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Early Postoperative Complications in Total Hip and Knee Arthroplasty Before and During the COVID-19 Pandemic: A Retrospective Analysis of 38,234 Patients

Open AccessPublished:September 04, 2022DOI:https://doi.org/10.1016/j.artd.2022.08.018

      Abstract

      Background

      The outcomes of total joint arthroplasty (TJA) during the COVID-19 pandemic are unknown. We sought to compare early postoperative complications in total hip arthroplasty (THA) and total knee arthroplasty (TKA) prior to and during the COVID-19 pandemic.

      Methods

      Patients in the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database who had THA or TKA in the latter halves (July to December) of 2019 and 2020 were identified. Patients were divided into pre-COVID-19 (2019) and during-COVID-19 (2020) cohorts. Propensity score matching and logistic regression were used to detect correlations between operative period and outcomes. Statistical significance was set at α=0.05.

      Results

      38,234 THA and 61,956 TKA patients were included. There was a significantly higher rate of outpatient procedures in 2020 compared to 2019 for both THA (41.68% vs 6.59%, P<0.001) and TKA (41.68% vs 7.56%, P<0.001). On matched analysis, surgery in 2020 had lower odds of hospital stay > 1 day (THA: OR 0.889; P<0.001) (TKA: OR 0.644; P<0.001) and non-home discharge (THA: 0.655; P<0.001) (TKA: 0.497; P<0.001). There was also increased odds of superficial surgical site infection (SSI) in THA (OR 1.272; P=0.040) and myocardial infarction (MI) in TKA patients (OR 1.488; P=0.042) in 2020 compared to 2019. There was no difference in the 15 other outcomes assessed.

      Conclusions

      TJA surgery remains safe despite the COVID-19 pandemic. A statistically significant increase was detected in superficial SSI and MI risk during 2020 compared to 2019; however, the clinical significance of this is questionable. A shift away from inpatient stay was also present, possibly reflecting efforts to minimize nosocomial exposure to COVID-19.

      Keywords

      Abbreviations:

      TJA (Total Joint Arthroplasty), TKA (Total Knee Arthroplasty), THA (Total Hip Arthroplasty), ACS-NSQIP (American College of Surgeons National Surgical Quality Improvement Program), SSI (Surgical Site Infection), MI (Myocardial Infarction)

      Introduction

      The first case of coronavirus disease 2019 (COVID-19) in the United States (US) was reported in January 2020 [
      • Holshue M.L.
      • DeBolt C.
      • Lindquist S.
      • et al.
      First Case of 2019 Novel Coronavirus in the United States.
      ]. During this first wave, entities such as the American College of Surgeons (ACS) and American Academy of Orthopaedic Surgeons (AAOS) published guidelines recommending that non-emergent surgeries be deferred, and resources be redirected to critical care efforts and personnel to accommodate incoming COVID-19 patients [
      American College of Surgeons
      COVID-19: Guidance for Triage of Non-Emergent Surgical Procedures.
      ,

      Guy D, Brosco JS. AAOS Guidelines for Elective Surgery - American Academy of Orthopaedic Surgeons. Published 2020. Accessed January 23, 2022. https://www.aaos.org/about/covid-19-information-for-our-members/aaos-guidelines-for-elective-surgery/

      ,

      Centers for Medicare & Medicaid Services. CMS Releases Recommendations on Adult Elective Surgeries, Non-Essential Medical, Surgical, and Dental Procedures During COVID-19 Response | CMS. Published online 2020:1-4. Accessed January 23, 2022. https://www.cms.gov/newsroom/press-releases/cms-releases-recommendations-adult-elective-surgeries-non-essential-medical-surgical-and-dental

