Total Knee Arthroplasty Volume Research Articles

Total Knee Arthroplasty During the COVID-19 Pandemic: Rapid Return to Baseline Volume and Continuation of Trend Toward Outpatient Surgery

Background: COVID-19 was a major disruptor in the United States throughput of total knee arthroplasty (TKA). After elective surgery resumed following initial suspensions, restrictions waxed and waned as COVID-19 waves peaked and ebbed. The specific impact of the pandemic on overall and outpatient TKA volume has not been fully studied. Purpose: Thus, this study aimed to observe how TKA volume and that proportion performed on an outpatient basis evolved through the pandemic. Methods: The PearlDiver database was utilized to identify patients undergoing elective TKA, from January 2018 to April 2021. Descriptive analysis was utilized to report the monthly changes in elective TKA volume and the proportion performed in the outpatient setting. A linear forecast analysis using historical data was utilized to determine the expected volume and proportion performed outpatient during the pandemic. This was compared to the observed case volume and setting. Results: Within 3 months following suspension of elective TKA, the total volume had returned to what was expected (Actual: 15,692; Expected: 15,586 (95% CI: 13,345-17,738). During the third peak of the pandemic, volume decreased but returned to projections within 2 months (Actual: 16,227; Expected: 17,181 (95% CI: 14,540-19,823). The pandemic did not cause the proportion of outpatient cases to differ from pre-pandemic predictions. Conclusion: In this nationwide analysis, the pandemic was not shown to have a lasting effect on TKA volume. The shift toward outpatient TKA during the pandemic seems likely to have represented a transition which had already begun prior to March 2020.

The Financial Burden of Aspirin versus Oral Factor Xa Inhibitors for Thromboprophylaxis Following Total Knee Arthroplasty

BackgroundAspirin and oral factor Xa inhibitor thromboprophylaxis regimens are associated with similarly low rates of venous thromboembolism following total knee arthroplasty (TKA). However, the rate of prosthetic joint infection (PJI) is lower with aspirin use. This study aimed to compare the cost differential between aspirin and factor Xa inhibitor thromboprophylaxis with respect to PJI management. MethodsWe used previously published rates of PJI following aspirin and factor Xa inhibitor thromboprophylaxis in primary TKA patients at a single, large institution. Prices for individual drugs were obtained from our hospital’s pharmacy service. The cost of PJI included that of 2-stage septic revision, with or without the cost of 1-year follow-up. National data were obtained to determine annual projected TKA volume. ResultsThe per-patient costs associated with a 28-day course of aspirin versus factor Xa inhibitor thromboprophylaxis were $17.36 and $3,784.20, respectively. Including cost of follow-up, per-patient costs for a 28-day course of aspirin versus factor Xa inhibitors increased to $73,358.76 and $77,125.60, respectively. The weighted average per-patient costs for a 28-day course were $237.38 and $4,370.93, respectively. The annual cost difference could amount to over $14.1 billion in the United States by 2040. ConclusionsThe per-patient cost associated with factor Xa inhibitor thromboprophylaxis is as much as 1,980.6% higher than that of an aspirin regimen due to increased costs of primary treatment, differential PJI rates, and high costs of management. In an era of value-based care, the use of aspirin is associated with major cost advantages.

Length of stay and inpatient charges of total knee arthroplasty in China: analysis of a national database.

There are limited data on the resource utilization of total knee arthroplasty (TKA) in China. This study aimed to examine the length of stay (LOS) and inpatient charges of TKA in China, and to investigate their determinants. We included patients undergoing primary TKA in the Hospital Quality Monitoring System in China between 2013 and 2019. LOS and inpatient charges were obtained, and their associated factors were further assessed using multivariable linear regression. A total of 184,363 TKAs were included. The LOS decreased from 10.8 days in 2013 to 9.3 days in 2019. The admission-to-surgery interval decreased from 4.6 to 4.2 days. The mean inpatient charges were 61,208.3 Chinese Yuan. Inpatient charges reached a peak in 2016, after which a gradual decrease was observed. Implant and material charges accounted for a dominating percentage, but they exhibited a downward trend, whereas labor-related charges gradually increased. Single marital status, non-osteoarthritis indication, and comorbidity were associated with longer LOS and higher inpatient charges. Female sex and younger age were associated with higher inpatient charges. There were apparent varieties of LOS and inpatient charges among provincial or non-provincial hospitals, hospitals with various TKA volume, or in different geographic regions. The LOS following TKA in China appeared to be long, but it was shortened during the time period of 2013 to 2019. The inpatient charges dominated by implant and material charges exhibited a downward trend. However, there were apparent sociodemographic and hospital-related discrepancies of resource utilization. The observed statistics can lead to more efficient resource utilization of TKA in China.

