL, sacral slope (SS) and sagittal vertical axis (SVA) were similar in the BMI < 25 and BMI ≥ 25 groups. However, the BMI ≥25 group had lower mean LL (p = 0.015) and higher PI minus LL (p = 0.09) postoperatively. The BMI ≥25 groups also had significantly smaller LL (p = 0.026), smaller SS (p = 0.049) and higher SVA (p = 0.041) at the final follow-up, compared to the BMI < 25 group.

CONCLUSIONS

In the present study, no difference in medical or surgical complications after ASD surgery was found between overweight/obese patients (BMI ≥ 25) and those with BMI < 25. However, correction of LL and SVA was smaller in patients with overweight/obese patients.

Survival bias may explain the appearance of the obesity paradox in hip fracture patients

Patients with low-energy hip fractures do not follow the obesity paradox as previously reported. In datasets where injury mechanism is not available, the use of age >50 years (as opposed to commonly used >65 years) as a surrogate for a low-energy hip fracture patients may be a more robust inclusion criterion.  PURPOSE: In elderly patients with a hip fracture, limited data suggests that obese patients counterintuitively have improved survival compared to normal-weight patients. This "obesity paradox" may be the byproduct of selection bias. We hypothesized that the obesity paradox would not apply to elderly hip fracture patients.

METHODS

The National Surgical Quality Improvement Project dataset identified 71,685 hip fracture patients ≥50 years-of-age with complete body mass index (BMI) data that underwent surgery. Patients were stratified into under and over 75-year-old cohorts (n=18,956 and 52,729, respectively). Within each age group, patients were stratified by BMI class and compared with respect to preoperative characteristics and 30-day mortality. Significant univariate characteristics (p<0.1) were included in multivariate analysis to determine the independent effect of obesity class on 30-day mortality (p<0.05).

RESULTS

Multivariate analysis of <75-year-old patients with class-III obesity were more likely to die within 30-days than similarly aged normal-weight patients (OR 1.91, CI 1.06-3.42, p=0.030). Multivariate analysis of ≥75-year-old overweight (OR 0.69, CI 0.62-0.77, p<0.001), class-I obese (OR 0.62, CI 0.51-0.74, p<0.001), or class-II obese (OR=0.69, CI 0.50-0.95, p=0.022) patients were less likely to die within 30-days when compared to similarly aged normal-weight patients.

CONCLUSIONS

Our data suggest that obesity is a risk factor for mortality in low-energy hip fracture patients, but the appearance of the "obesity paradox" in elderly hip fracture patients results from statistical bias that is only evident upon subgroup analysis.

Influence of body mass index and age on day-of-surgery discharge, prolonged admission, and 90-day readmission after fast-track unicompartmental knee arthroplasty

Background and purpose - The indications for unicompartmental knee arthroplasty (UKA) have become less restrictive and, today, high age and high BMI are not considered contraindications by many surgeons. While the influence of these patient characteristics on total knee arthroplasty is well documented, evidence on UKA is lacking. We investigated the effect of BMI and age on day of surgery (DOS) discharge, prolonged admission, and 90-day readmission following UKA surgery.Patients and methods - This retrospective cohort study included 3,897 UKA patients operated on between 2010 and 2018 in 8 fast-track arthroplasty centers. Patients were divided into 5 BMI groups and 5 age groups. Differences between groups in the occurrence of DOS discharge, prolonged admission > 2 days, and 90-day readmission was investigated using a chi-square test and mixed-effect models adjusted for patient characteristics using surgical center as a random effect.Results - Median LOS was 1 day. DOS discharge was achieved in 26% of patients with no statistically significant differences between BMI groups. DOS discharge was less likely in UKA patients aged > 70 years (age 71-80; odds ratio [OR] 0.7 [95% CI 0.6-0.9]). Prolonged admission was not affected by BMI or age in the adjusted analysis. 90-day readmission was more likely in patients with BMI > 35 (OR 1.9 [CI 1.1-3.1]) and patients aged 71-80 (OR 1.5 [CI 1.1-2.1]).Interpretation - Age > 70 years decreased the likelihood of DOS discharge after UKA. High BMI as well as advanced age increased the likelihood of 90-day readmission. This should be noted by surgeons operating on patients with high BMI and age.

