Is the New Outpatient Prospective Payment System Classification for Outpatient Total Knee Arthroplasty Appropriate?

BackgroundIn 2018, the Centers for Medicare and Medicaid Services removed total knee arthroplasty (TKA) from the inpatient-only list, resulting in payment through the Outpatient Prospective Payment System with an average $3157 reduction. The purpose of this study is to determine if the reimbursement is justified by comparing the difference in facility costs between inpatient and outpatient TKAs.MethodsWe identified 4496 consecutive primary TKA procedures performed at 2 hospitals from 2015 to 2019. Itemized facility costs were calculated using a time-driven activity-based costing algorithm. Outpatient procedures were defined as those with a length of stay of less than 2 midnights (3851, 86%). Patient demographics, comorbidities, and itemized costs were compared between groups. A multivariate regression analysis was performed to determine the independent effect of outpatient status on true facility costs.ResultsOutpatient TKA patients had lower mean postoperative personnel costs ($1809 vs $947, P < .001), supply costs ($4347 vs $4229, P < .001), and overall total facility costs ($7371 vs $6937, P < .001) than inpatient TKA patients. Controlling for a younger patient cohort with fewer medical comorbidities, outpatient status was associated with a reduction in total facility costs of $972 (95% confidence interval $883-$1060, P < .001) compared to inpatient TKA.ConclusionOutpatient TKA costs hospitals nearly $1000 per patient less than inpatient TKA, yet the average difference in Medicare reimbursement for an outpatient procedure is $3157 less per patient. Centers for Medicare and Medicaid Services should reconsider the Outpatient Prospective Payment System classification of TKA to better incentivize surgeons to perform TKA as a lower cost outpatient procedure when safe and appropriate.     

Staging Total Hip and Knee Arthroplasty Procedures Within 90 Days Increases Costs in Bundled Payment Programs

BackgroundUnder current Medicare bundled payment programs, when a patient undergoes a subsequent elective procedure within the 90-day episode-of-care, the first procedure is excluded from the bundle and a new episode-of-care initiated. The purpose of this study was to determine if staging bilateral total hip (THA) and total knee arthroplasty (TKA) procedures within 90 days have an effect on bundled episode-of-care costs.MethodsWe reviewed a consecutive series of Medicare patients undergoing staged primary THA and TKA from 2015-2019. Patients who underwent a prior procedure within 90 days were compared to those who had undergone a procedure 90-120 days prior. We then performed a multivariate analysis to identify the independent effect of staging timeframe on costs and outcomes.ResultsOf the 136 patients undergoing a staged bilateral THA or TKA, 48 patients underwent staged procedures within 90 days (35%) and 88 patients between 91-120 days (65%). There were no significant differences observed for demographics, comorbidities, complications, readmissions, or discharge disposition (all P > .05). Patients undergoing a staged procedure within 90 days had increased episode-of-care costs by $2021 (95% CI $11-$4032, P = .049), increased postacute care costs by $2019 (95% CI $66-$3971, P < .001), and reduced per-patient margin by $2868 (95% CI-$866-$4869, P = .005).DiscussionPatients undergoing staged bilateral THA or TKA within 90 days have increased episode-of-care costs compared to those undergoing a staged procedure from 91-120 days. Since patients may still not be fully recovered from the first procedure, CMS should address the inappropriate allocation of costs to ensure institutions are not penalized.     

Risk-Adjusted Cost Performance for 90-Day Total Hip Arthroplasty Episodes: Comparing US Hospitals Nationwide Before CJR