The impact of COVID-19 on hip and knee arthroplasty surgical volume in China.

The reduction of hip and knee arthroplasty surgical volume has been reported in many countries during the COVID-19 pandemic. In China, there is no national joint registry system and the impact of COVID-19 towards surgical volume remains unclear. The aim of this study was to investigate the hip and knee arthroplasty surgical volume in China during the pandemic and evaluate its change trends. Annual sale numbers of prostheses used in total knee arthroplasty (TKA), total hip arthroplasty (THA), and femoral head replacement (FHR) from 2011 to 2021 was collected from providers registered in National Medical Products Administration (NMPA). Annual surgical volume of TKA, THA, FHR, unicompartmental knee arthroplasty (UKA), and revision of hip/knee arthroplasty (RJA) was collected from member hospitals of Beijing Joint Society (BJS). We used linear regression to estimate the loss of surgical volume. Annual surgical volume obtained from Britain and Australian joint registries were used to make comparison. In China, the surgical volume of THA/FHR, TKA, and UKA in 2020 all decreased compared to the predicted value, with a reduction of 82,525 cases (13.46%), 165,178 cases (33.50%), and 151 cases (0.65%), respectively. All the three procedures showed significant recovery in 2021. The surgical volumes of THA/FHR and UKA were 68,813 and 9402 cases higher than predicted levels, respectively, while TKA volume remained slightly below the predicted level. The regional statistics in Beijing showed similar change mode. In 2020, the surgical volume of THA/FHR, TKA, FHR, and UKA all decreased compared to the predicted value, with a reduction of 5031 cases (43.37%), 5290 cases (40.69%), 620 cases (29.18%), and 925 cases (39.11%), respectively. In 2021, with the exception of FHR, the number of these procedures increased compared to 2020, but remained below the predicted value. Compared with the data from Britain and Australia, China experienced less reduction and faster recovery in the proportions of elderly people (> 65years old) who undergo hip and knee arthroplasty during the COVID-19 pandemic. During the COVID-19 pandemic, although hip and knee arthroplasty surgical volume in China showed a similar "restoration-recovery" change pattern with other countries, China took fewer losses in this field.

Black Patients are More Likely to Undergo Early Revision Total Knee Arthroplasty in a Matched Cohort Regardless of Surgeon Experience

BackgroundBlack patients are at an increased risk of aseptic revision total knee arthroplasty (TKA) when compared to White patients. The goal of this study was to determine whether racial disparities in revision TKA risk are related to surgeon characteristics. MethodsThis was an observational cohort study. We used inpatient administrative data to identify Black patients who underwent unilateral primary TKA in New York State. There were 21,948 Black patients who were matched 1:1 to White patients on age, sex, ethnicity, and insurance type. The primary outcome was aseptic revision TKA within 2 years of primary TKA. We calculated annual surgeon TKA volume and identified surgeon characteristics such as training in North America, board certification, and years of experience. ResultsBlack patients had a higher odds of aseptic revision TKA (odds ratio (OR) 1.32, 95% CI 1.12–1.54, P < .001) and were disproportionately cared for by low volume surgeons (≤12 TKA/year). The relationship between low volume surgeons and risk of aseptic revision was not statistically significant (OR 1.24, 95% CI 0.72-2.11, P = .436). The adjusted odds ratio (aOR) for aseptic revision TKA in Black versus White patients varied across surgeon/hospital TKA volume category pairs, with the greatest aOR when TKA were performed by the highest volume surgeons at the highest volume hospitals (aOR 2.8, 95% CI 0.98– 8.09, P = .055). ConclusionBlack patients were more likely to undergo aseptic TKA revision than matched White patients. This disparity was not explained by surgeon characteristics.

National Inpatient Datasets May No Longer Be Appropriate for Overall Total Hip and Knee Arthroplasties Projections after Removal from Inpatient-Only Lists.

