The Removal of Total Hip and Total Knee Arthroplasty From the Inpatient-Only List Increases the Administrative Burden of Surgeons and Continues to Cause Confusion

Is Hospital-Based Outpatient Revision Total Knee Arthroplasty Safe? An Analysis of 2,171 Outpatient Aseptic Revision Procedures

BACKGROUND

Outpatient primary total knee arthroplasty (TKA) has been well-established as a safe and effective procedure; however, the safety of outpatient revision TKA remains unclear. Therefore, this study utilized a large database to compare outcomes between outpatient and inpatient revision TKA.

METHODS

An all-payor database was queried to identify patients undergoing revision TKA from 2010 to 2022. Patients who had diagnosis codes related to periprosthetic joint infection (PJI) were excluded. Outpatient surgery was defined as a length of stay < 24 hours. Cohorts were matched by age, sex, Elixhauser Comorbidity Index, comorbidities (diabetes, obesity, tobacco use), components revised (1-versus 2-component), and revision etiology. Medical complications at 90 days and surgical complications at 1 and 2 years postoperatively were evaluated through multivariate logistic regression. A total of 4,342 aseptic revision TKAs were included.

RESULTS

No differences in patient characteristics, procedure type, or revision etiologies were seen between groups. The outpatient cohort had a lower risk of PJI (odds ratio (OR): 0.547, 95% confidence interval (CI): 0.337 to 0.869; P = .012), wound dehiscence (OR: 0.393, 95% CI: 0.225 to 0.658; P < .001), transfusion (OR: 0.241, 95% CI: 0.055 to 0.750; P = .027), reoperation (OR: 0.508, 95% CI: 0.305 to 0.822; P = .007), and any complication (OR: 0.696, 95% CI: 0.584 to 0.829; P < .001) at 90 days postoperatively. At 1 year and 2 years postoperatively, outpatient revision TKA patients had a lower incidence of revision for PJI (OR: 0.332, 95% CI: 0.131 to 0.743; P = .011 and OR: 0.446, 95% CI; 0.217 to 0.859; P = .020, respectively) and all-cause revision (OR: 0.518, 95% CI: 0.377 to 0.706; P < .001 and OR: 0.548, 95% CI: 0.422 to 0.712; P < .001, respectively).

CONCLUSIONS

Our findings suggest that revision TKA can be safely performed on an outpatient basis in appropriately selected patients who do not have an increased risk of adverse events relative to inpatient revision TKA. However, we could not ascertain case complexity in either cohort, and despite controlling for several potential confounders, other less tangible differences could exist between groups.

Risk Factors of Failure to Discharge Before "Two Midnights" in Outpatient-Designated Total Hip Arthroplasty

INTRODUCTION

The Centers for Medicare and Medicaid Services removed total hip arthroplasty (THA) from the inpatient-only list but continued to classify admissions as inpatient if they include two midnights, complicating care if an outpatient THA requires extended hospitalization. This study evaluates risk factors of patients undergoing outpatient-designated THA with a length of stay (LOS) ≥ 2 days.

METHODS

A total of 17,063 THA procedures designated as outpatient in the National Surgical Quality Improvement Program database between 2015 and 2020 were stratified by LOS < 2 days (n = 2,294, 13.4%) and LOS ≥ 2 days (n = 14,765, 86.6%). Demographics, comorbidities, and outcomes were compared by univariate analysis. Multivariable regression analysis identified predictors of LOS ≥ 2 days.

RESULTS

Outpatients with extended LOS were older (mean 65.3 vs. 63.5 years; P < 0.01); were more likely to have body mass index (BMI) > 35 (24.0 vs. 17.8%; P < 0.01); and had higher incidences of smoking (15.1% vs. 10.3%; P < 0.01), diabetes (15.4% vs. 9.9%; P < 0.01), chronic obstructive pulmonary disease (4.4% vs. 2.3%; P < 0.01), and hypertension (57.6% vs. 49.2%; P < 0.01). Patients with LOS ≥ 2 days had a higher incidence of surgical site infection ( P < 0.01), hospital readmission ( P < 0.01), and revision surgery ( P < 0.01) over 30 days. Multivariable analysis demonstrated advanced age, female sex, African American race, Hispanic ethnicity, diabetes, smoking, and hypertension were independent risk factors for LOS ≥ 2 days.

CONCLUSION

Despite removal from the inpatient-only list, a subset of outpatient THA remains at risk of an extended LOS. This study informs surgeons on the relevant risk factors of extended stay, enabling early inpatient preauthorization.

The Epidemiology of the Revision Total Hip Arthroplasty in the United States From 2016 to 2022

Background

The number of revision total hip arthroplasties (THAs) is projected to reach 572,000 cases annually by 2030 in the United States. This may be attributed to the successes of primary THAs combined with an aging population, patients desire to remain active, and expanded indications for younger patients. Given the evolving nature of revision THAs, an epidemiological analysis of (1) etiologies; (2) demographics, including age and region; and (3) lengths of stay (LOSs) may minimize the gap between appropriate understanding and effective intervention.

Methods

From 2016 to 2022, a national, all-payer database was queried. Incidences and indications were analyzed for a total of 102,476 patients who had revision THA procedures. Patients were stratified according to etiology of failure, age, US census region, primary payor class, and mean LOS.

Results

The most common etiologies for revision THA procedures were dislocation (16.7%) and infection (12.7%), followed by periprosthetic fracture (6.9%). The largest age group was 65-74 years (30.9%), followed by >75 years (28.6%), then 55-64 (26.5%). The South had the largest total procedure cohort (36.9%), followed by the Midwest (27.5%), then the Northeast (19.7%), and the West (15.9%). The mean LOS was 4.10 days (range, 1.0-20.0).

Conclusions

Dislocation and infection remain leading indications for revision THA. These findings can properly guide surgeons toward appropriate management as well as toward active steps to minimizing these outcomes.

Same Day Total Hip and Knee Arthroplasty Performed at Canada's First Academic Ambulatory Surgical Center Is Safe and Effective: Population Level Results

BACKGROUND

Total hip arthroplasty (THA) and total knee arthroplasty (TKA) are being increasingly performed as an outpatient procedure. Performing these procedures at an ambulatory surgical center (ASC) has been proposed as a way to create greater access to surgical care, improve efficiency, and contain costs. The purpose of this review was to analyze the introduction of a same-day THA and TKA program at Canada's first academic ASC.

METHODS

An inpatient THA and TKA cohort and ASC cohort were developed with aggregate data collected from the Canadian Institute for Health Information and Canadian Joint Replacement Registry spanning January 2019 to March 2021. Quality was assessed via patient length of stay, 30-day readmissions, emergency department visits, and revision surgeries. Costs were assessed utilizing methodology and data provided by Canadian Institute for Health Information. Statistical analysis was performed comparing patient cohorts via Chi-square and t-tests.

RESULTS

Patients in the ASC cohort were significantly younger, more medically complex, and less likely to visit the emergency department within 30 days of surgery (P ≤ 0.001). Overall, 3.7% of patients failed same-day discharge and required a short stay. There was substantial cost savings of 1,721 Canadian Dollars per total joint arthroplasty (TJA) in cases performed at the ASC (P ≤ 0.001).

CONCLUSIONS

A THA and TKA performed at an academic-based ASC reduced costs and additional health care utilization within 30 days of surgery. This model of same-day surgery at an ambulatory center could help improve timely access to care for a proportion of Canadian patients.

Total Hip Surgical Approach Efficiency Outside of Surgical Time in the Ambulatory Surgical Center

BACKGROUND

Rising demand for total hip arthroplasty (THA) in ambulatory surgery centers (ASCs) requires improved efficiency, considering varying surgical approach time requirements, to manage caseloads and ensure safe same-day discharge (SDD). This study examines care phase durations, SDD success and delays, and outcomes, including 90-day complication rates and 1-year patient-reported outcomes (PROs).

