Risk Reduction Compared with Access to Care: Quantifying the Trade-Off of Enforcing a Body Mass Index Eligibility Criterion for Joint Replacement

Examining the Relationship Between Relative Value Units and Patient-reported Outcomes: Implications for Value-based Care

INTRODUCTION

Compensation based on work relative value unit (wRVU) production is common among orthopaedic surgeons. With increased adoption of value-based payments, a greater portion of surgeon compensation will be linked to quality and outcome measures-including patient-reported outcomes. Therefore, we aimed to evaluate the relationship between wRVUs and changes in Patient-reported Outcomes Measurement Information System-Physical Function (PROMIS-PF) scores to assess whether wRVUs could serve as a marker of patient-reported functional improvements.

METHODS

A retrospective review of 2,996 orthopaedic surgeries at a single institution was done. Patient characteristics, total wRVUs billed by the surgeon for the case, operating room (OR) time, and change in PROMIS-PF scores from baseline to 6 months postoperatively were compared across subspecialties. Pearson correlation and multivariable linear regression were used to assess the relationship between wRVUs, OR time, and PROMIS-PF change.

RESULTS

Statistically significant differences in average wRVUs, OR times, and PROMIS-PF scores were observed across subspecialties. A strong positive correlation between wRVUs and OR time existed ( r = 0.732, P < 0.001) that explained approximately 54% of OR-time variability. A weak positive correlation between wRVUs and change in PROMIS-PF scores was observed ( r = 0.058, P = 0.002) that explained <1% of the variation. Each 1-point increase in wRVU was associated with a 3-minute increase in surgical duration (β = 3.04, P < 0.001) after controlling for demographics, comorbidities, and subspecialty, accounting for approximately 63% of OR-time variation. Each 1-point increase in wRVU was independently associated with a 0.02-point increase in PROMIS-PF change (β = 0.02, P = 0.036), explaining approximately 7% of the variation.

CONCLUSION

Across orthopaedic subspecialties, notable variability in both wRVUs and physical function improvements at 6 months postoperatively exists. Although highly correlated with surgical time, wRVUs show little association with functional improvement across subspecialties. As the transition toward value-based payment models continues, measurement of and compensation for work complexity and functional outcomes must remain separate and distinct.

Effect of BMI on the risk of postoperative complications following total hip arthroplasty

Aims

While obesity is associated with an increased risk of complications after total hip arthroplasty (THA), the relationship between BMI and the risk of early postoperative complications has not been fully characterized. This study sought to describe the relationship between BMI and the risk of early postoperative complications, including periprosthetic joint infection (PJI), and composite surgical and composite medical complications.

Methods

Primary, elective THAs performed from 1 October 2015 to 31 December 2021 were identified using the Premier Healthcare Database. The study's primary outcome was the diagnosis of PJI within 90 days of THA. Using BMI as a continuous variable, logistic regression was used to develop restricted cubic splines (RCSs) to determine the impact of BMI on PJI risk. Bootstrap simulation was used to identify an inflection point in the final RCS model. The same technique was used to characterize the effects of BMI on composite medical and surgical complications.

Results

We found that PJI risk increased exponentially beyond a BMI threshold of 37.4 kg/m2. Relative to this threshold, patients with a BMI of 40 or 50 kg/m2 were at a 1.22-fold and 2.55-fold increased risk of developing PJI, respectively. Surgical complications increased at a BMI of 32 kg/m2 and medical complications increased at a BMI of 39 kg/m2. Relative to these cut points, patients with a BMI of 50 kg/m2 were at a 1.36-fold and 2.07-fold increased risk of developing medical and surgical complications, respectively.

Conclusion

The results of this study indicate a non-linear relationship between patient BMI and early postoperative risk of PJI, composite medical complications, and composite surgical complications following THA. The identified cut points with associated odds ratios can serve as tools to help risk-stratify and counsel patients seeking primary THA.

Increased Waist Circumference Is Associated With Severe Postoperative Medical Complications Following Total Knee Arthroplasty: Understanding Waist Circumference and Relation to Body Mass Index

BACKGROUND

Obesity is projected to affect nearly 42% of Americans nationwide by 2050. Waist circumference (WC), an estimate of central obesity or adiposity, has been shown to be a better predictor for cardiometabolic morbidity and mortality than body mass index (BMI), which does not consider body fat distribution. This study aimed to evaluate whether: 1) WC correlates with increasing BMI cohorts; and 2) WC is a predictor of severe Clavien-Dindo IV complications within 30 days following total knee arthroplasty (TKA).

METHODS

A national dataset was retrospectively queried to identify patients who received primary TKA for knee osteoarthritis between 2010 and 2020 (N = 385,996). A validated model converted each patient's BMI to WC. The BMI cohorts were grouped into underweight, healthy weight, overweight, and obesity classes 1 to 3. Primary outcomes included comparing WC among different BMI cohorts undergoing TKA. The secondary outcome was to evaluate if WC was associated with severe surgical complications within 30 days. Clavien-Dindo IV complications included cardiac arrests, myocardial infarctions, septic shock episodes, pulmonary emboli, acute renal failures, and cerebrovascular accidents. Multivariable logistic regressions were adjusted for age, functional status, frailty, various comorbidities, and obesity to evaluate the odds ratios (ORs) between WC and postoperative complications following TKA, with P-values less than 0.001 as significant.

RESULTS

The mean WC significantly correlated with increasing BMI cohorts (P < 0.001). The mean WC was significantly higher among patients who developed Clavien-Dindo IV complications (112.4 versus 110.5 centimeters, P < 0.001). For all TKA patients, each centimeter increase in WC was associated with developing a postoperative complication (OR: 1.11, P < 0.001). Subanalysis of only obese patients showed WC to be a better predictor than BMI class (OR: 1.35, P < 0.001).

CONCLUSIONS

Central adiposity, measured by WC, was associated with severe complications following TKA, even when controlling for obesity. Screening interventions using waist measurements may assist joint arthroplasty surgeons in risk-stratifying patients who have higher BMIs. Further study is warranted on how to integrate WC into TKA practice.

GLP-1 Agonists for Weight Loss: Do They Increase Complications in Non-diabetic Patients Undergoing Primary Total Hip Arthroplasty?

BACKGROUND

Glucagon-like peptide 1 (GLP-1) agonists are an effective medication for glycemic control and weight loss. These effects may reduce complications in diabetic patients undergoing total hip arthroplasty (THA). However, there remains a paucity of data on the impact of GLP-1 medications in nondiabetic patients using the medication solely for weight reduction. There is concern that rapid weight loss associated with GLP-1 agonists may lead to malnutrition and increase the risk of postoperative complications in patients undergoing THA.

METHODS

A retrospective query was performed from January 1, 2010, to January 1, 2022, using an insurance claims database to identify patients undergoing primary THA on GLP-1 agonists (n = 839,715). Patients on GLP-1 therapy (n = 5,345) at the time of surgery were propensity score-matched 1:1 to controls who were not on GLP-1 agonists (n = 5,345) based on age, sex, the Elixhauser Comorbidity Index, and its components. Patients who had diabetes mellitus were excluded. The 90-day outcomes were evaluated, including medical complications, readmission, and reoperation rates. We also examined the incidence of all-cause revision and implant-related complications at a 2-year follow-up. Odds ratios (ORs) were generated using logistic regression analyses.

RESULTS

Patients who were on GLP-1 agonist medications were less likely to develop acute blood loss anemia (OR: 0.57; 95% confidence interval [CI]: 0.34 to 0.96) and require postoperative transfusion (OR: 0.53; 95% CI: 0.36 to 0.78) or visit the emergency department within 90 days of surgery (OR: 0.81; 95% CI: 0.69 to 0.92) when compared to patients who did not have GLP-1 therapy. Patients were at comparable risk of deep venous thrombosis, pulmonary embolism, mortality, stroke, myocardial infarction, acute kidney injury, and sepsis regardless of GLP-1 status (P > 0.05). Notably, the rate of aspiration pneumonia was similar between groups (OR: 1.17; 95% CI: 0.62 to 2.19). Also, GLP-1 therapy did not put patients at higher risk of surgical complications, including periprosthetic joint infection, instability, fracture, loosening, or all-cause revision, at 90 days and two years (P > 0.05).

CONCLUSIONS

Use of a GLP-1 agonist does not appear to increase the odds of postoperative medical and surgical complications after THA in nondiabetic patients taking GLP-1 medications for weight loss alone.

Ask, Acknowledge, Ascend: Addressing Mistrust as a Strategy to Address Disparities in Orthopaedic Ambulatory Care

Advances in minimally invasive surgical techniques, robotics, anesthesia techniques, and recovery protocols have been instrumental in shifting orthopaedic surgical care from the hospital-based operating room to ambulatory surgical centers. Outpatient surgical services are thought to offer a lower-cost model of care, reduced out-of-pocket expenses, more predictable scheduling, faster recovery times, convenience, and lower risk of nosocomial infections. With these known advantages, it is critical to examine whether this safer environment is accessible to all. Racial/ethnic and gender disparities have been well-documented in the inpatient orthopaedic environment and concern has been raised that the shift toward outpatient surgery could widen disparities and access to care. This article describes ongoing disparities in ambulatory orthopaedic surgery for racialized minorities, women, and people with obesity. Having experienced these disparities, many lack trust in health care providers and the health system. Approaches for addressing this mistrust to create meaningful patient-centered care are described.

