Should All Patients Be Included in Alternative Payment Models for Primary Total Hip Arthroplasty and Total Knee Arthroplasty?

Risk Stratification in Orthopaedic Surgery: An Important Adjustment for Value-Based Health Care and Quality Measurement

➢ Risk stratification in orthopaedic surgery is complex and depends on the outcome of interest and multiple interdependent factors. Effective risk stratification has uses for limiting and predicting adverse events in patients undergoing discretionary surgery, avoiding the penalization of surgeons for operating on candidates whose health is situated in more difficult circumstances, and ensuring that inordinate attention is not placed on discrete musculoskeletal pathophysiology when there are other pressing health priorities.➢ For individual patient decision-making, no comprehensive risk-stratification tool currently exists, in part due to the heterogeneity of orthopaedic procedures performed and the diverse patient population treated. The Elixhauser Comorbidity Measure and the Risk Stratification Index 3.0 appear to be most promising.➢ At a population level, risk stratification may be useful in alternative payment models to ensure that hospitals that treat a disproportionate number of high-risk patients are not penalized and that cherry-picking (preferentially selecting only healthier patients with a lower risk of complications) does not occur. Any attempt to risk-stratify may have unintended consequences.➢ Orthopaedic surgeons must be aware of the tools available, their strengths, and their limitations in order to be included in decision-making as payment models and public health policies are implemented.

Early Discharge for Revision Total Knee and Hip Arthroplasty: Predictors of Success

BACKGROUND

The rate of revision total joint arthroplasties is expected to increase drastically in the near future. Given the recent pandemic, there has been a general push toward early discharge. This study aimed to assess for predictors of early postoperative discharge after revision total knee arthroplasty (rTKA) and revision total hip arthroplasty (rTHA).

METHODS

There were 77 rTKA and 129 rTHA collected between January 1, 2019 and December 31, 2021. Demographic data, comorbidities, a comorbidity index, the modified frailty index (mFI-5), and surgical history were collected. The Common Procedural Terminology codes for each case were assessed. Patients were grouped into 2 cohorts, early discharge (length of stay [LOS] <24 hours) and late discharge (LOS >24 hours).

RESULTS

In the rTHA cohort, age >65 years, a history of cardiac or liver disease, an mFI-5 of >1, a comorbidity index of >2.7, a surgical time >122 minutes, and the need for a transfusion were predictors of prolonged LOS. Only the presence of a surgical time of >63 minutes or an mFI-5 >1 increased patient LOS in the rTKA cohort. In both rTHA and rTKA patients, periprosthetic joint infection resulted in a late discharge for all patients, mean 4.8 and 7.1 days, respectively. Dual component revision was performed in 70.5% of rTHA. Only 27.6% of rTKA were 2-component revisions or placements of an antibiotic spacer.

CONCLUSIONS

Several patient and surgical factors preclude early discharge candidacy. For rTHA, an mFI-5 of >2/5, comorbidity index of >4, or a surgical time of >122 minutes is predictive of prolonged LOS. For rTKA, an mFI-5 of >2/5, Charlson Comorbidity Index of >5, or a surgical time of >63 minutes predicts prolonged LOS.

Cardiovascular Disease in Total Knee Arthroplasty: An Analysis of Hospital Outcomes, Complications, and Mortality

Background

Cardiovascular comorbidities have been identified as a significant risk factor for adverse outcomes following surgery. The purpose of this study was to investigate its prevalence and impact on postoperative outcomes, hospital metrics, and mortality in patients undergoing total knee arthroplasty (TKA). Our hypothesis was that patients with cardiovascular comorbidities would have worse outcomes, greater postoperative complication rates, and increased mortality compared to patients without cardiovascular disease.

Methods

In this retrospective study, data from the National Inpatient Sample database from 2011 to 2020 were queried for patients who underwent TKA with preexisting cardiac comorbidities, including congestive heart failure (CHF), coronary artery disease (CAD), valvular dysfunction, and arrhythmia. Multivariate logistic regression analyses compared hospital metrics (length of stay, costs, and adverse discharge disposition), postoperative complications, and mortality rates while adjusting for demographic and clinical variables. All statistical analyses were performed using R studio 4.2.2 and Stata MP 17 and 18 with Python package.

Results

A total of 385,585 patients were identified. Those with preexisting CHF, CAD, valvular dysfunction, or arrhythmias were found to be older and at higher risk of adverse outcomes, including prolonged length of stay, increased hospital charges, and increased mortality (p < 0.001). Additionally, all preexisting cardiac diagnoses led to an increased risk of postoperative myocardial infarction, acute kidney injury (AKI), and need for transfusion (p < 0.001). The presence of valvular dysfunction, arrhythmia, or CHF was associated with an increased risk of thromboembolic events (p < 0.001). The presence of CAD and valvular dysfunction was associated with an increased risk of urologic infection (p < 0.001).

Conclusions

This study demonstrated that CHF, CAD, valvular dysfunction, and arrhythmia are prevalent among TKA patients and associated with worse hospital metrics, higher risk of perioperative complications, and increased mortality. As our use of TKA rises, a lower threshold for preoperative cardiology referral in older individuals and early preoperative counseling/intervention in those with known cardiac disease may be necessary to reduce adverse outcomes.

Is Discharge Within a Day Following Total Hip Arthroplasty Safe in the Septuagenarian and Octogenarian Population? A Propensity-Matched Cohort Study

BACKGROUND

Limited data exists on whether patients older than 70 can safely be discharged within a day (rapid discharge (RD)) following primary total hip arthroplasty (THA). The purpose of this study was to compare perioperative complications and readmission rates associated with RD in patients ≥70 years compared to longer lengths of stay following THA.

METHODS

A retrospective, propensity-matched cohort study was conducted using the National Surgical Quality Improvement Program database from 2006 to 2020. Patients ≥70 years undergoing RD following THA were propensity matched to patients ≥70 years who had longer hospital stays (nonrapid discharge). Sub-analyses were performed for septuagenarians and octogenarians. Following 1:1 matching, multivariate analyses were performed to compare perioperative complications and readmissions. Following propensity matching, both groups contained 2,192 patients.

RESULTS

The RD patients were found to have shorter operative times (P < .001), less bleeding complications (P < .001), and were more likely to have home discharges (P < .001). The 2 cohorts did not differ in the remaining complications or 30-day postoperative period readmissions among all patients and when evaluating septuagenarians and octogenarians.

CONCLUSION

Patients ≥70 years undergoing RD following THA had comparable complication and readmission rates to patients older than 70 undergoing nonrapid discharge. Furthermore, RD patients were more likely to have home discharges and have shorter operations with less bleeding complications. Septuagenarians receiving RD were more likely to have an unplanned readmission. These data suggest that RD following THA can be performed safely in select patients older than 70.

Trends and risk factors for readmissions following press-fit total knee arthroplasty for the treatment of end-stage osteoarthritis of the knee: a five-year analysis

INTRODUCTION

The development of new prostheses with improved osseointegration, bone preservation, and reduced cost has renewed interest in uncemented total knee arthroplasty (UCTKA). In the current study, we aimed to: (1) assess demographic data of patients who were and were not readmitted and (2) identify patient-specific risk factors associated with readmission.

METHODS

A retrospective query from the PearlDiver database was performed from January 1, 2015, to October 31, 2020. International Classification of Disease, Ninth Revision (ICD-9), ICD-10, or Current Procedural Terminology (CPT) coding was used to distinguish cohorts of patients who had osteoarthritis of the knee and underwent UCTKA. Patients readmitted within 90 days were classified as the study population, while those who were not readmitted were classified as control. A linear regression model was utilized to analyze readmission risk factors.

RESULTS

The query yielded 14,575 patients, with 986 (6.8%) being readmitted. Patient demographics such as age (P < 0.0001), sex (P < 0.009), and comorbidity (P < 0.0001) were associated with annual 90-day readmission. Patient-specific risk factors associated with 90-day readmission following press-fit total knee arthroplasty were: arrhythmia (OR: 1.29, 95% CI: 1.11-1.49, P < 0.0005), coagulopathy (OR: 1.36, 95% CI: 1.13-1.63, P < 0.0007), fluid and electrolyte abnormalities (OR: 1.59, 95% CI: 1.38-1.84, P < 0.0001), iron deficiency anemia (OR: 1.49, 95% CI: 1.27-1.73, P < 0.0001), and obesity (OR: 1.37, 95% CI: 1.18-1.60, P < 0.0001).

DISCUSSION

This study demonstrates that patients with comorbidities, such as fluid and electrolyte problems, iron deficiency anemia, and obesity, were at an increased risk of readmission after having an uncemented total knee replacement. The risks of readmission following an uncemented total knee arthroplasty can be discussed with patients who have certain comorbidities by arthroplasty surgeons.

Healthcare Market-Level and Hospital-Level Disparities in Access to and Utilization of High-Quality Hip and Knee Replacement Hospitals Among Medicare Beneficiaries

INTRODUCTION

This study aimed to determine whether healthcare markets with higher social vulnerability have lower access to high-quality hip and knee replacement hospitals and whether hospitals that serve a higher percentage of low-income patients are less likely to be designated as high-quality.