METHODS

A retrospective review of primary THA patients at a single ASC (January 2019 to January 2021) was conducted. Data on demographics, phase-of-care times, perioperative outcomes, 90-day complications, and PROs were stratified by surgical approach. Comparison was done using 2-tailed t-test and Fisher exact test. Stepwise regression controlled for age, gender, body mass index, assistive device use, class attendance, American Society of Anesthesia score, Charlson comorbidity index, and diagnosis.

RESULTS

Groups differed in age, BMI, assistive device use, class attendance, and preoperative Veterans Rand 12-Item Health Survey physical component scores. The direct anterior approach (DAA) and posterior approach (PA) cohorts showed significant differences in phase-of-care times, except for spinal-time, and total-physical therapy (PT)-time-in-postanesthesia care unit (PACU). DAA was faster in spinal-start-to-incision-time (26.8 versus 35.0; P < 0.001), set-up/take-down-time (20.5 versus 30.2; P < 0.001), operative time (OR; 37.5 versus 50.4; P < 0.001), total operating room time (57.8 versus 80.5; P < 0.001), and arrival-to-discharge-time (383.8 versus 418.4; P < 0.001). PA was faster in time-to-initiation-of-PT (46.3 versus 71.4; P < 0.001), PACU-arrival-to-PT-cleared-time (124.9 versus 144.3; P < 0.001), and total-PACU-time (127.8 versus 143.4; P < 0.001). Surgical approach, age, BMI, and preoperative assistive device use predicted time differences. Excessive spinal was the main cause of PT delays. No differences in 90-day complications or PROs were observed.

CONCLUSIONS

DAA showed shorter total OR and arrival-to-discharge-times compared to PA, with similar complications and PROs. Both approaches effectively achieved SDD. Operative and set-up/take-down-time drove DAA efficiency, but PT initiation was delayed due to standard spinal blocks with shorter OR times.

Should Chronological Age be a Consideration in Patients Undergoing Elective Primary Total Knee Arthroplasty?

BACKGROUND

The optimal time for total knee arthroplasty (TKA) requires a balance between patient disability and health state to minimize complications. While chronological age has not been shown to be predictive of complications in elective surgical patients, there is a point beyond which even optimized elderly patients would be at increased risk for complications. The purpose of this study was to examine the impact of chronological age on complications following primary TKA.

METHODS

Using an administrative database, the records of 2,129,191 patients undergoing elective unilateral TKA between 2006 and 2021 were reviewed. The primary outcomes of interest were cardiac and pulmonary complications, and their relationship to the Charlson-Deyo Comorbidity Index (CDI) and chronological age. Secondary outcomes included risk of renal, neurologic, infection, and intensive care utilization postoperatively. The results were analyzed using a graphical method. The impact of chronological age as a modifier of overall risk for complications was modeled as a continuous variable. An age cutoff threshold of 80 years was also assigned for clinical convenience.

RESULTS

The risk of complications correlated more closely to the CDI (odds ratio (OR) 1.37 to 2.1) than chronological age (OR 1.0 to 1.1) across the various complications [Table 1. However, beyond age 80 years, the risks of cardiac, pulmonary, renal, and cerebrovascular complications were significantly increased for all CDI categories (OR 1.73 to 3.40) compared to patients below age 80 years [Table 2] [Figures 1A and 1B].

CONCLUSIONS

Chronologic age can impact the risk of complications even in well-optimized elderly patients undergoing primary TKA. As arthroplasty continues to transition to outpatient settings and inpatient denials increase, these results can help patients, physicians, and payors mitigate risk while optimizing the allocation of resources.

Early Prosthetic Hip Dislocation: Does the Timing of the Dislocation Matter?

BACKGROUND

Early dislocation following total hip arthroplasty (THA) is a common reason for revision. The purpose of this study was to determine if the acuity of the dislocation episode affects the risk of revision surgery.

METHODS

A retrospective review of a national, all-payer administrative database comprised of claims from 2010 to 2020 was used to identify patients who had a prosthetic hip dislocation at various postoperative time intervals (0 to 7, 7 to 30, 30 to 60, and 60 to 90 days). Of the 45,352 primary unilateral THA patients who had sufficient follow-up, there were 2,878 dislocations within 90 days. Dislocators were matched 1:1 based on age, sex, and a comorbidity index with a control group (no dislocation). Demographics, surgical indications, comorbidities, ten-year revision rates, and complications were compared among cohorts. Multivariable logistic regression analysis was performed to identify risk factors for revision THA following early dislocation.

RESULTS

Among matched cohorts, dislocation at any time interval was associated with significantly increased odds of subsequent 10-years revision (OR [odds ratio] = 25.60 to 33.4, P < .001). Acute dislocators within 7 days did not have an increased risk of all cause revisions at 10 years relative to other early dislocators. Revision for indication of instability decreased with time to first dislocation (<7 days: 85.7% versus 60 to 90 days: 53.9%). Primary diagnoses of posttraumatic arthritis (OR = 2.53 [1.84 to 3.49], P < .001), hip fracture (OR = 3.8 [2.53 to 5.72], P < .001), and osteonecrosis (OR = 1.75 [1.12 to 2.73], P = .010) were most commonly associated with revision surgery after an early dislocation.

CONCLUSIONS

Dislocation within 90 days of THA is associated with increased odds of subsequent revision. Early dislocation within 7 days of surgery has similar all cause revision-free survivorship, but an increased risk of a subsequent revision for instability when compared to patients who dislocated within 7 to 90 days.

Outpatient vs. inpatient designation in total hip arthroplasty: can we predict who will require hospitalization?

INTRODUCTION

Following removal of total hip arthroplasty (THA) from the inpatient only (IPO) list by the Center for Medicare Services (CMS), arthroplasty surgeons face increased pressure to perform procedures on an outpatient (OP) basis. The purposes of the present study were to compare patients booked for THA as OP who required conversion to IP status postoperatively, to patients who were booked as, and remained OP, and to identify factors predictive of conversion from OP to IP status.

METHODS

We retrospectively reviewed all patients who underwent a primary THA at our institution between January 1, 2020 and April 26, 2022. All patients included were originally scheduled for OP surgery and were separated based on conversion to IP status postoperatively. Multiple regression analyses were used to determine the significance of all perioperative variables. Modeling via binary logistic regressions were used to determine factors predictive of status conversion.

RESULTS

Of 1,937 patients, 372 (19.2%) designated as OP preoperatively required conversion to IP status postoperatively. These patients had significantly higher facility discharge rates (P < 0.001) and 90-day readmission rates (P = 0.024). Patients aged 65 and older (P < 0.001), females (P < 0.001), patients with Black/African American race (P = 0.027), with a recovery room arrival time after 12 pm (P < 0.001), with a BMI > 30 kg/m2 (P = 0.001), and with a Charlson Comorbidity Index (CCI) ≥ 4 (P = 0.013) were Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation more likely to require conversion to IP designation. Marital status and time of procedure were also significant factors, as patients who were married (P < 0.001) and who were the first case of the day (P < 0.001) were less likely to be converted to IP.

CONCLUSION

Several factors were identified which could help determine appropriate hospital designation status at the time of surgical booking to ultimately avoid insurance claim denials. These included BMI, certain demographic factors, CCI ≥ 4, and patients 65 or older.

LEVEL III EVIDENCE

Retrospective Cohort Study.

A Cautionary Tale: Malaligned Incentives in Total Hip and Knee Arthroplasty Payment Model Reforms Threaten Promising Innovation and Access to Care

Over the past several years, there have been notable changes and controversies involving Medicare reimbursement for total hip (THA) and total knee arthroplasty (TKA). We have seen the development and implementation of experimental bundled payment model pilot programs goals of improving quality and decreasing overall costs of care during the last decade. Many orthopaedic surgeons have embraced these programs and have demonstrated the ability to succeed in these new models by implementing strategies, such as preservice optimization, to shift care away from inpatient or postdischarge settings and reduce postoperative complications. However, these achievements have been met with continual reductions in surgeon reimbursement rates, lower bundle payment target pricings, modest increases in hospital reimbursement rates, and inappropriate valuations of THA and TKA Common Procedural Terminology (CPT) codes. These challenges have led to an organized advocacy movement and spurred research involving the methods by which improvements have been made throughout the entire episode of arthroplasty care. Collectively, these efforts have recently led to a novel application of CPT codes recognized by payers to potentially capture presurgical optimization work. In this paper, we present an overview of contemporary payment models, summarize notable events involved in the review of THA and TKA CPT codes, review recent changes to THA and TKA reimbursement, and discuss future challenges faced by arthroplasty surgeons that threaten access to high-quality THA and TKA care.

