Preoperative Predictors of Patients Requiring Inpatient Admission for Total Hip Arthroplasty Following Removal From the Medicare Inpatient-Only List

Inconsistent Classification of "Outpatient" Surgeries Leads to Different Outcomes Following Total Hip Arthroplasty in Medicare Beneficiaries: A Critical Analysis

BACKGROUND

With rising utilization of outpatient total hip arthroplasty (THA) in older patients including Medicare beneficiaries, the objective was to compare differences in definition including (1) patient demographics; (2) lengths of stay (LOS); and (3) outcomes of "outpatient" (stated status) versus "same-day discharge" (SDD) (actual LOS = 0 days) utilizing a nationwide database.

METHODS

A national database from 2015 to 2019 was queried for Medicare-aged patients undergoing outpatient THA. Total outpatient THAs (N = 6,072) were defined in one of 2 ways: either "outpatient" by the hospital (N = 2,003) or LOS = 0 days (N = 4,069). Demographics, LOS, discharge destinations, and complications were compared between groups. Logistic regression models computed odds ratios (ORs) for factors leading to complications, readmissions, and nonhome discharges. P values < .008 were significant.

RESULTS

Women (OR: 1.19, P = .002), diabetes mellitus (OR: 1.31, P = .003), general anesthesia (OR: 1.24, P = .001), and longer operative times (≥95 minutes) (OR: 1.82, P < .001) were associated with 'outpatient' designation versus SDD. Within the hospital-defined 'outpatient' cohort, 49.1% (983 of 2,003) were discharged the same day (LOS = 0 days), and 21.8% had LOS 2 or more days. The hospital-defined 'outpatient' cohort had greater odds of nonhome discharges (6.3 versus 2.8%; OR: 1.88, P < .001) compared to SDD surgeries. The incidence was higher for any complication among hospital-defined 'outpatient' designated patients compared to SDD (5.5 versus 3.9%, P = .007).

CONCLUSIONS

Outpatient surgeries may be misleading and often do not correlate with SDD, as over 20% remain in the hospital 2 or more days. Investigators should quantitatively define the "outpatient" status by actual LOS to allow standardization and results comparison.

LEVEL OF EVIDENCE

III.

Same-Day Discharge Total Knee Arthroplasty in Octogenarians

BACKGROUND

One of the most important aspects of the transition to outpatient (OP) arthroplasty is patient selection, with guidance traditionally recommending that OP total knee arthroplasty (TKA) be reserved for patients <80 years old. However, there are limited data as to whether older age should really be considered a contraindication to OP-TKA. The purpose of this study is to assess the risk of complications and readmissions following OP-TKA in patients ≥80 years old.

METHODS

This is a retrospective, propensity-matched cohort study of the National Surgical Quality Improvement Program database from 2011 to 2019. Patients ≥80 years undergoing OP (same-day discharge) TKA were propensity matched to patients ≥80 years undergoing inpatient (IP) TKA based on age, gender, race, body mass index, American Society of Anesthesiologists classification, functional status, smoking status, anesthetic type, and medical comorbidities. There were 1,418 patients (709 IPs and 709 OPs) included. All baseline factors were successfully matched between IP-TKA versus OP-TKA (P ≥ .18 for all). Thirty-day complications, readmissions, reoperations, and mortality were subsequently analyzed.

RESULTS

Thirty-day readmission rates were identical between patients undergoing IP-TKA and OP-TKA (3.5% versus 3.5%, P = 1.0). Similarly, there was no significant difference in the incidence of major complications (2.7% versus 2.0%, P = .38), reoperations (1.3% versus 0.8%, P = .44), or mortalities (0.3% versus 0.3%, P = 1.0) within 30 days.

CONCLUSION

Octogenarians undergoing OP-TKA had comparable complication rates to similar patients undergoing IP-TKA. OP-TKA can be performed safely in select octogenarians and age ≥80 years likely does not need to be a uniform contraindication to OP-TKA.

