Is the Rise of Medicare Advantage Impacting the Fidelity of Traditional Medicare Claims Data? Implications for Reporting of Long-Term Total Hip Arthroplasty Survivorship.

BACKGROUND: Arthroplasty registries often use traditional Medicare (TM) claims data to report long-term total hip arthroplasty (THA) survivorship. The purpose of this study was to determine whether the large number of patients leaving TM for Medicare Advantage (MA) has compromised the fidelity of TM data. METHODS: We identified 10,962 THAs in 9,333 Medicare-eligible patients who underwent primary THA from 2000 to 2020 at a single institution. Insurance type was analyzed, and 83% of patients had TM at the time of THA. Survivorship free from any revision or reoperation was calculated for patients who have TM. The same survivorship end points were recalculated with censoring performed when a patient transitioned to an MA plan after their primary THA to model the impact of losing patients from the TM dataset. Differences in survivorship were compared. The mean follow-up was 7 years. RESULTS: From 2000 to 2020, there was a decrease in TM insurance (93 to 73%) and a corresponding increase in MA insurance (0 to 19%) among THA patients. Following THA, 23% of TM patients switched to MA. For patients who had TM at the time of surgery, 15-year survivorship free from any reoperation or revision was 90% and 93%, respectively. When censoring patients upon transition from TM to MA, survivorship free from any reoperation became significantly higher (92 versus 90% at 15 years; hazard ratio = 1.16, P = .033), and there was a trend toward higher survivorship free from any revision (95 versus 93% at 15 years; hazard ratio = 1.16, P = .074). CONCLUSIONS: Approximately 1 in 4 patients left TM for MA after primary THA, effectively making them lost to follow-up within TM datasets. The mass exodus of patients out of TM appears to have led to a slight overestimation of survivorship free from any reoperation and trended toward overestimating survivorship free from any revision. If MA continues to grow, efforts to obtain MA data will become even more important.

Comparison of Patient-Reported Outcomes and Functional Assessment Using a Marker-Less Image Capture System in End-Stage Knee Arthritis.

BACKGROUND: Patient self-assessment of knee function in end-stage osteoarthritis (OA) and following total knee arthroplasty (TKA) using patient-reported outcome measures (PROMs) has become standard for defining disability. The relationship of PROMs to functional performance requires a continued investigation. The purpose of this study was to determine correlations between patient demographics, PROMs, and functional performances using a marker-less image capture system (MICS). METHODS: Patients indicated for elective TKA completed the Knee Injury and Osteoarthritis Score for Joint Replacement (KOOS-JR) and an office-based functional assessment using a MICS. Patient age, body mass index (BMI), and gender were collected. A total of 112 patients were enrolled. Their mean age was 65.0 (±9.7) years, mean BMI was 32.5 (±6.6) kg/m2, and mean KOOS-JR was 14.5 (±5.7). The relationships between patient characteristics, KOOS-JR, MICS Alignment (coronal), MICS Mobility (flexion), and composite Total Joint scores were described using Spearman's correlation coefficients. RESULTS: BMI was weakly correlated with KOOS-JR (ρ = -0.22, P = .024), whereas age was not. Age and BMI were not correlated with performance scores. There were weak to no correlations between KOOS-JR and MICS Alignment (ρ = -0.01, P = .951), Mobility (ρ = 0.33, P < .001), and Total Joint scores (ρ = 0.06, P = .504). CONCLUSION: This study found no strong correlation between KOOS-JR and functional performance using a validated MICS for patients with end-stage knee OA. Further study is warranted in determining the relationship between PROMs and performance to optimize outcomes of patients undergoing nonoperative or surgical interventions for knee OA. The use of high-fidelity functional assessment tools that can be integrated into clinical workflow, such as the MICS used in this study, should permit PROM/functional performance comparisons in large populations.

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.

Who Is Still Receiving Blood Transfusions After Primary and Revision Total Joint Arthroplasty?