A Review of 1228 In-Office Hand Surgery Procedures With Wide Awake Local Anesthesia No Tourniquet (WALANT) at a Single Private Practice

BACKGROUND

This study examined the complication rate of Wide Awake Local Anesthesia No Tourniquet (WALANT) technique in the clinic setting with field sterility at a single private practice. We hypothesized that WALANT is safe and effective with a low complication rate.

METHODS

This retrospective chart review included 1228 patients who underwent in-office WALANT hand procedures at a single private practice between 2015 and 2022. Patients were divided into groups based on type of procedure: carpal tunnel release, A1 pulley release, first dorsal compartment release, extensor tendon repair, mass excision, foreign body removal, and needle aponeurotomy. Patient demographics and complications were recorded; statistical comparisons of cohort demographics and risk factors for complications were completed, and P < .05 was considered significant for all statistical comparisons.

RESULTS

The overall complication rate for all procedures was 2.77% for 1228 patients including A1 pulley release (n = 962, 2.7%), mass excision (n = 137, 3.7%), extensor tendon repair (n = 23, 4.3%), and first dorsal compartment release (n = 22, 8.3%). Carpal tunnel release, foreign body removal, and needle aponeurotomy groups experienced no complications. No adverse events (e.g. vasovagal reactions, digital ischemia, local anesthetic toxicity, inadequate vasoconstriction) were observed in any group. Patients with known autoimmune disorders and those who were currently smoking had a statistically significant higher complication rate.

CONCLUSIONS

Office-based WALANT procedures with field sterility are safe and effective for treating common hand maladies and have a similar complication profile when compared to historical controls from the standard operating room in an ambulatory center or hospital.

Health Status of Total Hip Versus Total Knee Arthroplasty Patients and Possible Effects on Decisions Regarding Surgical Location, Cost, and Access to Care

Background: Total hip arthroplasty (THA) and total knee arthroplasty (TKA) are no longer considered inpatient-only procedures. Qualifying for inpatient status reimbursement requires additional, unreimbursed administrative effort, and may limit care to these patients. Purpose: We sought to evaluate and compare the overall health status of patients receiving THA and TKA. Methods: We conducted a retrospective review evaluating 2207 patients undergoing primary THA and TKA from 2015 to 2018 at a single institution. Clinical parameters, surgical procedure, medical history, laboratory values, length of stay (LOS), and discharge location were recorded and compared between the 2 groups. Results: In 2202 patients, we observed differences for body mass index (THA = 29.4 ± 0.4, TKA = 32.1 ± 0.3), low-density lipoprotein cholesterol levels (THA = 105.8 ± 13.5 mg/dL; TKA = 128.6 ± 13.7 mg/dL), and blood glucose levels (THA = 98.2 ± 1.7 mg/dL; TKA = 101.4 ± 1.3 mg/dL), indicating that TKA patients were more likely than THA patients to be classified as obese, hypercholesterolemic, and hyperglycemic. We observed longer LOS in THA patients (51.25 hours, 95% CI ± 3.87 hours) than in TKA patients (36.93 hours, 95% CI ± 1.17 hours). A greater proportion of TKA patients were discharged home (81.97%, N = 1155) rather than to additional care facilities compared with THA patients (71.84%, N = 539). Conclusion: In this retrospective study, we observed that TKA patients had higher rates of comorbidities than did THA patients, but TKA patients spent less time in the hospital and were more likely to be discharged home. Future studies should evaluate reasons for poor clinical outcomes for patients undergoing total joint arthroplasty with an outpatient designation.

The Effect of Surgical Approach on the Outcomes of Same-Day Discharge Outpatient Total Hip Arthroplasty at a Single Ambulatory Surgery Center

BACKGROUND

Primary total hip arthroplasty (THA) is increasingly being performed in the outpatient setting. However, there is little known regarding the differences in same-day discharge (SDD) rates and complications of operative approach in same-day total hip arthroplasty in the ambulatory surgery center (ASC) setting.

METHODS

A retrospective chart review was performed between July 2019 and October 2021 for all patients who underwent primary THA in a single freestanding ASC. Successful SDDs, surgical approaches, lengths of surgery, estimated blood losses (EBL), complications, and readmission events were recorded for each patient. Complications were compared using Pearson Chi-Squares, while EBL and surgery lengths were compared with 1-way analysis of variances (ANOVA) (alpha = 0.5). There were 17 total complications in 326 total hip arthroplasties (5.2%), including direct admissions to the emergency department, 30-day and 90-day readmissions, wound complications, instability, infection, and revision surgery. Among all complications, there were 5 direct admissions, making the successful SDD rate 98.5%.

RESULTS

Complications and direct admissions were not associated with approach. The 30-day readmission rates were associated with approach, with no readmissions in the direct anterior approach (DAA) or the antero-lateral approach (AL) cohorts and 3 (4.3%) in the posterior approach (PA) cohort.

CONCLUSIONS

In the ASC setting, patients undergoing THA regardless of approach showed no difference in successful SDDs or complications aside from 30-day readmissions. Same-day THA can be safely performed in the DAA, AL, and PA to the hip.

Increasing the Volume of Outpatient Total Joint Arthroplasty Procedures: An Evaluation of a Novel Rapid Recovery Pathway Program Within an Academic Medical Center

Background

There has been a national trend toward shifting joint arthroplasty procedures to the outpatient setting. These cases are often performed in freestanding ambulatory surgery centers (ASCs), which are often not accessible to surgeons within academic practices.

Purposes

We sought to investigate a novel rapid recovery program used to transition arthroplasty patients to an outpatient-based care system within an academic medical center.

Methods

All patients undergoing hip or knee arthroplasty between November 2019 and April 2021 were retrospectively evaluated for their eligibility for a rapid recovery pathway through the Extended Stay Unit (ESU) based on clinical and social criteria. Once admitted, patients were evaluated for whether they were discharged from the unit or if hospital admission was necessary.

Results

Out of the 444 patients deemed candidates for the rapid recovery program, 188 patients were admitted to the ESU (42.3%); 18 (9.6%) required inpatient hospital admission, with the majority of these due to failing physical therapy (16; 88.9%). Of the ESU patients who were successfully discharged home, 55 (32.4%) were discharged on postoperative day (POD) 0 and 115 (67.6%) on POD 1 (<23 hours).

Conclusion

As total joint arthroplasties shift toward the outpatient setting, surgeons in academic institutions must employ strategies to increase their volume of patient candidates for outpatient procedures. Our retrospective study of prospectively collected data suggests the feasibility of creating a separate rapid recovery unit within the hospital that can be an effective method by which to eventually transition to the ASC setting.

Patient Designation Prior to Total Knee Arthroplasty: How Can Preoperative Variables Impact Postoperative Status?

BACKGROUND

Removal of total knee arthroplasty (TKA) from the inpatient only list has led to a greater focus on outpatient (OP) procedures. However, the impact of OP-centered models in at-risk patients is unclear. Therefore, the current analysis investigated the effect of conversion from OP to inpatient (IP) status on postoperative outcomes and determined which factors put patients at risk for status change postoperatively.

METHODS

We retrospectively reviewed all patients who underwent a primary TKA at our institution between January 2, 2018, and April 26, 2022. All patients included were originally scheduled for OP surgery and were separated based on conversion to IP status postoperatively. Multiple regression analyses were used to determine the significance of all perioperative variables. Modeling via binary logistic regressions was used to determine factors predictive of status conversion.

