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

Increased Body Mass Index Is Associated With Increased Cost for Primary Total Hip Arthroplasty Irrespective of Complications or Readmissions

BACKGROUND

Surgeons participating in alternative payment models may encounter financial disincentives in caring for patients whose care requires higher costs for the treatment facility. While smaller studies have shown a positive relationship between body mass index (BMI) and cost in total hip arthroplasty (THA), this question has yet to be examined using data in a nationally representative dataset. We sought to leverage a national dataset to assess the relationship between BMI and cost in THA.

METHODS

We queried a health care dataset from 2016 to 2022 to identify primary THAs using Current Procedural Terminology and International Classification of Disease-Procedure Coding System codes (27130, 0SR90xx, and 0SRB0xx) with a corresponding osteoarthritis diagnosis (International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM): M16). Patient demographics, characteristics, and cost variables were extracted directly from the dataset. Cost was defined by supplies, labor, and equipment and assessed over a 90-day period starting with the index surgical encounter. A multivariate generalized linear model estimated costs across eight BMI categories (World Health Organization BMI categories, with BMI > 40 patients grouped into BMI 40 to 45, BMI 45 to 50, and BMI > 50). A linear regression model assessed the effect of BMI on costs. Both models controlled for age, sex, payer, race, the Elixhauser comorbidity index, and ethnicity.

RESULTS

This study examined 10,366 primary THAs completed from 2016 to 2022. The mean BMI was 30.0 (standard error [SE] ± 0.1), the mean index cost was $14,632 (SE 52.9), and the mean 90-day cost was $16,527 (SE 145.4). Index and 90-day costs were lowest in the BMI 25 to 30 cohort ($14,344 and $15,865) and highest for the BMI >50 cohort ($17,503 and $28,281), respectively. On multivariate analyses, index and 90-day cost increased by $23 and $69, respectively, for every one-point increase in BMI (P < 0.001).

CONCLUSIONS

Results from this nationally representative dataset demonstrate that increasing BMI is associated with increased index and 90-day costs for THA. This information may be useful to stakeholders in the development of alternative payment models.

Trends, Demographics, and Outcomes for Glucagon-Like Peptide-1 Receptor Agonist Use in Total Knee Arthroplasty: An 11-Year Perspective

BACKGROUND

Obesity and diabetes mellitus (DM) pose challenges for patients undergoing total knee arthroplasty (TKA). Glucagon-like peptide-1 receptor agonists (GLP-1RAs) have emerged as agents for weight and DM management, but they affect multiple organ systems. Outcomes, trends, and demographics for perioperative GLP-1RA use in patients with TKA are not well understood.

METHODS

A retrospective review of 13,751 primary, elective TKAs with at least 90 days of follow-up at an urban academic health system between 2012 and 2023 identified 865 patients who had perioperative GLP-1RA use. A 10:1 propensity score match based on sex, age, smoking status, American Society of Anesthesiologists classification, and body mass index created a control cohort of 8,650 TKAs with no GLP-1RA use.

RESULTS

The use of GLP-1RAs varied significantly by race, Medicaid insurance, Charlson Comorbidity Index, and presence of DM. Black and Latino patients and those covered by Medicaid were significantly less likely to receive GLP-1RAs. The GLP-1RA group had significantly shorter length of stay (2.1 versus 2.5 days, P < 0.001) and a higher rate of home discharge (91.7 versus 84.2%, P < 0.001). The GLP-1RA users had significantly higher rates of 90-day emergency department visits (5.9 versus 4.0%, P = 0.008), but no differences in 90-day readmissions (4.3 versus 3.6%, P = 0.168) or 2-year revision (2.3 versus 2.6%, P = 0.362) compared to matched controls. The GLP-1RA patients had significantly lower all-cause revision rates at the last follow-up (2.7 versus 3.9%, P = 0.034), but there was no significant difference in Kaplan-Meier implant survival (P = 0.311). Before TKA, GLP-1RA patients had an average decrease in body mass index of 0.4, compared to an average increase of 1.2 for matched controls.

CONCLUSIONS

Our results demonstrate that the use of GLP-1RAs is significantly lower for minority patients and those covered by Medicaid. Patients using GLP-1RAs have noninferior clinical outcomes with the potential for weight loss leading up to TKA.

LEVEL OF EVIDENCE

III.

Decreased Risk of Readmission and Complications With Preoperative GLP-1 Analog Use in Patients Undergoing Primary Total Joint Arthroplasty

BACKGROUND

There has been considerable interest in the use of GLP-1 receptor analogs (GLP-1 RAs) for weight optimization in patients undergoing elective arthroplasty. As there is limited data regarding the implications of their use, our study aimed to evaluate the association between preoperative GLP-1 RA use and postoperative outcomes in patients undergoing primary total hip arthroplasty (THA) and total knee arthroplasty (TKA).

METHODS

The TrinetX research network was queried to identify all patients undergoing primary THA or TKA between May 2005 and December 2023 across 84 health care organizations. Patients were stratified based on preoperative GLP-1 RA use. Propensity score matching (1:1) was performed to account for baseline differences in demographics, laboratory investigations, and comorbidities. Subsequently, risk ratios were evaluated for postoperative outcomes.

