Preoperative Symptoms of Depression are Associated With Worse Capability 6-weeks and 6-months After Total Hip Arthroplasty for Osteoarthritis.

BACKGROUND: Symptoms of depression have been associated with greater incapability following total hip arthroplasty (THA). A brief, 2-question, measure of symptoms of depression - the Patient Health Questionnaire-2 (PHQ-2) - may be sufficient to measure associations with the magnitude of incapability during recovery from THA. This study investigated whether preoperative symptoms of depression (measured with the PHQ-2) correlated with levels of incapability 6 weeks and 6 months after THA, accounting for demographic and clinical factors. METHODS: We performed a prospective cohort study across 5 centers and recruited 101 patients undergoing THA, of whom 90 (89%) completed follow-up. Patients completed demographics, a preoperative 2-item (PHQ-2) measure of symptoms of depression, and the Hip Dysfunction and Osteoarthritis Outcome Score for Joint Replacement (HOOS JR) at 6-weeks and 6-months postoperatively. Negative binomial regression models determined factors associated with HOOS JR at 6 weeks and 6 months, accounting for potential confounders. RESULTS: Accounting for potential confounding factors, we found that higher preoperative PHQ-2 scores (reflecting greater symptoms of depression) were associated with lower HOOS JR scores (reflecting a greater level of hip disability) at both 6 weeks (regression coefficient = -0.67, P < .001) and 6 months (regression coefficient = -1.9, P < .001) after THA. CONCLUSIONS: Symptoms of depression on a 2-question preoperative questionnaire are common, and greater symptoms of depression are associated with reduced capability within the first year following THA. These findings support the prioritization of routine mental health assessments before THA. Measuring mindset using relatively brief instruments will be important considering the current shift toward implementing self-reported measures of health status in clinical practice and incorporating them within alternative payment models.

A Model for Evaluating Total Costs of Care and Cost Savings of Specialty Condition-Based Care for Hip and Knee Osteoarthritis in an Integrated Practice Unit.

OBJECTIVES: The viability of specialty condition-based care via integrated practice units (IPUs) requires a comprehensive understanding of total costs of care. Our primary objective was to introduce a model to evaluate costs and potential costs savings using time-driven activity-based costing comparing IPU-based nonoperative management with traditional nonoperative management and IPU-based operative management with traditional operative management for hip and knee osteoarthritis (OA). Secondarily, we assess drivers of incremental cost differences between IPU-based care and traditional care. Finally, we model potential cost savings through diverting patients from traditional operative management to IPU-based nonoperative management. METHODS: We developed a model to evaluate costs using time-driven activity-based costing for hip and knee OA care pathways within a musculoskeletal IPU compared with traditional care. We identified differences in costs and drivers of cost differences and developed a model to demonstrate potential cost savings through diverting patients from operative intervention. RESULTS: Weighted average costs of IPU-based nonoperative management were lower than traditional nonoperative management and lower in IPU-based operative management than traditional operative management. Key drivers of incremental cost savings included care led by surgeons in partnership with associate providers, modified physical therapy programs with self-management, and judicious use of intra-articular injections. Substantial savings were modeled by diverting patients toward IPU-based nonoperative management. CONCLUSIONS: Costing models involving musculoskeletal IPUs demonstrate favorable costs and cost savings compared with traditional management of hip or knee OA. More effective team-based care and utilization of evidence-based nonoperative strategies can drive the financial viability of these innovative care models.

Association of Unmet Social Needs With Level of Capability in People With Persistent Knee Pain.