Team Approach: An Interdisciplinary Framework for Weight Loss Before Total Joint Arthroplasty Surgery

» Obesity is a public health concern, with 41.9% of the US population classified as obese. Obesity increases the risk of chronic disease, type II diabetes, cardiovascular diseases, etc., leading to increased morbidity and mortality. Obesity has been identified as an independent risk factor of postoperative complications, including infection and impaired wound healing, following elective surgery. In total joint arthroplasty, it has been well elucidated that obese patients are predisposed to higher rates of postoperative complications, longer hospital stays, and increased cost of stay.» Obesity is influenced by the interplay between many societal, behavioral, and socioeconomic factors and requires a multidisciplinary approach to treatment. The patient's care team should be well versed in nutritional counseling, behavioral health counseling, medication management, and surgery to allow for a comprehensive approach.» Orthopaedic surgeons, dietitians, nutritionists, weight-loss physicians, and bariatric surgeons all play a critical role in treating this patient population. This review highlights the roles of these practitioners in developing an interdisciplinary framework to help patients with hip and knee arthritis lose weight before joint replacement surgery. Not only will this afford more patients the quality-of-life benefits that come with a hip or knee replacement but will also serve to decrease the complication rates associated with this patient cohort.» The aim of this review was to educate orthopaedic surgeons on various strategies that can be used to best optimize these patients for successful joint replacement surgery.

Body Mass Index is Not an Appropriate Proxy for the Condition of Peri-Incisional Adiposity in Primary Total Joint Arthroplasty Patients

BACKGROUND

The American Academy of Orthopaedic Surgeons defined the acceptable threshold for elective safe surgery as a body mass index (BMI) under 40 due to the increased risk of complications. A consequence of this recommendation has been a hard cutoff based on BMI, which restricts access to care for an increasingly large and diverse population. There is an improved understanding that excess adipose tissue confers additional risk for postoperative complications, including infection, through mechanical and physiologic mechanisms. But, it is unclear if BMI is an accurate indicator of adiposity in total joint arthroplasty (TJA) patients and, thus, whether BMI is capturing clinically relevant information in obese patients. Our objective was to determine the relationship between peri-incisional adiposity (PIA) and BMI in a consecutive series of diverse primary TJA patients.

METHODS

A consecutive series of patients indicated for primary TJA were preoperatively evaluated. For each patient, the following variables were collected: BMI and measures of PIA on radiographs and ultrasounds.

RESULTS

In THA patients (N = 99), Pearson's correlation coefficient (r) = 0.436, which indicates a moderate correlation between BMI and adiposity. In total knee arthroplasty patients (N = 271), r = 0.395 for femoral PIA (FPIA) and r = 0.249 for tibial PIA, which indicates a weak correlation between BMI and adiposity measured on radiography. In total knee arthroplasty patients, r = 0.560 for femoral PIA and r = 0.544 for tibial PIA, which indicates a moderate correlation between BMI and adiposity measured on ultrasound.

CONCLUSIONS

Quantification of obesity has become a common practice in the preoperative evaluation of primary TJA patients. The intent is to determine the magnitude of adipose tissue, which is one of the main drivers of postoperative complications in obesity. The BMI is ubiquitously used as a proxy for obesity due to its simplicity of attainment and calculation. We report that BMI has a weak-to-moderate association with PIA in this population. These findings indicate that BMI may not accurately represent the condition of peri-incisional adipose tissue and, thus, is not capturing the relevant obesity data for preoperative risk stratification in primary TJA patients.

LEVEL OF EVIDENCE

III.

Increasing Body Mass Index Not Associated With Worse Patient-Reported Outcomes After Primary THA or TKA

INTRODUCTION

As the US obesity epidemic continues to grow, so too does comorbid hip and knee arthritis. Strict body mass index (BMI) cutoffs for total hip and knee arthroplasty (THA and TKA) in the morbidly obese have been proposed and remain controversial, although current American Academy of Orthopaedic Surgeons guidelines recommend a BMI of less than 40 m/kg 2 before surgery. This study sought to compare patient-reported outcomes and 30-day complication, readmission, and revision surgery rates after THA or TKA between morbidly obese patients and nonmorbidly obese control subjects.

METHODS

All patients undergoing primary THA and TKA at our institution from May 2020 to July 2022 were identified. Patient demographics, surgical time, length of stay and 30-day readmission, revision surgery, and complication rates were prospectively collected. Preoperative and postoperative Hip and Knee Society (Hip Osteoarthritis Outcome Score [HOOS] and Knee Osteoarthritis Outcome Score [KOOS]) were collected. Patients were stratified by BMI as ideal weight (20 to 24.9), overweight (25 to 29.9), class I obese (30 to 34.9), class II obese (35 to 39.9), and morbidly obese (>40 m/kg 2 ).

RESULTS

A total of 1,423 patients were included for final analysis. No difference was observed in 30-day unplanned return to emergency department, readmission, or revision surgery in the morbidly obese cohort. Morbidly obese patients undergoing THA had lower preoperative HOOS (49.5 versus 54.5, P = 0.004); however, there was no difference in postoperative HOOS or KOOS at 12 months across all cohorts.

DISCUSSION

No difference was observed in 30-day return to emergency department, readmission, or revision surgery in the morbidly obese cohort. Despite a lower preoperative HOOS, there was no difference in 12-month HOOS or KOOS when stratified by BMI. These findings suggest that such patients may achieve similar benefit from arthroplasty as their ideal weight counterparts.

The Limited Utility of Hemoglobin A1c as a Predictor for Periprosthetic Joint Infection Following Total Joint Arthroplasty: A Continuous Variable Analysis

BACKGROUND

Patients who have poorly controlled diabetes mellitus are at increased risk of periprosthetic joint infection (PJI). Nevertheless, an optimal preoperative hemoglobin A1c (HbA1c) threshold has not been established. This study sought to identify preoperative HbA1c thresholds that were predictive of adverse outcomes for total hip arthroplasty (THA) and total knee arthroplasty (TKA) patients.

METHODS

A healthcare database was used to identify primary THAs or TKAs performed from 2016 to 2021 with a preoperative HbA1c value within 28 days of surgery. The primary outcome was PJI within 90 days postoperatively. Secondary outcomes included aggregate medical and surgical complications. Restricted cubic splines were generated using logistic regression to quantify the impact of HbA1c as a continuous variable on the risk of PJI. Between HbA1c values of 5 and 12%, relevant sensitivity and specificity measurements were calculated at intervals of 0.5%. A Youden's J statistic identified clinically relevant preoperative HbA1c thresholds.

RESULTS

In total, 17,481 elective arthroplasty patients who had a preoperative HbA1c were identified. The mean preoperative HbA1c was 6.5%. The previous two sentences should be placed at the end of the Methods section For TKA, a PJI threshold of 9.7% was identified (sensitivity: 19.4%, specificity: 99.1%), while for THA, a PJI threshold of 7.8% was identified (sensitivity: 22.7%, specificity: 89.9%). The threshold for aggregate medical complications was 6.8% for TKA (sensitivity: 53.7%, specificity: 59.1%) and 6.5% for THA (sensitivity: 45.5%, specificity: 66.5%). No association was observed between HbA1c and aggregate surgical complications for either THA or TKA.

CONCLUSIONS

This study identified PJI and medical complication HbA1c thresholds above which patients were at a significantly increased risk of early postoperative complications. While our findings suggest that HbA1c has limited predictive utility for postoperative complications, it remains an accessible biomarker that can aid in preoperative risk stratification. Future studies should explore other promising or complementary biomarkers that may be more effective for preoperative risk stratification.

LEVEL OF EVIDENCE

Level III.

Body Mass Index and the Risk of Postoperative Complications After Total Knee Arthroplasty

INTRODUCTION

Given the growing prevalence of obesity, it is crucial to understand the effect of obesity on complications after total knee arthroplasty (TKA). This study aims to assess the relationship between body mass index (BMI) and postoperative periprosthetic joint infection (PJI), medical complications, and surgical complications after TKA.

METHODS

The Premier Healthcare Database was used to identify all primary elective TKAs between 2016 and 2021. The primary outcome was risk of PJI within 90 days of surgery. Using logistic regression, restricted cubic splines were generated to assess the relationship between BMI as a continuous variable and PJI risk. Bootstrap simulation was then done to identify a BMI inflection point on the final restricted cubic spline model past which the risk of PJI increased. The relationship between BMI and composite 90-day medical and surgical complications was also assessed.

RESULTS

A direct relationship was observed between increasing BMI and increasing risk of PJI with a BMI changepoint of 31 kg/m 2 identified as being associated with increased risk. Above a BMI of 31 kg/m 2 , there was an average relative risk increase of PJI of 13.6% for every unit BMI. This relative risk per unit BMI increased from 5.8% for BMI 31 to 39 to 11.5% between BMI 40 and 49 kg/m 2 , and 21.3% for BMIs ≥50 kg/m 2 . Similarly, a direct relationship was also found between increasing BMI and both medical and surgical complications with BMI changepoints of 34 and 32 kg/m 2 identified, respectively.

DISCUSSION

Obese patients with a BMI >31 kg/m 2 were at increased risk of PJI. Although the relative risk increase was small per unit BMI above 31 kg/m 2 , the cumulative increase in risk may be marked for patients with higher BMIs.

CONCLUSION

These data should be used to inform discussions that involve shared decision making between patients and surgeons who weigh the risks and benefits of surgery.

A retrospective cohort review of BMI on SI joint fusion outcomes: examining the evidence to improve insurance guidelines

PURPOSE

The demand for SIJ fusion among obese patients has grown substantially. However, the clinical relevance of obesity in the context of SI joint fusion has not been well investigated specifically, whether there is a BMI cutoff above which the benefit-risk ratio is low.

METHODS

Adult patients ≥ 21 years of age who underwent minimally invasive SIJ fusion between 2020 and 2023. Participants were classified using the National Institutes for Health body mass index (BMI). Patients with a BMI of 30 to 39 with no significant comorbidity are considered obese, patients with a BMI of 35 to 39 with a significant comorbidity or a BMI of 40 or greater are considered morbidly obese. All subjects completed the Visual Analog Scale (VAS) and Oswestry Disability Index (ODI) at baseline and 12 months. One-way analysis of variance was used to examine the impact of BMI category on score changes.

RESULTS

Overall, mean VAS improved at 12 months by 2.5 points (p < .006). Over the 12-month follow-up period, BMI category did not impact mean improvement in VAS (ANOVA p = .08). Mean ODI at 12 months improved by 23.2 points (p < .001). BMI category did impact mean improvement in ODI (ANOVA p = .03).