It is unknown if the National Inpatient Sample (NIS) remains suitable to conduct projections for total knee arthroplasty (TKA) and total hip arthroplasty (THA), after their removal from "inpatient-only lists" in 2018 and 2020, respectively. We aimed to: (1) quantify primary THA and TKA volume from 2008 to 2018; (2) project estimates of future volume of THA and TKA until 2050; and (3) compare projections based on NIS data from 2008 to 2018 and 2008 to 2017, respectively. We identified all primary THA and TKA performed from 2008 to 2018 from the NIS. The projected volumes of THA and TKA were modeled using negative binomial regression models while incorporating log-transformed population data from the Centers for Disease Control and Prevention. Annual volume increased by 26% for THA and 11% for TKA (2008/2018: THA: 360,891/465,559; TKA:592,352/657,294). Based on 2008 to 2018 data, THA volume is projected to grow 120%, to 1,119,942 THAs by 2050. While, based on 2008 to 2017 data, THA volume is projected to grow 136%, to 1,219,852 THAs by 2050. Based on 2008 to 2018 data, TKA volume is projected to grow 4%, to 794,852 TKAs by 2050. While, based on 2008 to 2017 data, TKA volume is projected to grow 28%, to 1,037,474 TKAs by 2050. Projections based on 2008 to 2017 data estimated up to 240,000 (23%) more annual TKAs by 2050, compared with projections based on 2008 to 2018 data. The largest discrepancy among THA projections was an 8.2% difference (99,000 THAs) for 2050. After 2018 for TKA, and potentially 2020 for THA, projections based on the NIS will have to be interpreted with caution and may only be appropriate to estimate future inpatient volume. Level of evidence is prognostic level II.

Racial and Ethnic Disparities in Short-Stay Total Knee Arthroplasty

BackgroundThe purpose of this study was to understand racial and ethnic disparities in hospital-based, Medicare-defined outpatient total knee arthroplasty (TKA). We aimed to determine the following: 1) whether there are differences in preoperative characteristics or postoperative outcomes in outpatient TKA between racial/ethnic groups and 2) trends in outpatient TKA volume, based on race/ethnicity. MethodsThis was a retrospective cohort study of a large national database. Outpatient TKAs performed between 2012 and 2018 were identified. Patient demographics, comorbidities, and 30-day postoperative outcomes were compared between White, Black, Asian, and Hispanic patients. ResultsOf 54,183 outpatient patients, 85.6% were White, 7.4% Black, 2.6% Asian, and 4.1% Hispanic. Black patients had the highest body mass index, and there were higher rates of diabetes among all minority groups (P < .001). All minority groups were more likely to be discharged to a rehabilitation or a skilled care facility compared to White patients (P < .001). Annual percentage increases in outpatient TKA were most pronounced for Asians and Hispanics and least pronounced among Blacks, when compared to White patients. ConclusionThe outcomes of outpatient TKA are impacted by risk factors that reflect underlying disparities in healthcare. As joint arthroplasties have come off the inpatient-only list and procedures move to ambulatory settings, these disparities will likely magnify and impact outcomes, costs, and access points. Extensive preoperative optimization and interventions that target medical and social factors may help to reduce these disparities in TKA and increase access among minority patients. Level of EvidenceIII, retrospective cohort study.

Impact of social disadvantage among total knee arthroplasty places of service on procedural volume: a nationwide Medicare analysis.