BACKGROUND: Musculoskeletal providers are increasingly recognizing the importance of social factors and their association with health outcomes as they aim to develop more comprehensive models of care delivery. Such factors may account for some of the unexplained variation between pathophysiology and level of pain intensity and incapability experienced by people with common conditions, such as persistent nontraumatic knee pain secondary to osteoarthritis (OA). Although the association of one's social position (for example, income, employment, or education) with levels of pain and capability are often assessed in OA research, the relationship between aspects of social context (or unmet social needs) and such symptomatic and functional outcomes in persistent knee pain are less clear. QUESTIONS/PURPOSES: (1) Are unmet social needs associated with the level of capability in patients experiencing persistently painful nontraumatic knee conditions, accounting for sociodemographic factors? (2) Do unmet health-related social needs correlate with self-reported quality of life? METHODS: We performed a prospective, cross-sectional study between January 2021 and August 2021 at a university academic medical center providing comprehensive care for patients with persistent lower extremity joint pain secondary to nontraumatic conditions such as age-related knee OA. A final 125 patients were included (mean age 62 ± 10 years, 65% [81 of 125] women, 47% [59 of 125] identifying as White race, 36% [45 of 125] as Hispanic or Latino, and 48% [60 of 125] with safety-net insurance or Medicaid). We measured patient-reported outcomes of knee capability (Knee injury and Osteoarthritis Outcome Score for Joint Replacement), quality of life (Patient-Reported Outcome Measure Information System [PROMIS] Global Physical Health and PROMIS Global Mental Health), and unmet social needs (Accountable Health Communities Health-Related Social Needs Survey, accounting for insufficiencies related to housing, food, transportation, utilities, and interpersonal violence), as well as demographic factors. RESULTS: After controlling for demographic factors such as insurance status, education attained, and household income, we found that reduced knee-specific capability was moderately associated with experiencing unmet social needs (including food insecurity, housing instability, transportation needs, utility needs, or interpersonal safety) (standardized beta regression coefficient [ß] = -4.8 [95% confidence interval -7.9 to -1.7]; p = 0.002 and substantially associated with unemployment (ß = -13 [95% CI -23 to -3.8]; p = 0.006); better knee-specific capability was substantially associated with having Medicare insurance (ß = 12 [95% CI 0.78 to 23]; p = 0.04). After accounting for factors such as insurance status, education attained, and household income, we found that older age was associated with better general mental health (ß = 0.20 [95% CI 0.0031 to 0.39]; p = 0.047) and with better physical health (ß = 0.004 [95% CI 0.0001 to 0.008]; p = 0.04), but effect sizes were small to negligible, respectively. CONCLUSION: There is an association of unmet social needs with level of capability and unemployment in patients with persistent nontraumatic knee pain. This finding signals a need for comprehensive care delivery for patients with persistent knee pain that screens for and responds to potentially modifiable social risk factors, including those based on one's social circumstances and context, to achieve better outcomes. LEVEL OF EVIDENCE: Level II, prognostic study.

How to Create an Orthopaedic Arthroplasty Administrative Database Project: A Step-by-Step Guide Part I: Study Design.

BACKGROUND: Use of clinical and administrative databases in orthopaedic surgery research has grown substantially in recent years. It is estimated that approximately 10% of all published lower extremity arthroplasty research have been database studies. The aim of this review is to serve as a guide on how to (1) design, (2) execute, and (3) publish an orthopaedic administrative database arthroplasty project. METHODS: In part I, we discuss how to develop a research question and choose a database (when databases should/should not be used), detailing advantages/disadvantages of those most commonly used. To date, the most commonly published databases in orthopaedic research have been the National Inpatient Sample, Medicare, National Surgical Quality Improvement Program, and those provided by PearlDiver. General advantages of most database studies include accessibility, affordability compared to prospective research studies, ease of use, large sample sizes, and the ability to identify trends and aggregate outcomes of multiple health care systems/providers. RESULTS: Disadvantages of most databases include their retrospective observational nature, limitations of procedural/billing coding, relatively short follow-up, limited ability to control for confounding variables, and lack of functional/patient-reported outcomes. CONCLUSION: Although this study is not all-encompassing, we hope it will serve as a starting point for those interested in conducting and critically reviewing lower extremity arthroplasty database studies.

How to Create an Orthopaedic Arthroplasty Database Project: A Step-by-Step Guide Part II: Study Execution.

In recent years, the use of national databases in orthopaedic surgery research has grown substantially with database studies comprising an estimated ∼10% of all published lower extremity arthroplasty research. The aim of this review is to serve as a guide on how to: (1) design; (2) execute; and (3) publish an orthopaedic database arthroplasty project. In part II, we discuss how to collect data, propose a novel checklist/standards for presenting orthopaedic database information (SOPOD), discuss methods for appropriate data interpretation/analysis, and summarize how to convert findings to a manuscript (providing a previously published example study). Data collection can be divided into two stages: baseline patient demographics and primary/secondary outcomes of interest. Our proposed SOPOD is more orthopaedic-centered and builds upon previous standards for observational studies from the EQUATOR network. There are a host of statistical methods available to analyze data to compare baseline demographics, primary/secondary outcomes, and reduce type 1 errors seen in large datasets. When drafting a manuscript, it is important to consider and discuss the limitations of database studies, including their retrospective nature, issues with coding/billing, differences in statistical versus clinical significance (or relevance), lack of surgery details (approach, laterality, and implants), and limited sampling or follow-up. We hope this paper will serve as a starting point for those interested in conducting lower extremity arthroplasty database studies.