Low body mass index is associated with increased mortality in patients with pelvic and acetabular fractures

AIMS

Fractures of the pelvis and acetabulum are often the consequence of high energy trauma in young individuals or fragility fractures in osteoporotic bone. They can be life-threatening or life changing injuries. No published data exists comparing body mass index (BMI) and mortality for this patient group. The aim of this study was to identify if low BMI (<18.5) was a predictor of morbidity and mortality for patients with these injuries.

PATIENTS AND METHODS

Of the 1033 patients with pelvic or acetabular fractures referred to a single level 1 major trauma centre (MTC) over a 4.5-year period (August 2015 - January 2020); we retrospectively analysed data for all admitted patients. Data was collected on demographics, injury pattern, operative intervention and complications. Comparison was made between patients that were underweight (BMI<18.5) and patients that were not. Both in-hospital and post discharge complications were recorded including pulmonary embolus (PE), deep venous thrombosis (DVT), ileus, infection, loss of reduction and mortality at 6 months.

RESULTS

569 patients admitted to the MTC with a pelvic or acetabular fracture were included in our analysis. Underweight patients had a statistically significant increase in mortality both in-hospital (p = 0.019) and at 6 months post injury (p = 0.039) when compared to other BMI groups. No statistical significance was found between these BMI groups comparing morbidity: DVT (p = 0.712), PE (p = 0.736) nor ileus (p = 0.149). Covariate analysis showed that a low BMI was associated with triple the in-hospital mortality after correction for age and energy of injury (adjusted OR 3.028, 95% CI 1.059-8.659).

CONCLUSION

This is the first published study that demonstrates a statistically significant increase in mortality in patients with pelvic or acetabular fractures who are underweight. Surgeons should carefully consider appropriate peri-operative optimisation for these patients. Further investigation into the effects of low BMI and response to trauma is required.

Do Extended Oral Postoperative Antibiotics Prevent Early Periprosthetic Joint Infection in Morbidly Obese Patients Undergoing Primary Total Joint Arthroplasty?

BACKGROUND

Extended oral antibiotic prophylaxis after primary total knee arthroplasty (TKA) and total hip arthroplasty (THA) in patients with body mass index (BMI) ≥40 kg/m² may reduce the rate of early periprosthetic joint infection (PJI); however, existing data are limited. The purpose of this study was to examine rates of wound complications and PJI in patients with BMI ≥40 kg/m² treated with and without extended oral antibiotic prophylaxis after surgery.

METHODS

We retrospectively identified all primary THA and TKA performed since 2015 in patients with a BMI ≥40 kg/m² at a single institution. Extended oral antibiotic prophylaxis for 7-14 days after surgery was prescribed at the discretion of each surgeon. Wound complications and PJI were examined at 90 days postoperatively.

RESULTS

In total, 650 cases (205 THA and 445 TKA) were analyzed. Mean age was 58 years and 62% were women. Mean BMI was 44 kg/m². Extended oral antibiotic prophylaxis was prescribed in 177 cases (27%). At 90 days, there was no difference between prophylaxis and nonprophylaxis groups in rate of wound complications (11% vs 8%; P = .41) or PJI (1.7% vs 0.6%; P = .35). The univariate analysis demonstrated increased operative time (odds ratio (OR) 1.01; 95% confidence interval (95% CI) 1.01-1.02) and diabetes mellitus (OR 1.88; 95% CI 1.03-3.46) to be associated with increased risk of 90-day wound complications. No patient factors were associated with increased risk of PJI at 90 days postoperatively.

CONCLUSION

Extended oral antibiotic prophylaxis after primary THA and TKA did not reduce rates of wound complications or early PJI in a morbidly obese patient population.

Failure to Medically Optimize Before Total Hip Arthroplasty: Which Modifiable Risk Factor Is the Most Dangerous?

Background

There is mounting evidence that smoking, abnormal body mass index (BMI), uncontrolled diabetes, and poor nutritional status are associated with complications after total hip arthroplasty (THA). The goal of the present study was to evaluate the consequences of failure to medically optimize Medicare-eligible patients with respect to these key modifiable health targets by assessing complications in the early postoperative period after THA.

Methods

The National Surgical Quality Improvement Program database was queried for all primary THAs performed in 2018. Data were collected on preoperative serum albumin, BMI, diabetes, and tobacco use as well as postoperative infections, readmissions, complications, and mortality. We identified 47,924 THA patients with a median BMI of 29 kg/m² and age of 72 years, and 60% of whom were female.