As recent analyses have indicated that low-volume hospitals experience higher rates of complications following total knee arthroplasty (TKA), it remains important to evaluate how area deprivation index (ADI) of hospitals impacts the quantity of TKA performed. Our analysis sought to evaluate how the ADI of orthopedic surgeon's place of service influences TKA utilization. The Medicare Provider Utilization and Payment Data Public Use File (MPUP-PUF) was queried to identify claims between 2013 and 2019 associated with Healthcare Common Procedure Coding System (HCPCS) code 27447 (TKA). The MPUP-PUF file was linked with publicly available ADI information as well as information regarding each provider's practice location. The Mann-Kendall trend test was used to analyze significant differences in TKA volume between ADI quintiles and differences in TKA volume overall between the years 2013 and 2019. An adjusted multivariable linear regression analysis was conducted to evaluate how ADI, and practice-specific characteristics, influenced TKA utilization volume. When isolating by ADI quintiles, no significant changes in TKA volume were demonstrated for Quintile 4 (Kendall's τ = 0.524; p = 0.13) and Quintile 5 (Kendall's τ = 0.524; p = 0.13) between 2013 and 2019. However, a significant increase in TKA volume over the study period was observed in Quintile 1 (Kendall's τ = 0.714 p = 0.034), Quintile 2 (Kendall's τ = 0.714 p = 0.034), and Quintile 3 (Kendall's τ = 0.905 p = 0.007). The adjusted multivariable linear regression model demonstrated that each increase in ADI quintile was associated with significantly lower TKA utilization (β-estimate -1.16; 95% CI -2.04 to -0.29; p = 0.009). Our findings suggest that resource deprivation contributes to disparities in TKA utilization. With the ongoing recognition of how social and neighborhood-level deprivation may influence access to end-stage osteoarthritis care and related perioperative outcomes, the present study serves to encourage continued efforts at ensuring equity in orthopedic care.

Keeping the Lights On: The Impact of the COVID-19 Pandemic on Elective Total Joint Arthroplasty Utilization in the United States

BackgroundIt was estimated that up to 30,000 primary total hip arthroplasty (THA) and total knee arthroplasty (TKA) procedures would be cancelled each week during the moratorium on elective surgeries in the United States. The purpose of this study was to analyze the impact of the COVID-19 pandemic on elective total joint arthroplasty utilization in the United States. MethodsA retrospective study was conducted using the PearlDiver database. Patients who underwent primary elective THAs and TKAs were identified and filtered by state and month from January through September of both 2019 and 2020. The volume of these procedures immediately following the moratorium on elective surgeries was compared to that of the same months the previous year. ResultsFor THA, overall, there was a 27.39% reduction in volume from 2019 to 2020 in March and an 88.94% reduction in April. For TKA, overall, there was a 31.28% reduction in volume in March and a 96.61% reduction in April. When the states were separated into 2 cohorts by the 2020 presidential election vote, there was a significantly larger decrease in THA and TKA volume observed in the 25 states and Washington DC that voted democrat than that in the 25 states that voted republican in both March (P < .05) and April (P < .05). Both THA (118.29%) and TKA (101.02%) volume returned to prepandemic levels by June. ConclusionsOverall, this study demonstrated that elective total joint arthroplasty utilization did reduce as anticipated following the CMS moratorium on elective surgeries but quickly returned to prepandemic levels by June. Level of EvidenceLevel III.

Nationwide partial knee replacement uptake is influenced by volume and supplier--A Dutch arthroplasty register study.

Despite the established advantages of partial knee replacements (PKR), their usage remains limited. We investigated the effect of hospital knee arthroplasty (KA) volume and the availability of a frequently used PKR by the total KA supplier on the use of PKRs in a hospital. A total of 190,204 total knee replacements (TKR) and 18,134 PKRs were identified in the Dutch Arthroplasty Register (LROI) from 2007 to 2016. For each hospital we determined the annual absolute KA volume (TKR+PKR) into quartiles (<103, 103-197, 197-292, >292 knee replacements/year), and determined whether the TKR supplier provided a frequently used PKR. Hospitals were divided in routine PKR users (≥13 PKRs/year) or occasional/non PKR users (<13 PKRs/year). Based on these parameters, the effect of total KA volume and supplier on PKR usage was investigated, using chi-square tests. Logistic regression analysis was performed to evaluate the influence of the combination of these factors. In the lowest volume group, around 15% of the hospitals used PKRs, compared to 75% in the highest volume group. Having a TKR supplier that also provides a frequently used PKR resulted in a higher likelihood of performing PKR, especially in low volume hospitals. Hospitals' total KA volume and the availability of a frequently used PKR appear to influence the use of PKR.

Epidemiology of Revision Total Knee Arthroplasty in the United States, 2012 to 2019.

