A Nationwide Analysis of the Impact of Socioeconomic Status on Complications and Health Care Utilizations After Total Knee Arthroplasty Using the Area Deprivation Index: Consideration of the Disadvantaged Patient.

BACKGROUND: Socioeconomic status has been demonstrated to be an important prognostic risk factor among patients undergoing total joint arthroplasty. We evaluated patients living near neighborhoods with higher socioeconomic risk undergoing total knee arthroplasty (TKA) and if they were associated with differences in the following: (1) medical complications; (2) emergency department (ED) utilizations; (3) readmissions; and (4) costs of care. METHODS: A query of a national database from 2010 to 2020 was performed for primary TKAs. The Area Deprivation Index (ADI) is a weighted index comprised of 17 census-based markers of material deprivation and poverty. Higher numbers indicate a greater disadvantage. Patients undergoing TKA in zip codes associated with high ADI (90%+) were 1:1 propensity-matched to a comparison group by age, sex, and Elixhauser Comorbidity Index. This yielded 225,038 total patients, evenly matched between cohorts. Outcomes studied included complications, ED utilizations, readmission rates, and 90-day costs. Logistic regression models computed the odds ratios (OR) of ADI on the dependent variables. P values less than .003 were significant. RESULTS: High ADI led to higher rates and odds of any medical complications (11.7 versus 11.0%; OR: 1.05, P = .0006), respiratory failures (0.4 versus 0.3%; OR: 1.28, P = .001), and acute kidney injuries (1.7 versus 1.5%; OR: 1.15, P < .0001). Despite lower readmission rates (2.9 versus 3.5%), high ADI patients had greater 90-day ED visits (4.2 versus 4.0%; OR: 1.07, P = .0008). The 90-day expenditures ($15,066 versus $12,459; P < .0001) were higher in patients who have a high ADI. CONCLUSIONS: Socioeconomically disadvantaged patients have increased complications and ED utilizations. Neighborhood disadvantage may inform health care policy and improve postdischarge care. The socioeconomic status metrics, including ADI (which captures community effects), should be used to adequately risk-adjust or risk-stratify patients so that access to care for deprived regions and patients is not lost. LEVEL OF EVIDENCE: III.

Are Femoral Stems in Primary Total Knee Arthroplasty Cost Effective in High Fracture Risk Patients? A Risk Model and Cost Analysis.

Femoral stemmed total knee arthroplasty (FS TKA) may be used in patients deemed higher risk for periprosthetic fracture (PPF) to reduce PPF risk. However, the cost effectiveness of FS TKA has not been defined. Using a risk modeling analysis, we investigate the cost effectiveness of FS in primary TKA compared with the implant cost of revision to distal femoral replacement (DFR) following PPF. A model of risk categories was created representing patients at increasing fracture risk, ranging from 2.5 to 30%. The number needed to treat (NNT) was calculated for each risk category, which was multiplied by the increased cost of FS TKA and compared with the cost of DFR. The 50th percentile implant pricing data for primary TKA, FS TKA, and DFR were identified and used for the analysis. FS TKA resulted in an increased cost of $2,717.83, compared with the increased implant cost of DFR of $27,222.29. At 50% relative risk reduction with FS TKA, the NNT for risk categories of 2.5, 10, 20, and 30% were 80, 20, 10, and 6.67, respectively. At 20% risk, FS TKA times NNT equaled $27,178.30. A 10% absolute risk reduction in fracture risk obtained with FS TKA is needed to achieve cost neutrality with DFR. FS TKA is not cost effective for low fracture risk patients but may be cost effective for patients with fracture risk more than 20%. Further study is needed to better define the quantifiable risk reduction achieved in using FS TKA and identify high-risk PPF patients.

High Risk of Readmission After THA Regardless of Functional Status in Patients Discharged to Skilled Nursing Facility.