      ]. Fields with predominantly elective procedures, such as orthopaedic surgery, were most significantly affected [
      • Meredith J.W.
      • High K.P.
      • Freischlag J.A.
      Preserving Elective Surgeries in the COVID-19 Pandemic and the Future.
      ], with a recent study by Mattingly et al. reporting a 64% decrease in musculoskeletal procedures during the initial 2020 shutdown [
      • Mattingly A.S.
      • Rose L.
      • Eddington H.S.
      • et al.
      Trends in US Surgical Procedures and Health Care System Response to Policies Curtailing Elective Surgical Operations During the COVID-19 Pandemic.
      ]. Of these, joint arthroplasty procedures were the most impacted with an alarming surgical volume decrease of 89.5% [
      • Mattingly A.S.
      • Rose L.
      • Eddington H.S.
      • et al.
      Trends in US Surgical Procedures and Health Care System Response to Policies Curtailing Elective Surgical Operations During the COVID-19 Pandemic.
      ].
      With such significant decreases in joint arthroplasty procedures during the initial 2020 shutdown [
      • Mattingly A.S.
      • Rose L.
      • Eddington H.S.
      • et al.
      Trends in US Surgical Procedures and Health Care System Response to Policies Curtailing Elective Surgical Operations During the COVID-19 Pandemic.
      ], patients requiring joint replacement surgeries were left with disabling pain and limited mobility [
      • Pietrzak J.R.T.
      • Maharaj Z.
      • Erasmus M.
      • Sikhauli N.
      • Cakic J.N.
      • Mokete L.
      Pain and function deteriorate in patients awaiting total joint arthroplasty that has been postponed due to the COVID-19 pandemic.
      ,
      • Morris J.A.
      • Super J.
      • Huntley D.
      • Ashdown T.
      • Harland W.
      • Anakwe R.
      Waiting lists for symptomatic joint arthritis are not benign.
      ,
      • Scott C.E.H.
      • MacDonald D.J.
      • Howie C.R.
      ‘Worse than death’ and waiting for a joint arthroplasty.
      ,
      • Kapstad H.
      • Rustøen T.
      • Hanestad B.R.
      • Moum T.
      • Langeland N.
      • Stavem K.
      Changes in pain, stiffness and physical function in patients with osteoarthritis waiting for hip or knee joint replacement surgery.
      ]. Although there was clearly a necessity to resume elective orthopaedic procedures such as total joint replacements, there was also unease about the repercussions of performing surgery during the initial phase of the COVID-19 pandemic [
      • Besnier E.
      • Tuech J.J.
      • Schwarz L.
      We Asked the Experts: Covid-19 Outbreak: Is There Still a Place for Scheduled Surgery? “Reflection from Pathophysiological Data.”.
      ,
      • Bhangu A.
      • Nepogodiev D.
      • Glasbey J.C.
      • et al.
      Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study.
      ]. During the peak of the pandemic in 2020, some authors reported increased morbidity and mortality in COVID-19 patients with acute respiratory distress syndrome (ARDS) being the most common post-operative complication [
      • Besnier E.
      • Tuech J.J.
      • Schwarz L.
      We Asked the Experts: Covid-19 Outbreak: Is There Still a Place for Scheduled Surgery? “Reflection from Pathophysiological Data.”.
      ,
      • Bhangu A.
      • Nepogodiev D.
      • Glasbey J.C.
      • et al.
      Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study.
      ,
      • Kayani B.
      • Onochie E.
      • Patil V.
      • et al.
      The effects of COVID-19 on perioperative morbidity and mortality in patients with hip fractures.
      ]. This, in addition to the risk of infection transmission to staff and other patients made resumption of elective procedures controversial [
      • Anoushiravani A.A.
      • Barnes C.L.
      • Bosco J.A.
      • et al.
      Reemergence of Multispecialty Inpatient Elective Orthopaedic Surgery during the COVID-19 Pandemic: Guidelines for a New Normal.
      ]. Several authors and organizations drafted guidelines to minimize these risks as elective surgeries resumed [

      American College of Surgeons, American Society of Anesthesiologists, Association of periOperative Registered Nurses, American Hospital Association. Joint Statement : Roadmap for Resuming Elective Surgery after COVID-19 Pandemic.; 2020. Accessed January 23, 2022. https://www.facs.org/covid-19/clinical-guidance/roadmap-elective-surgery

      ,

      Newsroom April 2020: AAOS Releases Clinical Considerations for Resuming Elective Surgery. Accessed January 23, 2022. https://www.aaos.org/aaos-home/newsroom/press-releases/aaos-releases-clinical-considerations-for--resuming-elective-surgery/

      ]. Recommendations included only accommodating COVID-19 patients if the institution had sufficient staff and resources. Additionally, patients diagnosed or exposed to COVID-19 should have their surgeries rescheduled and follow the appropriate CDC recommendations [

      American College of Surgeons, American Society of Anesthesiologists, Association of periOperative Registered Nurses, American Hospital Association. Joint Statement : Roadmap for Resuming Elective Surgery after COVID-19 Pandemic.; 2020. Accessed January 23, 2022. https://www.facs.org/covid-19/clinical-guidance/roadmap-elective-surgery

      ,

      Newsroom April 2020: AAOS Releases Clinical Considerations for Resuming Elective Surgery. Accessed January 23, 2022. https://www.aaos.org/aaos-home/newsroom/press-releases/aaos-releases-clinical-considerations-for--resuming-elective-surgery/

      ,

      CDC. About Quarantine and Isolation. Cdc. 2020;(May 2008). Accessed January 23, 2022. https://www.cdc.gov/coronavirus/2019-ncov/your-health/quarantine-isolation.html

      ]. Despite the measures taken to ensure that only COVID-19 free patients undergo elective orthopaedic surgery, it is plausible that patient outcomes could have been affected during the COVID-19 pandemic.
      To this end, the aim of this study was to evaluate the short-term postoperative outcomes of patients that underwent elective total joint arthroplasty during the COVID-19 pandemic. We hypothesized that the rate of early postoperative complications in elective TJA surgery will not differ significantly between the pre-COVID-19 and during-COVID-19 pandemic cohorts.

      Materials and Methods

      This study did not require institutional review board approval or exemption as it was an analysis of publicly available, deidentified data.

      Data source

      We utilized the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database for this study. NSQIP is a multi-center, national, risk-adjusted database containing prospectively collected preoperative, intraoperative, and postoperative variables and outcomes [

      American College of Surgeons. ACS National Surgical Quality Improvement Program (ACS NSQIP). Published 2016. Accessed January 23, 2022. https://www.facs.org/quality-programs/acs-nsqip

      ].