BACKGROUND: Incidence of blood transfusions after primary and revision total hip and knee arthroplasty (primary total hip arthroplasty [pTHA], revision THA [rTHA], primary total knee arthroplasty [pTKA], and revision TKA [rTKA]) has been decreasing for a multitude of reasons. The purpose of this study was to assess whether transfusion rates have continued to decline and evaluate patient factors associated with transfusions. METHODS: The American College of Surgeons National Surgical Quality Improvement Program was queried to identify patients undergoing pTHA, pTKA, rTHA, and rTKA between 2011 and 2019. Patients undergoing bilateral procedures and arthroplasty for fracture, infection, or tumor were excluded. Trends in blood transfusions were assessed. Patient factor association with blood transfusions was evaluated using 2018 and 2019 data. RESULTS: Transfusion rates decreased from 21.4% in 2011 to 2.5% in 2019 for pTHA (P < .0001). For pTKA, transfusion rates declined from 17.6% to 0.7% (P < .0001). In rTHA, the transfusion rate decreased from 33.5% to 12.0% from 2011 to 2019 (P < .0001). Transfusion rates declined from 19.4% to 2.6% for rTKA during the study period (P < .0001). Transfusions were more frequent in patients who were older, female, with more comorbidities, with lower hematocrit, receiving nonspinal anesthesia, and with longer operative time. Lower preoperative hematocrit, history of bleeding disorders, and preoperative transfusion were associated with greater odds for postoperative transfusion after multivariate analysis. CONCLUSION: Transfusions after both primary and revision total joint arthroplasty have continued to decrease. Studies of arthroplasty complications should account for decreasing transfusions when assessing overall complication rates. Future studies should consider interventions to further reduce transfusions in revision arthroplasty.

Home Discharge Has Increased After Total Hip Arthroplasty, However Rates Vary Between Large Databases.

BACKGROUND: There have been significant advancements in perioperative total hip arthroplasty (THA) care and it is essential to quantify efforts made to better optimize patients and improve outcomes. The purpose of this study is to assess trends in discharge destination, length of stay (LOS), reoperations, and readmissions following THA. METHODS: Patients undergoing primary THA were identified using International Statistical Classification of Diseases and Current Procedural Terminology codes in the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) and Humana claims databases. Discharge destinations were assessed and categorized as home or not home. Trends in discharge destination, LOS, readmissions, reoperation, and comorbidity burden were assessed. RESULTS: In ACS NSQIP, 155,637 patients underwent THA and the percentage of patients discharging home increased from 72.2% in 2011 to 87.0% in 2017 (P < .0001). In Humana, 84,832 THA patients were identified, with an increase in home discharge from 56.6% to 72.8% (P < .0001). LOS decreased and proportion of patients with an American Society of Anesthesiologists score ≥3 or Charlson Comorbidity Index ≥2 increased significantly for both home and nonhome going patients. Patients discharged home had a decrease in readmissions in both databases. CONCLUSION: Patients undergoing THA more often discharged home and had shorter hospital LOS with lower readmission rates, despite an increasingly comorbid patient population. It is likely these changes in disposition and LOS have resulted in significant cost savings for both payers and hospitals. The efforts necessary to maintain improvements should be considered when changes to reimbursement are being evaluated. ACS NSQIP hospitals had a larger proportion of patients discharged home and the source of data used to benchmark hospitals should be considered as findings may differ.

More Patients Are Being Discharged Home After Total Knee Arthroplasty, However Rates Vary Between Large Databases.