Concerns surrounding application of artificial intelligence in hip and knee arthroplasty

Literature surrounding artificial intelligence (AI)-related applications for hip and knee arthroplasty has proliferated. However, meaningful advances that fundamentally transform the practice and delivery of joint arthroplasty are yet to be realized, despite the broad range of applications as we continue to search for meaningful and appropriate use of AI. AI literature in hip and knee arthroplasty between 2018 and 2021 regarding image-based analyses, value-based care, remote patient monitoring, and augmented reality was reviewed. Concerns surrounding meaningful use and appropriate methodological approaches of AI in joint arthroplasty research are summarized. Of the 233 AI-related orthopaedics articles published, 178 (76%) constituted original research, while the rest consisted of editorials or reviews. A total of 52% of original AI-related research concerns hip and knee arthroplasty (n = 92), and a narrative review is described. Three studies were externally validated. Pitfalls surrounding present-day research include conflating vernacular (“AI/machine learning”), repackaging limited registry data, prematurely releasing internally validated prediction models, appraising model architecture instead of inputted data, withholding code, and evaluating studies using antiquated regression-based guidelines. While AI has been applied to a variety of hip and knee arthroplasty applications with limited clinical impact, the future remains promising if the question is meaningful, the methodology is rigorous and transparent, the data are rich, and the model is externally validated. Simple checkpoints for meaningful AI adoption include ensuring applications focus on: administrative support over clinical evaluation and management; necessity of the advanced model; and the novelty of the question being answered.

Cite this article: Bone Joint J 2022;104-B(12):1292–1303.

Enhanced Preoperative Education Pathways: A Step Toward Reducing Disparities in Total Joint Arthroplasty Outcomes

BACKGROUND

Patients with increased comorbidities, lower socioeconomic status, and African American (AA) race have been shown to be at increased risk for suboptimal outcomes after total joint arthroplasty (TJA). Despite the body of evidence highlighting these disparities, few interventions aimed at improving outcomes specifically in high-risk patients have been evaluated. This study evaluates the impact of an enhanced preoperative education pathway (EPrEP) on outcomes after TJA.

METHODS

All patients included underwent unilateral primary total hip or knee arthroplasty at a single institution from September 1, 2020 to September 31, 2021. This is a retrospective observational cohort study comparing demographics, comorbidities, and outcomes of patients treated through EPrEP with those receiving routine care. Subgroup analysis of outcome differences by race was performed.

RESULTS

In total, 1,716 patients were included in the study: 802 went through the EPrEP and 914 did not. EPrEP patients had a higher comorbidity burden as measured by the Charlson Comorbidity Index (3.54 ± 1.71 vs 3.25 ± 1.75, P < .001). After risk adjustment, there was no significant relationship among EPrEP utilization and length of stay, home discharge, or 30-day readmissions. However, EPrEP patients were less likely to return to the emergency department 30 days postoperatively (odds ratio 0.49, 95% confidence interval 0.27-0.86, P = .016). No significant differences in outcomes between AA and non-AA patients were observed.

CONCLUSION

High-risk patients receiving individualized nurse navigator counseling experienced similar outcomes to the broader patient population undergoing TJA. Implementation of EPrEPs may be an effective means of enhancing the equity of care quality across all patients undergoing TJA.

The role of the lower extremity functional scale in predicting surgical outcomes for total joint arthroplasty patients

Background

The purpose of this study was to evaluate the relationship between lower extremity functional scale (LEFS) scores with postoperative functional outcomes for total joint arthroplasty (TJA) patients and to investigate the utility of this tool to create an individualized plan of care perioperatively.

Methods

Patients undergoing primary TJA at a single institution from 2016 to 2019 was retrospectively reviewed by a univariate analysis in terms of patient characteristics and outcomes across LEFS quartiles. Multivariate regression models were constructed to evaluate the association between the LEFS quartile and outcomes after controlling for confounding factors.

Results

A total of 1389 patients were included. All patients had a documented LEFS pre- and postoperatively with the last value documented at least 60 days to a maximum of 1 year after surgery. The following cutoffs for LEFS quartiles were observed: quartile 1 preoperative LEFS ≤27, quartile 2 ranges from 28 to 35, quartile 3 ranges from 36 to 43, and quartile 4 ≥ 44. Patients with a higher comorbidity burden and ASA score were more likely to have a lower LEFS. Higher levels of preoperative function were significantly associated with shorter LOS and higher rates of same day discharge, independent ambulation, mobility and activity scores, and rates of discharge home.