CONCLUSION

This study demonstrates similar benefits across all BMI categories. This data suggests that obese patients do benefit from minimally invasive SIJ fusion, specifically the 35-40 BMI cohort of patients, and should not be denied this procedure based on arbitrary healthcare organizations BMI criteria.

Mid-term radiographic evaluation of a monoblock trabecular metal tibia following total knee arthroplasty in obese and morbidly obese patients

BACKGROUND

Indications for primary total knee arthroplasty (TKA) have become more inclusive of morbidly obese patients, however, higher rates of complications and lower implant survival have also been reported in this population. The purpose of this study was to investigate the mid-term survival, clinical, and radiographic outcomes of a cementless trabecular metal monoblock tibial component in severely obese patients.

METHODS

This was a retrospective study of class II and III obese (BMI > 35) patients who received a cementless primary TKA. Standing radiographs were assessed for the presence of progressive tibial radiolucent lines (RLL), and clinical measures were assessed at least 2 years post-operative via the Oxford Knee Score (OKS), UCLA Activity and Satisfaction Score, and the Euro-QoL 5-dimension (EQ-5D-5L) index and visual analogue scale (EQ-VAS) health status.

RESULTS

Patients (n = 176) were 61.2 ± 8.3 years of age, BMI 44.9 ± 6.5 kg/m2, and were predominantly female (n = 118, 66.7%). Mean follow-up was 59.2 ± 17.1 months. There were two total revisions at 6- and 57-months post-operative, respectively, and the 5-year survival estimate was 98.3% (95% confidence interval: 93.0%, 99.6%). Patient satisfaction was 93.9% and the post-operative OKS, EQ-5D-5L index, and EQ-VAS were 40.2 ± 7.9, 0.856 ± 0.205, and 73.6 ± 14.7, respectively. No cases of radiolucent lines were detected.

CONCLUSIONS

At 6 years this cementless monoblock tibial component demonstrated excellent survival without radiographic indications of aseptic loosening in a population of severely obese patients.

Does morbid obesity negatively impact perioperative outcomes following elective reverse shoulder arthroplasty?: a propensity-matched comparative study

Background

The incidence of primary reverse total shoulder arthroplasty (rTSA) and the prevalence of obesity have increased in the United States. Despite this, the literature assessing the effect of morbid obesity (body mass index≥40 kg/m2) on perioperative surgical outcomes remains inconsistent.

Methods

A retrospective review of consecutive elective primary rTSA cases from January 2016 through September 2023 at a single tertiary referral center was performed. All cases involved a short-stem humeral component and screw-in glenoid baseplate from the same implant manufacturer. Surgical and patient demographic data were collected. Morbidly obese patients were propensity matched at least 1:1 with non-morbidly obese patients based on age, gender, modified 5-item frailty index score, adjusted Charlson comorbidity index score, and 12-month preoperative emergency department (ED) visit. Regression analysis was utilized to assess the relationship between morbid obesity and operative time, length of stay, intraoperative total blood volume loss, surgical postoperative complications, in-hospital medical complications, disposition, and 90-day ED return and readmission.

Results

There were a total of 175 short-stem rTSA cases performed with a median age of 71 years (interquartile range: 66, 76), of which 19 (10.9%) had a body mass index ≥40 kg/m2. These 19 patients were propensity score matched to 41 non-morbidly obese patients (9 at 1:3, 4 at 1:2, and 6 at 1:1). There were no significant differences between the groups with regard to intraoperative total blood volume loss, operative time, need for transfusion, hospital length of stay, discharge disposition, prevalence for 90-day return to ED, or unplanned 90-day readmission.

Conclusion

Morbid obesity should not be considered an absolute contraindication for elective rTSA, particularly in patients who have undergone appropriate preoperative medical clearance.

Obesity and Primary Total Hip Arthroplasty: The Absolute versus Relative Risk of Periprosthetic Joint Infection at 15 Years

BACKGROUND

To make an informed decision about total hip arthroplasty (THA), surgeons and patients need to understand the absolute and relative risks of periprosthetic joint infection (PJI). We sought to evaluate the long-term risk of PJI following primary THA stratified by body mass index (BMI) and PJI-related risk factors.

METHODS

We identified 21,550 primary THAs performed from 2000 to 2021 at a single institution. Patients were stratified as having 0, 1, or ≥ 2 PJI risk factors (diabetes, chronic kidney disease, nonprimary osteoarthritis, immunosuppression, or active smoking) and into BMI categories. The 15-year cumulative risk of PJI was evaluated by BMI and PJI risk factors.

RESULTS

For the entire cohort, the 15-year absolute risk of PJI was 2%. For patients who did not have PJI risk factors, the absolute risk of PJI at 15 years was 1% in normal weight, 2% in class III obesity, and 4% in class IV obesity. Patients who had class III and IV obesity had a 3-times and 9-times higher relative risk of PJI, respectively (P = .03, P < .001). Among patients who had ≥ 2 PJI risk factors, the absolute risk of PJI at 15 years was 2% in normal weight, 4% in class III obesity, and 18% in class IV obesity.

CONCLUSIONS

Healthy patients who had class III and IV obesity had a 3-times and 9-times increased risk of PJI at 15 years relative to normal weight patients. However, the absolute risk of PJI at 15 years was 2 and 4%, respectively. Given emerging data questioning whether BMI modification decreases PJI risk, surgeons and patients must consider both a 3-times to 9-times increased relative risk of PJI and a 2 to 4% absolute risk of PJI at 15 years for healthy patients who had a BMI ≥ 40.

LEVEL OF EVIDENCE

IV.

Consistent Factors Influence Body Mass Index Thresholds for Total Joint Arthroplasty Across Health-Care Systems: A Qualitative Study

BACKGROUND

Body mass index (BMI) thresholds are used as eligibility criteria to reduce complication risk in total joint arthroplasty (TJA). This approach oversimplifies preoperative risk assessment and inadvertently restricts access to effective surgical treatment for osteoarthritis. A prior survey of orthopaedic surgeons in the United States identified complex underlying factors that influence BMI considerations. To understand whether similar factors exist and influence surgeons in a different health-care system setting, we investigated Canadian surgeons' views and use of BMI criterion thresholds for TJA access.

METHODS

A cross-sectional online qualitative survey was conducted with orthopaedic surgeons performing TJA in the Canadian health-care system. Responses were anonymous and questions were open-ended to allow for candid perspectives. Survey data were coded and a systematic process was followed to identify major themes. Findings were compared with U.S. surgeon perspectives.

RESULTS

Sixty-nine respondents had a mean age of 49.0 ± 11.4 years (range, 33 to 79 years), with a mean surgical experience duration of 15.7 ± 11.4 years (range, 2 to 50 years). Surgeons reported variable use of BMI thresholds in practice. Twelve interconnected factors that influence BMI considerations were identified: (1) variable evidence interpretation, (2) surgical challenge, (3) surgeon beliefs and biases, (4) hospital differences, (5) access to resources, (6) health system bias, (7) patient health status, (8) patient body fat distribution, (9) patient decisional burden (to lose weight or accept risk), (10) evidence gaps and uncertainties, (11) need for innovation, and (12) societal views. Nine themes matched with findings from U.S. surgeons.

CONCLUSIONS

Parallel to the United States, complex, interconnected factors influence Canadian orthopaedic surgeons' variable use of BMI restrictions for TJA eligibility. Despite different health-care systems and reimbursement models, similar technical and personal factors were identified. With TJA practice guidelines advising against hard BMI criteria, attention regarding access to resources, surgical training, and innovations to address TJA complexity in patients with large bodies are critically needed. Future advancements in this sphere must balance barrier removal with risk reduction to ensure safe and equitable surgical care.

CLINICAL RELEVANCE

This study may influence surgeon behaviors with regard to hard BMI cutoffs for TJA and encourage critical thought about factors that influence decisions about surgical eligibility for patients with high BMI.

Glucagon-Like Peptide Receptor-1 Agonists Used for Medically-Supervised Weight Loss in Patients With Hip and Knee Osteoarthritis: Critical Considerations for the Arthroplasty Surgeon

Patients with morbid obesity and concomitant hip or knee osteoarthritis represent a challenging patient demographic to treat as these patients often present earlier in life, have more severe symptoms, and have worse surgical outcomes following total hip and total knee arthroplasty. Previously, bariatric and metabolic surgeries represented one of the few weight loss interventions that morbidly obese patients could undergo prior to total joint arthroplasty. However, data regarding the reduction in complications with preoperative bariatric surgery remain mixed. Glucagon-like peptide receptor-1 (GLP-1) agonists have emerged as an effective treatment option for obesity in patients with and without diabetes mellitus. Furthermore, recent data suggest these medications may serve as potential anti-inflammatory and disease-modifying agents for numerous chronic conditions, including osteoarthritis. This review will discuss the GLP-1 agonists and GLP-1/glucose-dependent insulinotropic polypeptide dual agonists currently available, along with GLP-1/glucose-dependent insulinotropic polypeptide/glucagon triple agonists presently being developed to address the obesity epidemic. Furthermore, this review will address the potential problem of GLP-1-related delayed gastric emptying and its impact on the timing of elective total joint arthroplasty. The review aims to provide arthroplasty surgeons with a primer for implementing this class of medication in their current and future practice, including perioperative instructions and perioperative safety considerations when treating patients taking these medications.

Effects of BMI on SI joint fusion outcomes: examining the evidence to improve insurance guidelines

BACKGROUND CONTEXT

Obesity is increasing. Previous studies have demonstrated an association between obesity and adverse events after lumbar fusion. There is limited evidence on the effect of obesity on minimally invasive SI joint fusion (SIJF) outcomes.

PURPOSE

The purpose of this study was to investigate the impact of obesity on patient-reported outcomes in patients undergoing SIJF surgery using triangular titanium implants (TTI).

STUDY DESIGN

Retrospective cohort study based on four prospective clinical trials (INSITE [NCT01681004], SIFI [NCT01640353], iMIA [NCT01741025], and SALLY [NCT03122899]).