      Patient Selection

      We included patients with current procedural terminology (CPT) codes for THA (27130) and/or TKA (27447), and International Classification of Disease-Tenth Revision (ICD-10) codes for osteoarthritis of the hip (M16, M160–M165, M169) and/or knee (M170–M175, M179). We excluded patients with CPT codes for revision arthroplasty (27486, 27487, 27138, 27137, 27134).
      For each procedure, we compared outcomes in 2020 (during-COVID-19) to outcomes in 2019 (pre-COVID-19). To capture the period after which elective surgery resumed in 2020, we only included patients undergoing procedures in quarters three and four of both years (July-December).

      Preoperative and Perioperative Characteristics

      Preoperative variables collected were demographic data (age, gender, weight, and height) and comorbidities including smoking, hypertension, diabetes mellitus, chronic obstructive pulmonary disease (COPD), congestive heart failure (CHF), end-stage renal disease (ESRD), diabetes mellitus, disseminated cancer, preoperative steroid or immunosuppressant use, bleeding disorder, preoperative anemia, preoperative transfusion, and American Society of Anesthesiology (ASA) Classification. Body mass index (BMI) was calculated for all patients. We classified preoperative anemia as hematocrit < 36 and 39 for females and males respectively. According to NSQIP, diabetes mellitus is defined as being on insulin or non-insulin anti-diabetic agent. Perioperative variables assessed were wound classification, and inpatient vs outpatient procedure.

      Postoperative Outcomes

      The ASC-NSQIP database documents postoperative outcomes and complications up to 30-days following surgery. Postoperative outcomes assessed included the following adverse events: superficial surgical site infection (SSI), deep SSI, wound dehiscence, pneumonia, unplanned reintubation, pulmonary embolism, deep venous thrombosis (DVT) or thrombophlebitis, failure to extubate, urinary tract infection (UTI), cerebrovascular accident (CVA), cardiac arrest, myocardial infarction (MI), sepsis, acute kidney injury, unplanned reoperation, prolonged hospital stay (>30 days), unplanned readmission, and 30-day mortality. We also evaluated for differences in hospital stay more than one day and discharge to rehab or acute care facility.

      Statistical Analysis

      Descriptive analyses were performed for pre- and perioperative variables and outcomes. Univariate analysis, including Student’s T-test and Pearson's chi-square test, was used to identify differences in continuous and categorical variables respectively. Since we were investigating the safety of arthroplasty, we wanted to increase the sensitivity of our analysis. Therefore, we set statistical significance at α = 0.05 rather than 0.01.
      To compare outcomes between 2020 and 2019, propensity score matching was performed. TKA and THA cohorts were analyzed separately. The propensity score was derived from a logistic regression model. All pre- and peri-operative variables were included in the propensity score model. We performed a nearest neighbor one-to-one matching between the 2020 and 2019 cohorts with no replacement. To compare postoperative outcomes, we then performed a bivariate logistic analysis of the unmatched cohorts and a multi-variable logistic regression analysis of the matched cohorts. All pre- and perioperative variables which were different between the matched cohorts at a P-value < 0.1 were included in the multi model. All statistical analyses were performed using Stata (StataCorp. 2019.Stata Statistical Software: Release 16.1.College Station, TX: StataCorp LP).

      Source of funding

      No funding was received or used for this project.