BACKGROUND: The postoperative period and subsequent discharge planning are critical in our continued efforts to decrease the risk of complications after THA. Patients discharged to skilled nursing facilities (SNFs) have consistently exhibited higher readmission rates compared with those discharged to home healthcare. This elevated risk has been attributed to several factors but whether readmission is associated with patient functional status is not known. QUESTIONS/PURPOSES: After controlling for relevant confounding variables (functional status, age, gender, caregiver support available at home, diagnosis [osteoarthritis (OA) versus non-OA], Charlson comorbidity index [CCI], the Area Deprivation Index [ADI], and insurance), are the odds of 30- and 90-day hospital readmission greater among patients initially discharged to SNFs than among those treated with home healthcare after THA? METHODS: This was a retrospective, comparative study of patients undergoing THA at any of 11 hospitals in a single, large, academic healthcare system between 2017 and 2022 who were discharged to an SNF or home healthcare. During this period, 13,262 patients were included. Patients discharged to SNFs were older (73 ± 11 years versus 65 ± 11 years; p < 0.001), less independent at hospital discharge (6-click score: 16 ± 3.2 versus 22 ± 2.3; p < 0.001), more were women (71% [1279 of 1796] versus 56% [6447 of 11,466]; p < 0.001), insured by Medicare (83% [1497 of 1796] versus 52% [5974 of 11,466]; p < 0.001), living in areas with greater deprivation (30% [533 of 1796] versus 19% [2229 of 11,466]; p < 0.001), and had less assistance available from at-home caregivers (29% [527 of 1796] versus 57% [6484 of 11,466]; p < 0.001). The primary outcomes assessed in this study were 30- and 90-day hospital readmissions. Although the system automatically flags readmissions occurring within 90 days at the various facilities in the overall healthcare system, readmissions occurring outside the system would not be captured. Therefore, we were not able to account for potential differential rates of readmission to external healthcare systems between the groups. However, given the large size and broad geographic coverage of the healthcare system analyzed, we expect the readmissions data captured to be representative of the study population. The focus on a single healthcare system also ensures consistency in readmission identification and reporting across subjects. We evaluated the association between discharge disposition (home healthcare versus SNF) and readmission. Covariates evaluated included age, gender, primary payer, primary diagnosis, CCI, ADI, the availability of at-home caregivers for the patient, and the Activity Measure for Post-Acute Care (AM-PAC) 6-clicks basic mobility score in the hospital. The adjusted relative risk (ARR) of readmission within 30 and 90 days of discharge to SNF (versus home healthcare) was estimated using modified Poisson regression models. RESULTS: After adjusting for the 6-clicks mobility score, age, gender, ADI, OA versus non-OA, living environment, CCI, and insurance, patients discharged to an SNF were more likely to be readmitted within 30 and 90 days compared with home healthcare after THA (ARR 1.46 [95% CI 1.01 to 2.13]; p= 0.046 and ARR 1.57 [95% CI 1.23 to 2.01]; p < 0.001, respectively). CONCLUSION: Patients discharged to SNFs after THA had a slightly higher likelihood of hospital readmission within 30 and 90 days compared with those discharged with home healthcare. This difference persisted even after adjusting for relevant factors like functional status, home support, and social determinants of health. These results indicate that for suitable patients, direct home discharge may be a safer and more cost-effective option than SNFs. Clinicians should carefully consider these risks and benefits when making postoperative discharge plans. Policymakers could consider incentives and reforms to improve care transitions and coordination across settings. Further research using robust methods is needed to clarify the reasons for higher SNF readmission rates. Detailed analysis of patient complexity, care processes, and causes of readmission in SNFs versus home health could identify areas for quality improvement. Prospective cohorts or randomized trials would allow stronger conclusions about cause-and-effect. Importantly, no patients should be unfairly "cherry-picked" or "lemon-dropped" based only on readmission risk scores. With proper support and care coordination, even complex patients can have good outcomes. The goal should be providing excellent rehabilitation for all, while continuously improving quality, safety, and value across settings. LEVEL OF EVIDENCE: Level III, therapeutic study.

Forty-Six Years of Technological Innovation in Musculoskeletal Medicine: An Analysis of a Patent Database (1973 to 2018).

BACKGROUND: Technological innovation in orthopaedics is key to advancing patient care. As emerging technologies near maturity, clinicians must be able to objectively assess where and when these technologies can be implemented. Patent databases are an underappreciated resource for quantifying innovation, especially within orthopaedic surgery. This study used a patent database to assess patent activity and relative growth of technologies in musculoskeletal medicine and orthopaedics over a period of 46 years. METHODS: A total of 121,471 patent records were indexed from Lens.org , a patent database. These patents were grouped into subspecialty clusters and technology clusters using patent codes. Five-year (2014 to 2018), 10-year (2009 to 2018), and 30-year (1989 to 2018) compound annual growth rates were calculated and compared for each cluster. RESULTS: Annual patent activity increased from one patent in 1973 to 4,866 patents in 2018. Of the eight subspecialty clusters, the largest number of patents were related to 'Inflammation' (n = 63,128; 40.57%). The 'Elbow', 'Shoulder', and 'Knee' clusters experienced increased annual patent activity since 2000. Of the 12 technological clusters, the largest number of patents were related to 'Drugs' (n = 55,324; 39.75%). The 'Custom/patient-specific instrumentation, 'Computer Modeling', 'Robotics', and 'Navigation' clusters saw growth in the average annual patent activity since 2000. DISCUSSION: Innovation, as measured by patent activity in musculoskeletal medicine and orthopaedics, has seen notable growth since 1973. The 'Robotics' cluster seems poised to experience exponential growth in industry investment and technological developments over the next 5 to 10 years. The 'Diagnostics', 'Computer Modeling', 'Navigation', and 'Design and Manufacturing' clusters demonstrate potential for exponential growth in industry investment and technological developments within the next 10 to 20 years.

