Can extant comorbidity indices identify patients who experience poor outcomes following total joint arthroplasty?

INTRODUCTION: It is uncertain if generic comorbidity indices commonly used in orthopedics accurately predict outcomes after total hip (THA) or knee arthroplasty (TKA). The purpose of this study was to determine the predictive ability of such comorbidity indices for: (1) 30-day mortality; (2) 30-day rate of major and minor complications; (3) discharge disposition; and (4) extended length of stay (LOS). METHODS: The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was retrospectively reviewed for all patients who underwent elective THA (n = 202,488) or TKA (n = 230,823) from 2011 to 2019. The American Society of Anesthesiologists (ASA) physical status classification system score, modified Charlson Comorbidity Index (mCCI), Elixhauser Comorbidity Measure (ECM), and 5-Factor Modified Frailty Index (mFI-5) were calculated for each patient. Logistic regression models predicting 30-day mortality, discharge disposition, LOS greater than 1 day, and 30-day major and minor complications were fit for each index. RESULTS: The ASA classification (C-statistic = 0.773 for THA and TKA) and mCCI (THA: c-statistic = 0.781; TKA: C-statistic = 0.771) were good models for predicting 30-day mortality. However, ASA and mCCI were not predictive of major and minor complications, discharge disposition, or LOS. The ECM and mFI-5 did not reliably predict any outcomes of interest. CONCLUSION: ASA and mCCI are good models for predicting 30-day mortality after THA and TKA. However, similar to ECM and mFI-5, these generic comorbidity risk-assessment tools do not adequately predict 30-day postoperative outcomes or in-hospital metrics. This highlights the need for an updated, data-driven approach for standardized comorbidity reporting and risk assessment in arthroplasty.

Blood management in total hip arthroplasty: a nationwide trend analysis from 2011 to 2018.

PURPOSE: With the advent of practice changes surrounding preoperative patient optimization and postoperative protocols, a marked reduction has been reported in blood transfusion rates following total hip arthroplasty (THA). Thus, the purpose of this study was to examine differences in the prevalence of preoperative anemia, thrombocytopenia, elevated international normalized ratio (INR), bleeding disorders, and pre- and postoperative blood transfusions over the last decade. METHODS: From 2011 to 2018, the American College of Surgeons National Quality Improvement Program database was queried for all primary THA procedures (n = 208,796). The following continuous variables were examined using analysis of variance: preoperative hematocrit (HCT), platelet count, and INR. The following categorical variables were analyzed by chi-squared tests: anemia (HCT < 35.5% for females and < 38.5% for males), thrombocytopenia (platelet count < 150,000/µL), INR > 2.0, bleeding disorders, preoperative transfusions, and postoperative transfusions. RESULTS: There were decreases in preoperative anemia (2011: 16.2%; 2018: 11.4%, p < 0.001) and postoperative transfusions (2011: high = 22.2%; 2018: low = 1.3%, p < 0.001). Statistically significant but clinically irrelevant changes were observed in preoperative HCT (2011: low = 40.3, 2018: high = 41.1, p < 0.001), platelet count (2011: low = 248,700; 2018: high = 250,100, p < 0.001), thrombocytopenia (2011: high = 4.9%; 2018: low = 4.3%, p = 0.036), INR > 2.0 (2011: high = 1.1%; 2018: low = 0.7%, p = 0.001), bleeding disorders (2011: high = 2.9%; 2018: low = 2.0%, p < 0.001), and preoperative transfusions (2011: high = 0.2%; 2018: low = 0.1%, p = 0.007). CONCLUSION: Large decreases in the number of patients with preoperative anemia and those receiving postoperative blood transfusion were observed during the study period. Future investigation is needed to ascertain whether this is due to patient optimization, practice changes, "cherry-picking" of healthy patients, or a combination of these factors. LEVEL OF EVIDENCE: III.

The Impact of Surgeon Variability on Patient-Reported Outcomes in Total Hip Arthroplasty.

BACKGROUND: Patient-related and surgery-related factors have been shown to be drivers of outcomes after total hip arthroplasty (THA); however, the impact of intersurgeon variability is poorly understood. The purpose of this study is to assess the following: (1) overall effect of surgeon on 1-year patient-reported outcome measures (PROMs), length of stay (LOS), discharge disposition, and 90-day readmission following THA; and (2) variability in 1-year PROMs among surgeons. METHODS: A prospective cohort of 3,695 patients who underwent THA between 2016 and 2018 was included. Seventy-eight percent of patients completed 1-year follow-up. Thirty-one surgeons from a large healthcare system were included. Likelihood ratio tests analyzed the relationship among surgeon and 1-year Hip Disability and Osteoarthritis Outcome Score (HOOS)-Pain, HOOS-Physical Function Short-Form, HOOS-Joint Replacement, University of California, Los Angeles activity score, Patient Acceptable Symptom State, LOS, discharge disposition, and 90-day readmission. Mixed-effect proportional odds and logistic regression models were used to determine variable importance for each outcome. RESULTS: In total, 90.5% of patients responded positively to 1-year Patient Acceptable Symptom State. There was a significant association among surgeon and 1-year PROMs, LOS, discharge disposition (P < .001), and readmission (P = .002). For HOOS-Pain, Physical Function Short-Form, and Joint Replacement, surgeon (Akaike information criterion increase: 34.6, 18.7, 17.1, respectively) was a greater contributor to outcome than patient-level factors, including age, gender, and comorbidity. Differences in the highest and lowest median probability of achieving any given score on 1-year PROMs ranged from 11% to 18.5%. Variability was not explained by approach (P = .431) or case volume (correlation coefficient, ρ = 0.19). CONCLUSION: Surgeon-level variability appears to be a greater driver of 1-year PROMs than some patient-level characteristics. Incorporating surgeon as a variable is beneficial for model-fitting and important for increasing value in THA.