Results

We found that preoperative albumin <3.5 g/dL, BMI ≥40 kg/m², tobacco use, and diabetes were all individually associated with increased risk of postoperative complications. Serum albumin <3.5 g/dL was the greatest overall risk factor for infection (odds ratio [OR]: 3.1, 95% confidence interval [CI]: 2.3-4.4, P < .0001), readmission (OR: 2.2, 95% CI: 1.9-2.5, P < .0001), any complication (OR: 4.2, 95% CI: 3.8-4.6, P < .0001), and mortality (OR: 7.5, 95% CI: 5.3-10.6, P < .0001).

Conclusions

Low albumin, elevated BMI, tobacco use, and diabetes are associated with increased risk of postoperative infection, readmission, any complication, and mortality after primary THA. Low albumin poses the greatest risk of these. Preoperative optimization should be obtained in all patients before elective surgery, and the final decision for surgery should be individually made between a surgeon and patient.

Level of Evidence

IV.

Are surgeons still performing primary total knee arthroplasty in the morbidly obese?

AIMS

The purpose of this study was to assess total knee arthroplasty (TKA) volume and rates of early complications in morbidly obese patients over the last decade, where the introduction of quality models influencing perioperative care pathways occurred.

METHODS

Patients undergoing TKA between 2011 to 2018 were identified in the American College of Surgeons National Surgical Quality Improvement Program database. Patients were stratified by BMI < 40 kg/m² and ≥ 40 kg/m² and evaluated by the number of cases per year. The 30-day rates of any complication, wound complications, readmissions, and reoperation were assessed. Trends in these endpoints over the study period were compared between groups using odds ratios (ORs) and multivariate analyses.

RESULTS

In total, 314,695 patients underwent TKA and 46,362 (15%) had BMI ≥ 40 kg/m². The prevalence of morbid obesity among TKA patients did not change greatly, ranging between 14% and 16%. Reoperation rate decreased from 1.16% to 0.96% (odds ratio (OR) 0.81 (95% confidence interval (CI) 0.66 to 0.99)) for patients with BMI < 40 kg/m², as did rates of readmission (4.46% to 2.87%; OR 0.61 (0.55 to 0.69)). Patients with BMI ≥ 40 kg/m² also had fewer readmissions over the study period (4.87% to 3.34%; OR 0.64 (0.49 to 0.83)); however, the rate of reoperation did not change (1.37% to 1.41%; OR 0.99 (0.62 to 1.56)). Significant improvements were not observed for infective complications over time for either group; patients with BMI ≥ 40 kg/m² had increased risk of both deep infection and wound complications compared to non-morbidly obese patients. Rate of any complication decreased for all patients.

CONCLUSION

The proportion of TKAs in morbidly obese patients has not significantly changed over the past decade. Although readmission rates improved for all patients, reductions in reoperation in non-morbidly obese patients were not experienced by the morbidly obese, resulting in a widening of the complication gap between these cohorts. Care improvements have not lowered the differential risk of infective complications in the morbidly obese. Cite this article: Bone Joint J 2021;103-B(6 Supple A):38-44.

Obesity is a predictor of increased morbidity after tracheostomy

OBJECTIVE

The purpose of this study was to analyze the relationship between body mass index (BMI) and 30-day morbidity and mortality risk in patients undergoing tracheostomy using the American College of Surgeons National Quality Improvement Program (ACS-NSQIP).

STUDY DESIGN

This is a retrospective, cross-sectional, cohort study.

SETTING

Patients were identified with Current Procedural Terminology codes in the ACS-NSQIP database.

SUBJECTS AND METHODS

Patients who underwent tracheostomy from 2005 to 2018 were queried. They were stratified into four BMI classes and matched to normal BMI cohorts. Multivariate logistic regression was used to identify independent predictors for complications, readmissions, and unplanned reoperations within 30 days.

RESULTS

Among 3784 patients meeting inclusion and exclusion criteria, obesity was shown to be a significant independent risk factor for overall complications (OR 1.439, 95% CI 1.226-1.689, p < 0.001), postoperative acute renal failure (OR 10.715, 95% CI 1.213-94.646, p = 0.033), and unplanned readmissions (OR 1.702, 95% CI 1.095-2.647, p = 0.018). A significantly lower rate of postoperative transfusions was observed for obese patients (OR 0.581, 95% CI 0.432-0.781, p < 0.001).