What Drives the Material Costs of Total Knee Arthroplasty in the Operating Room?

INTRODUCTION: Approximately one-third of US healthcare spending is related to surgical care. Optimizing operating room (OR) spending is crucial, specifically for high-volume procedures like total knee arthroplasty (TKA). Therefore, the primary objective was to identify leading material drivers of cost for TKA procedures within the OR. MATERIALS AND METHODS: Patients who underwent a primary, elective TKA from 2018 to 2019 were included (n=8,672). Intraoperative cost details for each TKA patient were captured from the Vizient Clinical Database Resource Manager (CDB/RM) data. Each cost type was categorized into (1) implant, (2) disposables, (3) wound care, and (4) miscellaneous. RESULTS: 7,124 patients undergoing primary TKA were included. Implant-related costs accounted for 87.3% of cost, disposable materials covered 10.7%, and wound care products took 2%. The leading subcategories of implant costs were primary prosthetics (85.1%), revision prosthetics (9.9%), cement (2.8%), and implant instruments (1.7%). Within disposables, surgical products accounted for 81.3% of the cost, patient care products for 8.9%, medical apparel for 7.9%, and electrolytes for 1.8%. For an average individual TKA procedure, 86.4% (±4.4) of total cost went towards the implant, 10.7% (±3.4) towards disposable materials, and 1.6% (±1.4) to wound care products. Within the implant category, 92.5% (± 12.8) of costs were associated with primary implants, 13.3% (± 6.9) with instruments, and 2.5% (± 2.8) with cement. CONCLUSIONS: The primary operative material expense category was costs associated with the TKA prosthesis and its fixation followed by disposable materials. A large amount of variation exists in the percent of the total cost for a given TKA procedure that can be attributed to each category.

Considering Mobility Status and Home Environment in Readmission Risk After Total Knee Arthroplasty.

BACKGROUND: Discharge disposition following total knee arthroplasty (TKA) offers varying levels of post-acute care monitoring depending on the medical status of the patient and his or her ability to function independently. Discharge disposition following TKA is associated with 30-day and 90-day hospital readmission, but prior studies have not consistently considered confounding due to mobility status after TKA, available caregiver support, and measures of home area deprivation. The purpose of this study was to examine 30-day and 90-day readmission risk for patients discharged to a skilled nursing facility (SNF) following TKA after controlling specifically for these factors, among other covariates. METHODS: This was a retrospective cohort study of patients undergoing TKA at any of 11 hospitals in a single, large, academic health-care system between January 2, 2017, and August 31, 2022, who were discharged to an SNF or home health care (HHC). The adjusted relative risk of readmission within 30 and 90 days of discharge to an SNF compared with HHC was estimated using modified Poisson regression models. RESULTS: There were 15,212 patients discharged to HHC and 1,721 patients discharged to SNFs. Readmission within 30 days was 7.1% among patients discharged to SNFs and 2.4% among patients discharged to HHC; readmission within 90 days was 12.1% for the SNF group and 4.8% for the HHC group. The adjusted relative risk after discharge to an SNF was 1.07 (95% confidence interval [CI], 0.79 to 1.46; p = 0.65) for 30-day readmission and 1.45 (95% CI, 1.16 to 1.82; p < 0.01) for 90-day readmission. CONCLUSIONS: Discharge to an SNF compared with HHC was independently associated with 90-day readmission, but not with 30-day readmission, after controlling for mobility status after TKA, available caregiver support, and home Area Deprivation Index, among other covariates. LEVEL OF EVIDENCE: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Simultaneous bilateral total knee arthroplasty has higher in-hospital complications than both staged surgeries: a nationwide propensity score matched analysis of 38,764 cases.

PURPOSE: To investigate (1) healthcare utilization, (2) in-hospital metrics and (3) total in-hospital costs associated with simultaneous versus staged BTKA while evaluating staged BTKA as a single process consisting of two combined episodes. METHODS: The national readmissions database was reviewed for simultaneous and staged (two primary unilateral TKAs12 months apart) BTKA patients (2016-2017). A total of 19,382 simultaneous BTKAs were identified, and propensity score matched (1:1) to staged BTKA patients (19,382 patients; 38,764 surgeries) based on demographics, comorbidities, and socioeconomic determinants. Outcomes included healthcare utilization [length of stay (LOS) and discharge disposition], in-hospital periprosthetic fractures, non-mechanical complications, and costs. Staged BTKA was evaluated as one process consisting of two episodes. For each staged patient, continuous outcomes were evaluated via the sum of both episodes. Categorical outcomes were added, and percents were expressed relative to total number of surgeries (n = 38,764). RESULTS: Simultaneous BTKA had longer LOS (5.0 days ± 4.7 vs. 4.5 days ± 3.5; p < 0.001), higher non-home discharge [36.9% (n = 7150/19,382) vs. 13.6% (n = 5451/38,764)], in-hospital periprosthetic fractures [0.13% (26/19,382) vs. 0.08% (31/38,764); p = 0.049], any non-mechanical complication [33.76% (6543/19,382) vs.15.93% (6177/38,764); p < 0.0001], hematoma/seroma formation [0.11% (22/19,382) vs. 0.05% (20/38,764); p = 0.0088], wound disruption [0.08% (16/19,382) vs. 0.04% (16/38,764); p = 0.0454], and any infection [1.13% (219/19,382) vs. 0.50% (194/38,764); p < 0.0001]. Average in-hospital costs for the two staged BTKA episodes combined were $5006 higher than those of simultaneous BTKA ($28,196 ± $18,488 vs. $33,202 ± $15,240; p < 0.001). CONCLUSION: Simultaneous BTKA had higher healthcare utilization and in-hospital complications than both episodes of staged BTKA combined, with a minimal in-hospital cost savings. Future studies are warranted to further explore patient selection who would benefit from BTKA.