      Results

      Study Samples

      In the latter half of 2020, 17,805 THA and 26,970 TKA cases were performed, compared to 20,429 THA and 34,976 TKA cases in 2019. Notably, 41.68% of THA cases and 45.20% of TKA cases were performed on an outpatient basis in 2020 compared to 6.59% of THA cases (P < 0.0001) and 27.95% of TKA (P < 0.0001) in 2019. ASA classification and proportion of outpatient procedures were significantly different between the unmatched THA cohorts, while age, proportion of patients with hypertension, proportion of patients with COPD, and proportion of outpatient procedures were significantly different between the unmatched TKA cohorts. Detailed demographic and preoperative data are presented in Table 1 and Table 2.
      Table 1Total Hip Arthroplasty Patient and Procedure Characteristics
      Unmatched Cohort (N=38,234)Matched Cohort (N=35,604)
      2019 (N=20,429)2020 (N=17,805)P-value2019 (N=17,802)2020 (N=17,802)P-value
      Age, mean [SD]66.08 [10.61]66.01 [10.50]0.52867.07 [10.47]66.01 [10.50]0.000
      Female, n (%)11,163 (54.65%)9,573 (53.77%)0.0859,825 (55.19%)9,571 (53.76%)0.007
      BMI, mean [SD]30.55 [6.12]30.52 [6.16]0.56830.75 [6.34]30.52 [6.16]0.001
      Smoker, n (%)2,222 (10.88%)1,918 (10.77%)0.7431,974 (11.09%)1,918 (10.77%)0.342
      HTN, n (%)11,257 (55.10%)9,778 (54.92%)0.71610,169 (57.12%)9,775 (54.91%)0.000
      CHF, n (%)72 (0.35%)77 (0.43%)0.21072 (0.40%)77 (0.43%)0.681
      COPD, n (%)954 (4.67%)769 (4.32%)0.099904 (5.08%)769 (4.32%)0.001
      ESRD, n (%)33 (0.16%)32 (0.18%)0.66732 (0.18%)32 (0.18%)1.000
      Bleeding disorder, n (%)367 (1.80%)296 (1.66%)0.317323 (1.81%)296 (1.66%)0.274
      Disseminated cancer, n (%)47 (0.23%)42 (0.24%)0.90638 (0.21%)42 (0.24%)0.654
      Diabetes, n (%)2,537 (12.42%)2,257 (12.68%)0.4482,419 (13.59%)2,254 (12.66%)0.010
      Anemia was defined as hematocrit < 36 and 39 for females and males respectively
      Preoperative anemia, n(%)
      3,143 (15.38%)2,827 (15.88%)0.1863,033 (17.04%)2,826 (15.87%)0.003
      Transfused preoperatively, n (%)8 (0.04%)4 (0.02%)0.3581 (0.01%)4 (0.02%)0.180
      Steroid/immunosuppressant use, n (%)617 (3.02%)557 (3.13%)0.541610 (3.43%)557 (3.13%)0.115
      Wound classification, n (%)0.5540.714
       Clean20,379 (99.76%)17,752 (99.70%)17,754 (99.73%)17,749 (99.70%)
       Clean/Contaminated43 (0.21%)46 (0.26%)41 (0.23%)46 (0.26%)
       Contaminated7 (0.03%)6 (0.03%)7 (0.04%)6 (0.03%)
       Dirty/Infected01 (0.01%)01 (0.01%)
      ASA class, n (%)0.0150.000
       1649 (3.18%)523 (2.94%)353 (1.98%)523 (2.94%)
       210,473 (51.27%)9,073 (50.96%)8,150 (45.78%)9,073 (50.97%)
       38,977 (43.94%)7,850 (44.09%)8,696 (50,38%)7,847 (44.08%)
       4330 (1.62%)359 (2.02%)330 (1.85%)359 (2.02%)
      Outpatient procedure, n (%)1,346 (6.59%)7,422 (41.68%)0.0001,345 (7.56%)7,420 (41.68%)0.000
      SD, standard deviation; BMI, body mass index; HTN, hypertension; CHF, congestive heart failure; COPD, chronic obstructive pulmonary disease; ESRD, end stage renal disease; ASA, American Society of Anesthesiologists
      Significant values are in bold
      1 Anemia was defined as hematocrit < 36 and 39 for females and males respectively
      Table 2Total Knee Arthroplasty Patient and Procedure Characteristics
      Unmatched Cohort (N=61,956)Matched Cohort (N=53,940)
      2019 (N=34,976)2020 (N=26,970)P-value2019 (N=26,970)2020 (N=26,970)P-value
      Age, mean [SD]67.47 [9.09]66.90 [9.16]0.00066.67 [9.26]66.90 [9.16]0.004
      Female, n (%)21,285 (60.86%)16,223 (60.15%)0.07616,240 (60.22%)16,223 (60.15%)0.881
      BMI, mean [SD]32.93 [6.46]33.00 [6.57]0.18233.09 [6.57]33.00 [6.57]0.115
      Smoker, n (%)2,591 (7.41%)1,954 (7.24%)0.4401,981 (7.35%)1,954 (7.24%)0.655
      HTN, n (%)22,314 (63.79%)16,723 (61.99%)0.00016,320 (60.51%)16,723 (61.99%)0.000
      CHF, n (%)162 (0.46%)109 (0.40%)0.270100 (0.37%)109 (0.40%)0.533
      COPD, n (%)1,988 (5.68%)1,399 (5.19%)0.0071,371 (5.08%)1,399 (5.19%)0.585
      ESRD, n (%)62 (0.18%)55 (0.20%)0.44961 (0.23%)55 (0.20%)0.577
      Bleeding disorder, n (%)619 (1.77%)483 (1.79%)0.844450 (1.67%)483 (1.79%)0.279
      Disseminated cancer, n (%)53 (0.15%)42 (0.16%)0.89543 (0.16%)42 (0.16%)0.914
      Diabetes, n (%)6,528 (18.66%)4,848 (17.98%)0.0294,770 (17.69%)4,848 (17.98%)0.380
      Anemia was defined as hematocrit < 36 and 39 for females and males respectively
      Preoperative anemia, n(%)
      5,677 (16.23%)4,396 (16.30%)0.8214,528 (16.79%)4,396 (16.30%)0.126
      Transfused preoperatively, n (%)7 (0.02%)8 (0.03%)0.4447 (0.03%)8 (0.03%)0.796
      Steroid/immunosuppressant use, n (%)1,138 (3.25%)937 (3.47%)0.1311,000 (3.71%)937 (3.47%)0.145
      Wound classification, n (%)0.0190.533
       Clean34,872 (99.69%)26,921 (99.80%)26,919 (99.81%)26,921 (99.80%)
       Clean/Contaminated93 (0.27%)40 (0.15%)41 (0.15%)40 (0.15%)
       Contaminated14 (0.04%12 (0.04%)10 (0.04%)12 (0.04%)
       Dirty/Infected2 (0.01%)2 (0.01%)02 (0.01%)
      ASA Class, n (%)0.4710.001
       1540 (1.54%)417 (1.55%)347 (1.29%)417 (1.55%)
       216,271 (46.51%)12,397 (45.96%)12,098 (44.86%)12,397 (45.96%)
       317,585 (50.27%)13,683 (50.72%)13,997 (51.90%)13,683 (50.72%)
       4585(1.67%)478 (1.77%)528 (1.96%)478 (1.77%)
      Outpatient procedure, n (%)9,777 (27.95%)12,192 (45.20%)0.0009,777 (36.25%)12,192 (45.20%)0.000
      SD, standard deviation; BMI, body mass index; HTN, hypertension; CHF, congestive heart failure; COPD, chronic obstructive pulmonary disease; ESRD, end stage renal disease; ASA, American Society of Anesthesiologists
      Significant values are in bold
      1 Anemia was defined as hematocrit < 36 and 39 for females and males respectively