BACKGROUND: There have been significant advancements in perioperative care for total knee arthroplasty (TKA). It is essential to quantify the impact of efforts to better optimize patients and deliver care. The purpose of this study is to assess trends in discharge destination, length of stay (LOS), and complications. METHODS: Patients undergoing primary TKA were identified in the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) and Humana claims databases using procedural codes. Patients were classified as being discharged home or not home (skilled nursing facility, acute rehab, other non-home destinations). Changes in discharge destination, LOS, comorbidity burden, readmissions, and reoperation were assessed. RESULTS: In total, 254,195 ACS NSQIP patients underwent TKA, with an increase in home discharge from 67.2% in 2011 to 85.3% in 2017 (P < .0001). There were 178,071 TKA patients in the Humana database and home discharge increased from 62.1% in 2007 to 74.7% in 2016 (P < .0001). LOS decreased and proportion of patients with an American Society of Anesthesiologists score ≥3 or Charlson Comorbidity Index ≥2 increased significantly for both home and non-home going patients. Home going patients had a decrease in 30-day readmissions (ACS NSQIP: 2011: 3.6%, 2017: 2.7%, P = .001; Humana: 2007: 4.0%, 2016: 2.4%, P < .0001). CONCLUSION: Patients undergoing TKA were discharged home more often, had shorter LOS, and had significantly lower readmission rates, despite an increasingly comorbid patient population. It is likely that these improvements in postoperative care have resulted in significant cost savings, for both payers and hospitals. The efforts necessary to create and maintain such improvements, as well as the source of data, should be considered when changes to reimbursement are being evaluated. The metrics studied in this paper should provide a comparison for further improvement with continued transition to bundle payments and transition to outpatient surgery with removal of TKA from the inpatient-only list.

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.

The Impact of Transitioning From International Classification of Diseases, Ninth Revision to International Classification of Diseases, Tenth Revision on Reported Complication Rates Following Primary Total Knee Arthroplasty.

BACKGROUND: In 2015, the healthcare system transitioned from International Classification of Diseases, Ninth Revision (ICD-9) coding to the Tenth Revision (ICD-10). We sought to determine the effect of this change on the reported incidence of complications following total knee arthroplasty (TKA). METHODS: The Humana administrative claims database was queried from 2 years prior to October 1, 2015 (ICD-9 cohort) and for 1 year after this date (ICD-10 cohort) to identify all TKA procedures. Complications occurring within 6 months of surgery were captured using the respective coding systems. Incidence of each complication was compared between cohorts using risk ratios (RR) and 95% confidence intervals. RESULTS: There were 19,009 TKAs in the ICD-10 cohort and 38,172 TKAs in the ICD-9 cohort. The incidence of each complication analyzed was significantly higher in the ICD-9 cohort relative to the ICD-10 cohort. Periprosthetic joint infection occurred in 1.9% vs 1.3% (RR 1.5, 1.3-1.9), loosening in 0.3% vs 0.1% (RR 2.7, 1.8-4.9), periprosthetic fracture in 0.3% vs 0.1% (RR 3.0, 1.6-4.5), and other mechanical complications in 0.7% vs 0.4% (RR 2.0, 1.5-2.5) (P < .05 for all). CONCLUSION: The transition from ICD-9 to ICD-10 coding has altered the reported incidence of complications following TKA. These results are likely due to the added complexity of ICD-10 which is joint and laterality specific. It is important to understand the differences between coding systems as this data is used for quality initiatives, risk adjustment models, and clinical research. Thoughtful methodology will be necessary when ICD-9 and ICD-10 data are being analyzed simultaneously.

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

BACKGROUND: On 1/1/2018, the Centers for Medicare and Medicaid Services removed total knee arthroplasty (TKA) from the Inpatient-Only (IPO) list. This change allowed expansion of outpatient TKA, potentially to include older, more frail patients at greater risk for perioperative complications. The purpose of this study was to evaluate the impact of removing TKA from the IPO list on early complications. METHODS: Patients undergoing TKA in the National Surgical Quality Improvement Program database were identified using CPT code 27447. Only cases with length of stay of zero days were included. Rates of 30-day complications, readmissions, and reoperation were compared before and after TKA was removed from the IPO list (2015-2017 vs 2018). The analysis was performed both with and without propensity score matching. RESULTS: 212,313 patients underwent TKA during the study period. 2466 (1.5%) were outpatient TKA in 2015-2017 and 3189 (5.6%) in 2018. After propensity matching, there were 2458 patients in each cohort. Rates of total 30-day complications were significantly lower in 2018 (3.7%) than the years TKA remained on the IPO (4.5%, P = .04). Similarly, rates of any reoperation decreased from 1.2% during 2015-2017 to 0.6% in 2018 (P = .03). There were no significant changes in rates of readmission (2.5% vs 2.2%, P = .5) or wound complications (0.8% vs 0.8%, P = 1.0). CONCLUSION: Removal of TKA from the IPO list did not result in an increase in complications or readmissions. These data suggest, despite the regulatory change, surgeons have continued to exercise sound judgment as to what patients can safely undergo outpatient TKA.