RESULTS

Of the 2,313 patients originally designated for OP TKA, 627 (27.1%) required a stay of 2 midnights or longer. Patients in the IP group had significantly higher facility discharge rates (P < .001) compared to the OP group. Factors predictive of conversion included age of 65 years and older (P < .001), women (P < .001), arriving at the postanesthesia care unit after 12 pm (P < .001), body mass index greater than 30 (P = .004), and Charlson Comorbidity Index of 4 and higher (P = .004). Being the first case of the day (P < .001) and being married (P < .001) were both protective against conversion.

CONCLUSION

Certain intrinsic patient factors may predispose a patient to an IP stay, and an understanding of predisposing factors which could lead to IP conversion may improve perioperative planning moving forward.

A Specialist-Led Care Model: Aligning the Patient and Specialist for the Greatest Impact

In the previous paper, discussing "Risk and the Future of Musculoskeletal Care," we reviewed the basic concepts of the risk corridor, implications on health care overall if we maintain a fee-for-service model, and the need for musculoskeletal specialists to begin taking on/managing risk to reinforce our presence in a "value-based care" system. This paper discusses the successes and failures of recent value-based care models and provides the framework for the paradigm of a specialist-led care model. We posit that orthopedic surgeons are the most knowledgeable physicians to manage musculoskeletal conditions, create new and innovative models, and lead value-based care to the next level.

Preoperative Prediction and Risk Factor Identification of Hospital Length of Stay for Total Joint Arthroplasty Patients Using Machine Learning

Background

The aim of this study was to improve understanding of hospital length of stay (LOS) in patients undergoing total joint arthroplasty (TJA) in a high-efficiency, hospital-based pathway.

Methods

We retrospectively reviewed 1401 consecutive primary and revision TJA patients across 67 patient and preoperative care characteristics from 2016 to 2019 from the institutional electronic health records. A machine learning approach, testing multiple models, was used to assess predictors of LOS.

Results

The median LOS was 1 day; outpatients accounted for 16.5%, 1-day inpatient stays for 38.0%, 2-day stays for 26.4%, and 3-days or more for 19.1%. Patients characteristically fell into 1 of 3 broad categories that contained relatively similar characteristics: outpatient (0-day LOS), short stay (1- to 2-day LOS), and prolonged stay (3 days or greater). The random forest models suggested that a lower Risk Assessment and Prediction Tool score, unplanned admission or hospital transfer, and a medical history of cardiovascular disease were associated with an increased LOS. Documented narcotic use for surgery preparation prior to hospitalization and preoperative corticosteroid use were factors independently associated with a decreased LOS.

Conclusions

After TJA, most patients have either an outpatient or short-stay hospital episode. Patients who stay 2 days do not differ substantially from patients who stay 1 day, while there is a distinct group that requires prolonged admission. Our machine learning models support a better understanding of the patient factors associated with different hospital LOS categories for TJA, demonstrating the potential for improved health policy decisions and risk stratification for centers caring for complex patients.

Trends in Outpatient Total Knee Arthroplasty (TKA) from 2012 to 2020

BACKGROUND

Trends over the past decade suggest a steady increase in the proportion of total knee arthroplasty (TKA) performed on an outpatient basis. However, the optimal patient selection criteria for outpatient TKA remain unclear. We aimed to describe longitudinal trends in patients selected for outpatient TKA and identify risk factors for 30-day morbidity following inpatient and outpatient TKA.

METHODS

We identified 379,959 primary TKA patients, 17,170 (4.5%) of whom underwent outpatient surgery from 2012 to 2020 within a large national database. We used regression models to evaluate trends in outpatient TKA, factors associated with undergoing outpatient (vs. inpatient) TKA and 30-day morbidity following outpatient and inpatient TKA. We used Receiver Operating Curves (ROC) to examine cut-off points for continuous risk factors.

RESULTS

The proportion of patients undergoing outpatient TKA increased from 0.4% in 2012 to 14.1% in 2020. Younger age, male sex, lower body mass index (BMI), higher hematocrit, and fewer comorbidities were associated with receiving outpatient (vs. inpatient) TKA. Variables associated with 30-day morbidity in the outpatient group included older age, chronic dyspnea, chronic obstructive pulmonary disease (COPD), and higher BMI. ROC curves indicated outpatients aged 68 and older, or with a BMI of 31.4 or higher were more likely to experience 30-day complications.

CONCLUSION

The proportion of patients undergoing outpatient TKA has been increasing since 2012. Older age (≥68 years), a higher BMI (≥31.4), and comorbidities such as chronic dyspnea, COPD, diabetes, and hypertension were associated with an increased odds of 30-day morbidity following outpatient TKA.

Cost Analysis of Conversion Total Knee Arthroplasty: A Multi-Institutional Database Study

BACKGROUND

Total knee arthroplasty (TKA) after prior knee surgery, also known as conversion TKA (convTKA), has been associated with higher complications, resource utilization, time, and effort. The increased surgical complexity of convTKA may not be reflected by the relative value units (RVUs) assigned under the current U.S. coding guidelines. The purpose of this study was to compare the RVUs of primary TKA and convTKA and to calculate the RVU per minute to account for work effort.

METHODS

The American College of Surgeons National Surgical Quality Improvement Project (NSQIP) database was analyzed for the years 2005 to 2020. Current Procedural Terminology (CPT) code 27447 alone was used to identify patients who underwent primary TKA, and 27447 plus 20680 were used to identify convTKA. After 1:1 propensity score matching, 1,600 cases were assigned to each cohort. The 2023 Medicare Physician Fee Schedule RVU-to-dollar conversion factor from the U.S. Centers for Medicare & Medicaid Services (CMS) was used to calculate RVU dollar valuations per operative time. Complication rates were compared using a multivariate logistic regression model controlling for baseline characteristics.

RESULTS

The mean operative time for TKA was 97.8 minutes, with a corresponding RVU per minute of 0.25, while the mean operative time for convTKA was 124.3 minutes, with an RVU per minute of 0.19 (p < 0.0001). Using the conversion factor of $33.06 per RVU, this equated to $8.11 per minute for TKA versus $6.39 per minute for convTKA. ConvTKA was associated with higher overall complication (10.9% versus 6.5%, p < 0.0001), blood transfusion (6.6% versus 3.7%, p < 0.01), reoperation (2.3% versus 0.94%, p < 0.0001), and readmission (3.7% versus 1.8%, p < 0.001) rates.

CONCLUSIONS

The current billing guidelines lead to lower compensation for convTKA despite its increased complexity. The longer operative time, higher complication rate, and increased resource utilization may incentivize providers to avoid performing this operation. CPT code revaluation is warranted to reflect the time and effort associated with this procedure.

LEVEL OF EVIDENCE

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

The removal of total hip arthroplasty from the inpatient-only list has improved patient selection and expanded optimization efforts

INTRODUCTION

On January 1, 2020, the Centers for Medicare and Medicaid Services removed total hip arthroplasty (THA) from the Inpatient-Only (IPO) list. This study evaluated patient demographics and comorbidities, pre-operative optimization efforts, and 30-day outcomes of patients undergoing outpatient THA pre- and post- IPO-removal. The authors hypothesized that patients undergoing THA post-IPO removal would have improved optimization of modifiable risk factors and equivalent 30-day outcomes.

METHODS

There were 17,063 outpatient THA in a national database stratified by surgery performed pre- (2015 to 2019: 5,239 patients) and post-IPO (2020: 11,824 patients) removal. Demographics, comorbidities, and 30-day outcomes were compared with univariable and multivariable analyses. Pre-operative optimization thresholds were established for the following modifiable risk factors: albumin, creatinine, hematocrit, smoking history, and body mass index. The percentage of patients who fell outside the thresholds in each cohort were compared.

