The Rise of Obesity among Total Knee Arthroplasty Patients

AbstractIn the United States, one-third of adults are considered obese, and demand for total knee arthroplasty (TKA) is expected to rise in these patients. Surgeons are reluctant to operate on obese patients, but it is important to understand how obesity has affected TKA utilization. This study utilizes a national database to evaluate incidence, demographics, outcomes, charges, and cost in nonobese, overweight, nonmorbidly obese, and morbidly obese TKA patients. We queried the National Inpatient Sample from 2009 to 2016 for primary TKA patients identifying 4,053,037 nonobese patients, 40,077 overweight patients, 809,649 nonmorbidly obese patients, and 428,647 morbidly obese patients. Chi-square was used to analyze categorical variables, and one-way analysis of variance was used to analyze continuous variables. Nonmorbidly obese and morbidly obese patients represented 23.2% of all TKAs. TKA utilization increased 4.1% for nonobese patients, 121.6% for overweight patients, 73.6% for nonmorbidly obese patients, and 83.9% for morbidly obese patients. Morbidly obese patients were younger (p < 0.001), female (p < 0.001), Black (p < 0.001), poor (p < 0.001), and utilized private insurance (p < 0.001). They also had the longest length of stay (p < 0.001) and the highest mortality rate (p < 0.001). More morbidly obese patients were discharged to other facilities (p < 0.001), and they had the highest rate of complications (p < 0.001). Patients with morbid obesity had the highest charges (p < 0.001), but overweight patients had the highest costs (p < 0.001). The results of this study demonstrate the rise in obese and morbidly obese patients seeking TKAs, which may be reflection of the obesity epidemic in America. Although TKA utilization has increased for morbidly obese patients, this body mass index (BMI) category also has the highest rates of charges and complications, suggesting morbid obesity to be a modifiable risk factor leading to worse surgical and economic outcomes. Obese patients undergoing TKA may benefit from preoperative optimization of their weight, in an effort to reduce the risk of adverse outcomes.

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The Use of Stems for Morbid Obesity in Total Knee Arthroplasty

The Journal of Knee Surgery ◽

10.1055/s-0039-1681078 ◽

2019 ◽

Vol 32 (07) ◽

pp. 607-610 ◽

Cited By ~ 1

Author(s):

Blake J. Schultz ◽

Malcolm R. DeBaun ◽

James I. Huddleston

Keyword(s):

Total Knee Arthroplasty ◽

Knee Arthroplasty ◽

High Risk Patient ◽

Morbidly Obese ◽

Obese Patients ◽

Limited Data ◽

Implant Fixation ◽

Knee Motion ◽

Total Knee ◽

Nonobese Patients

AbstractMorbidly obese patients undergoing total knee arthroplasty have worse functional outcomes and implant survival, and increased revision rates compared with nonobese patients. In addition to increased medical comorbidities and difficult exposure, increased stress on the tibial implant and altered kinematics of knee motion contribute to aseptic loosening and medial collapse. Increased implant fixation, including use of a stemmed tibial implant, may be a way to help avoid these complications. While there is limited data on tibial stems in the morbidly obese patients specifically, cemented stemmed tibial implants should be strongly considered in these patients, especially if bone quality is poor. The initial increased cost of a stemmed implant can be justified in this high-risk patient population to minimize the risk of costly revisions related to compromised tibia component fixation.

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Trends of Obese and Morbidly Obese Patients in Same-Day Bilateral Total Knee Arthroplasty from 2009 to 2016

The Journal of Knee Surgery ◽

10.1055/s-0040-1708038 ◽

2020 ◽

Author(s):

Ethan A. Remily ◽

Wayne A. Wilkie ◽

Nequesha S. Mohamed ◽

Mark Pastore ◽

Anthony Viola ◽

...