BackgroundWe characterize variation in total hip arthroplasty (THA) episode payments in the United States. Medicare population immediately preceding implementation of the comprehensive care for joint replacement (CJR) bundled care model and propose a model for ongoing evaluation of hospital performance.MethodsWe identified THA episodes in Medicare part A 2014-2016 (n = 366,380) and compared 90-day episode payments across years and geographic regions. We fit hierarchical models that regressed episode payments on patient-level fixed and region-level and hospital-level random effects. Random effects estimates were used to characterize risk-adjusted hospital cost performance. We ranked hospitals (n = 3218) in each region by their cost performance estimate and constructed 95% confidence intervals to visualize high-performing and low-performing hospitals.ResultsMean part A episode payments declined from 2014 to 2016 throughout the United States ($19,925-$17,775; P < .001), primarily attributable to decreased postacute care payments. Ninety-day readmission rates fell by a percentage point (from 7.9% to 6.8%; P < .001). We found significant variation in risk-adjusted episode payments, postacute care utilization, and readmission rates across regions, and ever greater variation at the hospital level.ConclusionMedicare part A payments decreased for THA episodes between 2014 and 2016. The time frame for this decrease is notable for preceding full implementation of CJR, thus suggesting a more universal embrace of value-based care principles before the start date of CJR. These decreases were primarily because of decreased postacute care utilization and possibly related to falling readmission rates. Yet, significant variation in hospital cost performance remains, even after risk adjustment.     

The Benefit in Patient-Reported Outcomes After Total Knee Arthroplasty was Comparable Across Income Quartiles

BackgroundFew studies have assessed how socioeconomic status (SES) influences patient-reported outcomes (PROMs) after total knee arthroplasty (TKA). This study evaluated the impact of patient median ZIP code income levels on PROMs after TKA.MethodsWe retrospectively reviewed patients at our institution undergoing primary, unilateral TKA from 2017 to 2020. Patients who did not have one-year postoperative PROMs were excluded. Patients were stratified based on the quartile of their home ZIP code median income from United States Census Bureau data. There were 1,267 patients included: 98 in quartile 1 (median income ≤ $46,308) (7.7%); 126 in quartile 2 (median income $46,309-$57,848) (10.0%); 194 in quartile 3 (median income $57,849-$74,011) (15.7%); and 849 in quartile 4 (median income ≥ $74,012) (66.4%). We collected baseline demographic data, 2-year outcomes, and PROMs preoperatively, as well as at 12 weeks and one year, postoperatively.ResultsThe Knee Injury and Osteoarthritis Outcome Score for Joint Replacement was significantly higher in quartile 4 preoperatively (P < .001), 12 weeks postoperatively (P < .001), and one year postoperatively (P < .001). There were no significant differences in delta improvements of Knee Injury and Osteoarthritis Outcome Score for Joint Replacement from preoperative to 12 weeks or one year postoperatively. There were no significant differences in lengths of stay, discharge dispositions, readmissions, or revisions.ConclusionPatients from lower income areas have slightly worse knee function preoperatively and worse outcomes following TKA. However, improvements in PROMs throughout the first year postoperatively are similar across income quartiles, suggesting that patients from lower income quartiles achieve comparable therapeutic benefits from TKA.Level III EvidenceRetrospective Cohort Study.     

Surgeon Reimbursement Unchanged as Hospital Charges and Reimbursements Increase for Total Joint Arthroplasty

BackgroundDespite increasing demands on physicians and hospitals to increase value and reduce unnecessary costs, reimbursement for healthcare services has been under downward pressure for several years. This study aimed to analyze the trend in hospital charges and payments relative to corresponding surgeon charges and payments in a Medicare population for total hip (THA) and knee arthroplasty (TKA).MethodsThe 5% Medicare sample database was used to capture hospital and surgeon charges and payments related to 56,228 patients who underwent primary THA and 117,698 patients who underwent primary TKA between 2005 and 2014. Two values were calculated: (1) the charge multiplier (CM), the ratio of hospital to surgeon charges and (2) the payment multiplier (PM), the ratio of hospital to surgeon payments. Year-to-year variation and regional trends in patient demographics, Charlson Comorbidity Index, length of stay (LOS), CM, and PM were evaluated.ResultsHospital charges were significantly higher than surgeon charges and increased substantially for both THA (CM increased from 8.7 to 11.5, P < .0001) and TKA (CM increased from 7.9 to 11.4, P < .0001). PM followed a similar trend, increasing for both THA and TKA (P < .0001). LOS decreased significantly for both THA and TKA (P < .0001), while Charlson Comorbidity Index remained stable. Both CM (r² = 0.84 THA, 0.90 TKA) and PM (r² = 0.75 THA, 0.84 TKA) were strongly negatively associated with LOS.ConclusionHospital charges and payments relative to surgeon charges and payments have increased substantially for THA and TKA despite stable patient complexity and decreasing LOS.     

