Aims. To identify variables independently associated with same-day discharge (SDD) of patients following revision total knee arthroplasty (rTKA) and to develop machine learning algorithms to predict suitable candidates for outpatient rTKA. Methods. Data were obtained from the American College of Surgeons National Quality Improvement Programme (ACS-NSQIP) database from the years 2018 to 2020. Patients with elective, unilateral rTKA procedures and a total hospital length of stay between zero and four days were included. Demographic, preoperative, and intraoperative variables were analyzed. A multivariable logistic regression (MLR) model and various machine learning techniques were compared using area under the curve (AUC), calibration, and decision curve analysis. Important and significant variables were identified from the models. Results. Of the 5,600 patients included in this study, 342 (6.1%) underwent SDD. The random forest (RF) model performed the best overall, with an internally validated AUC of 0.810. The ten crucial factors favoring SDD in the RF model include operating time, anaesthesia type, age, BMI, American Society of Anesthesiologists grade, race, history of diabetes, rTKA type, sex, and smoking status. Eight of these variables were also found to be significant in the MLR model. Conclusion. The RF model displayed excellent accuracy and identified clinically important variables for determining candidates for SDD following rTKA. Machine learning techniques such as RF will allow clinicians to accurately risk-stratify their patients preoperatively, in order to optimize resources and improve patient outcomes. Cite this article: Bone Jt Open 2023;4(6):399–407

Aims. In the last decade, perioperative advancements have expanded the use of outpatient primary total knee arthroplasty (TKA). Despite this, there remains limited data on expedited discharge after revision TKA. This study compared 30-day readmissions and reoperations in patients undergoing revision TKA with a hospital stay greater or less than 24 hours. The authors hypothesized that expedited discharge in select patients would not be associated with increased 30-day readmissions and reoperations. Methods. Aseptic revision TKAs in the National Surgical Quality Improvement Program database were reviewed from 2013 to 2020. TKAs were stratified by length of hospital stay (greater or less than 24 hours). Patient demographic details, medical comorbidities, American Society of Anesthesiologists (ASA) grade, operating time, components revised, 30-day readmissions, and reoperations were compared. Multivariate analysis evaluated predictors of discharge prior to 24 hours, 30-day readmission, and reoperation. Results. Of 21,610 aseptic revision TKAs evaluated, 530 were discharged within 24 hours. Short-stay patients were younger (63.1 years (49 to 78) vs 65.1 years (18 to 94)), with lower BMI (32.3 kg/m. 2. (17 to 47) vs 33.6 kg/m. 2. (19 to 54) and lower ASA grades. Diabetes, chronic obstructive pulmonary disease, hypertension, and cancer were all associated with a hospital stay over 24 hours. Single component revisions (56.8% (n = 301) vs 32.4% (n = 6,823)), and shorter mean operating time (89.7 minutes (25 to 275) vs 130.2 minutes (30 to 517)) were associated with accelerated discharge. Accelerated discharge was not associated with 30-day readmission and reoperation. Conclusion. Accelerated discharge after revision TKA did not increase short-term complications, readmissions, or reoperations. Further efforts to decrease hospital stays in this setting should be evaluated. Cite this article: Bone Joint J 2022;104-B(12):1323–1328

Abstract. Introduction. 30-day emergency readmission is an indicator of treatment related complication once discharged, resulting in readmission. A board-approved quality improvement pathway was introduced to reduce elective re-admissions. Method. The pathway involved telephone and email contact details provision to patients for any non-life threatening medical assistance, allowing for initial nurse led management of all issues. A new clinic room available 7 days, and same day ultrasound scanning for DVT studies were introduced. A capability, opportunity and behavior model of change was implemented. Readmission rates before and six months after implementation were collected from Model Hospital. A database used to document patient communications was interrogated for patient outcomes. Results. Prior to implementation, readmission rates following elective primary total knee replacement (TKR) at the 1st business quarter of 2021 (April – June 2021), was 8.7%, (benchmark 3.8%). Following implementation, readmission rates decreased to 4.1% (October – December 2021). 54% of patients making contact were managed with telephone advice. 15% of patients required face-to-face clinic. 32% of those required a same day scan to exclude DVT (1/4). 20 out of 684 TKRs performed following protocol introduction were re-admitted within 30 days. Readmissions were 41% surgical, 29% medical. 52% were unaware of the newly implemented protocol. Further improvements have been made to the protocol based on these findings. Implementation of a suitable pathway can significantly reduce re-admission rates in our center and could be used to reduce readmission rates in other national elective treatment centers