The Impact of Surgeon Variability on Patient-Reported Outcome Measures, Length of Stay, Discharge Disposition, and 90-Day Readmission in TKA.

BACKGROUND: Studies involving total knee arthroplasty (TKA) have focused on patient-related factors as drivers of outcomes. Although some studies have investigated surgeon and/or surgery-level factors (i.e., approach, volume), the measure of variance in postoperative outcomes across surgeons following TKA has not been determined. The aim of the current study was to evaluate the relationship between the surgeon and 1-year patient-reported outcome measures, the length of stay, the discharge disposition, and 90-day readmission after TKA, as well as the differences in these variables among surgeons. METHODS: Data were prospectively collected for 5,429 patients who underwent TKA at a large health-care system with 36 surgeons between 2016 and 2018. Likelihood ratio tests were performed to investigate the relationship between surgeon and the 1-year Knee injury and Osteoarthritis Outcome Score (KOOS)-Pain subscale, KOOS-Physical Function Shortform (KOOS-PS), KOOS for Joint Replacement (KOOS-JR), patient acceptable symptom state (PASS), length of stay, discharge disposition, and 90-day readmission. The minimal clinically important difference (MCID) was used to assess meaningful outcomes. Variable importance was determined by the Akaike information criterion (AIC) increase, using ordinal and binary-response mixed-effect models. RESULTS: There was a significant association between surgeon and KOOS-Pain (p < 0.001), KOOS-PS (p = 0.001), KOOS-JR (p < 0.001), PASS (p = 0.024), length of stay (p < 0.001), discharge disposition (p < 0.001), and 90-day readmission (p < 0.001). When modeling 1-year KOOS-Pain (AIC increase, 15.6), KOOS-PS (AIC increase, 6.8), KOOS-JR (AIC increase, 13.5), PASS (AIC increase, 1.9), length of stay, and discharge disposition, the surgeon variable contributed more to the 1-year outcome than some patient-level factors (e.g., body mass index, Charlson Comorbidity Index). The difference between the highest and lowest median probabilities of attaining the same value for the KOOS-Pain (11.2%), KOOS-PS (9.4%), KOOS-JR (11.8%), PASS (5.9%), length of stay (46.6%), discharge disposition (22.8%), and readmission (13.1%) indicated surgeon-level variability. CONCLUSIONS: Surgeon-related factors may be stronger contributors to the 1-year patient-reported outcome measures and length of stay than patient characteristics emphasized in the literature. Current findings have suggested variability in patient-reported outcome measures, length of stay, discharge location, and 90-day readmission among surgeons. Surgeon variability should be considered when model-fitting in the setting of TKA. LEVEL OF EVIDENCE: Prognostic Level II . See Instructions for Authors for a complete description of levels of evidence.

Reporting of Comorbidities in Total Hip and Knee Arthroplasty Clinical Literature: A Systematic Review.

BACKGROUND: The effects of comorbid disease remain an area of interest. Concurrent diagnoses not only affect clinical outcomes but also affect health-care reimbursement. As the rate of arthroplasty increases, consistent risk stratification is imperative. Therefore, our aim was to ascertain how comorbidities have been reported in the recent total hip arthroplasty (THA) and total knee arthroplasty (TKA)-related literature; we also wanted to quantify the use of comorbidity scores for the assessment of comorbid disease in arthroplasty research. METHODS: A systematic review of the recent THA and TKA literature that was published between January 1, 2019, and September 21, 2020, was performed using the PubMed and MEDLINE databases. Clinical studies that provided data on comorbidities were evaluated for method of comorbidity reporting. The prevalence of comorbidity reporting was assessed, and the manner of reporting was analyzed. RESULTS: Among 659 articles, a total of 207 studies (31.4%) reported comorbidities and met our inclusion criteria. Of the 207 studies that reported comorbidities, only 57% used a comorbidity index to report comorbid disease. Of all of the indices, the American Society of Anesthesiologists (ASA) Physical Status Classification System was the score that was most commonly used (TKA, 86.2%; THA, 83.3%). Additional scores were used at varying frequencies. For TKA, the scores included the Charlson Comorbidity Index (CCI) (15.5%); the New York Heart Association (NYHA) Functional Classification (3.4%); and the CCI-Deyo (adapted by Deyo et al.), the age-adjusted CCI, the Cumulative Illness Rating Scale (CIRS), and the Readmission Risk Assessment Tool (RRAT) (1.7% each). For THA, the scores included the CCI (16.7%), the Elixhauser Comorbidity Measure (ECM) (6.7%), and the CCI-Deyo (1.7%). CONCLUSIONS: Considering the impact of comorbid disease on outcomes, complications, and, ultimately, reimbursement, standardized risk stratification in arthroplasty is necessary. Current studies demonstrate inconsistent comorbidity reporting, making it challenging to further characterize the impact of comorbidities on outcomes. Future research should target the development of a standardized data-driven model for comorbidity assessment in the orthopaedic patient population.