Has Removal From the Inpatient-Only List Increased Complications After Outpatient Total Knee Arthroplasty?

BackgroundOn 1/1/2018, the Centers for Medicare and Medicaid Services removed total knee arthroplasty (TKA) from the Inpatient-Only (IPO) list. This change allowed expansion of outpatient TKA, potentially to include older, more frail patients at greater risk for perioperative complications. The purpose of this study was to evaluate the impact of removing TKA from the IPO list on early complications.MethodsPatients undergoing TKA in the National Surgical Quality Improvement Program database were identified using CPT code 27447. Only cases with length of stay of zero days were included. Rates of 30-day complications, readmissions, and reoperation were compared before and after TKA was removed from the IPO list (2015-2017 vs 2018). The analysis was performed both with and without propensity score matching.Results212,313 patients underwent TKA during the study period. 2466 (1.5%) were outpatient TKA in 2015-2017 and 3189 (5.6%) in 2018. After propensity matching, there were 2458 patients in each cohort. Rates of total 30-day complications were significantly lower in 2018 (3.7%) than the years TKA remained on the IPO (4.5%, P = .04). Similarly, rates of any reoperation decreased from 1.2% during 2015-2017 to 0.6% in 2018 (P = .03). There were no significant changes in rates of readmission (2.5% vs 2.2%, P = .5) or wound complications (0.8% vs 0.8%, P = 1.0).ConclusionRemoval of TKA from the IPO list did not result in an increase in complications or readmissions. These data suggest, despite the regulatory change, surgeons have continued to exercise sound judgment as to what patients can safely undergo outpatient TKA.     

Robotic-Assisted Versus Manual Unicompartmental Knee Arthroplasty: A Time-Driven Activity-Based Cost Analysis

BackgroundThe cost-effectiveness of robotic-assisted unicompartmental knee arthroplasty (RA-UKA) remains unclear. Time-driven activity-based costing (TDABC) has been shown to accurately reflect true resource utilization. This study aimed to compare true facility costs between RA-UKA and conventional UKA.MethodsWe identified 265 consecutive UKAs (133 RA, 132 conventional) performed at a specialty hospital in 2016-2020. Itemized facility costs were calculated using TDABC. Separate analyses including and excluding implant costs were performed. Multiple regression was performed to determine the independent effect of robotic assistance on facility costs.ResultsDue to longer operative time, RA-UKA patients had higher personnel costs and total facility costs ($2,270 vs $1,854, P < .001). Controlling for demographics and comorbidities, robotic assistance was associated with an increase in personnel costs of $399.25 (95% confidence interval [CI] $343.75-$454.74, P < .001), reduction in supply costs of $55.03 (95% CI $0.56-$109.50, P = .048), and increase in total facility costs of $344.27 (95% CI $265.24-$423.31, P < .001) per case. However, after factoring in implant costs, robotic assistance was associated with a reduction in total facility costs of $235.87 (95% CI $40.88-$430.85, P < .001) per case.ConclusionUsing TDABC, overall facility costs were lower in RA-UKA despite a longer operative time. To facilitate wider adoption of this technology, implant manufacturers may negotiate lower implant costs based on volume commitments when robotic assistance is used. These supply cost savings appear to offset a portion of the increased costs. Nonetheless, further research is needed to determine if RA-UKA can improve clinical outcomes and create value in arthroplasty.     