      Matched Samples

      The matched THA samples included 17,802 cases in 2020 and 17,802 cases in 2019. The matched TKA samples included 26,970 cases in 2020 and 26,970 cases in 2019. Age, gender, BMI, ASA class, and certain comorbidities (hypertension, COPD, diabetes, preoperative anemia) remained statistically different between the matched THA cohorts, with the 2020 cohort having lower age, BMI, females, and comorbidities. Meanwhile, age, ASA class, and proportion of hypertensive patients remained statistically different between the matched TKA cohorts, with age, proportion of hypertensive patients, and ASA classes 1 and 2 being higher in the 2020 sample. For both the TKA and THA matched cohorts, ratio of outpatient procedures was significantly higher in 2020. Detailed demographic and preoperative data of the matched cohorts are presented in Table 1 and Table 2.

      Postoperative Outcomes

      The incidence of the various postoperative outcomes is presented in Table 3. The overall complication rate for the THA cohort was 5.17% and 5.10% in 2019 and 2020 respectively (P=0.743). The overall complication rate for the TKA cohort was 5.48% and 5.25% in 2019 and 2020 respectively (P=0.212). There was no difference between 2020 and 2019 in the rates of any adverse event assessed (Table 3). However, patients treated in 2020 had a significantly lower rate of hospital stay > 1 day (THA: 28.78% vs 42.46%; P<0.001) (TKA: 32.72% vs 48.98%; P<0.001) and non-home discharge (THA: 5.25% vs 8.86%; P<0.001) (TKA: 4.83% vs 9.13%; P<0.001). Bivariate logistic regression of the unmatched samples also showed lower odds of hospital stay > 1 day and non-home discharge for both THA and TKA cohorts in 2020 with no difference in any of the analyzed adverse events (Table 4).
      Table 3Incidence of Adverse Events in Unmatched Cohorts
      Total Hip ArthroplastyTotal Knee Arthroplasty
      2019 (N=20,429)2020 (N=17,805)P-value2019 (N=34,976)2020 (N=26,970)P-value
      Any adverse event5.17%5.10%0.7435.48%5.25%0.212
       Superficial SSI0.86%0.97%0.2381.29%1.19%0.265
       Deep SSI0.12%0.15%0.4410.07%0.08%0.672
       Dehiscence0.14%0.15%0.8050.19%0.26%0.063
       Pneumonia0.23%0.17%0.1510.26%0.24%0.687
       Reintubation0.08%0.08%0.8750.09%0.08%0.565
       Pulmonary embolism0.20%0.23%0.4650.37%0.32%0.279
       DVT/thrombophlebitis0.34%0.28%0.3190.58%0.62%0.606
       Failure to extubate0.04%0.02%0.1990.04%0.04%0.995
       Urinary tract infection0.69%0.62%0.4210.63%0.65%0.682
       Stroke/CVA0.07%0.08%0.5780.08%0.05%0.146
       Arrest0.04%0.06%0.5960.05%0.06%0.946
       Myocardial infarction0.18%0.19%0.9230.18%0.24%0.140
       Sepsis0.19%0.14%0.2280.18%0.13%0.150
       Unplanned reoperation1.70%1.60%0.4320.97%0.94%0.674
       Unplanned 30-day readmission3.01%2.88%0.4562.76%2.58%0.175
       30-day mortality0.07%0.10%0.3560.07%0.09%0.541
       Acute kidney injury0.03%0.03%0.9760.03%0.04%0.414
      Hospital stay > 1 day42.46%28.78%0.00048.98%32.72%0.000
      Discharge to rehab or acute care facility8.86 %5.25%0.0009.13 %4.83%0.000
      SSI, surgical site infection; DVT, deep venous thrombosis; CVA, cerebral vascular accident
      Significant values are in bold
      Table 4Bivariate Logistic Regression Models of Unmatched Cohorts (2020 vs 2019)
      Total Hip ArthroplastyTotal Knee Arthroplasty
      OR95% CIP-valueOR95% CIP-value
      Any adverse event0.985[0.899- 1.079]0.7430.956[0.891- 1.026]0.891
       Superficial SSI1.136[0.919-1.402]0.4420.921[0.798-1.064]0.265
       Deep SSI1.243[0.713-2.166]0.4411.135[0.632-2.039]0.672
       Dehiscence1.068[0.632-1.805]0.8051.378[0.981-1.933]0.064
       Pneumonia0.717[0.454-1.131]0.1530.936[0.680-1.289]0.687
       Reintubation0.945[0.465-1.917]0.8750.851[0.491-1.476]0.566