RESULTS

A total of 268,504 and 386,356 patients underwent THA and TKA, of which 1,044 and 2,095 used preoperative GLP-1 RAs. After matching, GLP-1 RA use was associated with a decreased 90-day risk of periprosthetic joint infection (2.1 versus 3.6%, RR = 0.58, P = .042) and readmission (1.1 versus 2.0%, RR = 0.53, P = .017) following THA and TKA, respectively. There was no difference in the risk of all other outcomes between comparison groups.

CONCLUSIONS

Preoperative GLP-1 RA use is associated with a 42% decreased risk of periprosthetic joint infection and 47% decreased risk of readmission in the 90-day postoperative period following THA and TKA, respectively, with no difference in other risks, including aspiration. Our findings indicate that GLP-1 RAs may be safe to use in patients undergoing elective arthroplasty; however, further studies are warranted to inform the routine use of GLP-1 RAs for weight management in THA and TKA patients.

Ethical Considerations of Declining Surgical Intervention: Balancing Patient Wishes with Fiduciary Responsibility

ABSTRACT

Orthopaedic surgeons face increasing pressure to meet quality metrics due to regulatory changes and payment policies. Poor outcomes, including patient mortality, can result in financial penalties and negative ratings. Importantly, adverse outcomes often increase surgeon stress level and lead to job dissatisfaction and burnout. Despite optimization efforts, some orthopaedic patients remain at high risk for complications. In this article, we explore the ethical considerations when surgeons are presented with high-risk surgical candidates. We examine how the ethical tenets of patient interests, namely beneficence, nonmaleficence, autonomy, and justice, apply to such patients. We discuss external forces such as the malpractice environment, financial challenges in health-care delivery, and quality rankings. Informed consent and the challenges of communicating risks to patients are discussed, as well as the role of modifiable and nonmodifiable risk factors. Case examples with varied outcomes highlight the complexities of decision-making with high-risk patients and the potential role of palliative care. We provide recommendations for surgeons and care teams, including the importance of justifiable reasons for not operating, the utilization of institutional resources to help make care decisions, and the robust communication of risks to patients.

Is Preoperative Weight Reduction in Patients Who Have Body Mass Index ≥ 40 Associated With Lower Complication Rates After Primary Total Hip Arthroplasty?

BACKGROUND

Given the heightened risk of postoperative complications associated with obesity, delaying total hip arthroplasty (THA) in patients who have a body mass index (BMI) > 40 to maximize preoperative weight loss has been advocated by professional societies and orthopaedic surgeons. While the benefits of this strategy are not well-understood, previous studies have suggested that a 5% reduction in weight or BMI may be associated with reduced complications after THA.

METHODS

We identified 613 patients who underwent primary THA in a single institution during a 7-year period and who had a BMI >40 recorded from 9 to 12 months prior to surgery. Subjects were stratified into 3 cohorts based on whether their baseline BMI decreased by >5% (147 patients, 24%), was unchanged ( ± 5%) (336 patients, 55%), or increased by >5% (130 patients, 21%) on the day of surgery. The frequency of 90-days Hip Society and Centers for Medicare & Medicaid Services complications was compared between these cohorts. There were significant baseline differences between the cohorts with respect to baseline American Society of Anesthesiologists class (P < .001) and hemoglobin A1C (P = .011), which were accounted for in a multivariate regression analysis.

RESULTS

In univariate analysis, there was a lower incidence of readmission (P = .025) and total complications (P = .005) in the increased BMI cohort. The overall complication rate was 18.4% in the decreased BMI cohort, 17.6% in the unchanged cohort, and 6.2% in the increased cohort. However, multivariable regression analysis controlling for potential confounders did not find that preoperative change in BMI was associated with differences in 90-days complications between cohorts (P > .05).

CONCLUSIONS

Patients who have a BMI >40 and achieved a clinically significant (>5%) BMI reduction prior to THA did not have a lower risk of 90-days complications or readmissions. Thus, delaying THA in these patients to encourage weight loss may result in restricting access to a beneficial surgery without an appreciable safety benefit.

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.

The Impact of Obesity on Total Hip Arthroplasty Outcomes When Performed by High-Volume Surgeons-A Propensity Matched Analysis From a High-Volume Urban Center

BACKGROUND

Previous data suggest that obesity does not impact surgical outcomes following total knee arthroplasty performed by high-volume (HV) surgeons. However, this effect has yet to be studied in total hip arthroplasty (THA) patients. This study aimed to evaluate the impact of patient obesity on THA outcomes when surgery is performed by HV surgeons.