RESULTS

Patients undergoing outpatient THA post-IPO removal were significantly older; mean age 65 years (range, 18 to 92) vs 62 (range, 18 to 90) years (P<0.01), with a higher percentage of American Society of Anesthesiologists scores 3 and 4 (P<0.01). There was no difference in 30-day readmissions (P=0.57) or reoperations (P=1.00). A significantly lower percentage of patients fell outside the established threshold for albumin (P<0.01) post-IPO removal, and trended towards lower percentages for hematocrit and smoking status.

CONCLUSION

The removal of THA from the IPO list expanded patient selection for outpatient arthroplasty. Pre-operative optimization is critical to minimize post-operative complications, and the current study demonstrates that 30-day outcomes have not worsened post-IPO removal.

The Persistent Effects of the COVID-19 Pandemic on Total Joint Arthroplasty Changes in Practice Patterns in the United States From 2020 to 2021

BACKGROUND

The SARS-CoV-2 (COVID-19) pandemic has dramatically disrupted orthopaedic surgery practice patterns. This study aimed to examine differences between patients who underwent total joint arthroplasty (TJA) before the pandemic compared to 2020 and 2021.

METHODS

A retrospective cohort study was performed on all patients who underwent elective inpatient TJA from January 2017 to December 2021 using a national large database. Descriptive statistics were utilized to trend length of stay (LOS) and patient age. Patient demographics, discharge destinations, and rates of medical comorbidities were assessed for patients undergoing TJA in 2020 and 2021 compared to patients from prepandemic years (2017 to 2019). Overall, 1,173,366 TJAs were identified (2017 to 2019: 810,268 TJAs, average 270,089 cases/year; 2020: 175,185 TJAs; 2021: 187,627 TJAs). There was a 35.3% and 30.5% decrease in 2020 and 2021, respectively, when compared to the prepandemic annual average.

RESULTS

Average LOS decreased from 1.6 days in January 2020 to 0.9 days by December 2021. Same-day discharges increased from 6.2% of cases in 2019 to 30.5% in 2021. Discharge to skilled nursing facilities (SNF) reduced from 11.3% in 2017 to 2019 to 4.3% and 4.5% in 2020 and 2021, respectively. Patients ≥70 years old undergoing elective TJA decreased from 39.6% in 2017 to 2019 to 29.2% in April 2020.

CONCLUSION

In response to the COVID-19 pandemic, same-day discharges following primary elective TJA increased markedly, the average LOS decreased, discharges to SNFs decreased, and a preferential shift toward younger patients was observed.

LEVEL OF EVIDENCE

Therapeutic Level III.

Hospital Revenue, Cost, and Contribution Margin in Inpatient Versus Outpatient Primary Total Joint Arthroplasty

BACKGROUND

Removal of primary total knee arthroplasty (TKA) and primary total hip arthroplasty (THA) from the inpatient-only list has financial implications for both patients and institutions. The aim of this study was to evaluate and compare financial parameters between patients designated for inpatient versus outpatient total joint arthroplasty.

METHODS

We reviewed all patients who underwent TKA or THA after these procedures were removed from the inpatient-only list. Patients were statistical significance into cohorts based on inpatient or outpatient status, procedure type, and insurance type. This included 5,284 patients, of which 4,279 were designated inpatient while 1,005 were designated outpatient. Patient demographic, perioperative, and financial data including per patient revenues, total and direct costs, and contribution margins (CMs) were collected. Data were compared using t-tests and Chi-squared tests.

RESULTS

Among Medicare patients receiving THA, CM was 89.1% lower for the inpatient cohort when compared to outpatient (P < .001), although there was no statistical significance difference between cohorts for TKA (P = .501). Among patients covered by Medicaid or Government-managed plans, CM was 120.8% higher for inpatients receiving THA (P < .001) when compared to outpatients and 136.3% higher for inpatients receiving TKA (P < .001).

CONCLUSION

Our analyses showed that recent costs associated with inpatient stay inconsistently match or outpace additional revenue, causing CM to vary drastically depending on insurance and procedure type. For Medicare patients receiving THA, inpatient surgery is financially disincentivized leaving this vulnerable patient population at a risk of losing access to care.

LEVEL III EVIDENCE

Retrospective Cohort Study.

RAPT Scores Predict Inpatient Versus Outpatient Status and Readmission Rates After IPO Changes for Total Joint Arthroplasty: An Analysis of 12,348 Cases

BACKGROUND

Changes to Medicare's Inpatient Only List (IPO) and factors associated with the COVID pandemic have led to more total joint arthroplasty (TJA) patients to be designated as outpatient (OP). This potentially complicates postoperative care for patients with lower functional status and poor social support. These factors make the decision between OP versus inpatient (IP) designation particularly challenging for healthcare teams. The Risk Assessment and Prediction Tool (RAPT) was designed to indicate patient risk for needing posthospital discharge to facility and considers social and functional factors. The purpose of this study is to 1) evaluate the correlation of RAPT as a clinical tool to aid decision-making regarding OP versus IP for Total Hip and Knee Arthroplasty (THA and TKA), 2) assess the impact of recent changes to the IPO and the COVID pandemic on OP TJA readmission rates, and 3) determine whether 90-day readmissions are correlated with RAPT scores after OP TJA.

METHODS

We identified all elective TKA and THA patients from 2015 through 2021 in our electronic health record at our large, urban, academic health system. Fracture patients were excluded. For those patients with available RAPT scores, we determined OP and IP designations, with IP defined as those with length-of-stay 2 midnights or more. We performed subanalysis of OP between same-day and next-day discharge. RAPT scores and readmission rates were compared at time points related to changes in the IPO: before TKA removal in 2018 (period A), from 2018 until THA removal in 2020 (Period B), and after January 1, 2020, inclusive of impact from the COVID pandemic (Period C).

RESULTS

Reviewed were 11,819 elective TKAs and 10,212 elective THAs. RAPT scores were available for 6,759 TKA patients and 5,589 THA patients. For both TKA and THA, RAPT scores between IP, same-day, and next-day discharged OP were significantly different across all time periods (P < .001). The percentage of OP designation increased across all time periods for TKA and THA. Over these same time periods, mean RAPT scores decreased significantly for both OP TKA and OP THA (P < .01). Concurrent with these changes were significant increases in OP THA 90-day readmission rates across Periods A and B (P = .010) as well as A and C (P = .006). Readmitted OP TKA had significantly lower RAPT scores than OP TKA without readmission during Period B (P < .001). Readmitted OP THA had significantly lower RAPT scores than those without readmission for all periods (P < .05). To facilitate clinical utility, median RAPT scores were also analyzed, and showed that RAPT scores for OP THA patients with readmission were 1 to 2 points lower for all time periods.

CONCLUSION

RAPT scores correlate with IP versus OP status for both TKA and THA and vary significantly with same-day versus next-day discharge. OP TJA RAPT scores may also help predict readmission, and counsel some patients away from OP surgery. Average RAPT scores of 10, 9, and 8 appeared to be separators for same day, next day, and inpatient stay. Changes to the IPO and COVID pandemic correlate with decrease in RAPT scores for both TKA and THA patients within all designations. In addition, a shift toward lower RAPT for OP TJA correlates with increased 90-day readmission rates for OP TJA. Taken together, these results suggest that patients with poorer function and worse social support systems are increasingly being driven toward OP surgery by these changes, which may play a role in increasing readmission rates. Social support and functional factors should be considered for OP elective TKA and THA. Further, any OP TJA value-based payment system must account for these variables.

Bundled Care in Elective Total Joint Replacement: Payment Models in Sweden, Canada, and the United States: A Critical Analysis Review

➢

Rising health-care expenditures and payer dissatisfaction with traditional models of reimbursement have driven an interest in alternative payment model initiatives.

➢

Bundled payments, an alternative payment model, have been introduced for total joint replacement in Sweden, the United States, and Canada to help to curb costs, with varying degrees of success.

➢

Outpatient total knee arthroplasty and total hip arthroplasty are becoming increasingly common and provide value for patients and payers, but have negatively impacted providers participating in bundled payment models due to considerable losses and decreased reimbursement.

➢

A fine balance exists between achieving cost savings for payers and enticing participation by providers in bundled payment models.