Outcomes Vary Significantly Using a Tiered Approach to Define Success After Total Knee Arthroplasty.

BACKGROUND: Patient-reported outcome measures (PROM) allow assessment of clinical outcomes following primary total knee arthroplasty (TKA). The purpose of this study is to use progressively more stringent definitions of success to examine clinical outcomes of primary TKA at 1 year postoperatively and to determine which demographic variables were associated with achieving clinical success. METHODS: The American Joint Replacement Registry was queried from 2012 to 2020 for primary TKA. Patients who completed the following PROMs preoperatively and 1 year postoperatively were included: Western Ontario and McMaster Universities Arthritis Index (WOMAC), Knee Injury and Osteoarthritis Outcome Score (KOOS), and KOOS for Joint Replacement (KOOS JR). Mean PROM scores were determined for each visit and between-visit changes were evaluated using paired t-tests. Rates of achievement of minimal clinically important difference (MCID) by distribution-based and anchor-based criteria, Patient Acceptable Symptom State, and substantial clinical benefit were calculated. Logistic regression was used to evaluate the association between demographic variables and odds of clinical success. RESULTS: In total, 12,341 TKAs were included. Mean improvement in PROM scores were as follows: KOOS JR, 29; WOMAC-Pain, 33; and WOMAC-Function, 31 (P < .0001 for all). Rates of achievement of each metric were the following: distribution-based MCID, 84%-87%; anchor-based MCID, 46%-79%; Patient Acceptable Symptom State, 54%-82%; and substantial clinical benefit, 68%-81%. Patient age and gender were the most influential demographic factors on achievement of clinical success. CONCLUSION: Clinical outcomes at 1 year following TKA vary significantly when using a tiered approach to define success. A tiered approach to interpretation of PROMs should be considered for future research and clinical assessment.

Functional Outcomes of a Musculoskeletal Integrated Practice Providing Comprehensive Whole Person Care for Hip Osteoarthritis.

BACKGROUND: Outcomes of hip osteoarthritis (OA) management within integrated practice units (IPUs) are lacking. This study reports 6-month and 1-year patient-reported outcomes (PROs) of IPU care, the proportion of patients achieving minimal clinically important difference (MCID) and substantial clinical benefit (SCB) at 1 year, and baseline factors associated with the likelihood of achieving MCID and SCB. METHODS: We retrospectively evaluated 1009 new patients presenting to an IPU with hip OA between October 2017 and June 2020. Patients experienced multidisciplinary team-based management. Individuals with baseline and 6-month PROs or baseline and 1-year PROs (Hip Disability and Osteoarthritis Outcome Score Joint Replacement, HOOS JR) were included. We used anchor-based MCID and SCB thresholds and multivariable binary logistic regression models to identify baseline factors associated with achieving 1-year MCID and SCB. RESULTS: HOOS JR increased from baseline to 6 months (Δ = 19.1 ± 2.1, P = .065) and baseline to 1 year (Δ = 35.8 ± 2.9, P < .001). At 1 year, 72.7% (IPU only) and 88% (IPU-based total hip arthroplasty [THA]) achieved MCID (P < .001), and 62.3% (IPU only) and 88% (IPU-based THA) achieved SCB (P < .001). In multivariable regression, lower baseline HOOS JR scores (r = 0.96, P = .04), undergoing THA (r = 0.213, P < .001), and fewer symptoms of generalized anxiety (r = 0.932, P = .018) were independently associated with achieving MCID at 1 year. The same factors were independently associated with achieving SCB at 1 year. Lower baseline anxiety (Generalized Anxiety Disorder Questionnaire-7 item) and greater hip-related preoperative limitations result in greater likelihood of achieving MCID and SCB. CONCLUSION: Significant improvements in patient outcomes can be achieved by IPUs providing comprehensive care for hip OA including the management of psychological distress. Future prospective studies should compare the outcomes of IPUs with traditional care in managing diverse patient phenotypes.