Racial Disparities in Outcomes After THA and TKA Are Substantially Mediated by Socioeconomic Disadvantage Both in Black and White Patients.

BACKGROUND: Demographic factors have been implicated in THA and TKA outcome disparities. Specifically, patients' racial backgrounds have been reported to influence outcomes after surgery, including length of stay, discharge disposition, and inpatient readmissions. However, in the United States, health-impacting socioeconomic disadvantage is sometimes associated with racial differences in ways that can result in important confounding, thereby raising the question of whether race-associated post-THA/TKA adverse outcomes are an independent function of race or a byproduct of confounding from socioeconomic deprivation, which is potentially addressable. To explore this, we used the Area Deprivation Index (ADI) as a proxy for socioeconomic disadvantage, since it is a socioeconomic parameter that estimates the likely deprivation associated with a patient's home address. QUESTIONS/PURPOSES: The goal of this study was to investigate (1) whether race (in this study, Black versus White) was independently associated with adverse outcomes, including prolonged length of stay (LOS > 3 days), nonhome discharge, 90-day readmission, and emergency department (ED) visits while controlling for age, gender, BMI, smoking, Charlson comorbidity index (CCI), and insurance; and (2) whether socioeconomic disadvantage, measured by ADI, substantially mediated any association between race and any of the aforementioned measured outcomes. METHODS: Between November 2018 and December 2019, 2638 underwent elective primary THA and 4915 patients underwent elective primary TKA for osteoarthritis at one of seven hospitals within a single academic center. Overall, 12% (742 of 5948) of patients were Black and 88% (5206 of 5948) were White. We included patients with complete demographic data, ADI data, and who were of Black or White race; with these criteria, 11% (293 of 2638) were excluded in the THA group, and 27% (1312 of 4915) of patients were excluded in the TKA group. In this retrospective, comparative study, patient follow-up was obtained using a longitudinally maintained database, leaving 89% (2345 of 2638) and 73% (3603 of 4915) for analysis in the THA and TKA groups, respectively. For both THA and TKA, Black patients had higher ADI scores, slightly higher BMIs, and were more likely to be current smokers at baseline. Furthermore, within the TKA cohort there was a higher proportion of Black women compared with White women. Multivariable regression analysis was utilized to assess associations between race and LOS of 3 or more days, nonhome discharge disposition, 90-day inpatient readmission, and 90-day ED admission, while adjusting for age, gender, BMI, smoking, CCI, and insurance. This was followed by a mediation analysis that explored whether the association between race (the independent variable) and measured outcomes (the dependent variables) could be partially or completely attributable to confounding from the ADI (the mediator, in this model). The mediation effect was measured as a percentage of the total effect of race on the outcomes of interest that was mediated by ADI. RESULTS: In the THA group, after adjusting for age, gender, BMI, smoking, CCI, and insurance, White patients had lower odds of experiencing an LOS of 3 days or more (OR 0.43 [95% confidence interval (CI) 0.31 to 0.59]; p < 0.001) and nonhome discharge (OR 0.39 [95% CI 0.27 to 0.56]; p < 0.001). In mediation analysis, ADI partially explained (or mediated) 37% of the association between race and LOS of 3 days or more (-0.043 [95% CI -0.063 to -0.026]; p < 0.001) and 40% of the association between race and nonhome discharge (0.041 [95% CI 0.024 to 0.059]; p < 0.001). However, a smaller direct association between race and both outcomes was observed (LOS 3 days or more: -0.075 [95% CI -0.13 to -0.024]; p = 0.004; nonhome discharge: 0.060 [95% CI 0.016 to 0.11]; p = 0.004). No association was observed between race and 90-day readmission or ED admission in the THA group. In the TKA group, after adjusting for age, gender, BMI, smoking, CCI, and insurance, White patients had lower odds of experiencing an LOS of 3 days or more (OR 0.41 [95% CI 0.32 to 0.54]; p < 0.001), nonhome discharge (OR 0.44 [95% CI 0.33 to 0.60]; p < 0.001), 90-day readmission (OR 0.54 [95% CI 0.39 to 0.77]; p < 0.001), and 90-day ED admission (OR 0.60 [95% CI 0.45 to 0.79]; p < 0.001). In mediation analysis, ADI mediated 19% of the association between race and LOS of 3 days or more (-0.021 [95% CI -0.035 to -0.007]; p = 0.004) and 38% of the association between race and nonhome discharge (0.029 [95% CI -0.016 to 0.040]; p < 0.001), but there was also a direct association between race and these outcomes (LOS 3 days or more: -0.088 [95% CI -0.13 to -0.049]; p < 0.001; nonhome discharge: 0.046 [95% CI 0.014 to 0.078]; p = 0.006). ADI did not mediate the associations observed between race and 90-day readmission and ED admission in the TKA group. CONCLUSION: Our findings suggest that socioeconomic disadvantage may be implicated in a substantial proportion of the previously assumed race-driven disparity in healthcare utilization parameters after primary total joint arthroplasty. Orthopaedic surgeons should attempt to identify potentially modifiable socioeconomic disadvantage indicators. This serves as a call to action for the orthopaedic community to consider specific interventions to support patients from vulnerable areas or whose incomes are lower, such as supporting applications for nonemergent medical transportation or referring patients to local care coordination agencies. Future studies should seek to identify which specific resources or approaches improve outcomes after TJA in patients with socioeconomic disadvantage. LEVEL OF EVIDENCE: Level III, therapeutic 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.