➢

The design of each model is key to payer, provider, and patient satisfaction and should feature comprehensive coverage for a full cycle of care whether it is in the inpatient or outpatient setting, is linked to quality and patient-reported outcomes, features appropriate risk adjustment, and sets limits on responsibility for unrelated complications and extreme outlier events.

Trends in Revenue, Cost, and Contribution Margin for Total Joint Arthroplasty 2011-2021

BACKGROUND

Regulatory change has created a growing demand to decrease the hospital costs associated with primary total joint arthroplasty (TJA). Concurrently, the removal of lower extremity TJA from the in-patient only list has affected hospital reimbursement. The purpose of this study is to investigate trends in hospital revenue versus costs in primary TJA.

METHODS

We retrospectively reviewed all patients who underwent primary TJA from June 2011 to May 2021 at our institution. Patient demographics, revenue, total cost, direct cost, and contribution margin were collected. Changes over time as a percentage of 2011 numbers were analyzed. Linear regression analysis was used to determine overall trend significance and develop projection models.

RESULTS

Total knee arthroplasty (TKA) insured by government-managed/Medicaid (GMM) plans showed a significant upward trend (P = .013) in total costs. Direct costs of TKA across all insurance providers (P = .001 and P < .001) and total hip arthroplasty (THA) for Medicare (P = .009) and GMM (P = .001) plans demonstrated significant upward trends. Despite this, 2011-2021 modeling found no significant change in contribution margin for TKA and THA covered under all insurance plans. However, models based on 2018-2021 financial data demonstrated a significant downward trend in contribution margin across Medicare (P < .001) and GMM (P < .001) insurers for both TKA and THA.

CONCLUSION

Physician-led innovation in cost-saving strategies has maintained contribution margin over the past decade. However, the increase in direct costs seen over the past few years could lead to negative contribution margins over time, if further efficiency and cost-saving measures are not developed.

LEVEL III EVIDENCE

Retrospective Cohort Study.

Increased Patient-Level Payment After Removal of Total Knee Arthroplasty From the Inpatient-Only List

BACKGROUND

In January 2018, the Centers for Medicare and Medicaid Services removed total knee arthroplasty (TKA) from the Inpatient Only (IPO) list. This study aimed to compare patient-level payments in TKA cases with a length of stay (LOS) <2 midnights before and after removal of TKA from IPO list.

METHODS

In this retrospective cohort study, all Medicare patients who received a primary elective TKA from 2016-2019 with a LOS <2 midnights at an academic tertiary center were identified. Total and itemized charges and patient-level payments were compared between eligible TKA cases performed in 2016-2017 and those in 2018-2019. There were 351 eligible TKA cases identified: 151 in 2016-2017 and 200 in 2018-2019.

RESULTS

The percentage of patients making any out-of-pocket payment increased in 2018-2019 from 2016-2017 (51.0% versus 10.6%), as did median patient-level payment ($7.30 [range, $0.00-$3,389] versus $0.00 [range, $0.00-$1,248], P < .001 for both). A greater proportion of patients in 2018-2019 paid $1-$50 than in 2016-2017 (37.5% versus 1.3%, P < .001) with no change in the proportion of patients who made payments >$50. Total charges were less in 2018-2019 than in 2016-2017 (P = .001). Charges for drugs, laboratory tests, admissions/floor, and therapies decreased in 2018-2019, whereas charges for the operating room and radiology increased (P < .001 for all).

CONCLUSION

Patients receiving outpatient TKA in 2018-2019 were more likely to have out-of-pocket payments than patients with comparable hospital stay who were designated as inpatients, although most of these payments were less than $50.

Identifying and Creating Value for Employed Arthroplasty Surgeons in an Era of Decreasing Reimbursement

Recent regulatory changes made by the Center for Medicare and Medicaid Services (CMS) will result in a 9% decrease in reimbursement for hip and knee replacements by the end of 2022. Combining this with CMS's recent removal of total knee and total hip arthroplasty from the inpatient-only list has begun to take effect on the bottom line for hospital systems, which now employ around 50% of the arthroplasty community. Employed joint replacement surgeons should continue to innovate and be leaders within their hospital systems in the outpatient and ambulatory surgery space to recoup lost value, increase autonomy, and should be compensated for this work. Employed arthroplasty surgeon leaders can better align goals with and control the narrative in the C-suite to redefine their value as the most consistent, dependable, and transparent department within a larger health system or corporate medical group.

Life After BPCI: High Quality Total Knee and Hip Arthroplasty Care Can Still Exist Outside of a Bundled Payment Program

BACKGROUND

Concerns regarding target price methodology and financial penalties have led to withdrawal from Medicare bundled payment programs for total hip (THA) and knee arthroplasty (TKA), despite its early successful results. The purpose of this study was to determine whether there was any difference in patient comorbidities and outcomes following our institution's exit from the Bundled Payments for Care Improvement - Advanced (BPCI-A).

METHODS

We reviewed consecutive 2,737 primary TKA and 2,009 primary THA patients following our withdraw from BPCI-A January 1, 2020-March 30, 2021 and compared them to 1,203 TKA and 1,088 THA patients from October 1, 2018-August 2, 2019 enrolled in BPCI-A. We compared patient demographics, comorbidities, discharge disposition, complications, and 90-day readmissions. Multivariate analysis was performed to identify if bundle participation was associated with complications or readmissions.

RESULTS

Post-bundle TKA had shorter length of stay (1.4 vs 1.8 days, P < .001). Both TKA and THA patients were significantly less likely to be discharged to a rehabilitation facility (5.6% vs 19.2%, P < .001 and 6.0% vs 10.0%, P < .001, respectively). Controlling for confounders, post-bundle TKA had lower complications (OR = 0.66, 95% CI 0.45-0.98, P = .037) but no difference in 90-day readmission (OR = 0.80, 95% CI 0.55-1.16, P = .224).

CONCLUSIONS

Since leaving BPCI-A, we have maintained high quality THA care and improved TKA care with reduced complications and length of stay under a fee-for-service model. Furthermore, we have lowered rehabilitation discharge for both TKA and THA patients. CMS should consider partnering with high performing institutions to develop new models for risk sharing.

Ambulatory shoulder arthroplasty provides a mild reduction in overall cost compared with inpatient shoulder arthroplasty cost of ambulatory shoulder arthroplasty

HYPOTHESIS

The purpose of this study was to determine the relative cost difference of inpatient vs. ambulatory total shoulder arthroplasty (TSA) procedures.

METHODS

A retrospective case series was performed to identify a consecutive series of patients who underwent primary anatomic or reverse TSA at 2 orthopedic specialty hospitals between September 2015 and August 2020. Those undergoing surgery for fracture or revision were excluded. Itemized facility costs were analyzed with a time-driven activity-based costing model and compared between ambulatory and non-ambulatory procedures. Ambulatory patients were defined as those admitted and discharged on the same calendar day. All other patients were considered non-ambulatory.

RESULTS

A total of 1027 patients were analyzed, comprising 38 ambulatory patients (3.7%) and 989 non-ambulatory patients (96.3%). There was a higher proportion of anatomic TSA than reverse shoulder arthroplasty in the ambulatory group (81.6% vs. 51.7%, P < .0001). Overall, there was no difference in cost between the 2 groups ($8832 vs. $8841, P = .97). However, personnel costs were greater in the non-same-day group ($1895 vs. $2743, P < .0001) whereas supply costs were less ($6937 vs. $6097, P < .0003). When implant costs were excluded, outpatient shoulder arthroplasty provided a cost savings of $745.

CONCLUSION

Ambulatory shoulder arthroplasty provides a mild cost savings of $745 after controlling for fixed costs. This is much less dramatic than previously reported and should raise concern as shoulder arthroplasty continues to be targeted by payers as a potential for cost savings through decreased reimbursement.