       Pulmonary embolism1.176[0.761-1.819]0.4650.861[0.656-1.129]0.279
       DVT/thrombophlebitis0.831[0.577-1.196]0.3191.055[0.859-1.296]0.606
       Failure to extubate0.430[0.114-1.622]0.2130.997[0.437-2.275]0.995
       Urinary tract infection0.902[0.703-1.158]0.4211.042[0.854-1.272]0.682
       Stroke/CVA1.229[0.593-2.548]0.5780.625[0.330-1.184]0.150
       Arrest1.275[0.518-3.138]0.5971.023[0.520-2.015]0.946
       Myocardial infarction1.023[0.640-1.637]0.9231.297[0.917-1.835]0.141
       Sepsis0.735[0.444-1.215]0.2300.741[0.492-1.116]0.151
       Unplanned reoperation0.937[0.802-1.099]0.4320.965[0.820-1.137]0.674
       Unplanned 30-day readmission0.955[0.849-1.077]0.4560.934[0.846-1.031]0.175
       30-day mortality1.394[0.687-2.830]0.3581.193[0.677-2.102]0.541
       Acute kidney injury0.983[0.547-2.408]0.9761.423[0.605-3.359]0.416
      Hospital stay > 1 day0.548[0.525-0.572]0.0000.507[0.490-0.524]0.000
      Discharge to rehab or acute care facility0.570[0.525-0.619]0.0000.505[0.472-0.539]0.000
      SSI, surgical site infection; DVT, deep venous thrombosis; CVA, cerebral vascular accident
      Significant values are in bold
      As the matched cohorts had significant differences in baseline characteristics, we performed a multivariate logistic regression of the matched cohorts controlling for all statistically different baseline characteristics. The multivariate models are outlined in Table 5. Multivariate analysis demonstrated increased odds of superficial SSI in THA patients (OR 1.272; CI [1.101-1.602]; P=0.040) and myocardial infarction in TKA patients (OR 1.488; CI [1.014-2.184]; P=0.042) that underwent surgery in 2020 compared to 2019. There was also a decreased odds of hospital stay > 1 day (THA: OR 0.889; CI [0.847-0.935]; P<0.001) (TKA: OR 0.644; CI [0.620-0.669]; P<0.001) and discharge to rehab or acute care facility (THA: OR 0.655; CI [0.589-0.731]; P<0.001) (TKA: OR 0.497; CI [0.455-0.543]; P<0.001) in 2020. No other significant associations were present.
      Table 5Multivariate Logistic Regression Models of Matched Cohorts (2020 vs 2019)
      Total Hip ArthroplastyTotal Knee Arthroplasty
      OR95% CIP-valueOR95% CIP-value
      Any adverse event1.048[0. 948-1.159]0. 3621.008[0.935-1.089]0.821
       Superficial SSI1.272[1.101-1.602]0.0401.026[0.877-1.200]0.746
       Deep SSI1.623[0.884-3.003]0.1181.180[0.631-2.203]0.604
       Dehiscence1.114[0.625-1.986]0.7141.328[0.924-1.907]0.125
       Pneumonia0.802[0.492-1.310]0.3791.056[0.744-1.496]0.760
       Reintubation1.206[0.578-2.517]0.6180.959[0.529-1.736]0.889
       Pulmonary embolism1.506[0.937-2.418]0.0910.952[0.710-1.275]0.742
       DVT/thrombophlebitis0.998[0.674-1.479]0.9931.034[0.831-1.286]0.764
       Failure to extubate0.471[0.113-1.968]0.3021.021[0.424-2.462]0.962
       Urinary tract infection0.769[0.580-1.019]0.0681.058[0.854-1.310]0.604
       Stroke/CVA1.571[0.744-3.319]0.2360.662[0.338-1.297]0.230
       Arrest1.541[0.597-3.975]0.3711.214[0.576-2.558]0.609
       Myocardial infarction1.217[0.739-2.002]0.4401.488[1.014-2.184]0.042
       Sepsis0.778[0.446-1.360]0.3790.722[0.469-1.113]0.140
       Unplanned reoperation0.997[0.839-1.185]0.9750.954[0.802-1.134]0.597
       Unplanned 30-day readmission1.004[0.879-1.145]0.9550.949[0.854-1.055]0.336
       30-day mortality1.449[0.674-3.118]0.3421.423[0.746-2.716]0.284
       Acute kidney injury1.272[0.411-3.937]0.6761.294[0.519-3.229]0.580
      Hospital stay > 1 day0.889[0.847-0.935]0.0000.644[0.620-0.669]0.000
      Discharge to rehab or acute care facility0.655[0.589-0.731]0.0000.497[0.455-0.543]0.000
      SSI, surgical site infection; DVT, deep venous thrombosis; CVA, cerebral vascular accident
      Significant values are in bold