Aims. This study used an artificial neural network (ANN) model to determine the most important pre- and perioperative variables to predict same-day discharge in patients undergoing total knee arthroplasty (TKA). Methods. Data for this study were collected from the National Surgery Quality Improvement Program (NSQIP) database from the year 2018. Patients who received a primary, elective, unilateral TKA with a diagnosis of primary osteoarthritis were included. Demographic, preoperative, and intraoperative variables were analyzed. The ANN model was compared to a logistic regression model, which is a conventional machine-learning algorithm. Variables collected from 28,742 patients were analyzed based on their contribution to hospital length of stay. Results. The predictability of the ANN model, area under the curve (AUC) = 0.801, was similar to the logistic regression model (AUC = 0.796) and identified certain variables as important factors to predict same-day discharge. The ten most important factors favouring same-day discharge in the ANN model include preoperative sodium, preoperative international normalized ratio, BMI, age, anaesthesia type, operating time, dyspnoea status, functional status, race, anaemia status, and chronic obstructive pulmonary disease (COPD). Six of these variables were also found to be significant on logistic regression analysis. Conclusion. Both ANN modelling and logistic regression analysis revealed clinically important factors in predicting patients who can undergo safely undergo same-day discharge from an outpatient TKA. The ANN model provides a beneficial approach to help determine which perioperative factors can predict same-day discharge as of 2018 perioperative recovery protocols. Cite this article: Bone Joint J 2021;103-B(8):1358–1366

Aims. The purpose of this study was to assess total knee arthroplasty (TKA) volume and rates of early complications in morbidly obese patients over the last decade, where the introduction of quality models influencing perioperative care pathways occurred. Methods. Patients undergoing TKA between 2011 to 2018 were identified in the American College of Surgeons National Surgical Quality Improvement Program database. Patients were stratified by BMI < 40 kg/m. 2. and ≥ 40 kg/m. 2. and evaluated by the number of cases per year. The 30-day rates of any complication, wound complications, readmissions, and reoperation were assessed. Trends in these endpoints over the study period were compared between groups using odds ratios (ORs) and multivariate analyses. Results. In total, 314,695 patients underwent TKA and 46,362 (15%) had BMI ≥ 40 kg/m. 2. The prevalence of morbid obesity among TKA patients did not change greatly, ranging between 14% and 16%. Reoperation rate decreased from 1.16% to 0.96% (odds ratio (OR) 0.81 (95% confidence interval (CI) 0.66 to 0.99)) for patients with BMI < 40 kg/m. 2. , as did rates of readmission (4.46% to 2.87%; OR 0.61 (0.55 to 0.69)). Patients with BMI ≥ 40 kg/m. 2. also had fewer readmissions over the study period (4.87% to 3.34%; OR 0.64 (0.49 to 0.83)); however, the rate of reoperation did not change (1.37% to 1.41%; OR 0.99 (0.62 to 1.56)). Significant improvements were not observed for infective complications over time for either group; patients with BMI ≥ 40 kg/m. 2. had increased risk of both deep infection and wound complications compared to non-morbidly obese patients. Rate of any complication decreased for all patients. Conclusion. The proportion of TKAs in morbidly obese patients has not significantly changed over the past decade. Although readmission rates improved for all patients, reductions in reoperation in non-morbidly obese patients were not experienced by the morbidly obese, resulting in a widening of the complication gap between these cohorts. Care improvements have not lowered the differential risk of infective complications in the morbidly obese. Cite this article: Bone Joint J 2021;103-B(6 Supple A):38–44