PATIENT SAMPLE

Adult patients ≥18 years of age who underwent minimally invasive surgery (MIS) sacroiliac joint (SIJ) fusion between 2012 and 2021.

OUTCOME MEASURES

Visual analog scale (VAS Pain), Oswestry Disability Index (ODI).

METHODS

Participants were classified using the National Institutes of Health body mass index (BMI). Patients with a BMI of 30 to 39 with no significant comorbidity are considered obese, patients with a BMI of 35 to 39 with a significant comorbidity or a BMI of 40 or greater are considered morbidly obese. All subjects underwent either minimally invasive SIJ fusion with TTI or nonsurgical management (INSITE and iMIA studies only). All subjects completed SIJ pain scale scores (measured with a 100-point VAS) and disability scores (measured with ODI) at baseline and at scheduled visits to 24 months. Repeated measures analysis of variance was used to examine the impact of BMI category on score changes.

RESULTS

In the SIJF group, mean SIJ pain improved at 24 months by 53.3 points (p<.0001). Over the 24-month follow-up period, BMI category did not impact mean improvement in SIJ pain scale score (repeated measures analysis of variance (ANOVA) p=.44). In the SIJF group, mean ODI at 24 months improved by 25.8 points (p<.0001). BMI category did not impact mean improvement in ODI (ANOVA p=.60). In the nonsurgical management (NSM) group, mean improvements in SIJ pain scale and ODI were clinically small (8.7 and 5.2 points, respectively) and not affected by BMI category (ANOVA p=.49 and .40).

CONCLUSION

This study demonstrates similar benefits and risks of minimally invasive SIJ fusion with TTI across all BMI categories. This analysis suggests that obese patients benefit from minimally invasive SIJ fusion and should not be denied this procedure based solely on elevated BMI.

The Efficacy of Platelet-Rich Plasma Injection Therapy in Obese versus Non-Obese Patients with Knee Osteoarthritis: A Comparative Study

Background/Objectives: Obesity is a common comorbidity in knee osteoarthritis (KOA) patients. Platelet-Rich Plasma (PRP) injection therapy may mitigate KOA. To further clarify potential patient selection for PRP injection therapy, we compared the outcomes in patients with different body mass index (BMI). Methods: A total of 91 patients with mild to moderate KOA were treated with three intra-articular PRP injections at 10 to 14-day intervals. Range of motion (ROM), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Visual Analogue Scale (VAS) were documented before and after the injections at 15 days, 6 months, 12 months, and at the last follow-up. Outcomes were compared between patients with a BMI over 30 kg/m2 (obese, n = 34) and under 30 kg/m2 (non-obese, n = 57). Results: Significant difference during the follow-up was detected in WOMAC score at the last follow-up favouring BMI under 30 group [17.8 ± 18.8 versus 10.5 ± 11.7, p = 0.023]. The odds ratio (OR) in BMI over 30 kg/m2 group for total knee arthroplasty was 3.5 (95% CI 0.3-40.1, p = 0.553), and OR for any arthroplasty was 7.5 (95% CI 0.8-69.8, p = 0.085) compared to non-obese patients. Conclusions: Obese patients benefitted from PRP injections in KOA but there is a minimal difference favouring non-obese patients in symptom alleviation in follow-up stages after 12 months. The risk of arthroplasty is higher for obese KOA patients.

Is Morbid Obesity a Modifiable Risk Factor in Patients Who Have Severe Knee Osteoarthritis and do Not Have a Formal Perioperative Optimization Program?

BACKGROUND

Obesity is considered a modifiable risk factor prior to total knee arthroplasty (TKA); however, little data support this hypothesis. Our purpose was to evaluate patients who have a body mass index (BMI) >40 presenting for TKA to determine the incidence of: (1) patients who achieved successful weight loss through nutritional modification or bariatric surgery and (2) patients who underwent TKA over the study period without the presence of a formal optimization program.

METHODS

This was a retrospective, single-center analysis. Inclusion criteria included: Kellgren and Lawrence grade 3 or 4 knee osteoarthritis, BMI >40 at presentation, and minimum 1-year follow-up (mean 45 months) (N = 624 patients). Demographics, weight loss interventions, pursuit of TKA, maximum BMI change, and Patient-Reported Outcomes Measurement Information System scores were collected. Multivariable logistic and linear regressions evaluated associations of underlying demographic and treatment characteristics with outcomes.

RESULTS

There were 11% of patients who ended up pursuing TKA over the study period. Bariatric surgery was 3.7 times more likely to decrease BMI by minimum 10 compared to nonsurgical intervention (95% confidence interval [CI] [1.7, 8.1]; P = .001). Bariatric surgery resulted in mean BMI change of -3.3 (range, 0 to 22) compared to nonsurgical interventions (-2.6 [range, 0 to 12]) and no intervention (0.4 [range, 0 to 15]; P < .0001). Bariatric surgery patients were 3.1 times more likely to undergo TKA (95% CI [1.3, 7.1]; P = .008), and nonsurgical interventions were 2.4 times more likely to undergo TKA (95% CI [1.3, 4.5]; P = .006) compared to no intervention. Non-White patients across all interventions were less likely to experience loss >5 BMI compared to White patients (95% CI [0.2, 0.9]; P = .018).

CONCLUSIONS

Most patients were unable to reduce BMI more than 5 to 10 over a mean 4-year period without a formal weight optimization program. Utilization of bariatric surgery was most successful compared to nonsurgical interventions, although ultimate pursuit of TKA remained low in all cohorts.

Medical Weight Optimization for Arthroplasty Patients: A Primer of Emerging Therapies for the Joint Arthroplasty Surgeon

The obesity epidemic in the United States continues to grow with more than 40% of individuals now classified as obese (body mass index >30). Obesity has been readily demonstrated to increase the risk of developing hip and knee osteoarthritis and is known to increase the risk of complications following joint arthroplasty. Weight loss prior to arthroplasty may mitigate this risk of complications; however, the existing evidence remains mixed with no clear consensus on the optimal method of weight loss and timing prior to arthroplasty. Treatment options for weight loss have included nonsurgical lifestyle modifications consisting of structured diet, physical activity, and behavioral modification, as well as bariatric and metabolic surgery (ie, sleeve gastrectomy, Roux-en-Y gastric bypass, and the adjustable gastric band). Recently, glucagon-like peptide-1 receptor agonists have gained notable popularity within the scientific literature and media for their efficacy in weight loss. The aim of this review is to provide a foundational primer for joint arthroplasty surgeons regarding the current and emerging options for weight loss to aid surgeons in shared decision-making with patients prior to arthroplasty.

Long-Term Health Outcomes of Limb Salvage Compared with Amputation for Combat-Related Trauma

BACKGROUND

There are little long-term health data, particularly in terms of body composition and development of metabolic syndromes, to help surgeons to guide the decision between limb salvage and amputation in patients with limb-threatening trauma. The purpose of this study was to compare long-term health outcomes after high-energy lower-extremity trauma between patients who underwent attempted flap-based limb salvage or amputation.

METHODS

We performed a retrospective review of servicemembers with a minimum 10-year follow-up who underwent flap-based limb salvage followed by unilateral amputation or continued limb salvage after combat-related, lower-extremity trauma between 2005 and 2011. Patient demographic characteristics, injury characteristics, and health outcomes including body mass index (BMI) and development of metabolic disease (e.g., hyperlipidemia, hypertension, heart disease, and diabetes) were compared between treatment cohorts. Adjusted BMIs were calculated for the amputation cohort to account for lost surface area. We performed multivariable and propensity score analysis to determine the likelihood of developing obesity or metabolic disease.

RESULTS

In this study, 110 patients had available long-term follow-up (mean, 12.2 years) from the time of the injury. Fifty-six patients underwent limb salvage and 54 patients underwent unilateral amputation. There was no difference in preinjury BMI (p = 0.30). After adjusting for limb loss, the amputation cohort had a trend toward higher BMIs at ≥1 years after the injury, a higher rate of obesity, and a greater increase in BMI from baseline after the injury. The development of metabolic comorbidities was common after both amputation (23 [43%] of 54) and limb salvage (27 [48%] of 56). With the numbers available, we were unable to demonstrate a difference in risk for the development of hypertension, hyperlipidemia, diabetes, heart disease, or any comorbidity other than obesity (p > 0.05).

CONCLUSIONS

Amputations may be medically necessary and may decrease pain, improve mobility, and/or expedite return to activity compared with limb salvage after similar injuries. However, limb loss may negatively impact metabolic regulation and may contribute to a higher risk of obesity despite beneficial effects on mobility.

LEVEL OF EVIDENCE

Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Does Preoperative Weight Loss Within 6 Months or 1 Year Change the Risk of Adverse Outcomes in Total Knee Arthroplasty by Initial Body Mass Index Classification?

BACKGROUND

High body mass index (BMI) is associated with adverse outcomes after total knee arthroplasty (TKA). Thus, many patients are advised to lose weight before TKA. This study examined how weight loss before TKA is associated with adverse outcomes depending on patients' initial BMI.

METHODS

This was a retrospective study of 2,110 primary TKAs at a single academic center. Data on preoperative BMIs, demographics, comorbidities, and incidences of revision or prosthetic joint infection (PJI) were obtained. Multivariable logistic regressions segmented by patients' initial (1-year preoperative) BMI classifications were performed to determine if a > 5% BMI decrease from 1 year or 6 months preoperatively predicted PJI and revision controlling for patient age, race, sex, and Elixhauser comorbidity index.

RESULTS

Preoperative weight loss did not predict adverse outcomes for patients who had Obesity Class II or III. 6-month weight loss had greater odds of adverse outcomes than 1-year weight loss and most significantly predicted the occurrence of 1-year PJI (adjusted odds ratio: 6.55, P < .001) for patients who had Obesity Class 1 or lower.