Opioid Use After Total Knee Arthroplasty: Does Tramadol Have Lower Risk Than Traditional Opioids?

BACKGROUND: Preoperative opioid use has been shown to increase postoperative opioid use following total knee arthroplasty (TKA). Tramadol is recommended for symptomatic treatment of osteoarthritis; however, it acts on opioid receptors and may confer similar adverse effects. The purpose of this study is to assess postoperative opioid use with preoperative opioid and tramadol use. METHODS: Patients undergoing primary TKA were identified in the Humana administrative claims database. Patients were stratified by whether they filled a prescription for an opioid, tramadol, either, or neither within 3 months of TKA. Prescription claims were tracked for 12 months postoperatively and relative risk for each group was calculated. RESULTS: In total, 107,973 patients undergoing TKA were identified. Preoperatively, 29,890 (27.7%) patients filled a prescription for opioids, 8049 (7.5%) for tramadol, 44,403 (41.1%) for tramadol or opioids, and 63,570 (58.9%) did not fill a prescription for either. At 12 months postoperatively, an opioid prescription was filled by 6.0% of preoperative narcotic-free patients, 35.2% opioid users (relative risk [RR] 5.83 [5.63-6.03]), 9.2% tramadol users (RR 1.52 [1.40-1.63]), and 29.5% opioid or tramadol users (RR 4.88 [4.72-5.05]). Opioid or tramadol prescriptions were filled by 7.7% of preoperative narcotic-free patients, 37.3% opioid users (RR 4.84 [4.70-4.99]), 26.2% tramadol users (RR 3.40 [3.26-3.57]), and 35.7% opioid or tramadol users (RR 4.64 [4.50-4.78]) at 12 months. CONCLUSION: Patients taking tramadol preoperatively were found to be at lower risk for prolonged postoperative opioid use following TKA. Patients taking either narcotics preoperatively continued use of these medications at a higher rate than those who were not.

Total Joint Arthroplasty in the Morbidly Obese: How Body Mass Index ≥40 Influences Patient Retention, Treatment Decisions, and Treatment Outcomes.

BACKGROUND: The United States is in an obesity epidemic. Obesity has multiple common comorbid conditions, including lower extremity arthritis. We sought to examine the course of treatment for a population with body mass index (BMI) ≥40 kg/m2 and osteoarthritis (OA) of the hip or knee. We investigated decision criteria that influenced arthroplasty surgeons to recommend nonoperative management vs total joint arthroplasty (TJA). For those patients who ultimately received TJA, we compared outcomes in this population to those with BMI <40 kg/m2. METHODS: This study retrospectively reviewed 158 new patients with BMI ≥40 kg/m2 and moderate/severe OA of the hip or knee. Demographics, comorbidity profiles, and weight loss were compared between groups that underwent TJA and those that did not. The arthroplasty database was used to identify patients who underwent TJA during 2016-2018 (N = 1473). Comorbidities, readmissions, surgical site infections, and overall complications were compared between those with BMI ≥40 kg/m2 and BMI <40 kg/m2. RESULTS: About 51.3% of new patients with BMI ≥40 kg/m2 and moderate/severe OA did not return for a second clinic visit. Of those who did return, 42.9% eventually underwent surgery. BMI was higher in single visit patients vs those with multiple visits (49.5 vs 46.3 kg/m2, P < .001), no difference in those scheduled on an "as-needed" basis vs a specific return date (P = .18), and did not change significantly during the 2-year follow-up (P = .41). Patients who underwent TJA had a lower mean BMI at presentation than their nonoperative counterparts (44.5 vs 47.6 kg/m2, P < .01) and demonstrated significant weight loss prior to surgery (44.5 vs 42.6 kg/m2, P < .05). When comparing patients with BMI ≥40 kg/m2 vs BMI <40 kg/m2, overall complications were not higher in the BMI ≥40 kg/m2 group, although surgical site infections were higher in those undergoing total hip arthroplasty with BMI ≥40 kg/m2 (0.3% vs 3.1%, P < .05). CONCLUSION: A majority of patients with BMI ≥40 kg/m2 and moderate/advanced OA will be lost to orthopedic follow-up. A relatively lower BMI indicates a greater chance of retention in care, and ultimately surgery, but does not influence surgeons' recommendations to continue orthopedic management. Patients who persist in seeking treatment, lose significant weight, and exhaust nonoperative alternatives may be suitable for TJA despite a BMI ≥40 kg/m2, with an overall complication rate of 4.3%. However, only 9% of patients at 2-year follow-up achieved BMI <40 kg/m2 and only 20% of surgeries were performed on patients who had achieved this proposed cutoff.