What are the Causes, Costs and Risk-Factors for Emergency Department Visits Following Primary Total Hip Arthroplasty? An Analysis of 1,018,772 Patients.

BACKGROUND: Well-powered studies analyzing the relationship and nature of emergency department (ED) visits following primary total hip arthroplasties (THAs) are limited. The aim of this study was to: 1) compare baseline demographics of patients with/without an ED visit; 2) determine leading causes of ED visits; 3) identify patient-related risk factors; and 4) quantify 90-day episode-of-care healthcare costs divided by final diagnosis. METHODS: Patients undergoing primary THA between January 1, 2010 and October 1, 2020 who presented to the ED within 90-days postoperatively were identified using the Mariner dataset of PearlDiver, yielding 1,018,772 patients. This included 3.9% (n = 39,439) patients who did and 96.1% (n = 979,333) who did not have an ED visit. Baseline demographics between the control/study cohorts, ED visit causes, risk-factors, and subsequent costs-of-care were analyzed. Using Bonferroni-correction, a P-value less than 0.002 was considered statistically significant. RESULTS: Patients who presented to the ED post-operatively were most often aged 65-74 years old (41.09%) or female sex (55.60%). Nonmusculoskeletal etiologies comprised 66.8% of all ED visits. Risk factors associated with increased ED visits included alcohol abuse, depressive disorders, congestive heart failure, coagulopathy, and electrolyte/fluid derangements (P < .001 for all). Pulmonary ($28,928.01) and cardiac ($28,574.69) visits attributed to the highest costs of care. CONCLUSION: Nonmusculoskeletal causes constituted the majority of ED visits. The top five risk factors associated with increased odds of ED visits were alcohol abuse, electrolyte/fluid derangements, congestive heart failure, coagulopathy, and depression. This study highlights potential areas of pre-operative medical optimization that may reduce ED visits following primary THA.

A Call to Action for Musculoskeletal Research Funding: The Growing Economic and Disease Burden of Musculoskeletal Conditions in the United States Is Not Reflected in Musculoskeletal Research Funding.

ABSTRACT: As a result of an aging population, musculoskeletal disease is a growing source of health and economic burden in the United States. In 2019, musculoskeletal conditions affected approximately 127.4 million people (more than a third of the U.S. population); they were the top driver of health-care spending in 2016, with an estimated direct annual cost of $380.9 billion. While musculoskeletal conditions represent a substantial and growing burden in terms of prevalence, disability, and health-care costs, National Institutes of Health (NIH) research funding has remained disproportionately allocated to other disease conditions. Therefore, our purpose was to provide an assessment of the current burden of musculoskeletal disease in terms of prevalence, disability, and health-care costs, and compare the changing burden of disease to trends in NIH funding.

Nutritional Assessment and Interventions in Elective Hip and Knee Arthroplasty: a Detailed Review and Guide to Management.