METHODS

A retrospective analysis of patients who underwent primary, elective THA between January 2012 and December 2022 with a HV surgeon (top 25% of surgeons by number of annual primary THA) was performed. Patients were stratified by their body mass index (BMI) into 3 cohorts: BMI ≥ 40 (morbidly obese [MO]), 30 ≤ BMI < 40 (obese), and BMI < 30 (nonobese); and 1:1:1 propensity matched based on baseline characteristics. A total of 13,223 patients were evaluated, of which 669 patients were included in the final matched analysis (223 patients per group). The average number of annual THAs performed for HV surgeons was 171 cases.

RESULTS

The MO patients had significantly longer surgical times (P < .001) and hospital lengths of stay (P < .001). Rates of 90-day readmissions (P = .211) and all-cause, septic, and aseptic revisions at the latest follow-up (P = .268, P = .903, and P = .168, respectively) were comparable between groups. In a subanalysis for non-HV surgeons, MO patients had a significantly greater risk of revision (P = .021) and trended toward significantly greater readmissions (P = .056).

CONCLUSIONS

Clinical outcomes and complication rates after THA performed by a HV surgeon are similar regardless of patient obesity status. Patients who have MO may experience improved outcomes and reduced procedural risks if they are referred to HV surgeons.

LEVEL OF EVIDENCE

III.

In-hospital outcomes following primary and revision total hip arthroplasty in nonagenarian patients

PURPOSE

The primary goal of this study was to assess the risk of postoperative surgical and medical complications and problems among nonagenarian patients operated with hip arthroplasty.

METHODS

Data from a specific high-volume arthroplasty clinic, were collected to evaluate postoperative morbidity and complication rates after hip arthroplasty in nonagenarians, compared with a control group of younger, but similar patients. Outcomes evaluated included length of stay, transfusion rate, and postoperative medical and surgical complication rates.

RESULTS

A total of 97 nonagenarian patients (mean age 91.4 years) were included, and compared with 89 control group patients (mean age 70.18 years). Nonagenarian patients had significantly longer length of stay (11.44 vs. 7.98 days, p < 0.01), significantly higher risk of needing a transfusion (11.30% vs. 3.40%, p = 0.04), and significantly higher risk of a postoperative medical complication (28.90% vs. 11.20%, p = 0.03). There was no difference in postoperative surgical complication rate (7.20% vs. 2.20%, p = 0.12).

CONCLUSION

Nonagenarian patients, when compared to a younger control group, experience significantly longer hospital stays, and risk of non-surgical complications. Arthroplasty in nonagenarian patients carries with it a high risk of complications, and thus careful pre-operative evaluation and the care of these patients at high volume, specialized clinics is important to optimize outcomes.

LEVEL OF EVIDENCE

Level III retrospective cohort analysis.

A Reduction in Body Mass Index From ≥ 40 to < 40 Lowers Emergency Department Visits, but May Increase All-Cause Readmissions After Primary Total Hip Arthroplasty: Conflicting 90-Day Outcomes at a Single Institution

BACKGROUND

The American Association of Hip and Knee Surgeons tasked a 2013 workgroup to provide obesity-related recommendations in total joint arthroplasty. Morbidly obese patients (body mass index (BMI) ≥ 40) seeking hip arthroplasty were determined to be at increased perioperative risk, and surgeons were recommended to encourage these patients to reduce their BMI <40 presurgery. We report the effect of instituting a 2014 BMI <40 threshold on our primary total hip arthroplasties (THAs).

METHODS

We queried our institutional database to select all primary THAs from January 2010 to May 2020. There were 1,383 THAs that were pre-2014 and 3,273 THAs that were post-2014. The 90-day emergency department (ED) visits, readmissions, and returns to operating room (OR) were identified. Patients were propensity score weight-matched according to comorbidities, age, initial surgical consultation (consult) BMI, and sex. We conducted 3 comparisons: A) pre-2014 patients who had a consult and surgical BMI ≥40 against post-2014 patients who had a consult BMI ≥40 and surgical BMI <40; B) pre-2014 patients against post-2014 patients who had a consult and surgical BMI <40; and C) post-2014 patients who had a consult BMI ≥40 and surgical BMI <40 against post-2014 patients who had a consult BMI ≥40 and surgical BMI ≥40.

RESULTS

Post-2014 patients who had a consult BMI ≥ 40 and surgical BMI <40 had less ED visits (7.6 versus 14.1%, P = .0007), but similar readmissions (11.9 versus 6.3%, P = .22) and returns to OR (5.4 versus 1.6%, P = .09) compared to pre-2014 patients who had a consult BMI and surgical BMI ≥ 40. Post-2014 BMI <40 had less readmissions (5.9 versus 9.3%, P < .0001), and similar all-cause returns to OR and ED visits than patients pre-2014. Post-2014 patients who had a consult and surgical BMI ≥ 40 had lower readmissions (12.5 versus 12.8%, P = .05), and similar ED visits and returns to OR than consult BMI ≥ 40 and surgical BMI <40.

CONCLUSION

Patient optimization prior to total joint arthroplasty is critical. However, the BMI optimization that mitigates risk in primary total knee arthroplasty may not apply to primary THA. We observed a paradoxical increased readmission rate for patients who reduced their BMI before THA.

LEVEL OF EVIDENCE

III.