Keyword(s):

United States ◽

Total Knee Arthroplasty ◽

Knee Arthroplasty ◽

Hospital Costs ◽

The United States ◽

Morbidly Obese ◽

Obese Patients ◽

Bilateral Total Knee Arthroplasty ◽

Total Knee ◽

Chi Square Analysis

AbstractAs obesity in the United States increases, the proportion of obese and morbidly obese patients undergoing same-day bilateral total knee arthroplasty (sd-BTKA) remains unknown. Therefore, this study analyzed: (1) incidence, (2) patient demographics, (3) patient course, and (4) patient outcomes in obese and morbidly obese patients undergoing sd-BTKA in the United States from 2009 to 2016. The National Inpatient Sample was queried for all sd-BTKA patients from 2009 to 2016, yielding 39,901 obese and 20,394 morbidly obese patients. Analyzed variables included overall incidence, age, length of stay (LOS), sex, race, payer, Charlson comorbidity index (CCI) status, disposition, complications, location/teaching status, region of hospital, costs, and charges. Categorical variables were evaluated with chi-square analysis, while continuous variables were analyzed by Student's t-tests. Overall, the number of sd-BTKAs decreased over the study period, although the proportion of both obese and morbidly obese patients increased (p < 0.001 for all). The most common CCI status, 3 + , decreased in proportion for both groups (p < 0.001 for all). Hospital costs decreased and charges increased for both groups (p < 0.001 for all). Mean LOS decreased and patients were most commonly discharged to skilled nursing facilities, although these proportions decreased (p < 0.001 for all). Respiratory failures (p < 0.001 for all) increased for both groups, while proportion of deep vein thromboses and hematomas/seromas (p < 0.001 for all) increased for obese patients and proportion of pulmonary emboli (p < 0.001) increased for morbidly obese patients. The results of this study appear to portray improving optimization and patient selection of higher body mass index (BMI) individuals undergoing this procedure. More information is needed comparing the safety of the sd-BTKA across patients of all BMI groups.

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Is ICD-9 Coding of Morbid Obesity Reliable in Patients Undergoing Total Knee Arthroplasty?

The Journal of Knee Surgery ◽

10.1055/s-0038-1668567 ◽

2018 ◽

Vol 31 (10) ◽

pp. 934-939 ◽

Cited By ~ 1

Author(s):

Jaiben George ◽

Nipun Sodhi ◽

Hiba Anis ◽

Anton Khlopas ◽

Joseph Moskal ◽

...

Keyword(s):

Morbid Obesity ◽

Total Knee Arthroplasty ◽

Sensitivity And Specificity ◽

Knee Arthroplasty ◽

International Classification Of Diseases ◽

Morbidly Obese ◽

Obese Patients ◽

Primary Tkas ◽

Total Knee ◽

The Impact

AbstractMorbid obesity is considered to have a stronger association with complications after total knee arthroplasty (TKA). Although the impact of obesity coding errors has been previously reported, the extent of coding inaccuracies with respect to morbid obesity is unclear. Therefore, the purpose of this study was to assess (1) the utility of coding in identifying morbid obesity and (2) the effects of morbid obesity on 90-day complications after TKA when morbid obesity was defined by both body mass index (BMI) and International Classification of Diseases 9th edition (ICD-9) coding. A total of 18,030 primary TKAs performed at a single institution from 2004 to 2014 were identified. Patients were defined as morbidly obese based on ICD-9 codes or by BMI recorded in the electronic medical record (EMR). Patients were defined as obese (ICD-9 codes 278.0, 278.00, 278.01, 278.03, 649.10–14, 793.91, V85.30–39, V85.41–45, V85.54) or morbidly obese (278.01, V85.41–45) by ICD-9 codes. Patient EMRs were also reviewed to identify obese and morbidly obese patients (BMI cutoffs of 30 and 40 kg/m2, respectively). Complications between the cohorts were compared. Sensitivity and specificity were also calculated. Among the 2,880 surgeries performed in morbidly obese patients, a code for obesity was present in 1,618 (56.2%) surgeries, but only 57.9% (937) of these patients had a code specific for morbid obesity, with the rest having a code not specifying morbid obesity. The sensitivity and specificity of obesity coding were 34.5 and 96.0%, while that of morbid obesity were 32.5 and 96.7%, respectively (area under curve: 0.65 vs. 0.65, p = 0.214). A higher rate of complications was noted when patients were defined as morbidly obese by ICD-9 as when defined by EMR-reported BMI. Although morbidly obese patients are more likely to have a code for obesity compared with obese patients, these patients may not be correctly identified as morbidly obese due to a lack of specificity in the codes. These errors may lead to inadequate reimbursements, and may also overestimate the effect of morbid obesity on complications.