The Inaccuracy of ICD-10 Coding in Revision Total Hip Arthroplasty and Its Implication on Revision Data.

BACKGROUND: The International Statistical Classification of Diseases, 10th Revision (ICD-10), was adopted by the United States on October 1, 2015 and expanded coding from 3800 codes with the International Statistical Classification of Diseases, Ninth Revision, procedure code system (ICD-9-PCS) to 73,000. The increase in number of codes was designed to create more accurate representations of procedures like revision total hip arthroplasties (rTHAs). However, many worry that the increased complexity leads to more inaccurate coding. The purpose of this study is to determine the accuracy of ICD-10-PCS coding for rTHA and discuss the implications on registry data. METHODS: The rTHA databases at 2 large, academic medical centers were retrospectively reviewed for all rTHAs between October 1, 2015 and July 3, 2019. The laterality and specific revised components were recorded and compared with the ICD-10-PCS codes used for each procedure. The accuracy of ICD-10-PCS codes relative to the surgical record was determined using coding guidelines published by the American Joint Replacement Registry (AJRR). RESULTS: Overall, 895 cases were reviewed. Replacement coding was 22% accurate (195 of 895). For removal and replacement coding, accuracy dropped to 17% (152 of 895). All procedures had at least 1 rTHA trigger code that would signify correctly to AJRR that an rTHA occurred. CONCLUSION: In this study, the percent of correctly coded rTHA was low. All rTHA procedures had at least 1 AJRR trigger code; therefore, an rTHA would have been appropriately captured by AJRR. But these inaccuracies should make one pause when using ICD-10-PCS procedural data to try to evaluate specific rTHA details from administrative claims databases and ward against expanding ICD-10-PCS as a means to collect implant survival and registry data.

Two-Stage Exchange Arthroplasty for Periprosthetic Joint Infection Following Total Hip or Knee Arthroplasty Is Associated With High Attrition Rate and Mortality.

BACKGROUND: We sought to determine the ultimate fate of patients undergoing resection arthroplasty as a first stage in the process of 2-stage exchange and evaluate risk factors for modes of failure. METHODS: A retrospective case study was performed including all patients with minimum 2-year follow-up who underwent first-stage resection of a hip or knee periprosthetic joint infection from 2008 to 2015. Patient demographics, laboratory, and health status variables were collected. The primary outcome analyzed was defined as failure to achieve an infection-free 2-stage revision. Univariate pairwise comparison followed by multivariate regression analysis was used to determine risk factors for failure outcomes. RESULTS: Eighty-nine patients underwent resection arthroplasty in a planned 2-stage exchange protocol (27 hips, 62 knees). Mean age was 64 years (range, 43-84), 56.2% were males, and mean follow-up was 56.3 months. Also, 68.5% (61/89) of patients underwent second-stage revision. Of the 61 patients who complete a 2-stage protocol, 14.8% (9/61) of patients failed with diagnosis of repeat or recurrent infection. Mortality rate was 23.6%. Multivariate analysis identified risk factors for failure to achieve an infection-free 2-stage revision as polymicrobial infection (P < .004; adjusted odds ratio [AOR], 7.8; 95% confidence interval [CI], 2.1-29.0), McPherson extremity grade 3 (P < .024; AOR, 4.1; 95% CI, 1.2-14.3), and history of prior resection (P < .013; AOR, 4.7; 95% CI, 1.4-16.4). CONCLUSION: Patients undergoing resection arthroplasty for periprosthetic joint infection are at high risk of death (24%) and failure to complete the 2-stage protocol (32%). Those who complete the 2-stage protocol have a 15% rate of reinfection at 4.5-year follow-up.