Conclusion

These findings suggest that LEFS is a useful tool for aiding clinical resource allocation decisions, and incorporation of the measure into existing predictive models may improve their accuracy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s42836-021-00106-3.

Amount of CMS Reduction in Facility Reimbursement Following Removal of Total Hip Arthroplasty From the Inpatient-Only List Far Exceeds Reduction in Actual Care Cost

BACKGROUND

Starting in 2020, Centers for Medicare and Medicaid Services (CMS) removed total hip arthroplasty (THA) from the inpatient-only list, resulting in an average of $1637 per case reduction in facility reimbursement. The purpose of this study is to determine whether the reduction in reimbursement is justified by comparing the difference in true facility costs between inpatient and outpatient THA.

METHODS

We identified a consecutive series of 5271 primary THA procedures from 2015 to 2019. Itemized procedural costs were calculated using a time-driven activity-based costing algorithm. Outpatient procedures were defined as those with less than a 24-hour length of stay. We compared patient demographics, comorbidities, and itemized costs between inpatient and outpatient procedures. A multivariate analysis was performed to determine the independent effect of outpatient status on true facility costs.

RESULTS

There were 783 (14.9%) outpatient THA procedures. The outpatient THA procedures incurred lower mean personnel ($1428 vs $2226, P < .001), supply ($4713 vs $4739, P < .001), and overall facility costs ($6141 vs $6595, P < .001) when compared with the same THA procedures done inpatient. When controlling for confounding variables, outpatient status was associated with a reduction in total facility costs of $825 (95% confidence interval, $734-$916, P < .001).

CONCLUSION

The reduction in CMS reimbursement far exceeds the $825 per-patient cost savings that can be achieved by a facility by performing THA as an outpatient. CMS should reconsider the Outpatient Prospective Payment System classification of THA to better incentivize surgeons to perform THA as a lower-cost outpatient procedure when safe and appropriate.

A Novel Machine Learning Predictive Tool Assessing Outpatient or Inpatient Designation for Medicare Patients Undergoing Total Hip Arthroplasty

Background

The Centers for Medicare and Medicaid Services removed total hip arthroplasty (THA) from the inpatient-only list. This has created significant confusion regarding which patients qualify for an inpatient designation. The purpose of this study is to develop and validate a novel predictive tool for preoperatively objectively determining “outpatient” vs “inpatient” status for THA in the Medicare population.

Methods

A cohort of Medicare patients undergoing primary THA between January 2017 and September 2019 was retrospectively reviewed. A machine learning model was trained using 80% of the THA patients, and the remaining 20% was used for testing the model performance in terms of accuracy and the average area under the receiver operating characteristic curve. Feature importance was obtained for each feature used in the model.

Results

One thousand ninety-one patients had outpatient stays, and 318 qualified for inpatient designation. Significant associations were demonstrated between inpatient designations and the following: higher BMI, increased patient age, better preoperative functional scores, higher American Society of Anesthesiologist Physical Status Classification, higher Modified Frailty Index, higher Charlson Comorbidity Index, female gender, and numerous comorbidities. The XGBoost model for predicting an inpatient or outpatient stay was 78.7% accurate with the area under the receiver operating characteristic curve to be 81.5%.

Conclusions

Using readily available key baseline characteristics, functional scores and comorbidities, this machine-learning model accurately predicts an “outpatient” or “inpatient” stay after THA in the Medicare population. BMI, age, functional scores, and American Society of Anesthesiologist Physical Status Classification had the highest influence on this predictive model.

Opioid Use Following Inpatient Versus Outpatient Total Joint Arthroplasty

BACKGROUND

Although the risks of continued opioid use following inpatient total joint arthroplasty (TJA) have been well-studied, these risks in the outpatient setting are not well known. The purpose of the present study was to characterize opioid use following outpatient compared with inpatient TJA.