METHODS

This cross-sectional study used 2021 Centers for Medicare and Medicaid Services outcome measures and 2022 Joint Commission (JC) process-of-care measures to identify hospitals performing high-quality hip and knee replacement. A total of 2,682 hospitals and 304 healthcare markets were included. For the market-level analysis, we assessed the association of social vulnerability with the presence of a high-quality hip and knee replacement center. For the hospital-level analysis, we assessed the association of disproportionate share hospital (DSH) percentage with each high-quality designation. Healthcare markets were approximated by hospital referral regions. All associations were assessed with fractional regressions using generalized linear models with binomial family and logit links.

RESULTS

We found that healthcare markets in the most vulnerable quartile were less likely to have a hip and knee replacement hospital that did better than the national average (odds ratio [OR] 0.22, P = 0.02) but not more or less likely to have a hospital certified as advanced by JC (OR 0.41, P = 0.16). We found that hip and knee replacement hospitals in the highest DSH quartile were less likely to be designated by the Centers for Medicare and Medicaid Services as better than the national average (OR 0.18, P = 0.001) but not more or less likely to be certified as advanced by JC (OR 1.40, P = 0.28).

DISCUSSION

Geographic distribution of high-quality hospitals may contribute to socioeconomic disparities in patients' access to and utilization of high-quality hip and knee replacement. Equal access to and utilization of hospitals with high-quality surgical processes does not necessarily indicate equitable access to and utilization of hospitals with high-quality outcomes.

LEVEL OF EVIDENCE

Level III.

Orthopaedic Nurse Navigators and Total Joint Arthroplasty Preoperative Optimization: Improving Patient Access to Musculoskeletal Care

Preoperative optimization programs for total joint arthroplasty identify and address risk factors to reduce postoperative complications, thereby improving patients' ability to be safe surgical candidates. This article introduces preoperative optimization programs and describes the role of orthopaedic nurse navigators. This foundation will be used to produce an article series with recommendations for optimization of several modifiable biopsychosocial factors. We consulted orthopaedic nurse navigators across the United States and conducted a literature review regarding preoperative optimization to establish the importance of nurse navigation in preoperative optimization. The responsibilities of nurse navigators, cited resources, and structure of preoperative optimization programs varied among institutions. Optimization programs relying on nurse navigators frequently demonstrated improved outcomes. Our discussions and literature review demonstrated the integral role of nurse navigators in preoperative optimization. We will discuss specific risk factors and how nurse navigators can manage them throughout this article series.

Intra-articular Hip Injections Prior to Total Hip Arthroplasty: Infection and Cost-Related Associations

Intra-articular injections prior to total hip arthroplasty (THA) have been associated with postoperative infections. The purpose of this study was to determine whether a temporal relationship exists between hip injections prior to THA and infection. Specifically, we asked (1) Do patients who receive hip injections within 3 months of THA have a higher incidence of prosthetic joint infections (PJIs) or surgical site infections (SSIs)? and (2) Do these patients incur higher 90-day costs? Patients with hip injections prior to THA were identified using a national database from 2010 to 2019. Three laterality-specific groups (injection 0 to 3 months, 3 to 6 months, and 6 to 12 months prior to THA)were compared with a matched cohort without prior injection (n=277,841). Primary outcomes included PJIs, SSIs, and costs. Patients who had injections within 3 months of THA had a higher incidence of PJIs at 90 days (5.1% vs 1.6%, P<.01) and 1 year (6.8% vs 2.1%, P<.01), when compared with the matched cohort. They also had a higher incidence of SSIs at 90 days (2.8% vs 1.2%, P<.01) and 1 year (3.7% vs 1.7%, P<.01). Mean costs were 13.7% higher in this injection cohort. Patients who had injections between 3 and 6 months prior to THA had higher incidence and odds of postoperative PJIs at 90 days (2.6% vs 1.6%, P<.04), whereas those with injections beyond 6 months had no differences in PJIs (P≥.46). Patients who receive hip injections within 3 months of undergoing primary THA are at increased risk for postoperative PJIs, SSIs, and higher costs. This study reaffirms guidelines for when to perform THAs in these populations. [Orthopedics. 2023;46(1):19-26.].

Movement Is Life-Optimizing Patient Access to Total Joint Arthroplasty: Cardiovascular Health Disparities

Cardiovascular disease includes a collection of conditions with 6.7% of American adults having coronary artery disease and 45% having hypertension. Proper management of these conditions is low (<25%). Hypertension is highest among African Americans and is associated with lower socioeconomic status and education level. Heart disease is associated with postoperative complications, such as cardiovascular and cerebrovascular events, pulmonary and coagulopathy complications, and mortality. Underserved communities can be optimized beginning with a thorough preoperative assessment, which includes evaluating for food security, instituting dietary modifications and exercise regimens, and improving cardiovascular health with pharmacologic modalities and specialty care. Nurse navigators can be invaluable for guiding patients through a cardiovascular preoperative optimization pathway.

Predictive capacity of four machine learning models for in-hospital postoperative outcomes following total knee arthroplasty

Background

Machine learning (ML) methods have shown promise in the development of patient-specific predictive models prior to surgical interventions. The purpose of this study was to develop, test, and compare four distinct ML models to predict postoperative parameters following primary total knee arthroplasty (TKA).

Methods

Data from the Nationwide Inpatient Sample was used to identify patients undergoing TKA during 2016-2017. Four distinct ML models predictive of mortality, length of stay (LOS), and discharge disposition were developed and validated using 15 predictive patient and hospital-specific factors. Area under the curve of the receiver operating characteristic curve (AUCROC) and accuracy were used as validity metrics, and the strongest predictive variables under each model were assessed.

Results

A total of 305,577 patients were included. For mortality, the XGBoost, neural network (NN), and LSVM models all had excellent responsiveness during validation, while random forest (RF) had fair responsiveness. For predicting LOS, all four models had poor responsiveness. For the discharge disposition outcome, the LSVM, NN, and XGBoost models had good responsiveness, while the RF model had poor responsiveness. LSVM and XGBoost had the highest responsiveness for predicting discharge disposition with an AUCROC of 0.747.

Discussion

The ML models tested demonstrated a range of poor to excellent responsiveness and accuracy in the prediction of the assessed metrics, with considerable variability noted in the predictive precision between the models. The continued development of ML models should be encouraged, with eventual integration into clinical practice in order to inform patient discussions, management decision making, and health policy.

The Use of Artificial Neural Networks for the Prediction of Surgical Site Infection Following TKA

This is a retrospective study. Surgical site infection (SSI) is associated with adverse postoperative outcomes following total knee arthroplasty (TKA). However, accurately predicting SSI remains a clinical challenge due to the multitude of patient and surgical factors associated with SSI. This study aimed to develop and validate machine learning models for the prediction of SSI following primary TKA. This is a retrospective study for patients who underwent primary TKA. Chart review was performed to identify patients with superficial or deep SSIs, defined in concordance with the criteria of the Musculoskeletal Infection Society. All patients had a minimum follow-up of 2 years (range: 2.1-4.7 years). Five machine learning algorithms were developed to predict this outcome, and model assessment was performed by discrimination, calibration, and decision curve analysis. A total of 10,021 consecutive primary TKA patients was included in this study. At an average follow-up of 2.8 ± 1.1 years, SSIs were reported in 404 (4.0%) TKA patients, including 223 superficial SSIs and 181 deep SSIs. The neural network model achieved the best performance across discrimination (area under the receiver operating characteristic curve = 0.84), calibration, and decision curve analysis. The strongest predictors of the occurrence of SSI following primary TKA, in order, were Charlson comorbidity index, obesity (BMI >30 kg/m²), and smoking. The neural network model presented in this study represents an accurate method to predict patient-specific superficial and deep SSIs following primary TKA, which may be employed to assist in clinical decision-making to optimize outcomes in at-risk patients.

Outcome and cost analysis of primary total knee arthroplasty in end-stage renal disease patients: A nationwide population-based study

BACKGROUND

A number of patients with end-stage renal disease (ESRD) undergo total knee arthroplasty (TKA) due to advanced knee joint osteoarthritis. There are few studies describing the incidence, morbidities, mortality rate, and cost analysis regarding ESRD patients receiving TKA.

METHODS

We retrospectively retrieved patient data from National Health Insurance Research Database in Taiwan during 2005-2011, and evaluated the outcomes of TKA in patients with (ESRD group) and without ESRD (non-ESRD group). Patients' demographic data, comorbidities, mortality, and in-hospital cost were recorded.

RESULTS

A total of 578 TKAs and 110,895 TKAs were identified in the ESRD and non-ESRD group, respectively. The incidence of patients receiving TKA was higher in the ESRD than in non-ESRD group by at least 2 folds. The ESRD group showed significantly more medical complications (pneumonia, peptic ulcer disease, and acute myocardial infarction) after surgery. In prosthesis-related complications, the ESRD group also had more periprosthetic joint infections, and prosthetic loosenings by one year. The one-year mortality rate was more than 6 times higher in the ESRD than in the non-ESRD group. The ESRD group had higher in-hospital medical expense than the non-ESRD group, especially when there were complications, even when the dialysis-related costs were exempted.