Aims. Rates of readmission and reoperation following primary total knee arthroplasty (TKA) are under scrutiny due to new payment models, which penalize these negative outcomes. Some risk factors are more modifiable than others, and some conditions considered modifiable such as obesity may not be as modifiable in the setting of advanced arthritis as many propose. We sought to determine whether controlling for hypoalbuminaemia would mitigate the effect that prior authors had identified in patients with obesity. Methods. We reviewed the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database for the period of January 2008 to December 2016 to evaluate the rates of reoperation and readmission within 30 days following primary TKA. Multivariate logistic regression modelling controlled for preoperative albumin, age, sex, and comorbidity status. Results. Readmission rates only differed significantly between patients with Normal Weight and Obesity Class II, with a decreased rate of readmission in this group (odds ratio (OR) 0.82; 95% confidence interval (CI) 0.71 to 0.96; p = 0.010). The only group demonstrating association with increased risk of reoperation within 30 days was the Obesity Class III group (OR 1.38; 95% CI 1.05 to 1.82; p = 0.022). Hypoalbuminaemia (preoperative albumin < 35 g/L) was significantly associated with readmission (OR 1.62; 95% CI 1.41 to 1.86; p < 0.001) and reoperation (OR 1.52; 95% CI 1.18 to 1.96; p = 0.001) within 30 days. Conclusion. In this study, hypoalbuminaemia appears to be a more significant risk factor for readmission and reoperation than even the highest obesity categories. Future studies may assess whether preoperative albumin restoration or weight loss may improve outcomes for patients with hypoalbuminaemia. The implications of this study may allow surgeons to discuss risk of surgery with obese patients planning to undergo primary TKA procedures if other comorbidities are adequately controlled. Cite this article: Bone Joint J 2020;102-B(6 Supple A):31–35

Introduction. Perioperative optimization efforts have improved outcomes following primary total knee arthroplasty (TKA). However, morbidly obese patients continue to have increased rates of complications. The purpose of this study was to assess if rates of early complications after TKA have similarly improved for both morbidly obese and non-morbidly obese patients. Methods. Elective, primary TKA patients from 2011–2018 were identified in the National Surgical Quality Improvement Program database. Patients were stratified by body mass index (BMI) <40 kg/m. 2. and ≥40 kg/m. 2. Thirty-day rates of infectious complications, readmissions, and reoperation were assessed. Trends in these endpoints over the study period were compared between BMI groups utilizing odds ratios (OR) and multivariate analyses. Results. In total, 314,719 patients underwent TKA and 46,386 (15%) had BMI ≥40 kg/m. 2. From 2011–2018, the reoperation rate significantly improved from 1.2% to 1.0% (OR: 0.6 [0.6–0.7]) for patients with BMI <40 kg/m. 2. , as did rates of readmission (4.5% to 2.9%, OR: 0.8 [0.7–0.99]). Patients with BMI ≥40 kg/m. 2. also had a significant decrease in the rate of readmission over the study period (4.9% to 3.3%, OR: 0.6 [0.5–0.8]); however, the rate of reoperation did not significantly change (1.4% to 1.4%, OR: 1.0 [0.6–1.6]). Significant improvements were not observed for infectious complications over time for either group. However, patients with BMI ≥40 kg/m. 2. consistently had increased risk of both deep infection from 2014–2018 (2014 OR: 2.2 [1.4–3.4], 2018: 2.2 [1.6–3.0]) and wound complications from 2011–2018 (2011 OR: 1.7 [1.2–2.6], 2018 OR: 2.0 [1.7–2.4]) compared to non-morbidly obese patients. Conclusion. Although readmission rates significantly decreased for all patients, improvements in reoperation rates observed in non-morbidly obese patients were not experienced by the morbidly obese – resulting in a widening of the complication gap between these cohorts. Care improvements have not lowered the differential risk of infectious complications compared to non-morbidly obese

Aims. To evaluate the influence of discharge timing on 30-day complications following total knee arthroplasty (TKA). Patients and Methods. We identified patients aged 18 years or older who underwent TKA between 2005 and 2016 from the American College of Surgeons’ National Surgical Quality Improvement Program (NSQIP) database. We propensity score-matched length-of-stay (LOS) groups using all relevant covariables. We used multivariable regression to determine if the rate of complications and re-admissions differed depending on LOS. Results. Our matched cohort consisted of 76 246 TKA patients (mean age 67 years . (sd. 9)). Patients whose LOS was zero and four days had an increased risk of major complications by an odds ratio (OR) of 1.8 (95% confidence interval (CI) 1.0 to 3.2) and 1.5 (95% CI 1.2 to 1.7), respectively, compared with patients whose LOS was two days. Patients whose LOS was zero, three, and four days had an increased risk of minor complications (OR 1.8 (95% CI 1.3 to 2.7), 1.2 (95% CI 1.0 to 1.4), and 1.6 (95% CI 1.4 to 1.9), respectively), compared with patients whose LOS was two days. In addition, a LOS of three days increased the risk of re-admission by an OR of 1.2 (95% CI 1.0 to 1.3), and a LOS of four days increased the risk of re-admission by an OR of 1.5 (95% CI 1.3 to 1.6), compared with a LOS of two days. Conclusion. Patients discharged on days one to two postoperatively following TKA appear to have reduced major and minor complications compared with discharge on the day of surgery, or on days three to four. Prospective clinical data are required to confirm these findings. Cite this article: Bone Joint J 2019;101-B(7 Supple C):70–76