The Clinical and Financial Consequences of the Centers for Medicare and Medicaid Services’ Two-Midnight Rule in Total Joint Arthroplasty

BackgroundTo lessen the financial burden of total joint arthroplasty (TJA) and encourage shorter hospital stays, the Centers for Medicare and Medicaid Services (CMS) recently removed TKA from the inpatient-only list. This policy change now requires providers and institutions to apply the two-midnight rule (TMR) to short-stay (1-midnight) inpatient hospitalizations (SSIH).MethodsThe National Inpatient Sample from 2012 through 2016 was used to analyze trends in length of stay following elective TJA. Using publically-available policy documentation, published median Medicare payments, and National Inpatient Sample hospital costs, we analyzed the application of the TMR to SSIHs and compared the results to the previous policy environment. Specifically, we modeled 3 scenarios for all 2016 Medicare SSIHs: (1) all patients kept an extra midnight to satisfy the TMR, (2) all patients discharged as an outpatient, and (3) all patients discharged as an inpatient.ResultsThe overall percentage of Medicare SSIHs increased significantly from 2.7% in 2012 to 17.8% in 2016 (P < .0001). Scenario 1 resulted in no change in out-of-pocket (OOP) costs to patients, no change in CMS payments, and hospital losses of $117.0 million. Scenario 2 resulted in no change in patient OOP costs, reduction in payments from CMS of $181.8 million, and hospital losses of $357.3 million. Scenario 3 resulted in no change in patient OOP costs, no change in CMS payments, and an estimated $1.71 billion of SSIH charges at risk to hospitals for audit.ConclusionThe results of this analysis reveal the conflict between length of stay trends following TJA and the imposition of the TMR.     

High Bundled Payment Costs Following Total Hip and Knee Arthroplasty in African Americans

BackgroundConcerns exist that minorities who utilize more resources in an episode-of-care following total hip (THA) and knee arthroplasty (TKA) may face difficulties with access to quality arthroplasty care in bundled payment programs. The purpose of this study is to determine if African American patients undergoing TKA or THA have higher episode-of-care costs compared to Caucasian patients.MethodsWe queried Medicare claims data for a consecutive series of 7310 primary TKA and THA patients at our institution from 2015 to 2018. We compared patient demographics, comorbidities, readmissions, and 90-day episode-of-care costs between African American and Caucasian patients. A multivariate regression analysis was performed to identify the independent effect of race on episode-of-care costs.ResultsCompared to Caucasians, African Americans were younger, but had higher rates of pulmonary disease and diabetes. African American patients had increased rates of discharge to a rehabilitation facility (20% vs 13%, P < .001), with higher subacute rehabilitation ($1909 vs $1284, P < .001), home health ($819 vs $698, P = .022), post-acute care ($5656 vs $4961, P = .008), and overall 90-day episode-of-care costs ($19,457 vs $18,694, P = .001). When controlling for confounding comorbidities, African American race was associated with higher episode-of-care costs of $440 (P < .001).ConclusionAfrican American patients have increased episode-of-care costs following THA and TKA when compared to Caucasian patients, mainly due to increased rates of home health and rehabilitation utilization. Further study is needed to identify social variables that can help reduce post-acute care resources and prevent reduction in access to arthroplasty care in bundled payment models.     

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

BackgroundThe 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.MethodsWe 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.ResultsCompared 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.ConclusionDespite 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.     

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

BackgroundRemoval 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.MethodsWe 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.ResultsOf 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.ConclusionCertain 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.     

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

BackgroundConcerns 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).MethodsWe 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.ResultsPost-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).ConclusionsSince 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.     

Formal Physical Therapy Following Total Hip and Knee Arthroplasty Incurs Additional Cost Without Improving Outcomes