CONCLUSIONS

Obesity was found to be independently associated with an increased risk of overall complication, developing acute renal failure, and having an unplanned 30-day readmission following tracheostomy. The risk of postoperative transfusion appears to be lower in obese patients.

LEVEL OF EVIDENCE

4.

Implications of Obesity on Endoscopic Sinus Surgery Postoperative Complications: An Analysis of the NSQIP Database

Objective

To evaluate the influence of body mass index on postoperative adverse events in adult patients undergoing endoscopic sinus surgery.

Study Design

Retrospective cohort study.

Setting

Database of the American College of Surgeons NSQIP (National Surgical Quality Improvement Program) from 2006 to 2018.

Methods

The NSQIP database was queried for adult patients undergoing endoscopic sinus surgery. The total sample (N = 1546) was stratified by nonobese (18.5 kg/m2≤ body mass index <30 kg/m2) and obese (≥30 kg/m2). Demographics, comorbidities, intraoperative variables, and postoperative adverse events were compared via chi-square analysis and multivariable logistic regression.

Results

Obese patients accounted for 49.7% (n = 768) of the cohort. Obese patients had a higher American Society of Anesthesiologists classification (class III, 45.1% vs 29.5%; P < .001), rate of diabetes (18.2% vs 7.2%, P < .001), and rate of hypertension requiring medication (43.1% vs 23.0%, P < .001). Nonobese patients were more likely to be >58 years of age (23.4% vs 29.0%, P = .02) and have disseminated cancer (<1% vs 3.2%, P < .001). The obese cohort had a lower frequency of surgical complications (3.0% vs 5.4%, P = .027), driven by frequency of perioperative bleeding (1.8% vs 3.7%, P = .022). There was no statistical difference in medical complications ( P = .775), unplanned readmissions ( P = .286), unplanned reoperations ( P = .053), or 30-day mortality ( P > .999). After multivariable adjustment, obese subjects had decreased odds of any surgical complication (adjusted odds ratio [aOR], 0.567; 95% CI, 0.329-0.979), perioperative bleeding (aOR, 0.474; 95% CI, 0.239-0.942), and any adverse postoperative event (aOR, 0.740; 95% CI, 0.566-0.968).

Conclusion

Obesity does not increase the risk of 30-day adverse outcomes following endoscopic sinus surgery and may even be protective against perioperative bleeding.

Tissue adhesive for wound closure in enhanced-recovery total hip arthroplasty: a prospective, randomized and controlled study

Background

We aimed to present our experience of adopting tissue adhesive as adjunct to standard wound closure in total hip arthroplasty (THA) and evaluate its performance.

Methods

From September 2019 to November 2019, we prospectively enrolled consecutive patients who underwent simultaneous bilateral THA in this randomized and controlled study. Standard wound closure was applied on one side of hip while additional tissue adhesive was applied on the other side at random. We collected and analyzed patients’ information, including age, gender, body mass index (BMI), diagnosis, postoperative length of stay (LOS), dressing changes, wound evaluation scores, wound-related cost and complications.

Results

Thirty patients with simultaneous bilateral THA were enrolled in this study. During the hospital stay, the times of dressing change in hips with tissue adhesive was significantly less than that in the other hips (p = 0.000). However, the wound-related cost in hips with tissue adhesive was significantly higher (p = 0.000). According to patients’ feedback at one-month follow-up, wound evaluation of hips with tissue adhesive was significantly better than the other hips (p = 0.004). Seventeen patients preferred tissue adhesive and only five patients preferred standard wound closure.

Conclusions

Tissue adhesive could significantly reduce wound drainage and increase patients’ satisfaction, which can be an ideal adjunct to standard wound closure in enhanced-recovery THA.

Trial registration

Chinese Clinical Trial Registry; ChiCTR1900025730; Registered 6 September 2019.

Effects of Estimated Glomerular Filtration Rate on 30-Day Mortality and Postoperative Complications After Total Hip Arthroplasty: A Risk Stratification Instrument

BACKGROUND

Chronic kidney disease (CKD) is a relatively common comorbidity that has been shown to adversely affect outcomes in total hip arthroplasty (THA), as well as to increase the procedure's total costs. However, the effect of different stages of kidney disease and the association of estimated glomerular filtration rate (eGFR) with perioperative THA complications are less understood. Therefore, the aims of this study were to investigate the relationships between eGFR, both as a categorical and continuous variable and 30-day outcomes and complications.