Editorial Commentary: Fixing Health Care Requires Us to Evaluate Policy Through an Ethical and Societal (And Not Just a Financial) Lens.

Health care systems globally, including in the United States, continue to undergo a much-needed transformation focused on optimizing value-or health outcomes per dollar spent across a full cycle of care-for patients. Given the traditionally high cost and use of orthopaedic surgery services, the field is ripe for in-depth assessment and comparison of interventions to ensure that evidence-based, high-value care is prioritized. Cost-effectiveness analyses (CEAs) provide an important framework from which to begin effective policy discussions, and a recent study suggests that current orthopaedic economic literature is of high quality. However, the same study demonstrated that no authors published CEAs that also provided commentary on how their work can actually guide policy decisions. Furthermore, the ethical implications of their research or insight into the larger consequences of their findings within and outside the health care sector was not discussed. We must be better at "connecting the dots" between CEAs and value-based health care research and practical policy initiatives while also considering how such proposals promote health equity and address systemic injustices currently found in our health care system.

Editorial Commentary: The Value of Time-Driven, Activity-Based Costing in Health Care Delivery.

Time-driven activity-based costing (TDABC) provides a powerful approach to more targeted cost accounting based on resources actually used by patients during a cycle of care. Since its introduction in 2004 by Kaplan and Anderson, TDABC has gained increasing popularity in defining the actual costs of care for various orthopaedic processes and pathways. TDABC may demonstrate lower costs of care compared with traditional cost accounting methods, including ratio of costs to charges and relative value units. Weaknesses of traditional methods include approaching costs through the lens of charges, revenue, processes and procedures, adopting a "top-down" approach, and potentially overestimating costs. In contrast, TDABC builds costs from the individual level, taking a front-line, condition-focused, and patient-centered view. Existing organizational decision-making is oriented around revenue metrics (relative value units and ratio of costs to charges) rather than cost metrics, yet alternative payment models are shifting toward fixed revenues for certain conditions or procedures. The variability, including both financial upside and loss, will primarily be a function of the cost of care-a number that is profoundly opaque in most health care settings. We view TDABC as an approach that sheds light on variation, offers a more granular differentiation of costs compared with traditional approaches, mitigates risk, and sparks opportunities for increasing operational efficiency and waste reduction. The goal is to identify and provide the greatest-value orthopaedic care.

Preparing for an Era of Episode-Based Care in Total Joint Arthroplasty.

With a history of steadily rising healthcare costs, the United States faces an unprecedented set of health and financial challenges. The COVID-19 pandemic will only exacerbate these challenges, and it is of paramount importance to reform and refine health systems to maximize the value of care delivered to the patient. Recent developments related to value improvement in total joint arthroplasty suggest that episode-based payment is likely to become standard practice given the current healthcare environment. Consequently, developing episode-based care models for total joint arthroplasty is in the best interests of surgeons, health systems, and patients. In this article, we review important developments related to value-based care in total joint arthroplasty and present an episode-based framework for delivering high-value, patient-centric care. We examine each phase of a total joint arthroplasty episode-preoperative, acute, post-acute, and follow up-and present several ideas with developing bodies of evidence that can improve the value of care delivered to the patient.

Clinical and Administrative Databases Used in Lower Extremity Arthroplasty Research.

BACKGROUND: The use of national databases in lower extremity arthroplasty research has grown rapidly in recent years. We aimed to better characterize available databases by: (1) quantifying the number of these studies in the highest impact arthroplasty journals; (2) comparing respective sample sizes; and (3) contrasting their measured variables/outcomes. METHODS: An extensive literature search was conducted to identify all database studies in the top 12 highest impact factor journals that published arthroplasty research between January 1, 2018 and December 31, 2019. A total of 5070 publications were identified. These studies were sorted by both database utilized and journal published. Tables were constructed to compare/contrast databases by metrics and measured outcome parameters including coding, patient sample size, preoperative comorbidities, postoperative complications, and limitations/barriers to their use. RESULTS: Four hundred twenty-six database studies (8.4%, range 0.4%-29.7% per journal) were identified, of which 139 were from non-English-speaking arthroplasty databases. Among English-speaking arthroplasty databases, the 5 most common sources were National Surgical Quality Improvement Project (n = 72), Medicare (n = 62, 39 from Medicare Claims and 23 from PearlDiver), Nationwide Inpatient Sample (n = 35), PearlDiver non-Medicare private insurance (n = 18), and Statewide Planning and Research Cooperative System (n = 18). Metrics, outcome parameters, and features of commonly used registries were reviewed. CONCLUSION: Database studies constitute an important part of arthroplasty-specific orthopedic research. Their use will continue to grow in the future, and it would be beneficial for clinicians/researchers to be aware of and familiarize themselves with their features to understand which are most appropriate for their work.