CONCLUSION

The complication rate, mortality rate, and cost were higher in the ESRD patients receiving TKA. When considering TKA in ESRD patients, it is crucial to weigh the risks against benefits of TKA, and have a thorough discussion with the patients.

The Hospital Frailty Risk Score is Not an Accurate Predictor of Treatment Costs for Total Joint Replacement Patients in a Medicare Bundled Payment Population

BACKGROUND

Medically complex patients require more resources and experience higher costs within total joint arthroplasty (TJA) bundled payment models. While risk adjustment would be beneficial for such patients, no tool currently exists which can reliably identify these patients preoperatively. The purpose of this study is to determine if the Hospital Frailty Risk Score (HFRS) is a valid predictor of high-TJA treatment costs.

METHODS

Retrospective analysis was performed on patients who underwent primary TJA between 2015 and 2020 from a single large orthopedic practice. ICD-10 codes from an institutional database were used to calculate HFRS. Cost data including inpatient, postacute, and episode of care (EOC) costs were collected. Charlson comorbidity index, demographics, readmissions, and complications were analyzed.

RESULTS

4936 patients had a calculable HFRS and those with intermediate and high scores experienced more frequent readmissions/complications after TJA, as well as higher EOC costs. However, HFRS did not reliably predict EOC costs, yielding a sensitivity of 49% and specificity of 66%. Multivariate analysis revealed that both patient age and sex are superior individual cost predictors when compared with HFRS. Secondary analyses indicated that HFRS more effectively predicts TJA complications and readmissions but is still nonideal for clinical applications.

CONCLUSION

HFRS has poor sensitivity as a predictor of high-EOC costs for TJA patients but has adequate specificity for predicting postoperative readmissions and complications. Further research is needed to develop a scale that can appropriately predict orthopedic cost outcomes.

Predictive Factors of Extended Length of Hospital Stay Following Total Joint Arthroplasty in a Veterans Affairs Hospital Population

BACKGROUND

Improved perioperative care for total joint arthroplasty (TJA) procedures has resulted in decreased hospital length of stay (LOS), including effective discharge on postoperative day (POD) 1 in many patients. It remains unclear what contributes to discharge delay in patients that are not discharged on POD 1. This study investigated factors associated with delayed discharge in patients whose original planned discharge was on POD 1.

METHODS

A retrospective cohort of 451 patients who underwent a hip or knee TJA procedure from April 2015 to March 2018 with planned discharge on POD 1 was analyzed. Patient characteristics included demographics, lab values, course of treatment, procedure, Charlson Comorbidity Index (CCI), complications, and other factors. Statistical regression was used to identify factors associated with delayed discharge; odds ratios (OR) were calculated for significant factors (α = 0.05).

RESULTS

Of those studied, 70/451 (15.5%) experienced a delay from the planned POD 1 discharge. An increased likelihood of delayed discharge was associated with a nonhome discharge (P < .001, OR = 8.72 [95% CI: 4.22-18.06]) and higher CCI (P = .034, OR = 1.16 [95% CI: 1.01-1.32]). Inpatient physical therapy on the day of surgery was found to significantly correlate with successful discharge on POD 1 (P = .004, OR = 0.44 [95% CI: 0.25-0.77]).

CONCLUSION

Most patients can be discharged on POD 1 after TJA. Physical therapy on the day of surgery increased the likelihood of patients being discharged on POD 1. Those with a higher CCI and a nonhome discharge were more likely to have a discharge delay. This information can help surgeons counsel patients and prepare for postoperative care.

Demographic, Comorbidity, and Episode-of-Care Differences in Primary Total Knee Arthroplasty

BACKGROUND

Understanding time trends in age, demographic characteristics, and comorbidities is especially critical to highlight the effects on clinical practice change, outcomes, and the value of total knee arthroplasty (TKA). Therefore, the purpose of this study was to identify trends in the demographic characteristics, comorbidities, and episode-of-care outcomes for patients who underwent TKA from 2008 to 2018.

METHODS

The National Surgical Quality Improvement Program (NSQIP) was queried to identify patient demographic characteristics, comorbidities, and episode-of-care outcomes in patients who underwent primary TKA from 2008 to 2018 (n = 350,879). Trends for continuous variables were analyzed using analysis of variance, and categorical variables were analyzed using chi-square tests.

RESULTS

From 2008 to 2018, there was no clinically important difference in age, body mass index (BMI), and percentage of patients with BMI of >40 kg/m2 and no clinically important difference in chronic obstructive pulmonary disease (3.5% in 2008 and 3.2% in 2018), congestive heart failure within 30 days (0.3% in both 2008 and 2018), and acute renal failure (0.1% in 2008 and <0.1% in 2018) among patients undergoing TKA. However, modifiable comorbidities, including smoking status (9.5% in 2008 and 7.7% in 2018; p < 0.001), hypertension (71.0% in 2008 and 63.7% in 2018; p < 0.001), and anemia (16.2% in 2008 and 9.7% in 2018; p < 0.001), functional status, and overall morbidity and mortality probability have improved, with no clinically important difference in the percentage of diabetes (19.0% in 2008 and 18.1% in 2018). The hospital length of stay (mean [and standard deviation], 3.8 ± 2.2 days in 2008 and 2.1 ± 2.0 days in 2018; p < 0.001) and 30-day readmission (4.6% in 2011 and 3.0% in 2018; p < 0.001) decreased, with a significant increase in home discharge (65.6% in 2011 and 87.8% in 2018; p < 0.001).

CONCLUSIONS

The overall patient health status improved from 2008 to 2018, with improvement in the modifiable comorbidities of smoking status, malnutrition, hypertension, and anemia; the functional status; and the overall morbidity and mortality probability, with no clinically relevant change in patient age; patient BMI; percentage of patients with BMI of >40 kg/m2; or patients with diabetes mellitus, chronic obstructive pulmonary disease, congestive heart failure within 30 days, or acute renal failure. Our findings may be a reflection of a global shift toward value-based care focusing on patient optimization prior to arthroplasty, quality of care, and improved outcomes. The results of our study highlight the potential increase in TKA procedural value, which is paramount for health-care policy changes in today's incentivized, value-based, health-care environment.

Impact of Diabetes on 90-Day Episodes of Care After Elective Total Joint Arthroplasty Among Medicare Beneficiaries

BACKGROUND

In an effort to improve quality and reduce costs, reimbursement for total knee arthroplasty (TKA) and total hip arthroplasty (THA) in the United States is being based on the value of care provided, with adjustments for some qualifying comorbidities, including diabetes in its most severe form and excluding many diabetes codes. The aims of this study were to examine the effects of diabetes on elective TKA or THA complications and readmission risks among Medicare beneficiaries.

METHODS

Complication (n = 521,230) and readmission (n = 515,691) data were extracted from Medicare files in 2013 and 2014. Diabetes status (no diabetes, controlled-uncomplicated diabetes, controlled-complicated diabetes, and uncontrolled diabetes) was identified with ICD-9 (International Classification of Diseases, 9th Revision) codes. TKA or THA complications and readmission odds based on diabetes status were estimated using logistic regression and adjusted for sociodemographic and clinical characteristics, including comorbidities.

RESULTS

Compared with no diabetes, the odds ratio (OR) of TKA complications was significantly higher for uncontrolled diabetes (1.29, 95% confidence interval [CI] = 1.06 to 1.57). The OR of THA complications was significantly higher for controlled-complicated diabetes (1.45, 95% CI = 1.17 to 1.80). The OR of readmission was significantly higher for all diabetes groups (1.21 to 1.48 for TKA, 1.20 to 1.70 for THA).

CONCLUSIONS

Readmission odds were higher in all diabetes categories. The uncontrolled-diabetes group had the greatest TKA readmission and complication odds. The controlled-complicated diabetes group had the greatest THA readmission and complication odds. The findings suggest that including diabetes and associated systemic complications in cost adjustments in alternative payment models for arthroplasty should be considered.

LEVEL OF EVIDENCE

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

Higher complication rates after management of lower extremity fractures in lower socioeconomic classes: Are risk adjustment models necessary?

Introduction

Alternative payment models, such as bundled payments, have been proposed to control rising costs in orthopaedic trauma surgery. Without risk adjustment models, concerns exist about the financial burden incurred by so called “safety-net hospitals” that serve patients of lower socioeconomic status. The purpose of this study was to determine whether lower socioeconomic status was associated with increased complications and subsequently higher resource utilization following surgical treatment of high-energy lower extremity fractures.

Methods

The National Inpatient Sample database was queried for patients who underwent surgical fixation of the femur and tibia between 2005–2014. The top and bottom income quartiles were compared. Demographics, medical comorbidities, length of stay (LOS), complications, in-hospital mortality were compared between patients of top and bottom income quartiles. Multivariate logistic regression analysis was then performed to identify factors independently associated with complications, mortality, and increased resource utilization.