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Preoperative Weight Loss for Morbidly Obese Patients Undergoing Total Knee Arthroplasty

The Journal of Bone and Joint Surgery (American) ◽

10.2106/jbjs.18.01136 ◽

2019 ◽

Vol 101 (16) ◽

pp. 1440-1450 ◽

Cited By ~ 10

Author(s):

Benjamin J. Keeney ◽

Daniel C. Austin ◽

David S. Jevsevar

Keyword(s):

Weight Loss ◽

Total Knee Arthroplasty ◽

Knee Arthroplasty ◽

Morbidly Obese ◽

Preoperative Weight Loss ◽

Obese Patients ◽

Total Knee ◽

Preoperative Weight

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Safety of Bilateral Total Knee Arthroplasty in Morbidly Obese Patients

Orthopedics ◽

10.3928/01477447-20140225-57 ◽

2014 ◽

Vol 37 (3) ◽

pp. e252-e259 ◽

Cited By ~ 14

Author(s):

Adam A. Madsen ◽

Benjamin C. Taylor ◽

Craig Dimitris ◽

Dane C. Hansen ◽

Robert A. Steensen ◽

...

Keyword(s):

Total Knee Arthroplasty ◽

Knee Arthroplasty ◽

Morbidly Obese ◽

Obese Patients ◽

Bilateral Total Knee Arthroplasty ◽

Total Knee

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Preoperative risk stratification minimizes 90-day complications in morbidly obese patients undergoing primary total knee arthroplasty

The Bone & Joint Journal ◽

10.1302/0301-620x.103b6.bjj-2020-2409.r1 ◽

2021 ◽

Vol 103-B (6 Supple A) ◽

pp. 45-50

Author(s):

Yehuda E. Kerbel ◽

Mitchell A. Johnson ◽

Stephen R. Barchick ◽

Jordan S. Cohen ◽

Kimberly Lola Stevenson ◽

...

Keyword(s):

Total Knee Arthroplasty ◽

Risk Stratification ◽

Knee Arthroplasty ◽

Morbidly Obese ◽

Obese Patients ◽

Preoperative Risk ◽

Rehabilitation Facility ◽

Significant Difference ◽

Total Knee ◽

Preoperative Risk Stratification

Aims It has been shown that the preoperative modification of risk factors associated with obesity may reduce complications after total knee arthroplasty (TKA). However, the optimal method of doing so remains unclear. The aim of this study was to investigate whether a preoperative Risk Stratification Tool (RST) devised in our institution could reduce unexpected intensive care unit (ICU) transfers and 90-day emergency department (ED) visits, readmissions, and reoperations after TKA in obese patients. Methods We retrospectively reviewed 1,614 consecutive patients undergoing primary unilateral TKA. Their mean age was 65.1 years (17.9 to 87.7) and the mean BMI was 34.2 kg/m2 (SD 7.7). All patients underwent perioperative optimization and monitoring using the RST, which is a validated calculation tool that provides a recommendation for postoperative ICU care or increased nursing support. Patients were divided into three groups: non-obese (BMI < 30 kg/m2, n = 512); obese (BMI 30 kg/m2 to 39.9 kg/m2, n = 748); and morbidly obese (BMI > 40 kg/m2, n = 354). Logistic regression analysis was used to evaluate the outcomes among the groups adjusted for age, sex, smoking, and diabetes. Results Obese patients had a significantly increased rate of discharge to a rehabilitation facility compared with non-obese patients (38.7% (426/1,102) vs 26.0% (133/512), respectively; p < 0.001). When stratified by BMI, discharge to a rehabilitation facility remained significantly higher compared with non-obese (26.0% (133)) in both obese (34.2% (256), odds ratio (OR) 1.6) and morbidly obese (48.0% (170), OR 3.1) patients (p < 0.001). However, there was no significant difference in unexpected ICU transfer (0.4% (two) non-obese vs 0.9% (seven) obese (OR 2.5) vs 1.7% (six) morbidly obese (OR 5.4); p = 0.054), visits to the ED (8.6% (44) vs 10.3% (77) (OR 1.3) vs 10.5% (37) (OR 1.2); p = 0.379), readmissions (4.5% (23) vs 4.0% (30) (OR 1.0) vs 5.1% (18) (OR 1.4); p = 0.322), or reoperations (2.5% (13) vs 3.3% (25) (OR 1.2) vs 3.1% (11) (OR 0.9); p = 0.939). Conclusion With the use of a preoperative RST, morbidly obese patients had similar rates of short-term postoperative adverse outcomes after primary TKA as non-obese patients. This supports the assertion that morbidly obese patients can safely undergo TKA with appropriate perioperative optimization and monitoring. Cite this article: Bone Joint J 2021;103-B(6 Supple A):45–50.

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