CONCLUSION

This study does not show a statistically significant effect to patients who had Obesity Class II and III losing weight preoperatively with respect to PJI or revision. For patients who have Obesity Class I or lower pursuing TKA, future research should consider potential risks associated with weight loss. Further study is needed to determine if weight loss can be implemented as a safe and effective risk reduction strategy for specific BMI classes of TKA patients.

Obesity is Associated With Greater Improvement in Patient-Reported Outcomes Following Primary Total Knee Arthroplasty

BACKGROUND

Body mass index (BMI) cutoffs have been established for total knee arthroplasty (TKA) patients due to increased risk of medical complications in obese patients. However, evidence-based medical optimization may mitigate risk in these patients. This study examined the influence of BMI on patient-reported outcome measures (PROMs) following primary TKA with specialized perioperative optimization.

METHODS

Between 2016 and 2020, 1,329 consecutive primary TKAs using standardized perioperative optimization were retrospectively reviewed. Patients were categorized into ordinal groups based on BMI in 5 kg/m2 increments (range, 17 to 61). Primary outcomes related to activity level, pain, function, and satisfaction were evaluated. BMI groups ≥35 had significantly lower age, more women, and higher prevalence of comorbidities (P ≤ .004). Mean follow-up was 1.7 years (range, 1 to 5 years).

RESULTS

Each successive BMI group from 35 to ≥50 demonstrated continually greater improvement in pain with level walking and stair climbing (P ≤ .001), Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (P = .001), and greater satisfaction (P = .007). No patients who had a BMI ≥35 were revised for aseptic loosening, and rates of periprosthetic joint infection were not different between BMI groups (P = 1.000).

CONCLUSION

Despite being more debilitated preoperatively, patients who had a BMI ≥35 experienced greater improvements in PROMs compared to patients who had lower BMI. Given the significant improvements in PROMs and quality of life in obese patients, with appropriate perioperative optimization, these patients should not be prohibited from having a TKA when appropriately indicated.

LEVEL OF EVIDENCE

III.

Local adiposity may be a more reliable predictor for infection than body mass index following total knee arthroplasty: a systematic review

PURPOSE

Improved understanding of the factors that predispose TKA patients to infection has considerable economic and medical impact. BMI is commonly used as a proxy for obesity to determine the risk of postoperative infection. However, this metric appears to be fraught with inconsistency in this application. BMI is a simple calculation which provides general insight into body habitus. But it fails to account for anatomic distribution of adipose tissue and the proportion of the mass that is skeletal muscle. Our objective was to review the literature to determine if local adiposity was more predictive than BMI for infection following TKA.

METHODS

A database search was performed for the following PICO (Population, Intervention, Comparison, and Outcome) characteristics: local measurements of adiposity (defined as soft tissue thickness or fat thickness or soft tissue envelope at the knee) in patients over 18 years of age treated with total knee arthroplasty used to determine the relationship between local adiposity and the risk of infection (defined as prosthetic joint infection or wound complication or surgical site infection). Quality was assessed using the GRADE framework and bias was assessed using ROBINS-I .

RESULTS

Six articles (N=7081) met the inclusion criteria. Four of the six articles determined that adiposity was more associated with or was a better predictor for infection risk than BMI. One of the six articles concluded that increased adiposity was protective for short term infection and that BMI was not associated with the outcome of interest. One of the six articles determined that BMI was more strongly associated with PJI risk than soft tissue thickness.

CONCLUSION

The use of adiposity as a proxy for obesity in preoperative evaluation of TKA patients is an emerging concept. Although limited by heterogeneity, the current literature suggests that local adiposity may be a more reliable predictor for infection than BMI following primary TKA.

LEVEL OF EVIDENCE

IV systematic review.

How using body mass index cutoffs to determine eligibility for total shoulder arthroplasty affects health care disparities

BACKGROUND

The prevalence of obesity in the United States is continuously rising and is associated with increased morbidity, mortality, and health care costs. Body mass index (BMI) has been used as a risk stratification and counseling tool for patients undergoing total joint arthroplasty in an effort to focus on outcome-driven care. Although the use of BMI cutoffs may have benefits in minimizing complications when selecting patients for total shoulder arthroplasty (TSA), it may impact access to care for some patient populations and further increase disparities. The purpose of this study is to determine the implications of using BMI cutoffs on the eligibility for TSA among different ethnic and gender patient populations.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was queried to identify 20,872 patients who underwent anatomic and reverse TSA between 2015 and 2019. Patient demographics, including age, sex, race and ethnicity, and BMI, were compared between eligible and ineligible patients based on BMI for 5 cutoff values: 30, 35, 40, 45, and 50 kg/m2.

RESULTS

Of the total patient population studied, the mean age was 69 years, 55% were female, and the mean BMI was 31 kg/m2. For all BMI subgroups, there were more ineligible than eligible patients who were female or Black (P < .001). The relative rate of eligibility for Black patients was lower in each BMI cutoff group, whereas the relative rate of eligibility for White and Asian patients was higher for each group. There were more eligible than ineligible Asian patients for BMI cutoffs of 30 and 35 kg/m2 (both P < .001), and there were no differences in eligibility and ineligibility in Hispanic patients (P > .05). Furthermore, White patients were more eligible than ineligible for all BMI cutoff groups (P < .001).

CONCLUSIONS

Enforcing BMI cutoffs for access to TSA may limit the procedure for female or Black patients for all BMI cutoffs, thus furthering the health care disparities these populations already face. However, there are more eligible than ineligible White patients for all BMI cutoff groups, which indicates a disparity in the access to TSA based on sex and race. Physicians may inadvertently increase health care disparities observed in TSA if they use BMI as the sole risk stratification tool for patients, even though BMI has been known to increase complications after TSA. Moreover, orthopedic surgeons should only use BMI as one of many factors in a more holistic process when determining if a patient should undergo TSA.

Modern Perioperative Pain Management Strategies to Minimize Opioids after Total Knee Arthroplasty

Total Knee Arthroplasty is associated with significant postoperative pain that can limit functional outcomes and patient satisfaction. In recent years, the standard of care for postoperative pain management has reduced reliance on opioids in favor of multimodal analgesia. These regimens consist of systemic medications such as COX-2 inhibitors, acetaminophen, corticosteroids, and gabapentinoids, as well as regional and local approaches such as peripheral nerve blocks and local infiltrative analgesics. Newer therapies, such as cryoneurolysis, are still being studied but have shown promising results. Additional studies are needed to determine the ideal pain regimen that will optimize pain control and eliminate the need for postoperative opioids.

Go Big or Go Home: Obesity and Total Joint Arthroplasty

Obesity is highly prevalent, and it is expected to grow considerably in the United States. The association between obesity and an increased risk of complications following total joint arthroplasty (TJA) is widely accepted. Many believe that patients with body mass index (BMI) >40 have complications rates that may outweigh the benefits of surgery and should consider delaying it. However, the current literature on obesity and outcomes following TJA is observational, very heterogeneous, and full of confounding variables. BMI in isolation has several flaws and recent literature suggests shifting from an exclusively BMI <40 cutoff to considering 5 to 10% preoperative weight loss. BMI cutoffs to TJA may also restrict access to care to our most vulnerable, marginalized populations. Moreover, only roughly 20% of patients instructed to lose weight for surgery are successful and the practice of demanding mandatory weight loss needs to be reconsidered until convincing evidence exists that supports risk reduction as a result of preoperative weight loss. Obese patients can benefit greatly from this life-changing procedure. When addressing the potential difficulties and by optimizing preoperative assessment and intraoperative management, the surgery can be conducted safely. A multidisciplinary patient-centered approach with patient engagement, shared decision-making, and informed consent is recommended.

Losing weight to achieve joint or hernia surgery: is the intragastric balloon the answer?

BACKGROUND

Obesity is an epidemic, with its accompanying medical conditions putting patients at increased risk of postoperative complications. For patients undergoing elective surgery, preoperative weight loss provides an opportunity to decrease complications. We sought to evaluate the safety and efficacy of an intragastric balloon in achieving a body mass index (BMI) < 35 kg/m2 prior to elective joint replacement or hernia repair.

METHODS

Retrospective review of all patients who had intragastric balloon placement at a level 1A VA medical center from 1/2019 to 1/2023. Patients who had a scheduled qualifying procedure (knee/hip replacement or hernia repair) and had a BMI > 35 kg/m2 were offered intragastric balloon placement to achieve 30-50lbs (13-28 kg) weight loss prior to surgery. Participation in a standardized weight loss program for 12 months was required. Balloons were removed 6 months after placement, preferentially concomitant with the qualifying procedure. Baseline demographics, duration of balloon therapy, weight loss and progression to qualifying procedure were recorded.

RESULTS

Twenty patients completed intragastric balloon therapy and had balloon removal. Mean age 54 (34-71 years), majority (95%) male. Mean balloon duration was 200 ± 37 days. Mean weight loss was 30.8 ± 17.7lbs (14.0 ± 8.0 kg) with an average BMI reduction of 4.4 ± 2.9. Seventeen (85%) patients were successful, 15 (75%) underwent elective surgery and 2 (10%) were no longer symptomatic after weight loss. Three patients (15%) did not lose sufficient weight to qualify or were too ill to undergo surgery. Nausea was the most frequent side effect. One (5%) patient was readmitted within 30 days for pneumonia.

DISCUSSION

Intragastric balloon placement resulted in an average 30lbs (14 kg) weight loss over 6 months allowing more than 75% of patients to undergo joint replacement or hernia repair at an optimal weight. Intragastric balloons should be considered in patients requiring 30-50lbs (13-28 kg) weight loss prior to elective surgery. More study is needed to determine the long-term benefit of preoperative weight loss prior to elective surgery.

Is There a Difference in PROMs Between Morbidly Obese Patients and Nonobese Patients Following Primary Total Knee Arthroplasty?

Background

Patient satisfaction and patient-reported outcome measures (PROMs) are important for patients, surgeons, and payers in the current healthcare climate. Morbidly obese patients (body mass index [BMI] >40) have demonstrated higher incidence of complications after total knee arthroplasty (TKA) and can have difficulty obtaining access for their surgical care. The purpose of this study was to evaluate PROMs and patient satisfaction in morbidly obese patients undergoing primary TKA.