Migration Patterns for Revision Total Hip Arthroplasty in the United States as Reported in the American Joint Replacement Registry.

BACKGROUND: Revision total hip arthroplasty (revTHA) is associated with higher rates of complications and greater costs than primary procedures. The aim of this study is to evaluate the effect of hospital size, teaching status, and indication for revTHA, on migration patterns in patients older than 65 years old. METHODS: All THAs and revTHAs reported to the American Joint Replacement Registry from 2012 to 2018 were included and merged with the Centers for Medicare and Medicaid Services database. Migration rate was defined as a patient's THA and revTHA procedures that were performed at separate institutions by different surgeons. Migratory patterns were recorded based on hospital size, teaching status, and indication for revTHA. Analyses were performed by statisticians. RESULTS: The number of linked procedures included was 11,906. Migration rates in revTHA due to infection were higher for small hospitals than large hospitals (46.6% vs 28.6%, P < .0001). Migration rates were higher comparing non-teaching with teaching hospitals (55% vs 34%, P < .0001). This difference was significant for periprosthetic fractures (70.6% vs 37.2%, P = .005), instability (56.5% vs 35.5%, P = .04), and mechanical complications (88.9% vs 34.7%, P < .05). Most patients migrated to medium or large hospitals rather than small hospitals (89% vs 11%, P < .0001) and to teaching rather than non-teaching institutions (82% vs 18%, P < .0001). CONCLUSION: Hospital size and teaching status significantly affected migration patterns for revTHA. Migration rates were significantly higher in small non-teaching hospitals in revTHA due to infection, periprosthetic fracture, instability, and mechanical complications. Over 80% of patients migrated to larger teaching hospitals.

Metric Selection, Metric Targets, and Risk Adjustment Should be Considered in the Design of Gainsharing Models for Bundled Payment Programs in Total Joint Arthroplasty.

BACKGROUND: Under bundled payment models, gainsharing presents an important mechanism to ensure engagement and reward innovation. We hypothesized that metric selection, metric targets, and risk adjustment would impact surgeons' performance in gainsharing models. METHODS: Patients undergoing total joint arthroplasty at an urban health system from 2017 to September 2018 were included. Gainsharing metrics included the following: length of stay, % discharge-to-home, 90-day readmission rate, % of patients with episode spend under target price, and % of patients with patient-reported outcomes (PROs) collected. Four scenarios were created to evaluate how metric selection/adjustment impacted surgeons' performance designation: scenario 1 used "aspirational targets" (>60th percentile), scenario 2 used "acceptable targets" (>50th percentile), scenario 3 risk-adjusted surgeon performance prior to comparing aspirational targets, and scenario 4 included a PRO collection metric. Number of metrics achieved determined performance tier, with higher tiers getting a greater share of the gainsharing pool. RESULTS: In total, 2776 patients treated by 12 surgeons met inclusion criteria (mean length of stay 3.0 days, readmission rate 4.0%, discharge-to-home 74%, episode spend under target price 85%, PRO collection 56%). Lowering of metric targets (scenario 1 vs. 2) resulted in a 75% increase in the number of high performers and 98% of the gainsharing pool being eligible for distribution. Risk adjustment (scenario 3) caused 50% of providers to move to higher performance tiers and potential payments to increase by 28%. Adding the PRO metric did not change performance. CONCLUSION: Quality metric/target selection and risk adjustment profoundly impact surgeons' performance in gainsharing contracts. This impacts how successful these contracts can be in driving innovation and dis-incentivizing the "cherry picking" of patients. LEVEL OF EVIDENCE: Level III.

A Strategic Approach to Introducing New Technology Into Orthopaedic Practices.