BackgroundAs primary total knee arthroplasty volume continues to increase, so will the number of revision total knee arthroplasty (rTKA) procedures. The purpose of this study is to provide an updated perspective on the incidence, indications, and financial burden of rTKA in the United States.Material and methodsThis was a retrospective epidemiologic analysis using the National Inpatient Sample. International Classification of Diseases ninth and tenth revision codes were used to identify patients who underwent rTKA and create cohorts based on rTKA indications from 2012 to 2019. National and regional trends for length of stay, cost, and discharge location were evaluated.ResultsA total of 505,160 rTKA procedures were identified. The annual number of rTKA procedures increased by 29.6% over the study period (56,490 to 73,205). The top 3 indications for rTKA were aseptic loosening (23.1%), periprosthetic joint infection (PJI) (20.4%), and instability (11.0%). Over the study period, the proportion of patients discharged to skilled nursing facility decreased from 31.7% to 24.1% (P < .001). Hospital length of stay decreased from 4.0 days in 2012 to 3.8 days in 2019 (P < .001). Hospital costs increased by $1300 from $25,730 to $27,077 (P < .001). The proportion of rTKA cases performed at urban academic centers increased (52.1% to 74.3%, P < .001) while that at urban nonacademic centers decreased (39.0% to 19.2%, P < .001).ConclusionThe top 3 indications for rTKA were aseptic loosening, PJI, and instability, with PJI becoming the most common indication in 2019. These cases are increasingly being performed at urban academic centers and away from urban nonacademic centers.Level of Evidence3 (Retrospective cohort study).

Unicompartmental Knee Arthroplasty Utilization among Early Career Surgeons: An Evaluation of the American Board of Orthopaedic Surgery Part-II Database.

An updated understanding of unicompartmental knee arthroplasty (UKA) utilization is needed. The purpose of this study was to evaluate temporal trends in volume and utilization of UKA among early-career surgeons and to examine the influence of fellowship training status on utilization of UKA. The American Board of Orthopaedic Surgery (ABOS) Part-II database was queried from 2010 to 2019 to identify candidates who reported ≥1 total knee arthroplasty (TKA) or UKA. Self-reported history of fellowship training experiences was recorded. "High-volume" surgeons were defined as performing ≥7 UKA over the ABOS Part-II collection period. Trends were evaluated with the Cochrane-Armitage test and generalized linear models. From 2010 to 2019, a total of 2,045 candidates (28.1%) reported ≥1 TKA, while 585 candidates (8.0%) reported ≥1 UKA. The number of candidates reporting ≥1 UKA significantly increased (p = 0.001). An increase in UKA volume was observed over the study period (p < 0.001). Rates of utilization of UKA relative to TKA did not change significantly over the study period (p = 0.11). Sixty-three (2.4%) candidates met the study definition for high-volume UKA utilization. UKA procedure volume increased among ABOS Part-II candidates over the study period; however, rates of UKA utilization relative to TKA volume remained unchanged. Increasing volume of UKA performed by early-career surgeons is likely secondary to an increased number of surgeons trained in adult reconstruction. Only 2.4% of candidates who reported performing at least one knee arthroplasty procedure met the threshold for a high-volume UKA practice. Early-career surgeons should remain conscientious of UKA volume in their practice.

Periprosthetic joint infection after primary TKA in the medicare population: How frequently are patients revised at a different hospital?

BackgroundPeriprosthetic infection (PJI) after total knee arthroplasty (TKA) places a significant burden on hospitals. We sought to describe the proportion of patients undergoing revision for PJI at a different hospital within one year of primary TKA and whether patient characteristics or hospital volume were associated with this change. MethodsMedicare data from 2005 to 2014 was retrospectively reviewed using PearlDiver. All patients over 64 years undergoing revision for PJI within one year of primary TKA were stratified by the revision occurring within 90 days. Hospitals were grouped by annual TKA volume as Low (<50), Medium (51–100), High (101–200), and Very High (>200). Associations of patient characteristics and hospital volume with revision at a different hospital were assessed using Chi-squared tests and Somers' D. ResultsOf 8,337 patients undergoing revision within 90 days of TKA, 1,370 (16%) were revised at a different hospital. Changing hospitals was associated with having primary TKA at a lower volume hospital (24% for low, 15% medium, 12% high, and 12% very high; P < 0.001). Of 7,608 patients undergoing revision between 91 and 365 days, 1,110 (15%) were revised at a different hospital. Changing hospitals was associated with having primary TKA at a lower volume hospital (26% for low, 14% medium, 10% high, and 9% very high; P < 0.001). Changing hospitals was not associated with sex or age. ConclusionPatients frequently undergo revision for PJI at a different hospital, even within 90 days of TKA. Further research is needed to understand these implications of this care pathway shift.