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

Background

Methods

Results

Conclusions

Can Prior Episode-of-Care Costs Predict the Future? Identifying High-Cost Outliers for Subsequent Total Hip and Knee Arthroplasty

BACKGROUND

It remains unknown if a patient's prior episode-of-care (EOC) costs for total hip (THA) or knee (TKA) arthroplasty procedure can be used to predict subsequent costs for future procedures. The purpose of this study is to evaluate whether there is a correlation between the EOC costs for a patient's index and subsequent THA or TKA.

METHODS

We reviewed a consecutive series of 11,599 THA and TKA Medicare patients from 2015 to 2019 and identified all patients who underwent a subsequent THA and TKA during the study period. We collected demographics, comorbidities, short-term outcomes, and 90-day EOC claims costs. A multivariate analysis was performed to identify whether prior high-EOC costs were predictive of high costs for the subsequent procedure.

RESULTS

Of the 774 patients (6.7%) who underwent a subsequent THA or TKA, there was no difference in readmissions (4% vs 5%, P = .70), rate of discharge to a skilled nursing facility (SNF) (15% vs 15%, P = .89), and mean costs ($18,534 vs $18,532, P = .99) between EOCs. High-cost patients for the initial TKA or THA were more likely to be high cost for subsequent procedure (odds ratio 14.33, P < .01). Repeat high-cost patients were more likely to discharge to an SNF for their first and second EOC compared to normative-cost patients (P < .01).

CONCLUSION

High-cost patients for their initial THA or TKA are likely to be high cost for a subsequent procedure, secondary to a high rate of SNF utilization. Efforts to reduce costs in repeat high-cost patients should focus on addressing post-operative needs pre-operatively to facilitate safe discharge home.

Length of Stay After Joint Arthroplasty is Less Than Predicted Using Two Risk Calculators

BACKGROUND

Predicting the length of stay (LOS) after total joint arthroplasty (TJA) has become more important with their recent removal from inpatient-only designation. The American College of Surgeons (ACS) National Surgical Quality Improvement Program surgical risk calculator and the CMS' diagnosis-related group (DRG) calculator are two common LOS predictors. The aim of our study was to determine how our actual LOS compared with those predicted by both the ACS and DRG.

METHODS

99 consecutive TJA (49 hips and 50 knee procedures) were reviewed in Medicare-eligible patients from four fellowship-trained arthroplasty surgeons. Predicted LOS was calculated using the DRG and ACS risk calculators for each patient using demographics, medical histories, and comorbidities. LOS was compared between the predicted and the actual LOS for both total hip arthroplasty (THA) and total knee arthroplasty (TKA) using paired t-tests.

RESULTS

Actual LOS was shorter in the THA group vs the TKA group (1.29 days vs 1.46 days, P < .05). The actual LOS of patients at our institution was significantly shorter than both DRG and ACS predictions for both THA and TKA (P < .05). In both the THA and TKA patients, the actual LOS (1.29 and 1.46 day) was significantly shorter than the DRG-predicted LOS (2.15 and 2.15 days) which was significantly shorter than the ACS-predicted LOS (2.9 and 3.14 days).

CONCLUSION

We found the actual LOS was significantly shorter than that predicted by both the DRG and ACS risk calculators. Current risk calculators may not be accurate for contemporary fast-track protocols and newer tools should be developed.

Is Conversion TKA a Primary or Revision? Clinical Course and Complication Risks Approximating Revision TKA Rather Than Primary TKA

BACKGROUND

Conversion total knee arthroplasty (convTKA) is associated with increased resource utilization and costs compared with primary TKA. The purpose of this study is to compare 1) surgical time, 2) hospitalization length (LOS), 3) complications, 4) infection, and 5) readmissions in patients undergoing convTKA to both primary TKA and revision TKA patients.

METHODS

The American College of Surgeons National Surgical Quality Improvement Project database was queried from 2008 to 2018. Patients undergoing convTKA (n = 1,665, 0.5%) were defined by selecting Current Procedural Terminology codes 27,447 and 20,680. We compared the outcomes of interest to patients undergoing primary TKA (n = 348,624) and to patients undergoing aseptic revision TKA (n = 8213). Univariate and multivariate logistic regression was performed to identify the relative risk of postoperative complications.

RESULTS

Compared with patients undergoing primary TKA, convTKA patients were younger (P < .001), had lower body mass index (P < .001), and were less likely to be American Society of Anesthesiologist class III/IV (P < .001). These patients had significantly longer operative times (122.6 vs 90.3 min, P < .001), increased LOS (P < .001), increased risks for any complication (OR 1.94), surgical site infection (OR 1.84), reoperation (OR 2.18), and readmissions (OR 1.60) after controlling for confounders. Compared with aseptic TKA revisions, operative times were shorter (122.6 vs 148.2 min, P < .001), but LOS (2.91 vs 2.95 days, P = .698) was similar. Furthermore, relative risk for any complication (P = .350), surgical site infection (P = .964), reoperation (P = .296), and readmissions (P = .844) did not differ.

CONCLUSION

Conversion TKA procedures share more similarities with revision TKA rather than primary TKA procedures. Without a distinct procedural and diagnosis-related group, there are financial disincentives to care for these complex patients.

LEVEL OF EVIDENCE

II.

Enhanced Recovery After Surgery Protocols in Lower Extremity Joint Arthroplasty: Using Observational Data to Identify the Optimal Combination of Components

BACKGROUND

Enhanced recovery after surgery (ERAS) protocols are increasingly used in orthopedic surgery. Data are lacking on which combinations of ERAS components are (1) the most commonly used and (2) the most effective in terms of outcomes.

METHODS

This retrospective cohort study utilized claims data (Premier Healthcare, n = 1,539,432 total joint arthroplasties, 2006-2016). Eight ERAS components were defined: (A) regional anesthesia, (B) multimodal analgesia, (C) tranexamic acid, (D) antiemetics on day of surgery, (E) early physical therapy, and avoidance of (F) urinary catheters, (G) patient-controlled analgesia, and (H) drains. Outcomes were length of stay, "any complication," and hospitalization cost. Mixed-effects models measured associations between the most common ERAS combinations and outcomes. Odds ratios (ORs) and 95% confidence intervals (CIs) are reported.

RESULTS

In 2006-2012 and 2013-2016, the most common ERAS combinations were B/D/E/F/G/H (20%, n = 172,397) and B/C/D/E/F/G/H (17%, n = 120,266), respectively. The only difference between the most commonly used ERAS combinations over the years is the addition of C (addition of tranexamic acid to the protocol). The most pronounced beneficial effects in 2006-2012 were seen for combination A/B/D/E/F/G/H (6% of cases vs less prevalent ERAS combinations) for the outcome of "any complication" (OR 0.87, CI 0.83-0.91, P < .0001). In 2013-2016, the strongest effects were seen for combination B/C/D/E/F/G/H (17% of cases) also for the outcome of "any complication" (OR 0.86, CI 0.83-0.89, P < .0001). Relatively minor differences existed between ERAS protocols for the other outcomes.

CONCLUSION

Despite varying ERAS protocols, maximum benefits in terms of complication reduction differed minimally. Further study may elucidate the balance between an increasing number of ERAS components and incremental benefits realized.

LEVEL OF EVIDENCE

III.

Machine learning approaches in predicting ambulatory same day discharge patients after total hip arthroplasty

BACKGROUND

With continuing financial and regulatory pressures, practice of ambulatory total hip arthroplasty is increasing. However, studies focusing on selection of optimal candidates are burdened by limitations related to traditional statistical approaches. Hereby we aimed to apply machine learning algorithm to identify characteristics associated with optimal candidates.

METHODS

This retrospective cohort study included elective total hip arthroplasty (n=63 859) recorded in National Surgical Quality Improvement Program dataset from 2017 to 2018. The main outcome was length of stay. A total of 40 candidate variables were considered. We applied machine learning algorithms (multivariable logistic regression, artificial neural networks, and random forest models) to predict length of stay=0 day. Models' accuracies and area under the curve were calculated.