At our tertiary, large, academic healthcare system, we have access to an academic medical center (AMC), a community based, orthopedic friendly, efficient hospital (CBH) and several ambulatory care centers (ASC) which are being prepared to provide same day discharge (SDD) TJA and UKA. We had a near-capacity AMC with an excellent ability to care for medically and technically complicated TJA patients. However, efficiency was less than desired regardless of case complexity with an average effective case time of 4 hours. Concurrently, the orthopaedically, under-utilized community-based hospital (CBH) wanted to increase volume, improve margins, and become a TJA Center of Excellence with the ability to provide an efficient Hospital Outpatient Department (HOPD) and SDD TJA surgery experience. Methods. The CBH had a main operating floor and a separate floor of four OR suites which were repurposed with the goal of utilizing these rooms for TJA four days per week with an average of 3.5 cases per room per day. We preferentially performed primary, uncomplicated TJA, UKA, and minimally invasive TJA at the CBH. Revision surgeries, patients with extensive medical comorbidities, and complex primary surgeries would be performed at the AMC. Our goals were to decrease costs, readmissions, length of stay, and increase margins at the CBH while increasing efficiency, revenue and volume. Protocols were developed to facilitate SDD UKA and THA at both hospitals as well as rapid recovery protocols for TKA at both hospitals with the understanding that the CBH would perform more of these cases but the efficiency could also be implemented at the AMC when possible. We also needed a strategy to deal with TKA and eventually THA being removed from the Inpatient Only (IPO) list. CMS has utilized the “Two-Midnight Rule” to define outpatient status for both THA and TKA. This has distinct financial implications for the facility's reimbursement with outpatient being $10,123 on average versus $12,380 for inpatient status. A protocol-based system was put in place to make both hospitals compliant with the removal of TKA from the IPO List in order to avoid Quality Improvement Organization (QIO) and Recovery Audit Contractor (RAC) after implementation. Results. Comparing FY 2018 to FY 2019, volume increased 26.4% at the CBH. Outpatient case volume rose substantially from 14 cases to 243. Volumes were slightly decreased at the AMC (−4.57%) resulting in a substantial increase in margin contribution for the parent enterprise. Quality metrics at the CBH (surgical site infections (SSI), length of stay (LOS), readmissions, and mortality) were improved. LOS improved from 52% to 71% discharge before 48 hours. The LOS decreased 12% for THA and 8.1% for TKA. CBH readmission rates decreased from 1.38% to 0.9% with no deaths. Surgeon satisfaction is greatly improved as their volume, efficiency, quality metrics, and finances were enhanced. Financial performance was improved in aggregate and per case for the CBH. Although the CBH per-case revenue was 80.3% and 74.4% of the AMC for THA and TKA: the net margins were 3.6% and 18.8% higher for THA and TKA, respectively. The increased efficiency, lower hospital cost and higher volume at the CBH allowed for an increase in revenue despite lower reimbursement per case. Conclusions. A shifting reimbursement landscape, value-based payment initiatives, and increasing volume have challenged traditional TJA delivery systems. This demonstrates one strategy to help hospital systems improve net margins while improving patient care despite lower net revenue per TJA episode. These strategies will become increasingly important going forward with the transition of higher numbers of TJA patients to outpatient settings including ambulatory surgery centers which will be subjected to even further decreases in net revenue per patient