Orthopaedic surgeons have a strong legacy for the early of adoption of new technologies that promise to advance patient care. Such technologies are being developed at an extraordinary pace, leveraging advances in orthobiologics and cartilage restoration, surgical navigation, robotic surgery, 3-D printing, and manufacturing of customized implants and sensors. The functionality provided by this revolution is impressive, promising substantial benefits for patients. However, the value of these technologies resides not in their "newness" but in the ability to improve outcomes for patients and reduce overall costs of care. Deciding whether a new technology brings value to an orthopaedic practice can be difficult, especially in an environment of rising health care costs, abundant choice, competition, consumer pressures, variable quality in supporting data, and a shifting regulatory landscape. In this article, we explore the drivers for orthopaedic companies, institutions, and care providers to develop, evaluate, and incorporate new technology. We outline the technology innovation cycle and the major demographic and psychosocial characteristics of adopter groups. We introduce factors considered in evaluating new technologies, such as patient safety, product efficacy, regulatory issues, and their value. Finally, we summarize the ethical concerns associated with new technology, alongside education and training, network security, financial remuneration and informed consent. This article aims to empower orthopaedic surgeons with a balanced and critical approach to ensure the adoption of new technologies in a safe, effective, and ethical manner.

Adherence to the American Academy of Orthopaedic Surgeons Clinical Practice Guidelines for Nonoperative Management of Knee Osteoarthritis.

BACKGROUND: The American Academy of Orthopaedic Surgeons (AAOS) has published evidence-based Clinical Practice Guidelines (CPGs) for the nonarthroplasty management of knee osteoarthritis (OA). The purpose of this study is to determine how closely our orthopedic providers adhered to the recommendations included in those CPGs. METHODS: We retrospectively reviewed 1096 consecutive ambulatory visits with primary diagnosis of knee OA at a single center. Demographic, radiographic, and treatment information was collected. The primary outcome was the frequency of agreement between our treatment recommendations and the AAOS CPGs. A secondary outcome was the associated costs of care. RESULTS: The total number of interventions generated during the visits was 1955. Adherence to the AAOS guidelines was 65% (362/557), 60% (226/377), and 40% (413/1021) in new/never treated, new/previously treated, and return patients, respectively. Intra-articular injection with either corticosteroids or hyaluronic acid was the most common intervention (32%) followed by physical therapy (29%). As the severity of OA increased, adherence to the AAOS guidelines decreased (61%, 60%, 54%, and 49% for Kellgren-Lawrence grades I through IV, respectively). The estimated annual costs associated with our treatment recommendations were $2,403,543.18, of which $1,206,757.8 (50.2%) was supported by evidence. The most expensive treatment intervention was intra-articular hyaluronic acid injection, which carried a strong evidence against its use. CONCLUSION: Adherence to the recommendations contained within the AAOS CPGs was modest regardless of the Kellgren-Lawrence grade or history of treatment. Given the size of the affected patient population, there is a need for uniformly accepted guidelines to clarify the role and timing of the different treatment interventions. CPGs should be combined with education, patient engagement, and shared decision-making to minimize variation in treatment patterns, improve patient outcomes, and lower overall costs of care.

Manipulation Under Anesthesia After Total Knee: Who Still Requires a Revision Arthroplasty?

BACKGROUND: Stiffness after total knee arthroplasty (TKA) is a multifactorial complication involving patient, implant, surgical technique, and rehabilitation, occasionally necessitating manipulation under anesthesia (MUA) or revision. Few modern databases contain sufficient longitudinal information of all factors. We characterized MUA after primary TKA and identified independent risk factors for revision TKA after MUA from the American Joint Replacement Registry. METHODS: We retrospectively reviewed primary TKAs for American Joint Replacement Registry patients ≥65 years from January 1, 2012 to 31 March, 2019. We linked these to the Centers for Medicare and Medicaid Services database to identify MUA and revision TKA procedure codes. We compared groups with chi-squared testing, identifying independent risk factors for subsequent revision with binary logistic regression presented as odds ratios with 95% confidence intervals. RESULTS: Of 664,604 primary TKAs, 3918 (0.6%) underwent MUA after a median of 2.0 ± 1.0 months. Revision surgery occurred in 131 (3.4%) MUA patients after a median of 9.0 months. Timing of MUA was not different between revision and no revision patients (P = .09). Patients undergoing MUA compared to no MUA were older (age 71.5 vs 70.7, P < .01), predominantly female (63.9% vs 61.2%, P < .01), current/former tobacco users (24.2% vs 13.3%, P < .01), with osteoarthritis diagnoses (98.0% vs 84.3%, P < .01). Independent risk factors for revision after MUA were male gender (1.56, 1.09-2.22). CONCLUSION: The incidence of MUA after primary TKA is low (0.6%) in Medicare patients ≥65 years of age; 3.4% progress to revision after a median of 9 months. Being male was significantly associated with revision TKA after MUA.