METHODS

The National Surgical Quality Improvement Program database was used to identify 101,925 primary THAs between January 1, 2008, and December 31, 2016. The following outcomes were assessed: 30-day mortality, 30-day major complications, 30-day minor complications, specific complications, and discharge disposition. To evaluate the effect of eGFR status on outcomes and complication, multivariate regression models were created to adjust for differences in patient demographics and comorbidities. In addition, multivariate spline regressions were developed to assess the nonlinear relationships between eGFR as a continuous variable and the outcomes of interest.

RESULTS

Our study revealed that as eGFR decreases to <30 mL/min/1.73 m², there is an increased risk for mortality and nonhome discharge (P < .05). There was an increased risk for any major complication and any minor complication as well as several specific medical complications such as transfusion and myocardial infarction (P < .05) for an eGFR of <60 mL/min/1.73 m². Patients' eGFR had a nonlinear relationship with mortality (P = .0001), any major complication (P < .001), and any minor complication (P < .001), as well as a number of other specific medical complications. Once the eGFR, <60 mL/min/1.73 m² the increase was exponential for mortality, major complications, and minor complications. For example, mortality increased of 900% for <15 mL/min/1.73 m² or on dialysis, 600% for 15 to 30 mL/min/1.73 m² and 50% for 30 to 60 mL/min/1.73 m². Similarly, nonlinear relationships were discovered between eGFR and nonhome discharge (P < .001).

CONCLUSION

Patients with lower eGFR, and in particular those with <30 mL/min/1.73 m², are more likely to sustain medical complications and have 6 to 9 times higher mortality than patients with normal eGFR. THA patients with CKD should be appropriately counseled and advised on the risk of postoperative complications by using eGFR as a screening tool.

Spinal Anesthesia Is Associated With Decreased Complications After Total Knee and Hip Arthroplasty

BACKGROUND

We compared the following 30-day outcomes for total knee arthroplasty (TKA) and total hip arthroplasty in spinal anesthesia (SA) versus general anesthesia (GA) (1) mortality, (2) major and minor complication rates, and (3) discharge disposition.

METHODS

From 2011 to 2016, the American College of Surgeons National Surgical Quality Improvement Program database contained 45,871 SA total hip arthroplasties and 65,092 receiving GA. There were 80,077 SA TKAs and 103,003 GA TKAs. Adjusted multivariate logistic regression evaluated associations between anesthesia type and 30-day outcomes.

RESULTS

Anesthesia modality was not associated with 30-day mortality (P > 0.05). The GA cohorts were at a greater risk for any complication, major complications, and minor complications (P < 0.05). Patients who received GA were at an increased risk for nonhome discharge.

CONCLUSION

Patients who undergo total joint arthroplasty with SA experience fewer 30-day complications and are less likely to have a nonhome discharge than those with GA.

Trends in obesity prevalence among total hip arthroplasty patients and the effect on surgical outcomes, 2008-2016

INTRODUCTION

The prevalence of obesity continues to rise in parallel with demand for total hip arthroplasty (THA). This study aims to report obesity trends in primary THA and its effects on procedure outcomes in the United States, stratifying based on Body Mass Index (BMI).

METHODS

Primary THA procedures were identified in the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database (2008-2016). Patient demographic (including BMI), primary outcomes (death; serious morbidity), and secondary outcome variables were analyzed. Using BMI comparison groups (Obese: BMI > 30 [O]; Morbidly Obese: BMI > 40 [MO]) for case populations, univariate, propensity score-matched, and multivariate logistic regression analyses were performed.

RESULTS

The prevalence of obesity increased among primary THA (2008: 546/1200 [45.5%], 2016: 16,078/34,137 [47.1%]) cases. Data on 135,013 primary THA cases were analyzed. Propensity score-matched analyses demonstrated that both serious morbidity (O: OR = 0.73, p < 0.001; MO: OR = 0.84, p = 0.001) and frequency of discharges home (O: OR = 0.90, p < 0.001; MO: OR = 0.71, p < 0.001) were significantly reduced. Instead, long operative times (O: OR = 1.30, p < 0.001; MO: OR = 1.53, p < 0.001), readmission (O: OR = 1.27, p < 0.001; MO: OR = 1.49, p < 0.001), and reoperation (O: OR = 1.44, p < 0.001, MO: OR = 1.96, p < 0.001) were all significantly increased in both obese and morbidly obese cases. Death (OR = 0.29; p = 0.016) was decreased in the MO cohort, while length of stay (OR = 1.19, p = 0.004) was increased in the MO cohort.