Methods

A total of 75 patients with BMI >40 kg/m² undergoing robotic-assisted TKA were retrospectively identified and matched 2:1 to a consecutive cohort of patients with BMI <35. The average BMI of the study cohort was 42.4 kg/m² (39.5-51.3) compared to 28.6 kg/m² (18.5-34.9) in the control group. Clinical outcomes, PROMs, and patient satisfaction were evaluated at a minimum 2-year follow-up.

Results

The patients of the BMI >40 cohort were less likely to be discharged home (P = .0076), had less active flexion at 2 years (P = .0046), and had worse knee scores at 2 years (0.0497). Despite this, the percentage of patients who were satisfied or very satisfied after surgery was similar between the groups (87.5% vs 91.2%, P = .1943).

Conclusions

Morbidly obese patients are less likely to be discharged directly to home and may have functional differences after primary TKA. However, morbidly obese patients have similar PROMs and are as satisfied as nonobese patients at 2 years. Morbidly obese patients with end-stage knee osteoarthritis should also be able to enjoy the benefits of primary TKA following medical and surgical optimization.

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.

An Update on the Management and Optimization of the Patient with Morbid Obesity Undergoing Hip or Knee Arthroplasty

The prevalence of obesity in the United States is at a record high of 42%. In 1999, the Centers for Disease Control and Prevention recognized the obesity epidemic as a national problem, spurring the first generation of interventions for obesity prevention and control. Despite billions of dollars in funding, legislative changes, and public health initiatives, the trajectory of American obesity has not waivered. Obesity is also strongly associated with the development of osteoarthritis. The growing population of young, obese, and sick patients presents a unique dilemma for orthopedic surgeons performing joint replacement, as obesity levels and the demand for joint replacement are only expected to rise further.

"I Often Feel Conflicted in Denying Surgery": Perspectives of Orthopaedic Surgeons on Body Mass Index Thresholds for Total Joint Arthroplasty: A Qualitative Study

BACKGROUND

Use of a patient body mass index (BMI) eligibility threshold for total joint arthroplasty (TJA) is controversial. A strict BMI criterion may reduce surgical complication rates, but over-restrict access to effective osteoarthritis (OA) treatment. Factors that influence orthopaedic surgeons' use of BMI thresholds are unknown. We aimed to identify and explore orthopaedic surgeons' perspectives regarding patient BMI eligibility thresholds for TJA.

METHODS

A cross-sectional, online qualitative survey was distributed to orthopaedic surgeons who conduct hip and/or knee TJA in the United States. Survey questions were open-ended, and responses were collected anonymously. Survey data were coded and analyzed in an iterative, systematic process to identify predominant themes.

RESULTS

Forty-five surveys were completed. Respondents were 54.3 ± 12.4 years old (range, 34 to 75 years), practiced in 22 states, and had 21.2 ± 13.3 years (range, 2 to 44 years) of surgical experience. Twelve factors influencing BMI threshold use by orthopaedic surgeons were identified: (1) evidence interpretation, (2) personal experiences, (3) difficulty of surgery, (4) professional ramifications, (5) ethics and biases, (6) health-system policies and performance metrics, (7) surgical capacity and resources, (8) patient body fat distribution, (9) patient self-advocacy, (10) control of decision-making in the clinical encounter, (11) expectations for demonstrated weight loss, and (12) research and innovation gaps.

CONCLUSIONS

Multilevel, complex factors underlie BMI threshold use for TJA eligibility. Addressing identified factors at the patient, surgeon, and health-system levels should be considered to optimally balance complication avoidance with improving access to life-enhancing surgery.

CLINICAL RELEVANCE

This study may influence how orthopaedic surgeons think about their own practices and how they approach patients and consider surgical eligibility.

The Impact of Metabolic Syndrome and Obesity on Perioperative Total Joint Arthroplasty Outcomes: The Obesity Paradox and Risk Assessment in Total Joint Arthroplasty

Background

The relationship between elevated body mass index (BMI) and adverse outcomes in joint arthroplasty is well established in the literature. This paper aims to challenge the conventional thought of excluding patients from a total knee or hip replacement based on BMI alone. Instead, we propose using the metabolic syndrome (MetS) and its defining components to better identify patients at high risk for intraoperative and postoperative complications.

Methods

Patients who underwent primary, elective total knee and total hip arthroplasty were identified in the 2015-2020 American College of Surgeons National Surgical Quality Improvement Program database. Several defining components of MetS, such as hypertension, diabetes, and obesity, were compared to a metabolically healthy cohort. Postoperative outcomes assessed included mortality, length of hospital stay, 30-day surgical and medical complications, and discharge.

Results

The outcomes of 529,737 patients from the American College of Surgeons National Surgical Quality Improvement Program who underwent total knee and total hip arthroplasty were assessed. MetS is associated with increased complications and increased mortality. Both hypertension and diabetes are associated with increased complications but have no impact on mortality. Interestingly, while obesity was associated with increased complications, there was a significant decrease in mortality.

Conclusions

Our results show that the impact of MetS is more than the sum of its constitutive parts. Additionally, obese patients experience a protective effect, with lower mortality than their nonobese counterparts. This study supports moving away from strict BMI cutoffs alone for someone to be eligible for an arthroplasty surgery and offers more granular data for risk stratification and patient selection.

The safety and cost-analysis of simultaneous versus staged bilateral total knee arthroplasty in a Taiwan population

BACKGROUND

In patients with advanced osteoarthritis (OA) of the bilateral knees, uncertainty remains as to whether simultaneous bilateral total knee arthroplasty (SiTKA) or staged TKA (StTKA) is the treatment of choice. The purpose of this study was to investigate the safety and relative cost of SiTKA vs StTKA in Taiwan patients.

METHODS

Using the Big Data Center of Taipei Veterans General Hospital, we retrospectively reviewed all patients who underwent SiTKA or StTKA due to OA or spontaneous osteonecrosis of the knee from January 2011 to December 2016. We assessed length of stay, transfusion rate, early postoperative complications, 30- and 90-day readmission rate, 1-year reoperation rate, and the indication for reoperation. Furthermore, we analyzed the total cost of the two groups, including reimbursement from the national health insurance (NHI), cost of the procedures, and net income from each case.

RESULTS

A total of 2016 patients (1565 SiTKA and 451 StTKA) were included in this study. The two groups had no significant differences in rates of complications, 30- and 90-day readmission, or 1-year reoperation. The length of stay was on average 5.0 days longer for StTKA ( p < 0.01). In terms of cost, all categories of medical costs were significantly lower for SiTKA, while the net hospital income was significantly higher for StTKA.

CONCLUSION

SiTKA is a safe and cost-effective surgery. Both SiTKA and StTKA have similar rates of postoperative complications, readmission and reoperation, but SiTKA significantly reduces medical expenses for both the patient and the NHI.

The use of local adiposity as a proxy for obesity in primary total hip arthroplasty: A systematic review

Introduction

Preoperative optimization of obese patients is a critical component of risk stratification in primary total hip arthroplasty (THA). Body mass index is ubiquitously utilized as a proxy for obesity due to its ease of attainment and simplistic interpretation. The use of adiposity as a proxy for obesity is an emerging concept. Local adiposity provides insight into the magnitude of peri-incisional tissue and has demonstrated an association with postoperative complications. Our objective was to review the literature to determine if local adiposity is a reliable predictor for complications following primary total hip arthroplasty.

Methods

In keeping with the PRISMA guidelines, a database search of PubMed was conducted for articles which reported on the relationship between quantified measures of adiposity at the hip and rates of complication following primary THA. Methodological quality was assessed using GRADE and risk of bias using ROBINS-I.

Results

A total of six articles (N = 2931) met the inclusion criteria. Local adiposity at the hip was measured on anteroposterior radiograph in four articles and was measured intraoperatively in two. Across four of the six articles, adiposity was significantly associated with postoperative complications including prosthesis failure and infection.

Conclusion

The use of BMI as a predictor for postoperative complication has been fraught with inconsistency. There is momentum for adiposity to be used as a proxy for obesity in preoperative THA risk stratification. The current findings demonstrated that local adiposity may be a reliable predictor for complications following primary THA.

Total Hip and Knee Arthroplasty Surgery in the Morbidly Obese Patient: A Critical Analysis Review

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Obesity, defined as body mass index (BMI) ≥30, is a serious public health concern associated with an increased incidence of stroke, diabetes, mental illness, and cardiovascular disease resulting in numerous preventable deaths yearly.

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From 1999 through 2018, the age-adjusted prevalence of morbid obesity (BMI ≥40) in US adults aged 20 years and older has risen steadily from 4.7% to 9.2%, with other estimates showing that most of the patients undergoing hip and knee replacement by 2029 will be obese (BMI ≥30) or morbidly obese (BMI ≥40).

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In patients undergoing total joint arthroplasty (TJA), morbid obesity (BMI ≥40) is associated with an increased risk of perioperative complications, including prosthetic joint infection and mechanical failure necessitating aseptic revision.

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The current literature on the role that bariatric weight loss surgery before TJA has on improving surgical outcomes is split and referral to a bariatric surgeon should be a shared-decision between patient and surgeon on a case-by-case basis.

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Despite the increased risk profile of TJA in the morbidly obese cohort, these patients consistently show improvement in pain and physical function postoperatively that should be considered when deciding for or against surgery.

Can extant comorbidity indices identify patients who experience poor outcomes following total joint arthroplasty?

INTRODUCTION

It is uncertain if generic comorbidity indices commonly used in orthopedics accurately predict outcomes after total hip (THA) or knee arthroplasty (TKA). The purpose of this study was to determine the predictive ability of such comorbidity indices for: (1) 30-day mortality; (2) 30-day rate of major and minor complications; (3) discharge disposition; and (4) extended length of stay (LOS).