Choices, Compromises, and Controversies in Total Knee Arthroplasty.

Although condylar total knee arthroplasty (TKA) has been performed for almost 40 years, many choices, compromises, and controversies remain. In the effort to provide optimal care and beneficial, enduring treatment for an expanding population of patients with debilitating arthritis of the knee and who are using ever-diminishing provider and financial resources, orthopaedic surgeons must carefully examine the available evidence to determine best practices. First, there is debate as to who should be a candidate for TKA. Beyond the established criteria of disease severity, should all patients who can benefit from TKA undergo the procedure, or should surgeons develop exclusion criteria based on complication risk? Current concepts for identifying and managing modifiable risk factors should be considered. Second, there is debate regarding the choice of TKA versus partial knee arthroplasty to manage unicompartmental arthritis. Third, surgeons continue to debate the ideal implant design for primary condylar TKA, whether to proceed with an anatomic approach of preserving one or both cruciate ligaments or a functional approach of resecting and substituting for the cruciate ligaments in various ways.

Tobacco Use and Risk of Wound Complications and Periprosthetic Joint Infection: A Systematic Review and Meta-Analysis of Primary Total Joint Arthroplasty Procedures.

BACKGROUND: The purpose of this study was to perform a systematic review and meta-analysis to quantitatively assess the association between tobacco use and the risk of any wound complication and periprosthetic joint infection (PJI) after primary total hip and total knee arthroplasty procedures. METHODS: Relevant articles published before January 2018 were identified by systematically searching PubMed, EMBASE, and Cochrane library databases. Pooled odds ratios (OR) and 95% confidence intervals were calculated for end points of any wound complication and PJI. Additional analyses were performed to evaluate risks between current, former, and non-tobacco users. RESULTS: Fourteen studies were included in the meta-analysis. Tobacco users had a significantly higher risk of wound complications (OR, 1.78 [1.32-2.39]) and PJI (OR, 2.02 [1.47-2.77]) compared to non-tobacco users. Compared to non-tobacco users, there was an increased risk of PJI among current (OR, 2.16 [1.57-2.97] and former (OR, 1.52 [1.16-1.99]) tobacco users. Current tobacco users also had a significantly increased risk of PJI compared to former tobacco users (OR, 1.52 [1.07-2.14]). CONCLUSION: Tobacco use before total hip and total knee arthroplasty significantly increases the risk of wound complications and PJI. This increased risk is present for both current and former tobacco users. However, former tobacco users had a significantly lower risk of wound complications and PJI compared to current tobacco users, suggesting that cessation of tobacco use before TJA can help to mitigate these observed risks.

Artificial Intelligence and Machine Learning in Lower Extremity Arthroplasty: A Review.

BACKGROUND: Driven by the rapid development of big data and processing power, artificial intelligence and machine learning (ML) applications are poised to expand orthopedic surgery frontiers. Lower extremity arthroplasty is uniquely positioned to most dramatically benefit from ML applications given its central role in alternative payment models and the value equation. METHODS: In this report, we discuss the origins and model specifics behind machine learning, consider its progression into healthcare, and present some of its most recent advances and applications in arthroplasty. RESULTS: A narrative review of artificial intelligence and ML developments is summarized with specific applications to lower extremity arthroplasty, with specific lessons learned from osteoarthritis gait models, joint-specific imaging analysis, and value-based payment models. CONCLUSION: The advancement and employment of ML provides an opportunity to provide data-driven, high performance medicine that can rapidly improve the science, economics, and delivery of lower extremity arthroplasty.

Analysis of Outcomes After TKA: Do All Databases Produce Similar Findings?