CONCLUSION

Both obese and morbidly obese primary THA patient populations were associated with variably increased complication risks; morbidly obese patients had higher complication rates relative to obese patients. Orthopaedic surgeons should continue to consider obesity as a risk factor for THA complications. However, given similar functional outcomes and satisfaction levels as non-obese patients, denying patients THA surgery based on BMI alone may merit reconsideration.

Body mass index is associated with risk of reoperation and revision after primary total hip arthroplasty: a study of the Swedish Hip Arthroplasty Register including 83,146 patients

Background and purpose - The prevalence of obesity is on the rise, becoming a worldwide epidemic. The main purpose of this register-based observational study was to investigate whether different BMI classes are associated with increased risk of reoperation within 2 years, risk of revision within 5 years, and the risk of dying within 90 days after primary total hip arthroplasty (THA). We hypothesized that increasing BMI would increase these risks. Patients and methods - We analyzed a cohort of 83,146 patients who had undergone an elective THA for primary osteoarthritis between 2008 and 2015 from the Swedish Hip Arthroplasty Register (SHAR). BMI was classified according to the World Health Organization (WHO) into 6 classes: < 18.5 as underweight, 18.5-24.9 as normal weight, 25-29.9 as overweight, 30-34.9 as class I obesity, 35-39.9 as class II obesity, and ≥ 40 as class III obesity. Results - Both unadjusted and adjusted parameter estimates showed increasing risk of reoperation at 2 years and revision at 5 years with each overweight and obesity class, mainly due to increased risk of infection. Uncemented and reversed hybrid fixations and surgical approaches other than the posterior were all associated with increased risk. Obesity class III (≥ 40), male sex, and increasing ASA class were associated with increased 90-day mortality. Interpretation - Increasing BMI was associated with 2-year reoperation and 5-year revision risks after primary THA where obese patients have a higher risk than overweight or normal weight patients. As infection seems to be the main cause, customizing preoperative optimization and prophylactic measures for obese patients may help reduce risk.

Statistical Methods Dictate the Estimated Impact of Body Mass Index on Major and Minor Complications After Total Joint Arthroplasty

BACKGROUND

Elevated body mass index (BMI) is considered a risk factor for complications after THA and TKA. Stakeholders have proposed BMI cutoffs for those seeking arthroplasty. The research that might substantiate BMI cutoffs is sensitive to the statistical methods used, but the impact of the statistical methods used to model BMI has not been defined.

QUESTIONS/PURPOSES

(1) How does the estimated postarthroplasty risk of minor and major complications vary as a function of the statistical method used to model BMI? (2) What is the prognostic value of BMI for predicting complications with each statistical method?

METHODS

Using the American College of Surgeons National Surgical Quality Improvement Program from 2005 to 2012, we investigated the impact of BMI on major and minor complication risk for THA and TKA. Analyses were weighted with covariate-balancing propensity scores to account for the differential rate of comorbidities across the range of BMI. We specified BMI in two ways: (1) categorically by World Health Organization (WHO) BMI classes; and (2) as a smooth, continuous variable using splines. Models of risk for major complications (deep surgical site infection [SSI], pulmonary embolism, stroke, cardiac arrest, myocardial infarction, wound disruption, implant failure, unplanned intubation, > 48 hours on a ventilator, acute renal insufficiency, coma, sepsis, reoperation, or mortality) and minor complications (superficial SSI, pneumonia, urinary tract infection, deep vein thrombosis, or peripheral nerve injury) were constructed and were adjusted for confounding variables known to correlate with complications (eg, American Society of Anesthesiologists classification). Results were compared for different specifications of BMI. Receiver operating characteristic (ROC) curves were compared to determine the additive prognostic value of BMI.