PURPOSE OF REVIEW: 8.5 to 50% of total joint arthroplasty (TJA) patients are reported to have preoperative malnutrition. The narrative review identifies the relationship between preoperative malnutrition for TJA patients and postoperative outcomes as well as the use of perioperative nutritional intervention to improve postoperative complications. RECENT FINDINGS: Biochemical/laboratory, anthropometric, and clinical measures have been widely used to identify preoperative nutritional deficiency. Specifically, serum albumin is the most prevalent used marker in TJA because it has been proven to be correlated with protein-energy malnutrition due to the surgical stress response. However, there remains a sustained incidence of preoperative malnutrition in total knee arthroplasty (TKA) and total hip arthroplasty (THA) patients due to a lack of agreement among the available nutritional screening tools and utilization of isolated laboratory, anthropometric, and clinical variables. Previous investigations have also suggested preoperative malnutrition to be a prognostic indicator of complications in general, cardiac, vascular, and orthopaedic surgery specialties. Serum albumin, prealbumin, transferrin, and total lymphocyte count (TLC) can be used to identify at-risk patients. It is important to employ these markers in the preoperative setting because malnourished TKA and THA patients have shown to have worse postoperative outcomes including prolonged length, increased reoperation rates, increased infection rates, and increased mortality rates. Although benefits from high-protein and high-anti-inflammatory diets have been exhibited, additional research is needed to confirm the use of perioperative nutritional intervention as an appropriate treatment for preoperative TJA patients.

Staged Versus Simultaneous Bilateral Knee Arthroplasty: Does Minimal Cost Difference Justify Risks?

BACKGROUND: Simultaneous bilateral total knee arthroplasty (BTKA) is associated with a higher risk but can be perceived to afford faster improvement and mitigated costs versus staged BTKA. We aimed to explore (1) health care utilization, (2) surgical supply costs of simultaneous BTKA; and (3) 1-year improvement in patient-reported pain, function, and quality of life (QOL) versus staged BTKA. METHODS: A prospective cohort of 198 simultaneous and 625 staged BTKAs was obtained (2016-2020). Simultaneous BTKA cohort was propensity score-matched (1:2) to a similar group of staged patients (simultaneous = 198 versus staged = 396). Outcomes included length of stay, discharge disposition, 90-day readmission, 1-year reoperation, surgical episode supply cost, Knee Injury and Osteoarthritis Outcome Score (KOOS)-pain, KOOS-Physical Function Short Form, and KOOS-QOL. Rates of attaining minimal clinically important difference and Patient Acceptable Symptomatic State were calculated. RESULTS: Compared to both staged BTKA surgeries combined, simultaneous BTKA demonstrated shorter median net length of stay (2.00 [2.00, 3.00] days versus 2.00 [2.00, 4.00] days; P < .001) but higher rates of nonhome discharge (n = 56 [28.3%] versus n = 32 [4.04%]; P < .001), 90-day readmission (n = 20 [10.1%] versus n = 48 [6.06%]; P = .047) and similar reoperation rates (P = .44). Simultaneous BTKA afforded slight reduction in net surgical cost compared to that of both staged BTKAs combined ($643; P = .028). There was no significant difference in 1-year improvement and minimal clinically important difference attainment rates with simultaneous versus staged BTKA for KOOS-pain (P = .137 and P = .99), KOOS-QOL (P = .095 and P = .81), or KOOS-Physical Function Short Form (P = .75 and P = .49, respectively) or Patient Acceptable Symptomatic State (P = .12). CONCLUSION: Staged BTKA is associated with similar 1-year pain, function, and QOL at a better safety profile and minimal surgical supply cost increase compared to simultaneous BTKA.

Team Approach: Nutritional Assessment and Interventions in Elective Hip and Knee Arthroplasty.

¼: Nutritional assessment is a critical element of routine preoperative assessment and should be approached by an interdisciplinary team that involves the primary care physician, dietitian, and orthopaedist. ¼: Patients should be stratified on the basis of their nutritional risk, which influences downstream optimization and deficiency reversal. ¼: The scientific literature indicates that nutritional supplementation affords protection against adverse outcomes and helps functional recovery, even among patients who are not at nutritional risk. ¼: Published investigations recommend a sufficient preoperative interval (at least 4 weeks) to ensure an adequate nutritional intervention in malnourished patients as opposed to regarding them as nonsurgical candidates.

Neighborhood Socioeconomic Disadvantages Associated With Prolonged Lengths of Stay, Nonhome Discharges, and 90-Day Readmissions After Total Knee Arthroplasty.