Results

Patients with femur fracture in the bottom income quartile had longer length of stay (6.9 days vs 6.5 days, p < 0.001) and a higher mortality rate (1.9% vs 1.7%, p = 0.034). Patients with tibia fracture in the bottom income quartile had greater complication rates (7.3% vs 6.1%, p < 0.001), longer length of stay (5.3 days vs. 4.5 days, p < 0.001), and higher mortality (0.3% vs. 0.2%, p < 0.001).

Conclusions

Lower income status is associated with increased in-hospital mortality and longer length of stay in patients following lower extremity fractures. Risk adjustment models should consider the role of socioeconomic status in patient resource utilization to ensure continued access to orthopedic trauma care for all patients.

Low Socioeconomic Status Is Associated With Increased Complication Rates: Are Risk Adjustment Models Necessary in Cervical Spine Surgery?

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

The objective of this study was to determine whether lower socioeconomic status was associated with increased resource utilization following anterior discectomy and fusion (ACDF).

METHODS

The National Inpatient Sample database was queried for patients who underwent a primary, 1- to 2-level ACDF between 2005 and 2014. Trauma, malignancy, infection, and revision surgery were excluded. The top and bottom income quartiles were compared. Demographics, medical comorbidities, length of stay, complications, and hospital cost were compared between patients of top and bottom income quartiles.

RESULTS

A total of 69 844 cases were included. The bottom income quartile had a similar mean hospital stay (2.04 vs 1.77 days, P = .412), more complications (2.45% vs 1.77%, P < .001), and a higher mortality rate (0.18% vs 0.11%, P = .016). Multivariate analysis revealed bottom income quartile was an independent risk factor for complications (odds ratio = 1.135, confidence interval = 1.02-1.26). Interestingly, the bottom income quartile experienced lower mean hospital costs ($17 041 vs $17 958, P < .001).

CONCLUSION

Patients in the lowest income group experienced more complications even after adjusting for comorbidities. Therefore, risk adjustment models, including socioeconomic status, may be necessary to avoid potential problems with access to orthopedic spine care for this patient population.

Effects of Estimated Glomerular Filtration Rate on 30-Day Mortality and Postoperative Complications After Total Hip Arthroplasty: A Risk Stratification Instrument

BACKGROUND

Chronic kidney disease (CKD) is a relatively common comorbidity that has been shown to adversely affect outcomes in total hip arthroplasty (THA), as well as to increase the procedure's total costs. However, the effect of different stages of kidney disease and the association of estimated glomerular filtration rate (eGFR) with perioperative THA complications are less understood. Therefore, the aims of this study were to investigate the relationships between eGFR, both as a categorical and continuous variable and 30-day outcomes and complications.

METHODS

The National Surgical Quality Improvement Program database was used to identify 101,925 primary THAs between January 1, 2008, and December 31, 2016. The following outcomes were assessed: 30-day mortality, 30-day major complications, 30-day minor complications, specific complications, and discharge disposition. To evaluate the effect of eGFR status on outcomes and complication, multivariate regression models were created to adjust for differences in patient demographics and comorbidities. In addition, multivariate spline regressions were developed to assess the nonlinear relationships between eGFR as a continuous variable and the outcomes of interest.

RESULTS

Our study revealed that as eGFR decreases to <30 mL/min/1.73 m², there is an increased risk for mortality and nonhome discharge (P < .05). There was an increased risk for any major complication and any minor complication as well as several specific medical complications such as transfusion and myocardial infarction (P < .05) for an eGFR of <60 mL/min/1.73 m². Patients' eGFR had a nonlinear relationship with mortality (P = .0001), any major complication (P < .001), and any minor complication (P < .001), as well as a number of other specific medical complications. Once the eGFR, <60 mL/min/1.73 m² the increase was exponential for mortality, major complications, and minor complications. For example, mortality increased of 900% for <15 mL/min/1.73 m² or on dialysis, 600% for 15 to 30 mL/min/1.73 m² and 50% for 30 to 60 mL/min/1.73 m². Similarly, nonlinear relationships were discovered between eGFR and nonhome discharge (P < .001).

CONCLUSION

Patients with lower eGFR, and in particular those with <30 mL/min/1.73 m², are more likely to sustain medical complications and have 6 to 9 times higher mortality than patients with normal eGFR. THA patients with CKD should be appropriately counseled and advised on the risk of postoperative complications by using eGFR as a screening tool.

Oncology Patients Are High Cost Outliers in Total Joint Replacement Bundled Payment Systems

BACKGROUND

In 2016, the Centers for Medicare and Medicaid Services began its first mandatory bundled payment program, the Comprehensive Care for Joint Replacement (CJR) model, which covers a 90-day episode of care. This study determined whether oncology patients enrolled in the CJR bundle incur higher hospital costs than patients with osteoarthritis (OA).

METHODS

A retrospective review of all patients enrolled in the CJR bundled payments system from April 1, 2016 to June 31, 2018 at a single academic medical center was conducted. To determine whether tumor patients had higher total episode costs, this group was compared to patients diagnosed with OA using a 2-tailed t-test. To adjust for moderators of total hospital costs, we used generalized linear regression with a log-link, including multiple variables abstracted from chart review.

RESULTS

Three hundred fourteen patients met inclusion criteria (12 primary or metastatic tumors, 302 OA). Fifty-eight percent of tumor patients were over the target price vs 16% of OA patients. The mean tumor patient had $40,862 for total internal hospital costs compared to $16,356 in the OA group (P < .001). Length of stay was greater in the tumor group (6.75 vs 2.0 days, P < .001). A greater percentage of tumor patients were discharged to a skilled nursing facility (67% vs 27%, P = .006) with significantly higher skilled nursing facility episode costs ($18,852 vs $7731, P = .04). With adjustment for fracture status, tumor patients were 5.36 times more likely to exceed the CJR target price than OA patients (risk ratio 5.36, confidence interval 3.44-8.35, P < .001) and 50 times more likely to be outliers over the regional threshold than OA patients (risk ratio 50.33, confidence interval 16.33-155.19, P < .001).

CONCLUSION

Oncology patients enrolled in the CJR bundled payment model incur significantly higher costs and have higher cost variability than patients with OA. We recommend that oncology patients be excluded from the CJR bundle.

Deep Learning Preoperatively Predicts Value Metrics for Primary Total Knee Arthroplasty: Development and Validation of an Artificial Neural Network Model

BACKGROUND

The objective is to develop and validate an artificial neural network (ANN) that learns and predicts length of stay (LOS), inpatient charges, and discharge disposition before primary total knee arthroplasty (TKA). The secondary objective applied the ANN to propose a risk-based, patient-specific payment model (PSPM) commensurate with case complexity.

METHODS

Using data from 175,042 primary TKAs from the National Inpatient Sample and an institutional database, an ANN was developed to predict LOS, charges, and disposition using 15 preoperative variables. Outcome metrics included accuracy and area under the curve for a receiver operating characteristic curve. Model uncertainty was stratified by All Patient Refined comorbidity indices in establishing a risk-based PSPM.

RESULTS

The dynamic model demonstrated "learning" in the first 30 training rounds with areas under the curve of 74.8%, 82.8%, and 76.1% for LOS, charges, and discharge disposition, respectively. The PSPM demonstrated that as patient comorbidity increased, risk increased by 2.0%, 21.8%, and 82.6% for moderate, major, and severe comorbidities, respectively.

CONCLUSION

Our deep learning model demonstrated "learning" with acceptable validity, reliability, and responsiveness in predicting value metrics, offering the ability to preoperatively plan for TKA episodes of care. This model may be applied to a PSPM proposing tiered reimbursements reflecting case complexity.

Defining and Optimizing Value in Total Joint Arthroplasty From the Patient, Payer, and Provider Perspectives

BACKGROUND

The purpose of this study is to define value in bundled total joint arthroplasty (TJA) from the differing perspectives of the patient, payer/employer, and hospital/provider.

METHODS

Demographic, psychosocial, clinical, financial, and patient-reported outcomes (PROs) data from 2017 to 2018 elective TJA cases at a multihospital academic health system were queried. Value was defined as improvement in PROs (preoperatively to 1 year postoperatively) for patients, improvement in PROs per $1000 of bundle cost for payers, and the normalized sum of improvement in PROs and hospital bundle margin for providers. Bivariate analysis was used to compare high value vs low value (>50th percentile vs <50th percentile). Multivariate analysis was performed to identify predictors.

RESULTS

A total of 280 patients had PRO data, of which 71 had Medicare claims data. Diabetes (odds ratio [OR], 0.45; P = .02) predicted low value for patients; female gender (OR, 0.25), hypertension (OR, 0.17), pulmonary disease (OR, 0.12), and skilled nursing facility discharge (OR, 0.17) for payers (P ≤ .03 for all); and pulmonary disease (OR, 0.16) and skilled nursing facility discharge (OR, 0.19) for providers (P ≤ .04 for all).

CONCLUSION

This is the first article to define value in TJA under a bundle payment model from multiple perspectives, providing a foundation for future studies analyzing value-based TJA.

Are Patients Who Undergo THA for Infection at Higher Risk for 30-day Complications?

BACKGROUND

Value-based payment models, such as bundled payments, continue to become more widely adopted for total joint arthroplasty. However, concerns exist regarding the lack of risk adjustment in these payment and quality reporting models for THA. Providers who care for patients with more complicated problems may be financially incentivized to screen out such patients if reimbursement models fail to account for increased time and resources needed to care for these more complex patients.