National operating volume for primary hip and knee arthroplasty in the COVID-19 era: a study utilizing the Scottish arthroplasty project dataset.

AimsThe COVID-19 pandemic led to a national suspension of “non-urgent” elective hip and knee arthroplasty. The study aims to measure the effect of the COVID-19 pandemic on total hip arthroplasty (THA) and total knee arthroplasty (TKA) volume in Scotland. Secondary objectives are to measure the success of restarting elective services and model the time required to bridge the gap left by the first period of suspension.MethodsA retrospective observational study using the Scottish Arthroplasty Project dataset. All patients undergoing elective THAs and TKAs during the period 1 January 2008 to 31 December 2020 were included. A negative binomial regression model using historical case-volume and mid-year population estimates was built to project the future case-volume of THA and TKA in Scotland. The median monthly case volume was calculated for the period 2008 to 2019 (baseline) and compared to the actual monthly case volume for 2020. The time taken to eliminate the deficit was calculated based upon the projected monthly workload and with a potential workload between 100% to 120% of baseline.ResultsCompared to the period 2008 to 2019, primary TKA and THA volume fell by 61.1% and 53.6%, respectively. Since restarting elective services, Scottish hospitals have achieved approximately 40% to 50% of baseline monthly activity. With no changes in current workload, by 2021 there would be a reduction of 9,180 and 10,170 for THA and TKA, respectively. Conversely, working at 120% baseline monthly output, it would take over four years to eliminate the deficit for both TKA and THA.ConclusionThis national study demonstrates the significant impact that COVID-19 pandemic has had on overall THA and TKA volume. In the six months after resuming elective services, Scottish hospitals averaged less than 50% normal monthly output. Loss of operating capacity will increase treatment delays and likely worsen overall morbidity.Cite this article: Bone Joint Open 2021;2(3):203–210.

Robotic total knee arthroplasty: A missed opportunity for cost savings in Bundled Payment for Care Improvement initiatives?

BackgroundThe use of robotic total knee arthroplasty has become increasingly prevalent. Proponents of robotic total knee arthroplasty tout its potential to not only improve outcomes, but also to reduce costs compared with traditional total knee arthroplasty. Despite its potential to deliver on the value proposition, whether robotic total knee arthroplasty has led to improved outcomes and cost savings within Medicare’s Bundled Payment for Care Improvement initiative remains unexplored. MethodsMedicare beneficiaries who underwent total knee arthroplasty designated under Medicare severity diagnosis related group 469 or 470 in the year 2017 were identified using the 100% Medicare Inpatient Standard Analytic Files. Hospitals participating in the Bundled Payment for Care Improvement were identified using the Bundled Payment for Care Improvement analytic file. We calculated risk-adjusted, price-standardized payments for the surgical episode from admission through 90-days postdischarge. Outcomes, utilization, and spending were assessed relative to variation between robotic and traditional total knee arthroplasty. ResultsOverall, 198,371 patients underwent total knee arthroplasty (traditional total knee arthroplasty: n= 194,020, 97.8% versus robotic total knee arthroplasty: n = 4,351, 2.2%). Among the 3,272 hospitals that performed total knee arthroplasty, only 300 (9.3%) performed robotic total knee arthroplasty. Among the 183 participating in the Bundled Payment for Care Improvement, only 40 (19%) hospitals performed robotic total knee arthroplasty. Risk-adjusted 90-day episode spending was $14,263 (95% confidence interval $14,231–$14,294) among patients who underwent traditional total knee arthroplasty versus $13,676 (95% confidence interval $13,467–$13,885) among patients who had robotic total knee arthroplasty. Patients who underwent robotic total knee arthroplasty had a shorter length of stay (traditional total knee arthroplasty: 2.3 days, 95% confidence interval: 2.3–2.3 versus robotic total knee arthroplasty: 1.9 days, 95% confidence interval: 1.9–2.0), as well as a lower incidence of complications (traditional total knee arthroplasty: 3.3%, 95% confidence interval: 3.2–3.3 versus robotic total knee arthroplasty: 2.7%, 95% confidence interval: 2.3–3.1). Of note, patients who underwent robotic total knee arthroplasty were less often discharged to a postacute care facility than patients who underwent traditional total knee arthroplasty (traditional total knee arthroplasty: 32.4%, 95% confidence interval: 32.3–32.5 versus robotic total knee arthroplasty: 16.8%, 95% confidence interval 16.1–17.6). Both Bundled Payment for Care Improvement and non-Bundled Payment for Care Improvement hospitals with greater than 50% robotic total knee arthroplasty utilization had lower spending per episode of care versus spending at hospitals with less than 50% robotic total knee arthroplasty utilization. ConclusionOverall 90-day episode spending for robotic total knee arthroplasty was lower than traditional total knee arthroplasty (Δ $–587, 95% confidence interval: $–798 to $–375). The decrease in spending was attributable to shorter length of stay, fewer complications, as well as lower utilization of postacute care facility. The cost savings associated with robotic total knee arthroplasty was only realized when robotic total knee arthroplasty volume surpassed 50% of all total knee arthroplasty volume. Hospitals participating in the Bundled Payment for Care Improvement may experience cost-saving with increased utilization of robotic total knee arthroplasty.