METHODS

In this retrospective cohort study, opioid-naïve patients who underwent inpatient or outpatient (no overnight stay) primary, elective TJA from 2007 to 2017 were identified within a large national commercial-claims insurance database. For inclusion in the study, patients had to have been continuously enrolled in the database for ≥12 months prior to and ≥6 months after the TJA procedure. Multivariable analyses controlling for demographics, geography, procedure, year, and comorbidities were utilized to determine the association between surgical setting and risk of persistent opioid use, defined as the patient still filling new opioid prescriptions >90 days postoperatively.

RESULTS

We identified a total of 92,506 opioid-naïve TJA patients, of whom 57,183 (61.8%) underwent total knee arthroplasty (TKA). Overall, 7,342 patients (7.9%) underwent an outpatient TJA procedure, including 4,194 outpatient TKAs. Outpatient TJA was associated with reduced surgical opioid prescribing (78.9% compared with 87.6% for inpatient procedures; p < 0.001). Among the 80,393 patients (86.9%) who received surgical opioids, the total amount of opioids prescribed (in morphine milligram equivalents) was similar between inpatient (median, 750; interquartile range, 450 to 1,200) and outpatient procedures (median, 750; interquartile range, 450 to 1,140; p = 0.47); however, inpatient TJA patients were significantly more likely to still be taking opioids after 90 days postoperatively (11.4% compared with 9.0% for outpatient procedures; p < 0.001). These results persisted in adjusted analysis (adjusted odds ratio, 1.13; 95% confidence interval, 1.03 to 1.24; p = 0.01).

CONCLUSIONS

Outpatient TJA patients who received opioid prescriptions were prescribed a similar amount of opioids as those undergoing inpatient TJA procedures, but were significantly less likely to become persistent opioid users, even when controlling for patient factors. Outpatient TJA, as compared with inpatient TJA, does not appear to be a risk factor for new opioid dependence, and these findings support the continued transition to the outpatient-TJA model for lower-risk patients.

LEVEL OF EVIDENCE

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

Risk Factors for Discharge to a Non-Home Destination and Reoperation Following Outpatient Total Hip Arthroplasty (THA) in Medicare-Eligible Patients

Introduction:

The Centers for Medicare and Medicaid Services removed total hip arthroplasty (THA) from the inpatient-only (IO) list in January 2020. Given this recommendation, we analyzed Medicare-eligible patients undergoing outpatient THA to understand risk factors for nonroutine discharge, reoperations, and readmissions.

Materials and Methods:

The 2015-2018 American College of Surgeons–National Surgical Quality Improvement Program database was queried using Current Procedural Terminology code 27130 for Medicare eligible patients (≥ 65 years of age) undergoing outpatient THA. Postoperative discharge destination was categorized into home and non-home. Multivariate logistic regression models were used to evaluate risk factors associated with non-home discharge disposition. Secondarily, we evaluated rates and risk factors associated with 30-day reoperations and readmissions.

Results:

A total of 1095 THAs were retrieved for final analysis. A total of 108 patients (9.9%) experienced a non-home discharge postoperatively. Patients were discharged to rehab (n = 47; 4.3%), a skilled care facility (n = 47; 4.3%), a facility that was “home” (n = 8; 0.7%), a separate acute care facility (n = 5; 0.5%), or an unskilled facility (n = 1; 0.1%). Independent factors for a non-home discharge were American Society of Anesthesiologists Class >II (odds ratio [OR] 2.74), operative time >80 minutes (OR 2.42), age >70 years (OR 2.20), and female gender (OR 1.67). Eighteen patients (1.6%) required an unplanned reoperation within 30 days. A total of 40 patients (3.7%) required 30-day readmissions, with 35 readmissions related to the original THA procedure. Independent risk factors for 30-day reoperation were COPD (OR 5.85) and HTN (OR 5.24). Independent risk factors for 30-day readmission were HTN (OR 4.35) and Age >70 (OR 2.48).

Discussion:

The current study identifies significant predictors associated with a non-home discharge, reoperation, and readmission in Medicare-aged patients undergoing outpatient THA.

Conclusion:

Providers should consider preoperatively risk-stratifying patients to reduce the costs associated with unplanned discharge destination, complication or reoperation.