The Influence of Geographic Region on Hip and Knee Arthroplasty Literature From 1988 to 2018.

INTRODUCTION: Total joint arthroplasty constitutes a major focus of publications within orthopaedics. Because research expands and investigators from around the world contribute, it is important to understand the dynamics of publication. METHODS: PubMed was queried for hip and knee arthroplasty-related articles published between 1988 and 2018 within seven orthopaedic journals. A bibliometric analysis was done. The manuscript region of origin was determined by the affiliated country of the last author and used to examine trends in publication. RESULTS: A total of 6,160 publications were included. Forty-eight countries from six continents were identified. The quantity of arthroplasty-related publications increased over the study period (n = 246 in 1988 and n = 1,247 in 2018, P < 0.01). Articles were primarily published by North America (51.9%), Europe (32.5%), and Asia (12.4%). Clinical trials accounted for 45.6% of all publications. Articles from Asia received fewer citations than those from North America, Europe, and Oceania (P < 0.001). DISCUSSION: The volume of publications was five times greater in 2018 than in 1988, yet international articles constitute a marginal proportion of annual publications. Most of the literature (84.4%) originated from North America and Europe. Balanced publication of international research may favor global communication of findings, increasing the spectrum of available evidence applicable worldwide.

Comorbidity indices in orthopaedic surgery: a narrative review focused on hip and knee arthroplasty.

Comorbidity indices currently used to estimate negative postoperative outcomes in orthopaedic surgery were originally developed among non-orthopaedic patient populations.While current indices were initially intended to predict short-term mortality, they have since been used for other purposes as well.As the rate of hip and knee arthroplasty steadily rises, understanding the magnitude of the effect of comorbid disease on postoperative outcomes has become increasingly more important.Currently, the ASA classification is the most commonly used comorbidity measure and is systematically recorded by the majority of national arthroplasty registries.Consideration should be given to developing an updated, standardized approach for comorbidity assessment and reporting in orthopaedic surgery, especially within the setting of elective hip and knee arthroplasty. Cite this article: EFORT Open Rev 2021;6:629-640. DOI: 10.1302/2058-5241.6.200124.

Understanding the 30-day mortality burden after revision total knee arthroplasty.

BACKGROUND: In revision total knee arthroplasty (TKA), information regarding perioperative mortality risk is essential for careful decision-making. This study aimed to elucidate the (1) overall 30-day mortality rate and (2) 30-day mortality rate stratified by age, comorbidity, and septic vs aseptic failure after revision TKA. METHODS: The American College of Surgeons National Surgical Quality Improvement Program was reviewed for all patients undergoing revision TKA from 2011 to 2019. A total of 32,354 patients who underwent TKA were identified and categorized as mortality (n = 115) or mortality-free (n = 32,239). Patient characteristics were compared between cohorts and further stratified by septic and aseptic failure. RESULTS: The overall 30-day mortality rate was 0.36%. The percentage of deaths per age group (normalized per 1000) was 0% (18-29 years), 0% (30-39 years), 0.18% (40-49 years), 0.13% (50-59 years), 0.14% (60-69 years), 0.40% (70-79 years), 1.25% (80-89 years), and 6.93% (90+ years). The percentage of deaths per American Society of Anesthesiologists (ASA) class was 0.30% (ASA 1), 0.06% (ASA 2), 0.39% (ASA 3), 2.41% (ASA 4), and 14.29% (ASA 5). Septic revision (P < .001), general anesthesia (P < .001), body mass index ≤ 24.9 (P < .001), and insulin-dependent diabetes (P = .039) were associated with an increased risk of mortality. CONCLUSIONS: Increasing age, greater comorbidity burden, underweight or normal body mass index, insulin-dependent diabetes, septic revision, and general anesthesia were all associated with an increased risk of mortality after revision TKA. Notably, 1 in 80 patients aged 80-89 years died after revision TKA compared to 1 in 720 patients aged 60-69 years. Patients who underwent septic revision had a 4-fold increase in mortality compared to aseptic revision. Our stratified assessment of mortality provides a more individualized estimation of risk that can be used for patient counseling in revision TKA.