BackgroundRecent evidence has demonstrated that formal physical therapy (PT) may not be required for most patients undergoing total hip (THA) and knee (TKA) arthroplasty. This study compared the differences in costs and functional outcomes in patients receiving formal PT and those who did not follow primary THA and TKA.MethodsWe queried claims data from a single private insurer identifying patients who underwent primary THA or TKA from 2015 to 2017 in our practice. Demographics, comorbidities, number, and cost of PT visits in a 90-day episode of care were recorded. Outcomes were compared between patients using self-directed home exercises, home PT, outpatient PT, or both home and outpatient PT. A multivariate analysis was performed to identify significant predictors of outcomes.ResultsOf the 2971 patients included in analysis, patients using both services had higher 90-day PT costs (mean $2091, P < .001) than those using home PT alone ($1146), outpatient PT alone ($1356), or no formal PT ($0). Home PT had the greatest cost per visit for both private insurance patients ($177/visit) and Medicare Advantage patients ($157/visit), but patients using both home PT and outpatient PT services had the greatest overall PT cost, $2091 for private insurance and $1891 for Medicare Advantage. Patients who used home PT were at significantly higher risk of both complications (odds ratio = 3.21; 95% confidence interval, 2.1-4.9; P < .001) and readmissions (odds ratio = 3.4; 95% confidence interval, 2.1-5.5; P < .001).ConclusionParticipation in formal PT accounts for up to 8% of the episode of care following THA and TKA. The role of formal PT for most patients should take into account the cost-effectiveness of the intervention.     

Major National Shifts to Outpatient Total Knee Arthroplasties in the United States: A 10-Year Trends Analysis of Procedure Volumes,Complications, and Healthcare Utilizations (2010 to 2020)

BackgroundThe removal of total knee arthroplasty (TKA) from inpatient-only lists accelerated changes in orthopaedic surgical practices across the United States. This study aimed to (1) quantify the annual volume of inpatient/outpatient primary TKAs; (2) compare patient characteristics before/after the year 2018; and (3) compare annual trends in 30-day readmissions, 30-day complications, and healthcare utilization parameters for inpatient/outpatient TKAs.MethodsThe National Surgical Quality Improvement Program was reviewed (January 2010 to December 2020) for patients who underwent primary TKA (n = 470,456). The primary outcome was annual volumes of inpatient/outpatient TKA. Secondary outcomes included 30-day readmissions, 30-day reoperations, and 30-day major/minor complications. Demographic characteristics and healthcare utilization parameters (hospital lengths of stay and discharge dispositions) were compared between cohorts via Chi-square goodness-of-fit tests.ResultsOverall, 89% had inpatient TKA (n = 416,972) and 11% had outpatient TKA (n = 53,854). Between 2017 and 2020, annual volumes of outpatient TKA increased by 1,925 (1,019 to 20,633), while inpatient TKA decreased by 53% (61,874 to 29,280). Patients who had outpatient TKA after 2018 were older (P < .001), predominantly males (P < .001), more commonly White (P < .001), and had a greater proportion of American Society of Anesthesiologists class III (P < .001). The inpatient cohort had higher rates of 30-day readmissions, reoperations, and complications. Average length of stay and nonhome discharges decreased for both cohorts.ConclusionOutpatient TKA increased 20-fold at NSQIP hospitals. The changes in comorbidity profiles and the increase in volumes of outpatient TKA were not associated with a rise in cumulative 30-day readmissions and complications. Further research and policy endeavors should focus on identifying patients who still require or benefit from inpatient TKA.     

Impact of Compensated Cirrhosis Etiology on Postoperative Outcomes Following Total Knee Arthroplasty

BackgroundCirrhotics often demonstrate worse outcomes than their non-cirrhotic counterparts following orthopedic surgery; however, there are limited arthroplasty-focused data on this occurrence. Additionally, variances in postoperative outcomes among the different etiologies of cirrhosis have not been well described. The aim of this study is to evaluate the effect compensated cirrhosis had on postoperative outcomes following elective total knee arthroplasty (TKA).MethodsIn total, 1,734,568 patients who underwent primary TKA from 2006 to 2013 were identified using the Medicare Claims Database. Patients were divided into those with a history of compensated cirrhosis and those with no history of liver disease. Subgroup analysis was performed based on the etiology of cirrhosis. Multivariate logistic regression was used to evaluate postsurgical outcomes of interest.ResultsCirrhotic patients had higher risk of developing disseminated intravascular coagulation (odds ratio [OR] 2.76, P = .003), encephalopathy (OR 3.00, P < .001), and periprosthetic infection (OR 1.79, P < .001) compared to controls. Following subgroup analysis, alcoholic cirrhotics had high risk of periprosthetic infection (OR 2.12, P < .001), fracture (OR 3.28, P < .001), transfusion (OR 2.45, P < .001), and encephalopathy (OR 7.34, P < .001) compared to controls. Viral cirrhosis was associated with an increase in 90-day charges ($14,941, P < .001) compared to controls, while cirrhosis secondary to other causes was associated with few adverse outcomes compared to controls.ConclusionLiver cirrhosis is an independent risk factor for increased perioperative morbidity and financial burden following TKA. Cirrhosis due to etiologies other than viral infections and alcoholism are associated with few adverse outcomes. Surgeons should be aware of these complications to properly optimize postoperative management.     