BACKGROUND: Low socioeconomic status and neighborhood context has been linked to poor health care outcomes after total knee arthroplasty (TKA). The area deprivation index (ADI) addresses this relationship by ranking neighborhoods by socioeconomic disadvantage. We examined the following relationships of the ADI among TKA recipients: (1) patient demographics, (2) lengths of stay (LOS), (3) nonhome discharges, and (4) 90-day readmissions, emergency department visits, and reoperations. METHODS: We reviewed a consecutive series of primary TKAs from 2018 through 2020 at a tertiary health care system. A total of 3928 patients who had complete ADI data were included. A plurality of patients (14.9%) were categorized within ADI 31-40, below the national median ADI of 47. Associations between the national ADI decile and 90-day postoperative health care utilization metrics were evaluated using multivariate regressions (adjusted for patient demographics and comorbidities). RESULTS: The 91-100 ADI cohort was disproportionately African American, female, younger, and smokers. Compared with ADI 31-40 (reference), the ADI 61-70 cohort was associated with higher odds of LOS ≥3 days (odds ratio [OR] = 1.6 [1.08-2.36], P = .019) and nonhome discharges (OR = 1.73 [1.08-2.75], P = .021). The ADI 91-100 cohort was associated with the highest odds of prolonged LOS (OR = 2.27; [1.47-3.49], P < .001), nonhome discharges (OR = 3.49 [2.11-5.78], P < .001), and all-cause readmissions (OR: 1.79, [1.02-3.14], P = .044). No significant associations were found between the ADI and 90-day emergency department visits or reoperations (P > .05). CONCLUSION: A higher ADI was associated with prolonged LOS, nonhome discharge status, and 90-day readmissions after TKA. This index highlights potential areas of intervention for assessing health care outcomes.

Assessment of Clinical, Tissue, and Cell-Level Metrics Identify Four Biologically Distinct Knee Osteoarthritis Patient Phenotypes.

OBJECTIVE: Clinical heterogeneity of primary osteoarthritis (OA) is a major challenge in understanding pathogenesis and development of targeted therapeutic strategies. This study aims to (1) identify OA patient subgroups phenotypes and (2) determine predictors of OA severity and cartilage-derived stem/progenitor concentration using clinical-, tissue-, and cell- level metrics. DESIGN: Cartilage, synovium (SYN) and infrapatellar fatpad (IPFP) were collected from 90 total knee arthroplasty patients. Clinical metrics (patient demographics, radiograph-based joint space width (JSW), Kellgren and Lawrence score (KL)), tissue metrics (cartilage histopathology grade, glycosaminoglycans (GAGs)) and cell-based metrics (cartilage-, SYN-, and IPFP-derived cell concentration ([Cell], cells/mg), connective tissue progenitor (CTP) prevalence (PCTP, CTPs/million cells plated), CTP concentration, [CTP], CTPs/mg)) were assessed using k-mean clustering and linear regression model. RESULTS: Four patient subgroups were identified. Clusters 1 and 2 comprised of younger, high body mass index (BMI) patients with healthier cartilage, where Cluster 1 had high CTP in cartilage, SYN, and IPFP, and Cluster 2 had low [CTP] in cartilage, SYN, and IPFP. Clusters 3 and 4 comprised of older, low BMI patients with diseased cartilage where Cluster 3 had low [CTP] in SYN, IPFP but high [CTP] in cartilage, and Cluster 4 had high [CTP] in SYN, IPFP but low [CTP] in cartilage. Age (r = 0.23, P = 0.026), JSW (r = 0.28, P = 0.007), KL (r = 0.26, P = 0.012), GAG/mg cartilage tissue (r = -0.31, P = 0.007), and SYN-derived [Cell] (r = 0.25, P = 0.049) were weak but significant predictors of OA severity. Cartilage-derived [Cell] (r = 0.38, P < 0.001) and PCTP (r = 0.9, P < 0.001) were moderate/strong predictors of cartilage-derived [CTP]. CONCLUSION: Initial findings suggests the presence of OA patient subgroups that could define opportunities for more targeted patient-specific approaches to prevention and treatment.

Effects of Hospital and Surgeon Volume on Patient Outcomes After Total Joint Arthroplasty: Reported From the American Joint Replacement Registry.

BACKGROUND: The purpose of this study was to evaluate outcomes and complications because it relates to surgeon and hospital volume for patients undergoing primary total hip arthroplasty (THA) and total knee arthroplasty (TKA) using the American Joint Replacement Registry from 2012 to 2017. METHODS: A retrospective study was conducted on Medicare-eligible cases of primary elective THAs and TKAs reported to the American Joint Replacement Registry database and was linked with the available Centers of Medicaid and Medicare Services claims and the National Death Index data from 2012 to 2017. Surgeon and hospital volume were defined separately based on the median annual number of anatomic-specific total arthroplasty procedures performed on patients of any age per surgeon and per hospital. Values were aggregated into separate surgeon and hospital volume tertile groupings and combined to create pairwise comparison surgeon/hospital volume groupings for hip and knee. RESULTS: Adjusted multivariable logistic regression analysis found low surgeon/low hospital volume to have the greatest association with all-cause revisions after THA (odds ratio [OR], 1.63, 95% confidence interval [CI], 1.41-1.89, P < 0.0001) and TKA (OR, 1.72, 95% CI, 1.44-2.06, P < 0.0001), early revisions because of periprosthetic joint infection after THA (OR, 2.50, 95% CI, 1.53-3.15, P < 0.0001) and TKA (OR, 2.18, 95% CI, 1.64-2.89, P < 0.0001), risk of early THA instability and dislocation (OR, 2.47, 95% CI, 1.77-3.46, P < 0.0001), and 90-day mortality after THA (OR, 1.72, 95% CI, 1.27-2.35, P = 0.0005) and TKA (OR, 1.47, 95% CI, 1.15-1.86, P = 0.002). CONCLUSION: Our findings demonstrate considerably greater THA and TKA complications when performed at low-volume hospitals by low-volume surgeons. Given the data from previous literature including this study, a continued push through healthcare policies and healthcare systems is warranted to direct THA and TKA procedures to high-volume centers by high-volume surgeons because of the evident decrease in complications and considerable costs associated with all-cause revisions, periprosthetic joint infection, instability, and 90-day mortality. LEVEL OF EVIDENCE: III.