Enhanced Selection of Candidates for Same-Day and Outpatient Total Knee Arthroplasty.

BACKGROUND: Medicare removed total knee arthroplasty (TKA) from its inpatient-only list and private insurers created ambulatory surgical codes; these changes bring about logistical challenges for TKA episode planning. We identified preoperatively determined factors associated with hospital length of stay for (1) same-day discharge (SDD) and (2) inpatient TKA defined by Medicare's 2-midnight rule benchmark. METHODS: We retrospectively reviewed 325 consecutive unilateral primary TKAs performed on patients completing the Perioperative Surgical Home preoperative optimization pathway within a single hospital system. Stepwise logistic regression modeling was performed to identify preoperatively determined factors associated with (1) SDD and (2) inpatient TKA. We compared these models' ability to discern the length of stay category to the Risk Assessment and Prediction Tool (RAPT) score alone. RESULTS: The cohort included 32 (10%) SDD, 189 (58%) next-day discharges, and 104 (32%) inpatients. Lower body mass index (BMI; odds ratio [OR], 0.92; 95% CI, 0.85-0.1.0; P = .04) and fewer self-reported allergies (OR, 0.66; 95% CI, 0.46-0.95; P = .03) were associated with SDD. The SDD model outperformed the RAPT alone (C-statistic, 0.73 vs 0.52; P < .01). Older age (OR, 0.96; P = .04), higher BMI (OR, 0.93; P 0.01), lower RAPT score (OR, 1.2; P = .04), and later surgery start time (OR, 0.80; P < .01) were associated with inpatient discharge. The inpatient model outperformed the RAPT alone (C-statistic, 0.74 vs 0.62; P < .01). CONCLUSION: We identified preoperatively determined factors associated with (1) SDD as BMI and allergies and (2) inpatient TKA as age, BMI, RAPT score, and surgery start time. Hospitals, providers, patients, families, and payers can use this information for TKA episode planning.

What Are the Uses and Limitations of Time-driven Activity-based Costing in Total Joint Replacement?

BACKGROUND: With increasing emphasis on value-based payment models for primary total joint arthroplasty (TJA), there is greater need for orthopaedic surgeons and hospitals to better understand the actual costs and resource use of TJA. Time-driven activity-based costing (TDABC) is a methodology for accurate cost estimation, but its application in the TJA care pathway across institutions/regions has not yet been analyzed. QUESTIONS/PURPOSES: In this systematic review of studies applying TDABC to primary TJA, we investigated the following: (1) Is there variation in TDABC methodology and cost estimates across institutions? (2) Is a standard set of direct and indirect costs included across studies? (3) Is there a difference in cost estimates derived from TDABC and traditional hospital cost-accounting approaches? and (4) How are institutions using TDABC (process and outputs) with respect to the TJA care pathway? METHODS: A comprehensive search strategy was developed that included the keywords "TDABC," "time-driven activity-based cost," "THA," "TKA," "THR," "TKR," and "TJR" in the PubMed/MEDLINE, EMBASE, Web of Science, Ovid SP, Scopus, and ScienceDirect databases for articles published between 2004 and 2018 as well as extensive hand searching and citation mining. Relevant studies (n = 15) were screened to include THA or TKA as the focus of the TDABC model, full-text articles, TDABC-based cost estimates for TJA, and studies written in English (n = 8). Due to the heterogeneity of outcomes/methodology in TDABC studies involving TJA, quality assessment was based on each study's adherence to the seven steps delineated by Kaplan et al. in their original publication introducing TDABC in health care. RESULTS: There was substantial variation in TDABC methodology (especially in scope), adherence to the seven steps of TDABC, and data collection. Only five of eight studies incorporated indirect costs into their TDABC calculation, with notable differences in which direct and indirect expenses were included. TDABC-based cost estimates for TJA ranged from USD 7081 to USD 29,557, with variation driven by the TJA timeframe and whether implant costs were included in the costing calculation. TDABC was most frequently used to compare against traditional hospital accounting methods (n = 4), to increase operational efficiency (n = 4), to reduce wasted resources (n = 3), and to mitigate risk (n = 3). CONCLUSIONS: TDABC-based cost estimates are more granular and useful in practice than those calculated via traditional hospital accounting; however, there is a lack of standardized principles to guide TDABC implementation (especially for indirect costs) due to institutional and regional differences in TDABC application. Although TDABC methodology will likely continue to vary somewhat between studies, standardized principles are needed to guide the definition, estimation, and reporting of costs to enable detailed examination of study methodology and inputs by readers. LEVEL OF EVIDENCE: Level III, economic and decision analysis.