Predictors of Discharge Settings After Total Knee Arthroplasty in Medicare Patients

ObjectivesTo determine the factors associated with acute hospital discharge to the 3 most common postacute settings following total knee arthroplasty (TKA): inpatient rehabilitation facilities (IRFs), skilled nursing facilities (SNFs), and directly back to the community. DesignRetrospective cohort study. SettingAcute care hospitals submitting claims to Medicare. ParticipantsNational cohort (N=1,189,286) of 100% Medicare Part A data files from 2009-2011. InterventionsNot applicable. Main Outcome MeasuresObserved rates and adjusted odds of discharge to the 3 main postacute settings based on the clinical and facility level variables: amount of comorbidity, bilateral procedures, and facility TKA volume. ResultsUsing IRF discharge as the reference, patients who received a bilateral procedure had lower odds of both SNF and community discharge, patients with more comorbidity had lower odds for community discharge and higher odds for SNF discharge, and patients who received their TKA from hospitals with lower TKA volumes had lower odds of SNF and community discharge. ConclusionsClinical populations within Medicare beneficiaries may systematically vary across the 3 most common discharge settings following TKA. This information may be helpful for a better understanding on which patient or clinical factors influence postacute care settings following TKA. Additional research including functional status, living situation, and social support systems would be beneficial.

Inaugural Readmission Penalties for Total Hip and Total Knee Arthroplasty Procedures Under the Hospital Readmissions Reduction Program

The Hospital Readmissions Reduction Program (HRRP) is a Centers for Medicare and Medicaid Services policy that levies hospital reimbursement penalties based on excess readmissions of patients with 4 medical conditions and 3 surgical procedures. A greater understanding of factors associated with the 3 surgical reimbursement penalties is needed for clinicians in surgical practice. To investigate the first year of HRRP readmission penalties applied to 2 surgical procedures-elective total hip arthroplasty (THA) and total knee arthroplasty (TKA)-in the context of hospital and patient characteristics. Fiscal year 2015 HRRP penalization data from Hospital Compare were linked with the American Hospital Association Annual Survey and with the Healthcare Cost and Utilization Project State Inpatient Database for hospitals in the state of Florida. By using a case-control framework, those hospitals were separated based on HRRP penalty severity, as measured with the HRRP THA and TKA excess readmission ratio, and compared according to orthopedic volume as well as hospital-level and patient-level characteristics. The first year of HRRP readmission penalties applied to surgery in Florida Medicare subsection (d) hospitals was examined, identifying 60 663 Medicare patients who underwent elective THA or TKA in 143 Florida hospitals. The data analysis was conducted from February 2016 to January 2017. Annual hospital THA and TKA volume, other hospital-level characteristics, and patient factors used in HRRP risk adjustment. The HRRP penalties with HRRP excess readmission ratios were measured, and their association with annual THA and TKA volume, a common measure of surgical quality, was evaluated. The HRRP penalties for surgical care according to hospital and readmitted patient characteristics were then examined. Among 143 Florida hospitals, 2991 of 60 663 Medicare patients (4.9%) who underwent THA or TKA were readmitted within 30 days. Annual hospital arthroplasty volume seemed to follow an inverse association with both unadjusted readmission rates (r = -0.16, P = .06) and HRRP risk-adjusted readmission penalties (r = -0.12, P = .14), but these associations were not statistically significant. Other hospital characteristics and readmitted patient characteristics were similar across HRRP orthopedic penalty severity. This study's findings suggest that higher-volume hospitals had less severe, but not significantly different, rates of readmission and HRRP penalties, without systematic differences across readmitted patients.