QUESTIONS/PURPOSES

(1) Are patients who undergo revision THA for infectious causes at greater adjusted risk of 30-day short-term major complications, return to the operating room, readmission, and mortality compared with patients undergoing aseptic revision? (2) What are other independent factors associated with the risk of 30-day major complications, readmission, and mortality in this patient population?

METHODS

We queried the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database for all patients undergoing revision THA from 2012 to 2015. The NSQIP database allows for the analysis of 30-day surgical outcomes, including postoperative complications, return to the operating room, readmission, and mortality of patients from approximately 400 participating institutions. The NSQIP was selected over other larger databases, such as the National Impatient Sample (NIS), because the NSQIP includes readmission data and 30-day complications rates that were relevant to our study. Patients undergoing aseptic revision THA and those undergoing revision THA with a diagnosis of periprosthetic joint infection were identified. We identified 8973 patients who underwent revision THA and excluded six patients due to a diagnosis of malignancy leaving 8967 patients; 726 (8%) of these were due to infection. Demographic variables, medical comorbidities, and 30-day major complications, hospital readmissions, reoperations, and mortality were compared among patients undergoing aseptic and infected revision THA. A major complication was defined as myocardial infarction, postoperative mortality, sepsis, septic shock, and stroke. A multivariate logistic regression analysis was then performed to identify factors independently associated with the primary outcome of 30-day hospital readmission, and secondary endpoints of 30-day major complications, return to operating room, and mortality.

RESULTS

Controlling for medical comorbidities and demographic factors, the patients who underwent THA for infection were more likely to experience a major complication (odds ratio [OR], 4.637; 95% confidence interval [CI], 2.850-7.544; p < 0.001) within 30 days of surgery and more likely to return to the operating room (OR = 1.548; 95% CI, 1.062-2.255; p = 0.023). However, there were no greater odds of 30-day readmission (OR, 1.354; 95% CI, 0.975-1.880; p = 0.070) or 30-day mortality (OR, 0.661; 95% CI, 0.218-2.003; p = 0.465). Preoperative malnutrition was associated with an increased risk of return to the operating room (OR, 1.561; 95% CI, 1.152-2.115; p = 0.004), 30-day readmission (OR, 1.695; 95% CI, 1.314-2.186; p < 0.001), and 30-day mortality (OR, 7.240; 95% CI, 2.936-17.851; p < 0.001).

CONCLUSIONS

Patients undergoing revision THA for infection undergo reoperation and experience major complications more frequently in a 30-day episode of care than patients undergoing aseptic revision THA. Without risk adjustment to existing alternative payment and quality reporting models, providers may experience a disincentive to care for patients with infected THAs, who may face difficulties with access to care.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Bundled Care for Hip Fractures: A Machine-Learning Approach to an Untenable Patient-Specific Payment Model

OBJECTIVES

With the transition to a value-based model of care delivery, bundled payment models have been implemented with demonstrated success in elective lower extremity joint arthroplasty. Yet, hip fracture outcomes are dependent on patient-level factors that may not be optimized preoperatively due to acuity of care. The objectives of this study are to (1) develop a supervised naive Bayes machine-learning algorithm using preoperative patient data to predict length of stay and cost after hip fracture and (2) propose a patient-specific payment model to project reimbursements based on patient comorbidities.

METHODS

Using the New York Statewide Planning and Research Cooperative System database, we studied 98,562 Medicare patients who underwent operative management for hip fracture from 2009 to 2016. A naive Bayes machine-learning model was built using age, sex, ethnicity, race, type of admission, risk of mortality, and severity of illness as predictive inputs.

RESULTS

Accuracy was demonstrated at 76.5% and 79.0% for length of stay and cost, respectively. Performance was 88% for length of stay and 89% for cost. Model error analysis showed increasing model error with increasing risk of mortality, which thus increased the risk-adjusted payment for each risk of mortality.

CONCLUSIONS

Our naive Bayes machine-learning algorithm provided excellent accuracy and responsiveness in the prediction of length of stay and cost of an episode of care for hip fracture using preoperative variables. This model demonstrates that the cost of delivery of hip fracture care is dependent on largely nonmodifiable patient-specific factors, likely making bundled care an implausible payment model for hip fractures.

Socioeconomic Status Is Associated with Risk of Above-knee Amputation After Periprosthetic Joint Infection of the Knee

BACKGROUND

Above-knee amputation (AKA) is a severe but rare complication of TKA. Recent evidence suggests there are sex and racial disparities with regard to AKA after TKA. However, whether lower socioeconomic status is associated with an increased risk of AKA after TKA has not been conclusively established.

QUESTIONS/PURPOSES

(1) Is low socioeconomic status or use of public health insurance plans associated with an increased risk of AKA after periprosthetic joint infection (PJI) of the knee? (2) Is race or sex associated with an increased risk of AKA after PJI of the knee?

METHODS

This cross-sectional study screened the National Inpatient Sample (NIS) between 2010 and 2014 using the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) procedure and diagnosis codes to identify 912 AKAs (ICD 84.17) among 32,907 PJIs of the knee. The NIS is a large national database of inpatient hospitalizations frequently used by researchers to study outcomes and trends in orthopaedic procedures. The NIS was selected over other databases with more complete followup data such as the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) due to its unique ability to examine income levels and insurance type. Cases were identified by taking all patients with an ICD diagnosis code related to PJI of the knee and limiting that cohort to patients with an ICD procedure code specific to TKA. A total of 912 AKAs after PJI were identified (912 of 32,907, [3%] of all PJIs of the knee) with males comprising 52% of the AKA sample (p = 0.196). Multivariate logistic regression was used to compare risk of AKA after PJI of the knee after controlling for patient demographics, hospital characteristics, and comorbidities.

RESULTS

Compared with the wealthiest income quartile by ZIP code, patients in the lowest income quartile by ZIP code were more likely to sustain an AKA (OR = 1.58; 95% confidence interval [CI] 1.25-1.98; p < 0.001). Compared with patients with private insurance, patients with Medicare (OR = 1.94; 95% CI, 1.55-2.43; p < 0.001) and Medicaid (OR = 1.86; 95% CI, 1.37-2.53; p < 0.001) were at higher risk of AKA. There were no differences with regard to risk of AKA for white patients (670 of 24,004 [3%]; OR = 0.99; 95% CI, 0.77-1.26; p = 0.936) and black patients (95 of 3178 [3%], OR = 0.95; 95% CI, 0.69-1.30; p = 0.751) when compared with others (reference, 83 of 3159 [3%]). When compared with female patients, male patients did not have a greater risk of undergoing AKA (OR = 1.02; 95% CI, 0.88-1.29; p = 0.818).

CONCLUSIONS

This study did not observe any racial or sex disparities with regard to risk of AKA after PJI. However, there was a greater risk of AKA after PJI for poorer patients and patients participating in Medicare or Medicaid insurance plans. Surgeons should be cognizant when treating PJI in patients from lower income backgrounds as these patients may be at greater risk for AKA. Future research should explore the role of physician attitudes or preconceptions about predicted patient followup in treating PJI, as well as the effect of concurrent peripheral vascular disease on the risk of AKA after PJI.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Are Ceramic Bearings Becoming Cost-Effective for All Patients Within a 90-Day Bundled Payment Period?

BACKGROUND

We analyzed whether the total hospital cost in a 90-day bundled payment period for ceramic-on-polyethylene (C-PE) and ceramic-on-ceramic (COC) total hip arthroplasty (THA) bearings was changing over time, and whether the cost differential between ceramic bearings and metal-on-polyethylene (M-PE) bearings was approaching the previously published tipping point for cost-effectiveness of US$325.

METHODS

A total of 245,077 elderly Medicare patients (65+) who underwent primary THA between 2010 and 2015 were identified from the United States Medicare 100% national administrative hospital claims database. The total inpatient cost, calculated up to 90 days after index discharge, was computed using cost-to-charge ratios, and hospital payment was analyzed. The differential total inpatient cost of C-PE and COC bearings, compared to metal-on-polyethylene (M-PE), was evaluated using parametric and nonparametric models.

RESULTS

After adjustment for patient and clinical factors, and the year of surgery, the mean hospital cost up to 90 days for primary THA with C-PE or COC was within ±1% of the cost for primary THA with M-PE bearings (P < .001). From the nonparametric analysis, the median total hospital cost was US$296-US$353 more for C-PE and COC than M-PE. Cost differentials were found to decrease significantly over time (P < .001).

CONCLUSION

Patient and clinical factors had a far greater impact on the total cost of inpatient THA surgery than bearing selection, even when including readmission costs up to 90 days after discharge. Our findings indicate that the cost-effectiveness thresholds for ceramic bearings relative to M-PE are changing over time and increasingly achievable for the Medicare population.