BACKGROUND: Use of large clinical and administrative databases for orthopaedic research has increased exponentially. Each database represents unique patient populations and varies in their methodology of data acquisition, which makes it possible that similar research questions posed to different databases might result in answers that differ in important ways. QUESTIONS/PURPOSES: (1) What are the differences in reported demographics, comorbidities, and complications for patients undergoing primary TKA among four databases commonly used in orthopaedic research? (2) How does the difference in reported complication rates vary depending on whether only inpatient data or 30-day postoperative data are analyzed? METHODS: Patients who underwent primary TKA during 2010 to 2012 were identified within the National Surgical Quality Improvement Programs (NSQIP), the Nationwide Inpatient Sample (NIS), the Medicare Standard Analytic Files (MED), and the Humana Administrative Claims database (HAC). NSQIP is a clinical registry that captures both inpatient and outpatient events up to 30 days after surgery using clinical reviewers and strict definitions for each variable. The other databases are administrative claims databases with their comorbidity and adverse event data defined by diagnosis and procedure codes used for reimbursement. NIS is limited to inpatient data only, whereas HAC and MED also have outpatient data. The number of patients undergoing primary TKA from each database was 48,248 in HAC, 783,546 in MED, 393,050 in NIS, and 43,220 in NSQIP. NSQIP definitions for comorbidities and surgical complications were matched to corresponding International Classification of Diseases, 9 Revision/Current Procedural Terminology codes and these coding algorithms were used to query NIS, MED, and HAC. Age, sex, comorbidities, and inpatient versus 30-day postoperative complications were compared across the four databases. Given the large sample sizes, statistical significance was often detected for small, clinically unimportant differences; thus, the focus of comparisons was whether the difference reached an absolute difference of twofold to signify an important clinical difference. RESULTS: Although there was a higher proportion of males in NIS and NSQIP and patients in NIS were younger, the difference was slight and well below our predefined threshold for a clinically important difference. There was variation in the prevalence of comorbidities and rates of postoperative complications among databases. The prevalence of chronic obstructive pulmonary disease (COPD) and coagulopathy in HAC and MED was more than twice that in NIS and NSQIP (relative risk [RR] for COPD: MED versus NIS 3.1, MED versus NSQIP 4.5, HAC versus NIS 3.6, HAC versus NSQIP 5.3; RR for coagulopathy: MED versus NIS 3.9, MED versus NSQIP 3.1, HAC versus NIS 3.3, HAC versus NSQIP 2.7; p < 0.001 for all comparisons). NSQIP had more than twice the obesity as NIS (RR 0.35). Rates of stroke within 30 days of TKA had more than a twofold difference among all databases (p < 0.001). HAC had more than twice the rates of 30-day complications at all endpoints compared with NSQIP and more than twice the 30-day infections as MED. A comparison of inpatient and 30-day complications rates demonstrated more than twice the amount of wound infections and deep vein thromboses is captured when data are analyzed out to 30 days after TKA (p < 0.001 for all comparisons). CONCLUSIONS: When evaluating research utilizing large databases, one must pay particular attention to the type of database used (administrative claims, clinical registry, or other kinds of databases), time period included, definitions utilized for specific variables, and the population captured to ensure it is best suited for the specific research question. Furthermore, with the advent of bundled payments, policymakers must meticulously consider the data sources used to ensure the data analytics match historical sources. LEVEL OF EVIDENCE: Level III, therapeutic study.

Lower Extremity Geometry in Morbid Obesity-Considerations for Total Knee Arthroplasty.