METHODS

The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was retrospectively reviewed for all patients who underwent elective THA (n = 202,488) or TKA (n = 230,823) from 2011 to 2019. The American Society of Anesthesiologists (ASA) physical status classification system score, modified Charlson Comorbidity Index (mCCI), Elixhauser Comorbidity Measure (ECM), and 5-Factor Modified Frailty Index (mFI-5) were calculated for each patient. Logistic regression models predicting 30-day mortality, discharge disposition, LOS greater than 1 day, and 30-day major and minor complications were fit for each index.

RESULTS

The ASA classification (C-statistic = 0.773 for THA and TKA) and mCCI (THA: c-statistic = 0.781; TKA: C-statistic = 0.771) were good models for predicting 30-day mortality. However, ASA and mCCI were not predictive of major and minor complications, discharge disposition, or LOS. The ECM and mFI-5 did not reliably predict any outcomes of interest.

CONCLUSION

ASA and mCCI are good models for predicting 30-day mortality after THA and TKA. However, similar to ECM and mFI-5, these generic comorbidity risk-assessment tools do not adequately predict 30-day postoperative outcomes or in-hospital metrics. This highlights the need for an updated, data-driven approach for standardized comorbidity reporting and risk assessment in arthroplasty.

A Novel Method for Stratification of 30-Day Major Complication Risk Using Body Mass Index Thresholds for Patients Undergoing Total Knee Arthroplasty: A National Cohort of 443,157 Patients

INTRODUCTION

Many organizations have utilized pre-established body mass index (BMI) cut-offs to guide surgical decision making. As there have been many improvements in patient optimization, surgical technique, and perioperative care over time, it is important to reassess these thresholds as well as contextualize them to total knee arthroplasty (TKA). The purpose of this study was to calculate data-driven BMI thresholds that predict significant differences in risk of 30-day major complications following TKA.

METHODS

Patients who underwent primary TKA from 2010 to 2020 were identified in a national database. Stratum-specific likelihood ratio (SSLR) methodology was utilized to determine data-driven BMI thresholds at which the risk of 30-day major complications increased significantly. These BMI thresholds were tested using multivariable logistic regression analyses. A total of 443,157 patients were included, who had a mean age of 67 (range, 18 to 89), mean BMI of 33 (range 19 to 59), and 11,766 (2.7%) of patients had a 30-day major complication RESULTS: SSLR analysis identified four BMI thresholds that were associated with significant differences in 30-day major complications: 19 to 33, 34 to 38, 39 to 50, and 51+. When compared to those who had a BMI between 19 and 33, the odds of sustaining a major complication sequentially and significantly increased by 1.1, 1.3, and 2.1 times (p<0.05 for all) for the other thresholds.

CONCLUSION

This study identified four data-driven BMI strata utilizing SSLR analysis that were associated with significant differences in the risk of 30-day major complications following TKA. These strata can be utilized to guide shared decision making in patients undergoing TKA.

Perception of Perioperative Risk for Arthroplasty Patients: A Poll of Australian Orthopedic Surgeons

BACKGROUND

There is growing interest in the perioperative management of patients who have indications for hip and knee arthroplasty in the setting of modifiable risk factors such as morbid obesity, poorly controlled diabetes, and smoking. A recent survey of the American Association of Hip and Knee Surgeons (AAHKS) found that 95% of respondents address modifiable risk factors prior to surgery. The aim of this study was to poll Australian arthroplasty surgeons regarding their approach to patients who have modifiable risk factors.

METHODS

The survey tool used in the AAHKS study was adapted for use in the Australian context and distributed to the membership of the Arthroplasty Society of Australia via SurveyMonkey. There were 77 responses received, representing a response rate of 64%.

RESULTS

The majority of respondents were experienced, high volume arthroplasty surgeons. Overall, 91% of respondents restricted access to arthroplasty for patients who have modifiable risk factors. There were 72% restricting access for excessive body mass index, 85% for poor diabetic control, and 46% for smoking. Most respondents made decisions based on personal experience or literature review rather than hospital or departmental pressures. While 49% of surgeons believed that current payment systems did not impair their ability to achieve good outcomes, 58% believed that certain arthroplasty patients would benefit from additional intervention, based on their socioeconomic status.

CONCLUSION

Over 90% of surgeons who responded address modifiable risk factors prior to surgery. This finding aligns with the practice patterns of AAHKS members, despite differences in healthcare systems.

Access to hip and knee arthroplasty in England: commissioners' policies for body mass index and smoking status and implications for integrated care systems

BACKGROUND

Commissioning policies are in place in England that alter access to hip and knee arthroplasty based on patients' body mass index and smoking status. Our objectives were to ascertain the prevalence, trend and nature of these policies, and consider the implications for new integrated care systems (ICSs).

METHODS

Policy data were obtained from an internet search for all current and historic clinical commissioning group (CCG) hip and knee arthroplasty policies and use of Freedom of Information (FOI) requests to each CCG. Descriptive analyses of policy type, explicit threshold criteria and geography are reported. Estimates were made of the uptake of policies by ICSs based on the modal policy type of their constituent CCGs.

RESULTS

There were 106 current and 143 historic CCGs in England at the time of the search in June 2021. Policy information was available online for 56.2% (140/249) CCGs. With the addition of information from FOIs, complete policy information was available for 94.4% (235/249) of CCGs. Prevalence and severity of policies have increased over time. For current CCGs, 67.9% (72/106) had a policy for body mass index (BMI) and 75.5% (80/106) had a policy for smoking status for hip or knee arthroplasty. Where BMI policies were in place, 61.1% (44/72) introduced extra waiting time before surgery or restricted access to surgery based on BMI thresholds (modal threshold: BMI of 40 kg/m², range 30-45). In contrast, where smoking status policies were in place, most offered patients advice or optional smoking cessation support and only 15% (12/80) introduced extra waiting time or mandatory cessation before surgery. It is estimated that 40% of ICSs may adopt a BMI policy restrictive to access to arthroplasty.

CONCLUSIONS

Access policies to arthroplasty based on BMI and smoking status are widespread in England, have increased in prevalence since 2013, and persist within new ICSs. The high variation in policy stringency on BMI between regions is likely to cause inequality in access to arthroplasty and to specialist support for affected patients. Further work should determine the impact of different types of policy on access to surgery and health inequalities.

Projected Prevalence of Obesity in Aseptic Revision Total Hip and Knee Arthroplasty

Background

The purpose of this study was to develop projections of the prevalence of obesity in aseptic revision THA and TKA patients through the year 2029.

Methods

The National Surgical Quality Improvement Project (NSQIP) was queried for years 2011-2019. Current procedural terminology (CPT) codes 27134, 27137, and 27138 were used to identify revision THA and CPT codes 27486 and 27487 were used to identify revision TKA. Revision THA/TKA for infectious, traumatic, or oncologic indications were excluded. Participant data were grouped according to body mass index (BMI) categories: underweight/normal weight, <25 kg/m2; overweight, 25-29.9 kg/m2; class I obesity, 30.034.9 kg/m2; class II obesity, 35.0-39.9 kg/m2; morbid obesity ≥ 40 kg/m2. Prevalence of each BMI category was estimated from year 2020 to year 2029 through multinomial regression analyses.

Results

38,325 cases were included (16,153 revision THA and 22,172 revision TKA). From 2011 to 2029, prevalence of class I obesity (24% to 25%), class II obesity (11% to 15%), and morbid obesity (7% to 9%) increased amongst aseptic revision THA patients. Similarly, prevalence of class I obesity (28% to 30%), class II obesity (17% to 29%), and morbid obesity (16% to 18%) increased in aseptic revision TKA patients.

Conclusion

Prevalence of class II obesity and morbid obesity demonstrated the largest increases in revision TKA and THA patients. By 2029, we estimate that approximately 49% of aseptic revision THA and 77% of aseptic revision TKA will have obesity and/or morbid obesity. Resources aimed at mitigating complications in this patient population are needed. Level of Evidence: III.

A Novel Method for Stratification of Major Complication Risk Using Body Mass Index Thresholds for Patients Undergoing Total Hip Arthroplasty: A National Cohort of 224,413 Patients

INTRODUCTION

Elevated body mass index (BMI) is associated with complications following Total Hip Arthroplasty (THA). Since obese individuals are almost 10 times more likely to require THA compared to non-obese individuals, we need to understand the risk-benefit continuum while considering THA in obese patients. We aimed to determine data-driven thresholds for BMI at which the risk of major complications following THA increases significantly.

METHODS

Patients were identified in a national database who underwent primary THA from 2010 to 2020. BMI thresholds were identified using the stratum-specific likelihood ratio (SSLR) methodology, which is an adaptive technique that allows for identification of BMI cut-offs, at which the risk of major complications is increased significantly . BMI cutoffs identified using SSLR were used to create a logistic regression model.

RESULTS

A total of 224,413 patients were identified with a mean age of 66 ± 10, BMI 32 ± 6.7, and 7,186 (3%) sustained a major complication. BMI thresholds were defined as 19-31, 32-37, 38-49 and 50+. Overall, the absolute risk of major complications increased from 2.9% in the lowest BMI strata to 7.5% in the highest BMI strata. Compared to patients with a BMI between 19-31, the odds of sustaining a major complication sequentially increased by 1.2, 1.6, and 2.5-times for patients in each higher BMI strata (all, P < .05).

CONCLUSIONS

We have identified BMI cutoffs using SSLR that categorizes patients into four categories of risk for major complications in a nationally representative patient sample. These thresholds can be used in the surgical decision-making process between patients and surgeons.

Significant Reduction in Short-Term Complications Following Unicompartmental Versus Total Knee Arthroplasty: A Propensity Score Matched Analysis

BACKGROUND

Total knee arthroplasty (TKA) is a gold standard surgical treatment for end-stage arthritis and unicompartmental knee arthroplasty (UKA) is an alternative for localized disease in appropriate patients. Both have been shown to have equivalent complications in the short-term period. We aimed to explore the differences in 30-day complication rates between UKA and TKA using recent data.