Development and Validation of a Machine Learning Algorithm After Primary Total Hip Arthroplasty: Applications to Length of Stay and Payment Models

BACKGROUND

Value-based payment programs in orthopedics, specifically primary total hip arthroplasty (THA), present opportunities to apply forecasting machine learning techniques to adjust payment models to a specific patient or population. The objective of this study is to (1) develop and validate a machine learning algorithm using preoperative big data to predict length of stay (LOS) and patient-specific inpatient payments after primary THA and (2) propose a risk-adjusted patient-specific payment model (PSPM) that considers patient comorbidity.

METHODS

Using an administrative database, we applied 122,334 patients undergoing primary THA for osteoarthritis between 2012 and 16 to a naïve Bayesian model trained to forecast LOS and payments. Performance was determined using area under the receiver operating characteristic curve and percent accuracy. Inpatient payments were grouped as <$12,000, $12,000-$24,000, and >$24,000. LOS was grouped as 1-2, 3-5, and 6+ days. Payment model uncertainty was applied to a proposed risk-based PSPM.

RESULTS

The machine learning algorithm required age, race, gender, and comorbidity scores ("risk of illness" and "risk of morbidity") to demonstrate excellent validity, reliability, and responsiveness with an area under the receiver operating characteristic curve of 0.87 and 0.71 for LOS and payment. As patient complexity increased, error for predicting payment increased in tiers of 3%, 12%, and 32% for moderate, major, and extreme comorbidities, respectively.

CONCLUSION

Our preliminary machine learning algorithm demonstrated excellent construct validity, reliability, and responsiveness predicting LOS and payment prior to primary THA. This has the potential to allow for a risk-based PSPM prior to elective THA that offers tiered reimbursement commensurate with case complexity.

LEVEL OF EVIDENCE

III.

No Difference in Total Episode-of-Care Cost Between Staged and Simultaneous Bilateral Total Joint Arthroplasty

BACKGROUND

Due to concerns about higher complication rates, surgeons debate whether to perform simultaneous bilateral total joint arthroplasty (BTJA), particularly in the higher-risk Medicare population. Advances in pain management and rehabilitation protocols have called into question older studies that found an overall cost benefit for simultaneous procedures. The purpose of this study was to compare 90-day episode-of-care costs between staged and simultaneous BTJA among Medicare beneficiaries.

METHODS

We retrospectively reviewed a consecutive series of 319 simultaneous primary TJAs and 168 staged TJAs (336 procedures) at our institution between 2015 and 2016. We recorded demographics, comorbidities, readmission rates, and 90-day episode-of-care costs based upon Centers for Medicare and Medicaid Services claims data. To control for confounding variables, we performed a multivariate regression analysis to identify independent risk factors for increased costs.

RESULTS

Simultaneous patients had decreased inpatient facility costs ($19,402 vs $23,025, P < .001), increased post-acute care costs ($13,203 vs $10,115, P < .001), and no difference in total episode-of-care costs ($35,666 vs $37,238, P = .541). Although there was no difference in readmissions (8% vs 9%, P = .961), simultaneous bilateral patients were more likely to experience a thromboembolic event (2% vs 0%, P = .003). When controlling for demographics, procedure, and comorbidities, a simultaneous surgery was not associated with an increase in episode-of-care costs (P = .544). Independent risk factors for increased episode-of-care costs following BTJA included age ($394 per year increase, P < .001), cardiac disease ($4877, P = .025), history of stroke ($14,295, P = .010), and liver disease ($12,515, P = .016).

CONCLUSION

In the Medicare population, there is no difference in 90-day episode-of-care costs between simultaneous and staged BTJA. Surgeons should use caution in performing a simultaneous procedure on older patients or those with a history of stroke, cardiac, or liver disease.

Machine Learning and Primary Total Knee Arthroplasty: Patient Forecasting for a Patient-Specific Payment Model

BACKGROUND

Value-based and patient-specific care represent 2 critical areas of focus that have yet to be fully reconciled by today's bundled care model. Using a predictive naïve Bayesian model, the objectives of this study were (1) to develop a machine-learning algorithm using preoperative big data to predict length of stay (LOS) and inpatient costs after primary total knee arthroplasty (TKA) and (2) to propose a tiered patient-specific payment model that reflects patient complexity for reimbursement.

METHODS

Using 141,446 patients undergoing primary TKA from an administrative database from 2009 to 2016, a Bayesian model was created and trained to forecast LOS and cost. Algorithm performance was determined using the area under the receiver operating characteristic curve and the percent accuracy. A proposed risk-based patient-specific payment model was derived based on outputs.

RESULTS

The machine-learning algorithm required age, race, gender, and comorbidity scores ("risk of illness" and "risk of morbidity") to demonstrate a high degree of validity with an area under the receiver operating characteristic curve of 0.7822 and 0.7382 for LOS and cost. As patient complexity increased, cost add-ons increased in tiers of 3%, 10%, and 15% for moderate, major, and extreme mortality risks, respectively.

CONCLUSION

Our machine-learning algorithm derived from an administrative database demonstrated excellent validity in predicting LOS and costs before primary TKA and has broad value-based applications, including a risk-based patient-specific payment model.

Risk Adjustment Is Necessary in Medicare Bundled Payment Models for Total Hip and Knee Arthroplasty

BACKGROUND

Concerns exist that high-risk patients in alternative payment models may face difficulties with access to care without proper risk adjustment. The purpose of this study is to identify the effect of medical and orthopedic specific risk factors on the cost of a 90-day episode of care following total hip (THA) and knee arthroplasty (TKA).

METHODS

We queried the Medicare 5% Limited Data Set for all patients undergoing primary THA and TKA from 2010 to 2014. To evaluate the cost of an episode of care, we calculated all claims for 90 days following surgery. Multivariate analysis was performed to quantify the added episode-of-care costs for demographic variables, geography, medical comorbidities, and orthopedic specific risk factors.

RESULTS

Of the 58,809 TKA patients, the median 90-day Medicare costs was $23,800 (interquartile range, $18,900-$32,300), while the median of the 27,293 THA patients was $24,000 (interquartile range, $18,500-$33,900). Independent risk factors (all P < .05) resulting in at least a 10% increase in episode-of-care costs following TKA included malnutrition, age over 85, male gender, pulmonary disorder, failed internal fixation, Northeast region, lower socioeconomic status, neurologic disorder, and rheumatoid arthritis. Independent risk factors (all P < .05) resulting in at least a 10% increase in episode-of-care costs following THA included malnutrition, male gender, age over 85, failed internal fixation, hip dysplasia, Northeast region, neurologic disorder, lower socioeconomic status, conversion THA, avascular necrosis, and depression.

CONCLUSION

Certain comorbidities and orthopedic risk factors increase 90-day episode-of-care costs in the Medicare population. The current lack of proper risk stratification could be a powerful driver of decreased access to care for our most medically challenged members of society.

Medicaid is associated with increased readmission and resource utilization after primary total knee arthroplasty: a propensity score-matched analysis

Background

Medicaid payer status has been shown to affect resource utilization across multiple medical specialties. There is no large database assessment of Medicaid and resource utilization in primary total knee arthroplasty (TKA), which this study sets out to achieve.

Methods

The Nationwide Readmissions Database was used to identify patients who underwent TKA in 2013 and corresponding “Medicaid” or “non-Medicaid” payer statuses. Demographics, 15 individual comorbidities, readmission rates, length of stay, and direct cost were evaluated. A propensity score–based matching model was then used to control for baseline confounding variables between payer groups. A chi-square test for paired proportions was used to compare readmission rates between the 2 groups. Length of stay and direct cost comparisons were evaluated using the Wilcoxon signed-rank test.

Results

A total of 8372 Medicaid and 268,261 non-Medicaid TKA patients were identified from the 2013 Nationwide Readmissions Database. A propensity score was estimated for each patient based on the baseline demographics, and 8372 non-Medicaid patients were propensity score matched to the 8372 Medicaid patients. Medicaid payer status yielded a statistically significant increase in overall readmission rates of 18.4% vs 14.0% (P < .0001, relative risk = 1.31, 95% confidence interval [1.23-1.41]) with non-Medicaid status and 90-day readmission rates of 10.0% vs 7.4%, respectively (P < .001, relative risk = 1.35, 95% confidence interval [1.22-1.48]). The mean length of stay was longer in the Medicaid group compared with the non-Medicaid group at 4.0 days vs 3.3 days (P < .0001) as well as the mean total cost of $64,487 vs $61,021 (P < .0001).

Conclusions

This study demonstrates that Medicaid payer status is independently associated with increased resource utilization, including readmission rates, length of stay, and total cost after TKA.

Impact of Perioperative HbA1c on Reimbursements in Diabetes Mellitus Patients Undergoing Total Hip Arthroplasty: A Nationwide Analysis

BACKGROUND

Patients who have diabetes mellitus (DM) are at an increased risk of postoperative complications following total hip arthroplasty (THA). Therefore, much interest has been paid to perioperative glycemic control. However, no prior studies have evaluated the patient variation of HbA1c levels on costs. Therefore, the purpose of this study was to evaluate the impact of obtaining preoperative HbA1c levels on (1) day of surgery (DOS) cost; (2) subsequent 89-day costs; and (3) global 90-day cost.