What Are the Migration Patterns for U.S. Primary Total Joint Arthroplasty Patients?

BACKGROUND: Evaluation of total joint arthroplasty (TJA) patient-reported outcomes and survivorship requires that records of the index and potential revision arthroplasty procedure are reliably captured. Until the goal of the American Joint Replacement Registry (AJRR) of more-complete nationwide capture is reached, one must assume that patient migration from hospitals enrolled in the AJRR to nonAJRR hospitals occurs. Since such migration might result in loss to followup and erroneous conclusions on survivorship and other outcomes of interest, we sought to quantify the level of migration and identify factors that might be associated with migration in a specific AJRR population. QUESTIONS/PURPOSES: (1) What are the out-of-state and within-state migration patterns of U.S. Medicare TJA patients over time? (2) What patient demographic and institutional factors are associated with these patterns? METHODS: Hospital records of Medicare fee-for-service beneficiaries enrolled from January 1, 2004 to December 31, 2015, were queried to identify primary TJA procedures. Because of the nationwide nature of the Medicare program, low rates of loss to followup among Medicare beneficiaries, as well as long-established enrollment and claims processing procedures, this database is ideal for examining patient migration after TJA. We identified an initial cohort of 5.33 million TJA records from 2004 to 2016; after excluding patients younger than 65 years of age, those enrolled solely due to disability, those enrolled in a Medicare HMO, or residing outside the United States, the final analytical dataset consisted of 1.38 million THAs and 3.03 million TKAs. The rate of change in state or county of residence, based on Medicare annual enrollment data, was calculated as a function of patient demographic and institutional factors. A multivariate Cox model with competing risk adjustment was used to evaluate the association of patient demographic and institutional factors with risk of out-of-state or out-of-county (within-state) migration. RESULTS: One year after the primary arthroplasty, 0.61% (95% confidence interval [CI], 0.60-0.61; p < 0.001 for this and all comparisons in this Results section) of Medicare patients moved out of state and another 0.62% (95% CI, 0.60-0.63) moved to a different county within the same state. Five years after the primary arthroplasty, approximately 5.41% (95% CI, 5.39-5.44) of patients moved out of state and another 5.50% (95% CI, 5.46-5.54) Medicare patients moved to a different county within the same state. Among numerous factors of interest, women were more likely to migrate out of state compared with men (hazard ratios [HR], 1.06), whereas black patients were less likely (HR, 0.82). Patients in the Midwest were less likely to migrate compared with patients in the South (HR, 0.74). Patients aged 80 and older were more likely to migrate compared with 65- to 69-year-old patients (HR, 1.19). Patients with higher Charlson Comorbidity Index scores compared with 0 were more likely to migrate (index of 5+; HR, 1.19). CONCLUSIONS: Capturing detailed information on patients who migrate out of county or state, with associated changes in medical facility, requires a nationwide network of participating registry hospitals. At 5 years from primary arthroplasty, more than 10% of Medicare patients were found to migrate out of county or out of state, and the rate increases to 18% after 10 years. Since it must be assumed that younger patients might exhibit even higher migration levels, these findings may help inform public policy as a "best-case" estimate of loss to followup under the current AJRR capture area. Our study reinforces the need to continue aggressive hospital recruitment to the AJRR, while future research using an increasingly robust AJRR database may help establish the migration patterns of nonMedicare patients. LEVEL OF EVIDENCE: Level III, therapeutic study.