METHODS

Current Procedural Terminology codes identified patients in the American College of Surgeons National Surgical Quality Improvement Program database who underwent primary TKA or UKA from 2014 to 2018. Propensity score matching addressed demographic differences. Rate of any adverse event (AAE) and complications were compared.

RESULTS

We identified 279,852 patients with 270,786 and 9,066 undergoing TKA and UKA. No significant difference was observed in baseline demographics after matching. The AAE rate differed significantly between TKA (5.07%) and UKA (2.38%) cohorts (P < .001). TKA group experienced more wound dehiscence, cerebrovascular accident, postoperative blood transfusion, deep vein thrombosis, and requirement for postoperative intubation. Rate of extended length of stay differed between the TKA (11.35%) and UKA (4.89%) cohorts (P < .001). Accounting for all other variables, preoperative corticosteroid use, bleeding disorder, and chronic obstructive pulmonary disease increased the risk for AAE for both groups. Increasing American Society of Anesthesiologists class also increased the odds for complication proportionally with increasing age and operative time.

CONCLUSION

Contrary to previous data, we found a significantly higher 30-day complication rate in TKA patients. TKA patients had a higher likelihood of having an extended length of stay. Multivariable analysis identified preoperative steroid use, bleeding disorder, and chronic obstructive pulmonary disease as risk factors for developing adverse events for both groups.

LEVEL OF EVIDENCE

Level III.

Total Hip Arthroplasty in Morbidly Obese: Does a Strict Body Mass Index Cutoff Yield Meaningful Change?

PURPOSE

The number of obese patients seeking total hip arthroplasty (THA) continues to expand despite body mass index (BMI) cutoffs. We sought to determine the outcomes of THA in the morbidly obese patient, and hypothesized they would have comparable outcomes to two cohorts of obese, and normal weight patients.

MATERIALS AND METHODS

THA performed on morbidly obese patients (BMI >40 kg/m²) at a single academic center from 2010 until 2020 were retrospectively reviewed. Eighty morbidly obese patients were identified, and matched in a 1:3:3 ratio to control cohorts with BMI 30-40 kg/m² and BMI <30 kg/m². Acute postoperative outcomes and BMI change after surgery were evaluated for clinical significance with univariate and regression analyses. Cox proportional hazard ratio was calculated to evaluate prosthetic joint infection (PJI) and revision surgery through follow-up. Mean follow-up was 3.9 years.

RESULTS

In the acute postoperative period, morbidly obese patients trended towards increased hospital length of stay, facility discharge and 90-day hospital returns. At final follow-up, a higher percentage of morbidly obese patients had clinically significant (>5%) BMI loss; however, this was not significant. Cox hazard ratio with BMI <30 kg/m² as a reference demonstrated no significant difference in survival to PJI and all-cause revision in the morbidly obese cohort.

CONCLUSION

Morbidly obese patients (BMI >40 kg/m²) require increased resource expenditure in the acute postoperative period. However, they are not inferior to the control cohorts (BMI <30 kg/m², BMI 30-40 kg/m²) in terms of PJI or all-cause revisions at mid-term follow-up.

Timing and Type of Bariatric Surgery Preceding Total Knee Arthroplasty Leads to Similar Complications and Outcomes

BACKGROUND

No consensus exists regarding the appropriate timing of bariatric surgery (BS) or the complication profiles between Roux-en-Y Gastric Bypass (RYGB) and sleeve gastrectomy (SG) prior to total knee arthroplasty (TKA). We sought to compare 90-day medical and up to two-year surgical complications and revisions among (1) BS performed 6 months and 1 year prior to TKA; (2) between BS types (RYGB and SG) prior to TKA; and (3) with comparison to 2 non-BS cohorts of morbidly and nonmorbidly obese patients.

METHODS

We queried a national database to identify patients undergoing BS (RYGB and SG) prior to TKA from 2010 to 2020. Timing (six-month and one-year intervals) and type of BS (RYGB and SG) were identified. Cohorts without prior BS served as comparators: BMI, kg/m² > 40 and 20-35. Ninety-day to two-year medical/surgical complications and revisions were assessed. Multivariate regression analyses examined the risk factors for prosthetic joint infections (PJIs) and revisions.

RESULTS

The timing of BS (6 months and 1 year) had similar incidences of medical/surgical complications and revisions, with both lower than the BMI > 40 cohort (P < .001). Differences between types of BS were also lower than the BMI > 40 cohort (P < .001). The BMI 20-35 had lower complications and revisions among all cohorts. No differences were observed between BS timing or type as risk-factors for PJIs and revisions.

CONCLUSION

Timing (6 months or 1 year prior to TKA) and type of BS shared similar complication profiles, lower than BMI > 40 and higher than BMI 20-35. These findings support a surgeon's decision to proceed with TKA at six months post-BS if indicated.

Predictors of Reinfection in Prosthetic Joint Infections Following Two-Stage Reimplantation

BACKGROUND

Two-stage reimplantation is an effective treatment for periprosthetic joint infection (PJI). Many factors are involved in the variable success of this procedure. The purpose of this study is to examine the relationship between patient risk factors, comorbidities, and the pathogen on reinfection rates following two-stage reimplantation.

METHODS

We evaluated 158 patients treated for PJI from 2008-2019. Only patients who had completed a two-stage exchange were included. Patient demographics, comorbidities, laboratory values, time-to-reimplantation, pathogen, antibiotic sensitivities, host status, and reinfection rates were assessed. Multivariate analysis was performed to identify correlation between risk factors and reinfection. A P-value < .05 was considered statistically significant.

RESULTS

31 patients experienced a reinfection (19.6%). There was a statistically significant association between infection with Methicillin Sensitive Staphylococcus Aureus (MSSA) and reinfection (P = .046). Patients with a reinfection also had a significantly greater median serum C-reactive protein (CRP) level (12.65 g/dL) at the time of diagnosis compared to patients without a reinfection (5.0 g/dL) (P = .010). Median Erythrocyte Sedimentation Rate (ESR) (56 in no re-infection and 69 in re-infection) and time-to-reimplantation (101 days in no reinfection and 141 days in reinfection) demonstrated a trend toward an association with re-infection but were not statistically significant (P = .055 and P = .054 respectively).

CONCLUSION

As the number of arthroplasties continue to rise, PJIs are increasing proportionately and represent a significant revision burden. Elevated C-reactive protein (CRP) levels and Methicillin Sensitive Staphylococcus aureus (MSSA) infection were strongly associated with failure of a two-stage reimplantation. While not statistically significant with our numbers, there were strong trends toward an association between elevated Erythrocyte Sedimentation Rate (ESR), longer time-to-reimplantation, and reinfection.

What Is the Impact of Body Mass Index Cutoffs on Total Hip Arthroplasty Complications?

BACKGROUND

Body mass index (BMI) cutoffs are commonly utilized to decide whether to offer obese patients elective total hip arthroplasty (THA). However, weight loss goals may be unachievable for many, and some patients are thereby denied complication-free surgery. The purpose of this study was to assess the impact of varying BMI cutoffs on the rates of complication-free surgery after THA.

METHODS

Patients undergoing THA between 2015 and 2018 were identified in the American College of Surgeons National Surgical Quality Improvement Program database using Common Procedural Terminology code 27130. BMI and rates of 30-day complications were collected. BMI cutoffs of 30, 35, 40, 45, and 50 kg/m² were applied to model the incidence of complications if THA would have been allowed to proceed based on BMI.

RESULTS

A total of 192,394 patients underwent THA, and 13,970 (7%) of them had a BMI ≥40 kg/m². With a BMI cutoff of 40 kg/m², 178,424 (92.7%) patients would have proceeded with THA. From this set, 170,296 (95.4%) would experience complication-free surgery, and 11.8% of complications would be prevented. THA would proceed for 191,217 (99.3%) patients at a BMI cutoff of 50 kg/m², of which 182,123 (95.2%) would not experience a complication, and 1.3% of complications would be prevented. Using 35 kg/m² as the BMI cutoff would prevent 28.6% of complications and permit 75.9% of complication-free surgeries to proceed.

CONCLUSION

Lower BMI cutoffs for THA can result in fewer complications although they will consequentially limit access to complication-free THA. Consideration of risks of obesity in THA may be best considered as part of a holistic assessment and shared decision-making when deciding on goals for weight reduction.

Projected Prevalence of Obesity in Primary Total Knee Arthroplasty: How Big Will the Problem Get?

BACKGROUND

Obesity is a well-established risk factor for complications following primary total knee arthroplasty (TKA). The purpose of this study is to utilize 3 national databases to develop projections of obesity within the general population and primary TKA patients in the United States through 2029.

METHODS

Data from the National Surgical Quality Improvement Program (NSQIP), the Behavior Risk Factor Surveillance System (BRFSS), and the National Health and Nutrition Examination Survey were queried for years 1999-2019. Current Procedural Terminology code 27447 was used to identify primary TKA patients in NSQIP. Individuals were categorized according to body mass index (kg/m²) by year: normal weight (≤24.9); overweight (25.0-29.9); obese (30.0-39.9); and morbidly obese (≥40). Multinomial logistic regression was used to project categorical body mass index data for years 2020-2029.

RESULTS

A total of 8,372,221 individuals were included (7,986,414 BRFSS, 385,807 NSQIP TKA). From 2011 to 2019, the prevalence of normal weight and overweight individuals declined in the general population (BRFSS) and in primary TKA. Prevalence of obese/morbidly obese individuals increased in the general population from 31% to 36% and in primary TKA from 60% to 64%. Projection models estimate that by 2029, 46% of the general population will be obese/morbidly obese and 69% of primary TKA will be obese/morbidly obese.

CONCLUSION

By 2029, we estimate ≥69% of primary TKA to be obese/morbidly obese. Increased resources dedicated to care pathways and research focused on improving outcomes in obese arthroplasty patients will be necessary as this population continues to grow.

LEVEL OF EVIDENCE

Level III, Retrospective Cohort Study.