METHODS

A retrospective query of the Humana insurance claims database was performed from 2007 to 2015 for all DM patients undergoing THA. Only patients with HbA1c (%) levels within 3 months before or after the THA were included. Patients were stratified into 6 groups based on HbA1c starting at 5.5% and increasing by 1% increments to 11.5%; one additional group (11.5%-20%) for extreme cases was analyzed. Correlations between HbA1c level and reimbursements for DOS, subsequent 89-day, and global 90-day period were performed.

RESULTS

HbA1c level demonstrated a significant correlation to DOS (correlation coefficient = 0.664), subsequent 89-day (correlation coefficient = 0.789), and global 90-day period (correlation coefficient = 0.747) costs. DOS, 89-day, and global 90-day costs significantly increased with increasing HbA1c levels (P < .0001).

CONCLUSION

Higher perioperative HbA1c levels increase the DOS, subsequent 89-day, and global 90-day costs of THA. This was expected as these patients require multidisciplinary care, have longer LOS, and develop more complications. Further investigation into postoperative complications based on glycemic control is warranted.

Maximizing Physician-Hospital Alignment: Lessons Learned From Effective Models of Joint Arthroplasty Care

BACKGROUND

With recent healthcare reform efforts focusing on rewarding value instead of volume, it has become important for orthopedic surgeons to partner and align with their hospitals. We report our experience in aligning clinical and financial incentives with 6 health systems in our geographic area.

METHODS

By managing the entire episode-of-care continuum for total hip and total knee arthroplasty patients, our standardized, evidence-based protocols have improved the quality of care for our joint arthroplasty patients. While most studies focus on cost through insurance claims data, we have been able to accurately determine the costs to our practice and each facility through time-driven activity-based costing.

RESULTS

We have also achieved measureable claims and actual cost reduction by reducing unnecessary care, inappropriate variation in care, and avoidable complications through demand matching, risk stratification, and our nurse navigator program. Our joint ventures with our hospital partners in both specialty hospitals and our ambulatory surgery centers have also been critical to our success.

CONCLUSION

Our experience demonstrates that large private practice groups can successfully align both clinical and financial incentives with healthcare systems to provide quality joint arthroplasty care at a lower cost.

Effect of Obesity on Postacute Outcomes of Skilled Nursing Facility Residents with Hip Fracture

OBJECTIVES

To examine the effect of obesity (body mass index (BMI)≥30.0 kg/m² ) on outcomes of older adults admitted to skilled nursing facilities (SNFs) for hip fracture postacute care (PAC).

DESIGN

Retrospective cohort study.

SETTING

U.S. Medicare- and Medicaid-certified SNFs from 2008 to 2015.

PARTICIPANTS

Medicare fee-for-service beneficiaries discharged to a SNF after hospitalization for hip fracture (N=586,683; n=82,768 (14.1%) meeting obesity criteria). Exclusion criteria were aged younger than 65, being underweight (BMI<18.5 kg/m² ), and SNF use in the year prior to index hospitalization.

MEASUREMENTS

Residents were divided into 4 BMI categories according to cutoffs that the World Health Organization has established: not obese (BMI 18.5-29.9 kg/m² ), mild obesity (BMI 30.0-34.9 kg/m² ), moderate obesity (BMI 35.0-39.9 kg/m² ), and severe obesity (BMI≥40.0 kg/m² ). Robust Poisson regression was used to compare differences in average nursing facility length of stay (LOS) and rates of 30-day hospital readmission, successful discharge to community, and becoming a long-stay resident (LOS>100) according to obesity level. Models were adjusted for individual-level covariates and facility fixed effects.

RESULTS

Residents with mild (adjusted relative risk (aRR)=1.16, 95% CI=1.12-1.19), moderate (aRR=1.27, 95% CI=1.20-1.35), and severe (aRR=1.67, 95% CI=1.54-1.82) obesity were more likely to be readmitted within 30 days than those who were not obese. The average difference in LOS between residents without obesity and those with mild obesity was 2.6 days (95% CI=2.2-2.9 days); moderate obesity, 4.2 days (95% CI=3.7-5.1 days); and severe obesity, 7.0 days (95% CI=5.9-8.2 days). Residents with obesity were less likely to be successfully discharged and more likely to become long-stay nursing home residents.

CONCLUSION

Obesity was associated with worse outcomes in postacute SNF residents with hip fracture. Efforts to provide targeted care to residents with obesity may be essential to improve outcomes. Obesity may be an overlooked risk adjuster in quality-of-care measures and in payment reforms related to PAC for individuals with hip fracture.

Trochanteric Bursitis Following Primary Total Hip Arthroplasty: Incidence, Predictors, and Treatment

BACKGROUND

Trochanteric bursitis (TB) remains a common complication after total hip arthroplasty (THA), with an incidence between 3% and 17%, depending on the surgical approach, with the posterior approach (PA) being relatively protective compared to the lateral approach. The purposes of this study were to determine the incidence of TB after primary THA, identify potential risk factors for TB, and examine the utility of different modes of treatment.

METHODS

Retrospective cohort data of 990 primary THAs performed in a single institution, including 613 PAs and 377 direct anterior approaches (DAAs), were analyzed. Data abstracted included demographic data, operative diagnosis, comorbidities, radiographic assessment, and other specific predictors of interest that were compared between patients diagnosed with TB following THA and controls.

RESULTS

The incidence of TB following primary THA was 5.4% (54/990) for the entire cohort. The incidence did not differ significantly between the PA and DAA (5% vs 6.1%, respectively; P = .47). Charlson comorbidity index and American Society of Anesthesiology did not differ significantly in the TB group. Lumbar spinal stenosis and history of past smoking were significantly more common in patients who developed TB (P = .03, P = .01, respectively), but did not continue to be significant risk factors on multivariate analysis. All patients were treated nonoperatively by the time of final follow-up. Seventy-four percent required a local steroid injection and 30% required treatment with more than one modality.

CONCLUSION

The occurrence of TB is not influenced by the surgical approach (PA or DAA), and could not be predicted by specific comorbidities or radiographic measurements. However, it can be effectively treated conservatively in most cases.

Bundle Payment for Musculoskeletal Care: Current Evidence (Part 1)

In the face of escalating costs and variations in quality of care, bundled payment models for total joint arthroplasty procedures are becoming increasingly common, both through the Centers for Medicare & Medicaid Services and private payer organizations. The effective implementation of these payment models requires cooperation between multiple service providers to ensure economic viability without deterioration in care quality. This article introduces a stepwise model for the financial analysis of bundled contracts for use in negotiations between hospitals and private payer organizations.

Perioperative Outcomes and Complications in Patients With Heart Failure Following Total Knee Arthroplasty

BACKGROUND

Heart failure (HF) is a common comorbidity in the aging population and they will require major elective surgery. The purpose of this study is to determine if HF is a risk factor for adverse perioperative outcomes and short-term complications following total knee arthroplasty.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was utilized to identify all patients who underwent total knee arthroplasty for osteoarthritis from 2008 to 2014. Any diagnosis other than osteoarthritis was excluded. A total of 111,634 patients were identified and 251 of these patients had a preoperative diagnosis of HF. The main outcomes included operative time, lengths-of-stay, discharge disposition, return to operating room, readmission, and short-term complications, including death.

RESULTS

Patients with HF were found to have longer hospital stays (β = 0.59, 95% confidence interval [CI] 0.12-1.06) following total knee arthroplasty, and were more likely to return to the operating room (odds ratio 2.00, 95% CI 1.01-3.94) and be readmitted (OR 1.88, 95% CI 1.21-2.94). In addition, HF was found to be a risk factor for 1 or more complications (OR 1.41, 95% CI 1.05-1.90), wound dehiscence (OR 4.86, 95% CI 1.68-14.03), and myocardial infarction (OR 4.81, 95% CI 1.90-12.16) postoperatively.

CONCLUSION

Patients with HF are more likely to have a longer length-of-stay, return to the operating room, and be readmitted. Additionally, they have a higher risk for at least one postoperative complication, myocardial infarction, and wound dehiscence.

Can Bundled Payments Be Successful in the Medicaid Population for Primary Joint Arthroplasty?

BACKGROUND

Although some bundled payment models have had success in total joint arthroplasty, concerns exist about access to care for higher cost patients who use more resources. The purpose of this study is to determine whether Medicaid patients have increased hospital costs and more resource utilization in a 90-day episode of care than Medicare or privately insured patients.

METHODS

We retrospectively reviewed a consecutive series of 7268 primary hip and knee arthroplasty patients at a single institution. Using a propensity score-matching algorithm for demographic variables, we matched the 92 consecutive Medicaid patients with 184 privately insured and 184 Medicare patients. Hospital-specific costs, discharge disposition, complications, and 90-day readmissions were analyzed.

RESULTS

Medicaid patients had higher mean inpatient hospital costs than both of the matched Medicare and privately insured groups ($15,396 vs $12,165 vs $13,864, P < .001) with longer length of stay (3.34 vs 2.49 vs 1.46 days, P < .001). Medicaid and Medicare patients were more likely to be discharged to a rehabilitation facility than privately insured patients (17% vs 21% vs 1%, P < .001). When controlling for demographic factors and comorbidities, Medicaid insurance was a significant independent risk factor for increased hospital costs (odds ratio 3.64, 95% confidence interval 1.80-7.38, P < .001).