Differences in Pain,Opioid Use,and Function Following Unicompartmental Knee Arthroplasty compared to Total Knee Arthroplasty

BackgroundWe sought to determine if immediate postsurgical pain, opioid use, and clinical function differed between unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA).MethodsA single-institution database was utilized to identify patients who underwent elective total joint arthroplasty between 2016 and 2019.ResultsIn total, 6616 patients were identified: 98.20% TKA (6497) and 1.80% (119) UKA. UKA patients were younger, had lower body mass index, and more often male than the TKA cohort. Aggregate opioid consumption (75.94 morphine milligram equivalents vs 136.5 morphine milligram equivalents; P < .001) along with the first 24-hour and 48-hour usage was significantly less for UKA as compared to TKA. Similarly, pain scores (1.98 vs 2.58; P < .001) were lower for UKA while Activity Measure for Post-Acute Care mobilization scores were higher (21.02 vs 18.76; P < .001). UKA patients were able to be discharged home on the day of surgery 37% of the time as compared to 2.45% of TKA patients (P < .0001). Notably, when comparing UKA and TKA patients who were discharged home on the day of surgery, no differences regarding pain scores, opioid utilization, or mobilization were observed.ConclusionUKA patients are younger, have lower body mass index and American Society of Anesthesiologists scores, and more often male than TKA patients. UKA patients had significantly shorter length of stay than TKA patients and were discharged home more often than TKA patients, on both the day of surgery and following hospital admission. Most notably, UKA patients reported lower pain scores and were found to require 45% lower opioid medication in the immediate postsurgical period than TKA patients. Surprisingly, UKA and TKA patients discharged on the day of surgery did not differ in terms of pain scores, opioid utilization, or mobilization, suggesting that our rapid rehabilitation UKA protocols can be successfully translated to outpatient TKAs with similar outcomes.Level III EvidenceRetrospective Cohort Study.     

Outpatient Total Knee Arthroplasty Shows Decreasing Complication Burden From 2010 to 2020

BackgroundThe number of total knee arthroplasties (TKAs) performed on an outpatient basis continues to increase. The purpose of this study was to compare complication rates over the last decade to evaluate trends in the safety of outpatient TKA.MethodsPatients who underwent TKA from 2010 to 2020 from a large administrative claims database were retrospectively identified and stratified based on the year of surgery. Propensity-score matching was performed to match patients who were discharged within 24 hours of surgery to inpatients based on age, sex, comorbidity index, and year of surgery. Linear regression analyses were used to compare trends from 2010 to 2020. The 90-day adverse events in the early cohort (2010-2012) were compared to those in the late cohort (2018-2020) using multivariable regression analyses. Of the 547,137 patients in the sample, 28,951 outpatients (5.3%) were propensity matched to inpatients.ResultsThe incidence of outpatient TKA increased from 2010 to 2018 (1.9 versus 13.8%, P < .001). Despite a similar complication rate early (24.1 versus 22.6%, P = .164), outpatient TKA had fewer complications at the end of the study period (13.7 versus 16.7%, P < .001). Multivariate analyses demonstrated that the risk of any complication after outpatient TKA was lower than inpatient from 2018 to 2020 (odds ratio, 0.78; 95% confidence interval, 0.71-0.84).ConclusionsComplications in both cohorts declined dramatically suggesting improvements in quality of care over time, with the greatest decline in patients undergoing outpatient surgery. These results suggest that outpatient TKA today is not higher risk for the patient than inpatient TKA.Level of EvidenceLevel III.