Is Inpatient or Clinic-Based Rehabilitation Necessary After Total Knee Arthroplasty?

The rising volume of total knee arthroplasties (TKAs) in the U.S. has led to increased use of bundled payments for postoperative rehabilitation, which

Projected increase in total knee arthroplasty in the United States - an alternative projection model.

The purpose of our study was to estimate the future incidence rate (IR) and volume of primary total knee arthroplasty (TKA) in the United States from 2015 to 2050 using a conservative projection model that assumes a maximum IR of procedures. Furthermore, our study compared these projections to a model assuming exponential growth, as done in previous studies, for illustrative purposes. A population based epidemiological study was conducted using data from US National Inpatient Sample (NIS) and Census Bureau. Primary TKA procedures performed between 1993 and 2012 were identified. The IR, 95% confidence intervals (CI), or prediction intervals (PI) of TKA per 100,000 US citizens over the age of 40 years were calculated. The estimated IR was used as the outcome of a regression modelling with a logistic regression (i.e., conservative model) and Poisson regression equation (i.e., exponential growth model). Logistic regression modelling suggests the IR of TKA is expected to increase 69% by 2050 compared to 2012, from 429 (95%CI 374-453) procedures/100,000 in 2012 to 725 (95%PI 121-1041) in 2050. This translates into a 143% projected increase in TKA volume. Using the Poisson model, the IR in 2050 was projected to increase 565%, to 2854 (95%CI 2278-4004) procedures/100,000 IR, which is an 855% projected increase in volume compared to 2012. Even after using a conservative projection approach, the number of TKAs in the US, which already has the highest IR of knee arthroplasty in the world, is expected to increase 143% by 2050.

Meaningful Thresholds for the Volume-Outcome Relationship in Total Knee Arthroplasty.

Increasing evidence supports the finding that patients undergoing a total knee arthroplasty with high-volume physicians and hospitals achieve better outcomes. Unfortunately, the existing definitions for high-volume surgeons and hospitals are highly variable and entirely arbitrary. The aim of this study was to identify a set of meaningful hospital and surgeon total knee arthroplasty volume thresholds. Using 289,976 patients undergoing primary total knee arthroplasty from an administrative database, we applied stratum-specific likelihood ratio (SSLR) analysis of a receiver operating characteristic (ROC) curve to generate sets of volume thresholds most predictive of adverse outcomes. The outcomes considered for surgeon volume included 90-day complication and 2-year revision. For hospital volume, we considered 90-day complications and 90-day mortality. SSLR analysis of the ROC curves for 90-day complication and 2-year revision rates by surgeon volume identified four volume categories: 0 to 12, 13 to 59, 60 to 145, and ≥146 total knee arthroplasties per year. Complication rates decreased significantly (p < 0.05) in progressively higher-volume categories. Revision rates followed a similar pattern, but did not decrease between surgeons performing 60 to 145 arthroplasties per year and those performing ≥146 arthroplasties per year. SSLR analysis of 90-day complication and 90-day mortality rates by hospital volume also identified four volume categories: 0 to 89, 90 to 235, 236 to 644, and ≥645 total knee arthroplasties per year. Complication rates decreased significantly (p < 0.05) in progressively higher-volume categories, but the rates did not decrease between hospitals performing 236 to 644 arthroplasties per year and those performing ≥645 arthroplasties per year. Mortality rates for hospitals with ≥645 total knee arthroplasties per year were significantly lower (p < 0.05) than those below the threshold. Our study supports the use of SSLR analysis of ROC curves for risk-based volume stratification in total knee arthroplasty volume-outcomes research. SSLR analysis established meaningful volume definitions for low, medium, high, and very high-volume total knee arthroplasty surgeons and hospitals. This should help patients, surgeons, hospitals, and policymakers to make decisions with regard to the optimal delivery of total knee arthroplasty. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.