RESULTS

The type of BMI parameterization leads to different assessments of risk of postarthroplasty complications for BMIs > 30 kg/m and < 20 kg/m with the spline specification showing better fit in all adjusted models (Akaike Information Criteria favors spline). Modeling BMI categorically using WHO classes indicates that BMI cut points of 40 kg/m for TKA or 35 kg/m for THA are associated with higher risks of major complications. Modeling BMI continuously as a spline suggests that risk of major complications is elevated at a cut point of 44 kg/m for TKA and 35 kg/m for THA. Additionally, in these models, risk does not uniformly increase with increasing BMI. Regardless of the method of modeling, BMI is a poor prognosticator for complications with area under the ROC curves between 0.51 and 0.56, false-positive rates of 96% to 97%, and false-negative rates of 2% to 3%.

CONCLUSIONS

The statistical assumptions made when modeling the effect of BMI on postarthroplasty complications dictate the results. Simple categorical handling of BMI creates arbitrary cutoff points that should not be used to inform larger policy decisions. Spline modeling of BMI avoids arbitrary cut points and provides a better model fit at extremes of BMI. Regardless of statistical management, BMI is an inadequate independent prognosticator of risk for individual patients considering total joint arthroplasty. Stakeholders should instead perform comprehensive risk assessment and avoid use of BMI as an isolated indicator of risk.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Acute hip fracture surgery anaesthetic technique and 30-day mortality in Sweden 2016 and 2017: A retrospective register study

Background: Hip fractures affect 1.6 million patients yearly worldwide, often elderly with complex comorbidity. Mortality following surgery for acute hip fracture is high and multifactorial; high age, comorbidities and complication/deterioration in health following surgery. Whether the anaesthesia technique affects the 30-day mortality rate has been studied widely without reaching a consensus. The primary aim of this study was to determine anaesthetic techniques used in Sweden and their impact on the 30-day mortality rate in elderly undergoing acute hip fracture surgery. Other aims were to study the impact of age, gender, ASA class, fracture type and delay in surgery on the 30-day mortality rate. Methods: Data from 13,649 patients ≥50 years old who had undergone acute hip fracture surgery and been reported to Swedish perioperative register (SPOR) between 2016 and 2017 were analysed.     Results: The most commonly used anaesthetic technique was neuraxial anaesthesia (NA; 11,257, 82%), followed by general anaesthesia (GA; 2,190, 16%) and combined general and neuraxial anaesthesia (CA; 202, 1.5%) out of the 13,649 studied. The 30-day mortality rate was 7.7% for the entire cohort; GA 7.8%, NA 7.7% and CA 7.4%. Mortality was higher in elderly patients, those with a high ASA class, pertrochanteric fracture and males.     Conclusions: The present study showed that NA is by far the most common anaesthetic technique for acute hip fracture surgery in Sweden. However, the anaesthetic technique used during this type of surgery had no impact on the 30-day mortality rate in patients. Increasing age, ASA class and male gender increased the 30-day mortality.

Acute hip fracture surgery anaesthetic technique and 30-day mortality in Sweden 2016 and 2017: A retrospective register study

Background: Hip fractures affect 1.6 million patients yearly worldwide, often elderly with complex comorbidity. Mortality following surgery for acute hip fracture is high and multifactorial; high age, comorbidities and complication/deterioration in health following surgery. Whether the anaesthesia technique affects the 30-day mortality rate has been studied widely without reaching a consensus. The primary aim of this study was to determine anaesthetic techniques used in Sweden and their impact on the 30-day mortality rate in elderly undergoing acute hip fracture surgery. Other aims were to study the impact of age, gender, ASA class, fracture type and delay in surgery on the 30-day mortality rate.

Methods: Data from 13,649 patients ≥50 years old who had undergone acute hip fracture surgery and been reported to Swedish perioperative register (SPOR) between 2016 and 2017 were analysed.    

Results: The most commonly used anaesthetic technique was neuraxial anaesthesia (NA; 11,257, 82%), followed by general anaesthesia (GA; 2,190, 16%) and combined general and neuraxial anaesthesia (CA; 202, 1.5%) out of the 13,649 studied. The 30-day mortality rate was 7.7% for the entire cohort; GA 7.8%, NA 7.7% and CA 7.4%. Mortality was higher in elderly patients, those with a high ASA class, pertrochanteric fracture and males.    

Conclusions: The present study showed that NA is by far the most common anaesthetic technique for acute hip fracture surgery in Sweden. However, the anaesthetic technique used during this type of surgery had no impact on the 30-day mortality rate in patients. Increasing age, ASA class and male gender increased the 30-day mortality.