The Cost-Effectiveness of Robotic-Assisted Versus Manual Total Knee Arthroplasty: A Markov Model-Based Evaluation.

INTRODUCTION: The purpose of this study was to investigate the cost-effectiveness of robotic-assisted total knee arthroplasty (TKA) versus conventional manual TKA in patients with knee osteoarthritis. METHODS: A Markov model simulated the lifetime outcomes of TKA of patients at average age 60 years. Costs of robotic-assisted TKA included a preoperative CT scan and the costs for acquisition and use of robotic equipment (average $706,250). We used three institutional case volumes to generate average per-case robotic costs: low volume (10 cases, $71,025 per case), mid volume (100 cases, $7,463 per case), and high volume (200 cases, $3,931 per case). Systematic reviews were used to determine early (≤1 year) and late (> 1 year) revision rates after robotic-assisted TKA (0.3 and 0.6%, respectively) and conventional TKA (0.78% and 1.5%, respectively). Outcomes were total costs and health outcomes measured in quality-adjusted life-years (QALYs). Costs and QALYs were organized into incremental cost-effectiveness ratios (ICERs). A procedure was considered cost-effective if its ICER fell below willingness-to-pay (WTP) thresholds of $50,000 and $100,000/QALY. Sensitivity analyses evaluated the effect of data uncertainty. RESULTS: Robotic-assisted TKA produced 13.55 QALYs versus 13.29 QALYs for conventional TKA. Total costs per case for robotic-assisted TKA were $92,823 (low volume), $29,261 (mid volume), and $25,730 (high volume) compared with $25,113 for conventional. The ICERs for robotic-assisted TKAs were $256,055/QALY (low volume), $15,685/QALY (mid volume), and $2,331/QALY (high volume). ICERs for mid- and high-volume institutions were below WTP. Average number needed to treat was >42 and >24 robotic-assisted TKAs for cost-effectiveness at the $50,000 and $100,000/QALY WTP. Robotic-assisted TKAs remained cost-effective when annual revision rates <1.6% and quality of life values were >0.85. CONCLUSION: With lower annualized revision rates and higher postoperative quality of life, robotic-assisted TKAs potentially offer improved health outcomes, especially when annual institutional case volume >24 cases per year. Continued prospective investigation will be crucial to demonstrate the value of this new technology.

Procedures With Longer Intraoperative Times Undervalue Surgeon Work in Total Joint Arthroplasty: A Large, Nationwide Database Study.

BACKGROUND: Work relative value units (wRVUs) measure a surgeon's time and intensity required to perform the pre-service, intra-service, and post-service work of a surgical procedure and are commonly used to compare a physician's work between different procedures. Previous literature across multiple specialties report that longer, often revision, operations are undervalued when compared to primary procedures. Our study aims to analyze the differences in intra-operative time, and its corresponding wRVU/h between the Medicare benchmarks and real-world time-stamped data for total joint arthroplasty procedures. METHODS: Thirteen primary and revision hip and knee arthroplasty procedures were identified, and intra-operative times were collected using the National Surgical Quality Improvement Program databases from 2014 to 2019. The Relative Value Scale Update Committee's (RUC) estimated median intra-operative times for each procedure was compared to the calculated median intra-operative times from National Surgical Quality Improvement Program, as were their corresponding wRVU/h. Procedures were additionally stratified by "long" (>110 minutes) and "short" (≤110 minutes) intra-operative times. RESULTS: The RUC over-estimated intra-operative time by 35.24% on average and this overestimation was more profound in longer operations than shorter operations (47.75% vs 15.22%, P = .011). The RUC intensity per unit time values (wRVU/h) between "long" and "short" procedures were significantly different (P < .001) and showed the undervaluation of intensity for the longer procedures by an average of 3.47 wRVU/h. CONCLUSION: Our study provides further evidence that physician work is undervalued in revision total hip and knee surgeries.