      Discussion

      As we continue to learn about COVID-19, experts are increasingly suspecting the evolution of this virus into an endemic pathogen [
      • Phillips N.
      The coronavirus is here to stay - here’s what that means.
      ]. With that in mind, it is important to assess the safety of orthopaedic surgery during the COVID-19 era. In this analysis of TJA postoperative outcomes before and after the COVID-19 pandemic, we found no difference in the 18 postoperative complications assessed on unmatched bivariate analysis. Matched multivariable analysis demonstrated a small increase in superficial SSI and myocardial infarction rates in THA and TKA respectively in 2020.
      Overall, our results suggest that short-term complications in TJA surgery were not significantly different before and during the COVID-19 pandemic. Several previous studies have reported increased mortality in COVID-19 patients undergoing surgical treatment [
      • Besnier E.
      • Tuech J.J.
      • Schwarz L.
      We Asked the Experts: Covid-19 Outbreak: Is There Still a Place for Scheduled Surgery? “Reflection from Pathophysiological Data.”.
      ,
      • Bhangu A.
      • Nepogodiev D.
      • Glasbey J.C.
      • et al.
      Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study.
      ,
      • Kayani B.
      • Onochie E.
      • Patil V.
      • et al.
      The effects of COVID-19 on perioperative morbidity and mortality in patients with hip fractures.
      ,
      • Haffner M.R.
      • Le H.V.
      • Saiz A.M.
      • et al.
      Postoperative In-Hospital Morbidity and Mortality of Patients with COVID-19 Infection Compared with Patients without COVID-19 Infection.
      ]. Kayani et al. found a 20% increase in mortality rates in patients with COVID-19 that underwent THA for hip fractures [
      • Kayani B.
      • Onochie E.
      • Patil V.
      • et al.
      The effects of COVID-19 on perioperative morbidity and mortality in patients with hip fractures.
      ]. Haffner et al. analyzed 10,940 patients undergoing various procedures and found that COVID-19 patients were twice as likely to die postoperatively compared to their healthy counterparts [
      • Haffner M.R.
      • Le H.V.
      • Saiz A.M.
      • et al.
      Postoperative In-Hospital Morbidity and Mortality of Patients with COVID-19 Infection Compared with Patients without COVID-19 Infection.
      ]. Nonetheless, as opposed to these studies which analyzed COVID-19 patients specifically, we found no increase in postoperative mortality in 2020 among all patients who underwent arthroplasty. This suggests that guidelines and safety precautions, such as preoperative COVID-19 screening, were successful in mitigating complications associated with performing surgery on COVID-19 patients. Furthermore, our findings support a previous study by Kader et al. which estimated that the overall probability of a patient admitted for elective orthopaedic surgery having a false negative preoperative test leading to postoperative mortality would be around 1 in every 7,000 (or 0.01%) [
      • Kader N.
      • Clement N.D.
      • Patel V.R.
      • Caplan N.
      • Banaszkiewicz P.
      • Kader D.
      The theoretical mortality risk of an asymptomatic patient with a negative SARSCoV-2 test developing COVID-19 following elective orthopaedic surgery.
      ]. This small rate of mortality would also help explain why we did not find an increase in mortality in patients undergoing TJA in 2020. Furthermore, the risk of postoperative death by nosocomial COVID-19 infection has also been shown to be low in several clinical studies [
      • Kane A.D.
      • Paterson J.
      • Pokhrel S.
      • et al.
      Peri-operative COVID-19 infection in urgent elective surgery during a pandemic surge period: a retrospective observational cohort study.
      ,
      • Sutherland L.
      • Hastie J.
      • Takayama H.
      • et al.
      Low rate of health care-associated transmission of coronavirus disease 2019 (COVID-19) in the epicenter.
      ].
      We found a slightly increased risk of superficial SSI in patients undergoing THA in 2020 compared to 2019. To our knowledge, there is no literature directly associating COVID-19 infection with an increased risk of SSI. One explanation may be decreased follow-up of patients undergoing hip replacement during the COVID-19 pandemic. It is known that clinical outpatient visits decreased during the start of the pandemic due in part to patient fear of contracting COVID-19 [
      • Patel S.Y.
      • Mehrotra A.
      • Huskamp H.A.
      • Uscher-Pines L.
      • Ganguli I.
      • Barnett M.L.
      Trends in Outpatient Care Delivery and Telemedicine during the COVID-19 Pandemic in the US.
      ,
      • Chatterji P.
      • Li Y.
      Effects of the COVID-19 pandemic on outpatient providers in the United States.
      ]. The decreased clinical supervision could have led to inappropriate wound care by patients. Even though telemedicine visits have been shown to be effective in diagnosing and following SSIs [
      • McLean K.A.
      • Mountain K.E.
      • Shaw C.A.
      • et al.
      Remote diagnosis of surgical-site infection using a mobile digital intervention: a randomised controlled trial in emergency surgery patients.
      ], they may have not been able to compensate for the decrease in outpatient visits. Patel et al. analyzed the visit patterns of almost 17 million commercial insurance enrollees and found that total outpatient visits, including in-person and telemedicine visits, decreased by 9.1%, with decreases in total visit rates by state ranging from 16% to 73% after expansion of telehealth coverage by Medicare [
      • Patel S.Y.
      • Mehrotra A.
      • Huskamp H.A.
      • Uscher-Pines L.
      • Ganguli I.
      • Barnett M.L.
      Trends in Outpatient Care Delivery and Telemedicine during the COVID-19 Pandemic in the US.
      ]. Despite the statistical significance, the clinical significance of this increased superficial SSI risk is questionable as the magnitude of increase was minimal (OR 1.272) and superficial SSI is often treatable. Further, the reporting of SSI may have been inconsistent, as many of these patients were treated on outpatient basis. With these considerations, this small increase may be interesting if reproducible but unlikely to be compelling or actionable at this time.
      We also found an increased risk of MI in patients undergoing TKA in 2020. COVID-19 infection is strongly associated with a pro-inflammatory and pro-thrombotic state, leading to an increased theoretical risk of MI [
      • Toscano O.
      • Cosentino N.
      • Campodonico J.
      • Bartorelli A.L.
      • Marenzi G.
      Acute Myocardial Infarction During the COVID-19 Pandemic: An Update on Clinical Characteristics and Outcomes.
      ]. Our finding of increased post-operative MI incidence in 2020 could be related to a small percentage of patients with COVID-19 who were missed during preoperative screening. Furthermore, patients previously hospitalized with severe COVID-19 were found to have a high prevalence (40%) of occult cardiac ischemia/infarction on perfusion analysis even after complete recovery [
      • Toscano O.
      • Cosentino N.
      • Campodonico J.
      • Bartorelli A.L.
      • Marenzi G.
      Acute Myocardial Infarction During the COVID-19 Pandemic: An Update on Clinical Characteristics and Outcomes.
      ]. This could suggest that even recovered COVID-19 patients may have an increased predisposition for coronary syndromes when the heart is stressed with surgery. This could explain the increased risk of MI we found despite rigorous preoperative screening. However, it is difficult to make any conclusions without accounting for COVID-19 status in the analysis. Future studies should reevaluate this and focus on the long-term cardiovascular consequences of COVID-19, as this can have large implications on patient selection for elective, non-urgent procedures.
      Interestingly, on both matched and unmatched analyses, the 2020 cohort was much more likely to undergo THA and TKA on an outpatient basis, and was less likely to have non-home discharge and hospital stay more than 1 day. This probably is a result of efforts to decrease patient stay in locations, such as hospitals and rehab/care centers, where there is a possibility of COVID-19 exposure [