BACKGROUND: Obesity has been associated with varying adverse outcomes related to total knee arthroplasty (TKA) and has long been associated with various mechanical complications. Computational modeling holds promise for investigating biomechanical aberrations related to TKA in obese patients. However, basic anthropometric information regarding the shape of the lower extremity in obese patients is lacking. We, therefore, developed a method to determine lower extremity shape both generally and subject specific as a function of body mass index (BMI) and sex. METHODS: A unique set of 4 radiographs (knee anteroposterior/lateral; EOS long-leg alignment anteroposterior/lateral) were reviewed for patients with BMI exceeding 30 kg/m2 before undergoing TKA. Soft tissue thickness in both the coronal and sagittal planes, including anterior adipose tissue thickness overlying the tibial tubercle and patella, was measured. Elliptical parameters were then determined for any distance along the lower extremity. Additional measurements were obtained, including prepatellar thickness and pretubercular thickness and anteroposterior and mediolateral dimensions of the proximal tibia. A total of 232 obese subjects were analyzed. RESULTS: Girth increased as a function of BMI. Anterior prepatellar and pretubercular subcutaneous fat thickness in females exceeded that in males for all values of BMI. Wide variation was seen with regard to overall patterns of adiposity among same-sex subjects with similar BMI. Proximal tibial osseous dimensions did not demonstrate an association with BMI; however, males were found to have deeper and wider tibias compared with females. CONCLUSIONS: BMI and sex influence lower extremity shape. The prediction algorithms developed here holds implications for future biomechanical studies of TKA in obese patients.

Venous Thromboembolism Following Total Knee Arthroplasty: Does Race Matter?

BACKGROUND: Venous thromboembolism (VTE) (deep venous thrombosis and pulmonary embolism) is a known complication following total knee arthroplasty (TKA). Recent literature has identified differences in VTE risk based on race with African Americans having higher risk of VTE. This study evaluated the impact of race on VTE following TKA using a large multicenter database. METHODS: We queried the American College of Surgeons National Surgical Quality Improvement Program to identify patients who underwent primary TKA in 2010-2014. Patients were stratified based on race: Asian, Black/African American, White, and Other. Demographics were compared to determine the impact on 30-day postoperative complications. Multivariate logistic regression analysis was performed to control for confounding demographics and comorbidities between races. Primary outcomes included overall complications and VTE. RESULTS: In total, 96,230 patients were included. Univariate analysis demonstrated that Blacks had a significantly higher rate of any complication (5.5%), deep venous thrombosis (1.3%), and pulmonary embolism (1.1%) than other races (P = .007, P < .001, and P < .001, respectively). Overall mortality rate did not differ between races (P = .26). Multivariate regression analysis identified that Blacks were significantly more likely to have a VTE than Whites (odds ratio 1.7, 95% confidence interval 1.4-2.0). Overall complications were significantly higher for Blacks than Whites (odds ratio 1.1, 95% confidence interval 1.02-1.3). There were no differences in the rates of VTE or overall complications between Asians/Other races and Whites. CONCLUSION: Blacks have a significantly higher risk of VTE following primary TKA than other races. Future studies should investigate causes for this disparity.

Identifying Risk Factors for the Development of Stiffness After Revision Total Knee Arthroplasty.

BACKGROUND: Although there are several studies concerning manipulation under anesthesia (MUA) after primary total knee arthroplasty, there is a paucity of literature evaluating MUA after revision total knee arthroplasty (rTKA). The purpose of this study was to determine the incidence, timing, and risk factors associated with MUA after rTKA. METHODS: The Humana database was reviewed from 2007 to 2015 for all patients who underwent rTKA. Patients who underwent rTKA followed by ipsilateral MUA were identified. Time to MUA was calculated monthly. Possible risk factors analyzed included preoperative narcotic use, smoking, anxiety and/or depression, diabetes, obesity, age, and sex. Multivariate logistic regression was used to determine odds ratio. RESULTS: In total, 5414 rTKAs were included in the study and 1.7% (n = 96) underwent MUA after surgery. Sixty-nine percent of MUAs occurred within the first 3 months after rTKA. Young patients (<50 years) had significantly higher odds of MUA after rTKA (6.5, P < .0001). No difference in odds of MUA (1.0, P = .85) occurred between males and females. A diagnosis of obesity, diabetes, anxiety and/or depression, previous history of narcotic use, or a history of smoking demonstrated no increased risk of MUA after rTKA. Multivariate logistic regression analysis demonstrated that younger age remained predictive of higher odds of MUA after rTKA. CONCLUSION: In this large multicenter cohort study, 1.7% of patients underwent MUA after rTKA and younger patients were 6 times more likely to have a MUA than patients over 50 years old. These data should serve to help counsel patients regarding their risk of MUA after rTKA.