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

Abstract

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.

Does Value-Based Care Threaten Joint Arthroplasty Access for Vulnerable Patient Populations?

“…While determining the appropriate level of risk stratification for various medical comorbidities and socioeconomic factors is challenging, these efforts must be initiated to protect access for vulnerable patients. For example, although TJA has been shown to be cost-effective in morbidly obese patients, there is evidence that the rate of complications and costs are higher with increasing obesity [18][19][20][21][22][23] . Although not perfect, area-based geocodes and dualeligibility status do represent reasonable surrogates for socioeconomic status that have been associated with poorer outcomes or increased cost of care 38,39 .…”

“…Bariatric surgery, even when associated with substantial weight loss, has not decreased complications related to TJA 17 . Finally, while obesity has clearly been shown to be associated with higher rates of complications in patients undergoing TJA 18,19 , studies have shown that TJA has an acceptable level of risk, is beneficial for patients and society, and is cost-effective in morbidly obese patients, even those with comorbidities [20][21][22][23] .…”

What’s New in Adult Reconstructive Knee Surgery

“…A study using the Scandinavian Obesity Surgery Registry and the Swedish Knee Arthroplasty Register seemed to indicate that undergoing a bariatric surgical procedure before TKA does not reduce the risk of revision 18 . However, it is promising that the use of a risk stratification tool, which includes a comprehensive assessment, and the modification of risk factors make it possible for morbidly obese patients to have postoperative adverse outcomes similar to those of non-obese patients who undergo primary TKA 19 . For patients with type-2 diabetes undergoing TKA, the use of metformin significantly reduces the odds of readmissions, emergency department visits, PJI, deep vein thrombosis, acute kidney injury, hypoglycemic events, 1-year revision, and longer length of stay when compared with patients with diabetes who were not taking metformin 20 .…”

Orthopaedic Nurse Navigators and Total Joint Arthroplasty Preoperative Optimization

“…Among patients seeking TJA, weight and nutrition status are often identified as risk factors for postoperative complications (Kerbel et al, 2021; Purcell et al, 2022; Rhind et al, 2020; Wall & de Steiger, 2020). Obesity, which is defined by a body mass index (BMI) of 30 kg/m 2 or more, is a risk factor for osteoarthritis (OA) (Al-Otaibi, 2021; Changulani et al, 2008), and patients with obesity comprise a growing proportion of TJA patients (Ekhtiari et al, 2021).…”