      Where Are All the Patients? Addressing Covid-19 Fear to Encourage Sick Patients to Seek Emergency Care | Catalyst non-issue content. Accessed January 23, 2022. https://catalyst.nejm.org/doi/full/10.1056/CAT.20.0193

      ]. Additionally, utilization of outpatient centers such as ambulatory surgery centers has been recommended to allow isolation of healthy patients undergoing elective surgery from COVID-19 patients, and to relieve some load from the COVID-19 strained hospital systems [
      • Zeegen E.N.
      • Yates A.J.
      • Jevsevar D.S.
      After the COVID-19 Pandemic: Returning to Normalcy or Returning to a New Normal?.
      ,
      • Gilat R.
      • Haunschild E.D.
      • Tauro T.
      • Cole B.J.
      Recommendations to Optimize the Safety of Elective Surgical Care While Limiting the Spread of COVID-19: Primum Non Nocere.
      ]. The Centers for Medicare and Medicaid Services also agreed to cover outpatient arthroplasty procedures as of January 2020 [

      CMS. January 2020 Update of the Hospital Outpatient Prospective Payment System (OPPS). Centers For Medicare and Medicaid Services. 2020. Accessed June 24, 2020. https://www.cms.gov/files/document/mm11605.pdf

      ]. This shift to outpatient TJA surgery is supported by recent literature showing no increased complication rates compared to inpatient surgery [
      • DeMik D.E.
      • Carender C.N.
      • Kohler J.G.
      • An Q.
      • Brown T.S.
      • Bedard N.A.
      Recent Increases in Outpatient Total Hip Arthroplasty Have Not Increased Early Complications.
      ].
      This study has several limitations. Firstly, as with any retrospective analysis, only association can be established and not causation. Secondly, we were limited by the variables recorded in NSQIP, and could not determine the COVID-19 status of included patients or account for other confounders that may have affected our findings. Thirdly, NSQIP only records complications within 30 days, resulting in underestimation of possible longer-term complications. Fourthly, variability in reporting is likely present in any large database. As such, inaccuracies may have been introduced to our analysis due to reporting differences. Finally, we could not account for other consequences of the COVID-19 pandemic, such as decreased availability of healthcare workers and supplies and economic decline, which could have affected patient outcomes. Despite these limitations, this is, to our knowledge, the first study to assess the safety of TJA during COVID-19 pandemic using a large national database.

      Conclusions

      Broadly, THA and TKA short-term complications remained largely similar to pre-pandemic rates during 2020. A statistically significant increase in superficial SSI and MI risk was present in 2020; however, further studies are required to determine the clinical significance and persistence of this finding. There was also a shift away from inpatient surgery in 2020, possibly reflecting efforts to avoid nosocomial exposure of patient to COVID-19. Our current findings suggest that TJA procedures may be safely carried out during the COVID-19 pandemic without a substantially increased risk of most short-term postoperative complications.

      Conflict of Interests

      ☐ The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
      ☒ The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:
      Julius K. Oni has the following conflict of interest to declare:
      AAOS Knee Program Committee: Board or committee member
      AAHKS Humanitarian Committee: Board or committee member
      DePuy Synthes: Paid consultant
      Zimmer Biomet: Paid consultant
      Fellowship Support (Omega, Smith and Nephew): Other financial or material support from a company or supplier
      All other Authors have no conflict of interest to declare.
      No funding was received in support of this work.

      Uncited reference

      [
      • Duchman K.R.
      • Gao Y.
      • Pugely A.J.
      • Martin C.T.
      • Callaghan J.J.
      Differences in short-term complications between unicompartmental and total knee arthroplasty: A propensity score matched analysis.
      ].

      Acknowledgment and funding sources:*

      *(Please note that you should not include a statement to the effect that there is no acknowledgment or funding, only actual funding details or acknowlegments should be included in this section)

      Appendix A. Supplementary data

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