RESULTS

Applying machine learning models to compare length of stay=0 day to length of stay=1-3 days cases, we found area under the curve of 0.715, 0.762, and 0.804, accuracy of 0.65, 0.73, and 0.81 for logistic regression, artificial neural networks, and random forest model, respectively. Regarding the most important predictive features, anesthesia type, body mass index, age, ethnicity, white blood cell count, sodium level, and alkaline phosphatase were highlighted in machine learning models.

CONCLUSIONS

Machine learning algorithm exhibited acceptable model quality and accuracy. Machine learning algorithms highlighted the as yet unrecognized impact of laboratory testing on future patient ambulatory pathway assignment.

Projections of the Impact to Arthroplasty Surgeons With Changes to the 2021 Medicare Physician Fee Schedule-A Looming Crisis of Access to Care?

BACKGROUND

The Centers for Medicare and Medicaid Services 2021 Physician Fee Schedule (PFS) includes increases in office reimbursement but decreases in the valuation of total hip arthroplasty and total knee arthroplasty and the conversion factor. The purpose of this study was to determine the financial impact of these changes on arthroplasty surgeons.

METHODS

We queried data for 35 arthroplasty surgeons within our practice from 10/2019 to 10/2020 and captured all office and arthroplasty-related surgical procedure codes. We compared the difference in both work relative value units (RVUs) and Medicare reimbursement by surgeon based on the current 2020 PFS to the 2021 changes. We also estimated the impact of several proposals to include office increases to the global surgical package for each code.

RESULTS

While the mean per surgeon RVU amount for primary arthroplasty procedures will decrease (6267 vs 6,088, P = .78), the mean office work RVU (2755 vs 3,220, P = .16) will increase in 2021. However, the reduction in surgical reimbursement ($530,076 in 2020 to $464,414 in 2021) far exceeds the gains from the office ($99,456 vs $107,374), leading to an overall decrease in reimbursement ($629,532 vs $571,788), a reduction of 9%. The passage of the coronavirus disease 2019 relief bill delays many of the PFS cuts and will result in an overall reduction in reimbursement of 2.4% ($629,532 vs $612,475, P = .61).

CONCLUSION

Arthroplasty surgeons are projected to lose 2.4% of Medicare reimbursement in 2021 with the changes in the Centers for Medicare and Medicaid Services PFS. Further study is needed to determine whether these cuts will limit access to care for Medicare patients.

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.

Despite Equivalent Medicare Reimbursement, Facility Costs for Outpatient Total Knee Arthroplasty Are Higher Than Unicompartmental Knee Arthroplasty

BACKGROUND

With the recent removal of total knee arthroplasty (TKA) from the Centers for Medicare and Medicaid Services (CMS) Inpatient Only list, facility reimbursement for outpatient TKA now falls under the Outpatient Prospective Payment System at the same rate as unicompartmental knee arthroplasty (UKA). The purpose of this study was to compare true facility costs of patients undergoing outpatient TKA with those undergoing UKA.

METHODS

We reviewed a consecutive series of 2310 outpatient TKA and 231 UKA patients from 2018 to 2019. Outpatient status was defined as a hospital stay of less than 2 midnights. Facility costs were calculated using a time-driven, activity-based costing algorithm. Implants, supplies, medications, and personnel costs were compared between outpatient TKA and UKA patients. A multivariate analysis was performed to control for confounding medical and demographic variables.

RESULTS

When compared with patients undergoing UKA, outpatient TKA patients had higher implant costs ($3403 vs $3081; P < .001) and overall hospital costs ($6350 vs $5594; P < .001). Outpatient TKA patients had a greater length of stay (1.2 vs 0.5 days; P < .001) and greater postoperative personnel costs ($783 vs $166; P < .001) than UKA patients. When controlling for comorbidities, outpatient TKA was associated with a $803 (P < .001) increase in overall facility costs compared with UKA.

CONCLUSION

Despite equivalent reimbursement from CMS as UKA, outpatient TKA has increased facility costs to the hospital. Although implant costs can vary greatly by institution, CMS should consider appropriately reimbursing outpatient TKA for the additional personnel costs when compared with UKA.

From Winners to Losers: The Methodology of Bundled Payments for Care Improvement Advanced Disincentivizes Participation in Bundled Payment Programs

BACKGROUND

The Bundled Payments for Care Improvement (BPCI) initiative improved quality and reduced costs following total hip (THA) and knee arthroplasty (TKA). In October 2018, the BPCI-Advanced program was implemented. The purpose of this study is to compare the quality metrics and performance between our institution's participation in the BPCI program with the BPCI-Advanced initiative.

METHODS

We reviewed a consecutive series of Medicare primary THA and TKA patients. Demographics, medical comorbidities, discharge disposition, readmission, and complication rates were compared between BPCI and BPCI-Advanced groups. Medicare claims data were used to compare episode-of-care costs, target price, and margin per patient between the cohorts.

RESULTS

Compared to BPCI patients (n = 9222), BPCI-Advanced patients (n = 2430) had lower rates of readmission (5.8% vs 3.8%, P = .001) and higher rate of discharge to home (72% vs 78%, P < .001) with similar rates of complications (4% vs 4%, P = .216). Medical comorbidities were similar between groups. BPCI-Advanced patients had higher episode-of-care costs ($22,044 vs $18,440, P < .001) and a higher mean target price ($21,154 vs $20,277, P < .001). BPCI-Advanced patients had a reduced per-patient margin compared to BPCI ($890 loss vs $1459 gain, P < .001), resulting in a $2,138,670 loss in the first three-quarters of program participation.

CONCLUSION

Despite marked improvements in quality metrics, our institution suffered a substantial loss through BPCI-Advanced secondary to methodological changes within the program, such as the exclusion of outpatient TKAs, facility-specific target pricing, and the elimination of different risk tracks for institutions. Medicare should consider adjustments to this program to keep surgeons participating in alternative payment models.

A Simple Tool for Recommending Postoperative Status After Lower Extremity Total Joint Replacement

There is an increasing impetus to perform primary total hip arthroplasty and total knee arthroplasty on an outpatient basis and in the outpatient setting. However, with recent federal regulatory changes, orthopedic surgeons must now evaluate patients on a case-by-case basis to determine whether an inpatient admission will be medically necessary and appropriate. We thus created our prototype Lower Extremity Inpatient-Outpatient (LET-IN-OUT) total joint replacement tool as a simple, consistent way for other clinicians to identify specific major preoperative patient comorbidities and thus to recommend independently and objectively to the orthopedic surgeon postoperative inpatient or outpatient status for a given patient.

Medicare Total Knee Arthroplasty Patients Need Not Stay 2 Midnights for Full Facility Reimbursement

BACKGROUND

Health care systems are concerned that facility reimbursements will be reduced based on patient length of stay (LOS) of <2 midnights with the removal of total knee arthroplasty (TKA) from the inpatient-only list. The purpose of this study was to evaluate the effect of LOS and postdischarge disposition on facility reimbursement.

METHODS

We evaluated a consecutive series of 470 primary Medicare TKA patients performed at a single institution from 2018 to 2019. We analyzed facility reimbursement based on patient LOS and discharge disposition. Descriptive statistics were analyzed using chi-square test, analysis of variance, and Student t test calculations.

RESULTS

Overall, the facility was fully reimbursed in 401 patients (85%) at a mean of $11,169. The facility received full reimbursement for 323 of 326 (99%) patients with an LOS of <2 midnights who were discharged to home at a mean of $11,156. This reimbursement was significantly (P < .001) higher than patients who had an LOS <2 midnights who were discharged with home health (mean, $9773) or to a facility (mean, $10,095). For those with LOS >2 midnights, there was no difference in mean reimbursement among discharge dispositions ($11,202 vs $11,249 vs $11,085, P = .65).

CONCLUSION

In this study, Medicare TKA patients with LOS <2 midnights were fully reimbursed 99% of the time as an inpatient as long as they are discharged to home without home health or to a rehabilitation facility. Those discharged before 2 midnights who require home health service or inpatient facility are more likely to be reimbursed at a lower penalized rate.