CONCLUSION

Because of increased hospital costs, current bundled payment models should not include Medicaid patients because of concerns about patient selection and access to care. Further study is needed to determine whether bundling Medicaid arthroplasty costs in a stand-alone program with a separate target price will result in improved outcomes and decreased costs.

Preoperative Opiate Use Independently Predicts Narcotic Consumption and Complications After Total Joint Arthroplasty

BACKGROUND

Multimodal pain protocols have reduced opioid requirements and decreased complications after elective total hip arthroplasty (THA) and total knee arthroplasty (TKA). However, these protocols are not universally effective. The purposes of this study are to determine the risk factors associated with increased opioid requirements and the impact of preoperative narcotic use on the length of stay and inhospital complications after THA or TKA.

METHODS

We prospectively evaluated a consecutive series of 802 patients undergoing elective primary THA and TKA over a 9-month period. All patients were managed using a multimodal pain protocol. Data on medical comorbidities and history of preoperative narcotic use were collected and correlated with deviations from the protocol.

RESULTS

Of the 802 patients, 266 (33%) required intravenous narcotic rescue. Patients aged <75 years (odds ratio [OR], 1.85; 95% confidence interval [CI], 1.10-3.12; P = .019) and with preoperative narcotic use (OR, 2.74; 95% CI, 2.01-3.75; P < .001) were more likely to require rescue. Multivariate logistic regression analysis demonstrated that preoperative narcotic use (OR, 2.74; 95% CI, 2.01-3.75; P < .001) was the largest independent predictor of increased postoperative opioid requirements. These patients developed more inhospital complications (OR, 1.92; 95% CI, 1.34-2.76; P < .001). This was associated with an increased length of stay (OR, 1.59; 95% CI, 1.06-2.37; P = .025) and a 2.5-times risk of requiring oral narcotics at 3 months postoperatively (OR, 2.48; 95% CI, 1.61-3.82; P < .001).

CONCLUSION

Despite the effectiveness of multimodal postoperative pain protocols, younger patients with preoperative history of narcotic use require additional opioids and are at a higher risk for complications and a greater length of stay.

Can an arthroplasty risk score predict bundled care events after total joint arthroplasty?

Background

The validated Arthroplasty Risk Score (ARS) predicts the need for postoperative triage to an intensive care setting. We hypothesized that the ARS may also predict hospital length of stay (LOS), discharge disposition, and episode-of-care cost (EOCC).

Methods

We retrospectively reviewed a series of 704 patients undergoing primary total hip and knee arthroplasty over 17 months. Patient characteristics, 90-day EOCC, LOS, and readmission rates were compared before and after ARS implementation.

Results

ARS implementation was associated with fewer patients going to a skilled nursing or rehabilitation facility after discharge (63% vs 74%, P = .002). There was no difference in LOS, EOCC, readmission rates, or complications. While the adoption of the ARS did not change the mean EOCC, ARS >3 was predictive of high EOCC outlier (odds ratio 2.65, 95% confidence interval 1.40-5.01, P = .003). Increased ARS correlated with increased EOCC (P = .003).

Conclusions

Implementation of the ARS was associated with increased disposition to home. It was predictive of high EOCC and should be considered in risk adjustment variables in alternative payment models.

Effect of Bundled Payments and Health Care Reform as Alternative Payment Models in Total Joint Arthroplasty: A Clinical Review

BACKGROUND

In an effort to control rising healthcare costs, healthcare reforms have developed initiatives to evaluate the efficacy of alternative payment models (APMs) for Medicare reimbursements. The Center for Medicare and Medicaid Services Innovation Center (CMMSIC) introduced the voluntary Bundled Payments for Care Improvement (BPCI) model experiment as a means to curtail Medicare cost by allotting a fixed payment for an episode of care. The purpose of this review is to (1) summarize the preliminary clinical results of the BPCI and (2) discuss how it has led to other healthcare reforms and alternative payment models.

METHODS

A literature search was performed using PubMed and the CMMSIC to explore different APMs and clinical results after implementation. All studies that were not in English or unrelated to the topic were excluded.

RESULTS

Preliminary results of bundled payment models have shown reduced costs in total joint arthroplasty largely by reducing hospital length of stay, decreasing readmission rates, as well as reducing the number of patients sent to in-patient rehabilitation facilities. In order to refine episode of care bundles, CMMSIC has also developed other initiatives such as the Comprehensive Care for Joint Replacement (CJR) pathway and Surgical Hip and Femur Fracture (SHFFT).

CONCLUSION

Despite the unknown future of the Affordable Care Act, BPCI, and CJR, preliminary results of alternative models have shown promise to reduce costs and improve quality of care. Moving into the future, surgeon control of the BPCI and CJR bundle should be investigated to further improve patient care and maximize financial compensation.

Bundled payments in total joint arthroplasty and spine surgery

PURPOSE OF REVIEW

The goal of this manuscript is to provide an overview and analysis of bundled payment models for joint replacement and select spine procedures. Advantages and disadvantages of bundled payment models will be discussed.

RECENT FINDINGS

In select populations, bundled payment models have been shown to reduce costs while maintaining satisfactory outcomes. These models have not been tested with complex patient cohorts, such as older adults with fragility hip fractures, and limited data exist with bundled payment analysis in spine procedures. The reduction of healthcare costs, satisfactory patient outcomes, and favorable payments to healthcare systems can be achieved through bundled payments. Modifications of existing bundled payment models should be critically tested prior to implementation across higher risk populations. Bundled payment models will also require healthcare systems to define what services are necessary for an episode of care regarding a specific condition or disease.

Revision Total Hip and Knee Arthroplasties After Solid Organ Transplant

BACKGROUND

As solid organ transplant (SOT) patients' survival improves, the number undergoing total hip (THA) and total knee arthroplasty (TKA) is increasing. Accordingly, the number of revision procedures in this higher-risk group is also increasing. The goals of this study were to identify the most common failure mechanisms, associated complications, clinical outcomes, and patient survivorship of SOT patients after revision THA or TKA.

METHODS

A retrospective review identified 39 revision procedures (30 revision THAs and 9 revision TKAs) completed in 37 SOT patients between 2000 and 2013. The mean age at revision surgery was 62 years with a mean follow-up of 6 years.

RESULTS

The most common failure mode for revision THA was aseptic loosening (10/30, 33%), followed by periprosthetic joint infection (PJI; 7/30, 23%). The most common failure mode for revision TKA was PJI (5/9, 56%). There were 6 re-revision THAs for PJI (3/30; 10%) and instability (3/30; 10%). There were 2 reoperations after revision TKA, both for acute PJI (2/9; 22%). Final Harris Hip Scores significantly (P = .03) improved as did Knee Society Scores (P = .01). Estimated survivorship free from mortality at 5 and 10 years was 71% and 60% after revision THA and 65% and 21% after revision TKA, respectively.

CONCLUSION

Revision THA and TKA after solid organ transplantation carry considerable risk for re-revision, particularly for PJI. Although SOT recipients demonstrate improved clinical function after revision procedures, patient survivorship at mid- to long-term follow-up is low.

Higher Modified Charlson Index Scores Are Associated With Increased Incidence of Complications, Transfusion Events, and Length of Stay Following Revision Hip Arthroplasty

BACKGROUND

Revision total hip arthroplasty (RHA) has been associated with greater morbidity and length of stay (LOS) compared to primary total hip arthroplasty. Despite this, few validated metrics exist for risk stratification in RHA cohorts. The Charlson Comorbidity Index (CCI) has been associated with complications in total hip arthroplasty, but its utility in revision surgery remains unexplored. The purpose of this study was to examine the relationship between preoperative CCI and a variety of outcome metrics following RHA.

METHODS

The National Surgical Quality Improvement Program database was used to identify all patients undergoing aseptic RHA between 2006 and 2013. A variety of demographics and perioperative variables were collected. Modified CCI scores were computed for each patient based on a validated formula incorporating comorbidities found in the National Surgical Quality Improvement Program database. Outcome variables of interest included mortality, major postoperative complications, minor adverse events, incidence of transfusion, and prolonged LOS. Perioperative factors were tested for association with these outcomes using bivariate analysis and significant variables were then incorporated into a logistic regression model to explore the relationship between preoperative CCI scores and postoperative events.

RESULTS

In a multivariable regression model controlling for the significant perioperative variables, operative time, and American Society of Anesthesiologists classification, higher CCI scores were significantly associated with mortality (odds ratio [OR] 1.89, 95% confidence interval [CI] 1.64-2.18, P < .001), major complications (OR 1.12, 95% CI 1.05-1.20, P = .001), minor complications (OR 1.53, 95% CI 1.39-1.69, P < .001), transfusions (OR 1.14, 95% CI 1.09-1.20, P < .001), and prolonged LOS (OR 1.32, 95% CI 1.26-1.39, P < .001).

CONCLUSION

Higher preoperative CCI scores were independent risk factors for numerous complications. This highlights the potential utility of the CCI in risk stratification for RHA populations.