Introduction. Revision total knee arthroplasty (revision TKA) occurs for a wide variety of indications and along with revision total hip arthroplasty is billed for using Diagnosis-Related Groups (DRGs) 466, 467, and 468 in the United States. However, DRGs do not account for revision etiology, a potentially substantial driver of cost. This study investigates revision TKA costs and 30-day complications by indication, employing both local granular as well as national standardized databases. Methods. Hospitalization costs and complication rates for 1,422 aseptic revision TKAs performed at a high-volume center between 2009 and 2015 were retrospectively reviewed. Additionally, charges for 28,173 revision TKAs in the National Inpatient Sample (NIS) were converted to costs using the Healthcare Cost and Utilization Project cost-to-charge ratios. 30-day complication rates for 3,450 revision TKAs were obtained using the American College of Surgeons National Surgical Quality Improvement Project (ACS-NSQIP). Costs and complications were compared between revision TKAs performed for the indication of fracture, wear/loosening, and instability with use of simultaneous and pairwise comparisons and a multivariable model accounting for American Society of Anesthesiologists (ASA) score, age, and sex. Results. Local hospitalization costs for fracture (median, $30,643) were significantly higher than those for wear/loosening ($24,734; p < 0.001) or instability ($22,932; p < 0.001), with differences remaining significant even after adjusting for patient comorbidities (p < 0.001). Local fracture patients were admitted for an average of 1.9 days longer (mean length of stay [LOS]: 4.8 days; IQR: 3 – 6) than instability patients (mean LOS: 2.9; IQR: 2 – 3; p < 0.001) and 1.7 days longer than wear/loosening patients (mean LOS: 3.1, IQR: 2 – 3; p < 0.001) but had similar 30-day orthopedic-specific complication rates (10.8%) as compared to instability (11.2%; p > 0.999) and wear/loosening (15.9%; p = 0.333). Nationally, NIS costs for fracture (median, $31,207) were higher than those for other aseptic indications (wear/loosening: $21,747; instability: $16,456; p< 0.001). Combined medical and surgical complication rates for fracture (56.6% of patients with ≥1 complication) were significantly higher than those for wear/loosening (19.7%) and instability (15.5%) (p < 0.001), with 3.5 – 5.4 fold increased transfusion rates (45.7% fracture, 13.2% wear/loosening, 8.5% instability; p < 0.001) and 1.2 – 3.3 fold increased urinary tract infection rates (2.3% fracture, 0.7% wear/loosening, 1.9% instability; p = 0.004). Discussion and Conclusion. Hospitalization costs for revision TKA for fracture were 37% to 50% higher than for all other aseptic revision TKAs, both locally and nationally. This increased cost persisted even after multivariable comorbidity adjustment, the current approach for DRG assignment for both revision TKA and THA reimbursement. Indication-specific coding and reimbursement systems are necessary to maintain sustainable access to revision TKA for all patients. For figures, tables, or references, please contact authors directly

Introduction. In November 2017, the Center for Medicare and Medicaid Services (CMS) finalized the 2018 Medicare Outpatient Prospective Payment System rule that removed total knee arthroplasty (TKA) procedures from the Medicare inpatient-only (IPO) list of procedures. This action had significant and unexpected consequences. For several years, CMS has utilized a rule called the “Two-Midnight Rule” to define outpatient status for all procedures not on the IPO list. CMS made TKA subject to the “Two-Midnight Rule” in conjunction with the decision to move TKA off the IPO list. According to the “Two-Midnight Rule,” a hospital admission should be expected to span at least two midnights in order to be covered as an inpatient procedure. If it can be reliably expected that the patient will not require at least two midnights in the hospital, the “Two-Midnight Rule” suggests that the patient is considered an outpatient and is therefore subject to outpatient payment policies. Under prior guidance related to the “Two-Midnight Rule;” however, CMS also states that Medicare may treat some admissions spanning less than two midnights as inpatient procedures if the patient record contains documentation of medical need. The final rule was clear in stating CMS's expectation was that the great majority of TKAs would continue to be provided in an inpatient setting. Methods. We looked at 3 different levels of the IPO rule impact on TKA for Medicare beneficiaries: a national comparison of fee for service (FFS) inpatient and outpatient classification for 2017 vs 2018; a survey of AAHKS surgeons completed in April of 2019; and an in-depth analysis of a large academic medical center experience. An analysis of change in inpatient classification of TKA patients over time, number of Quality Improvement Organization (QIO) audits, compliance solutions of organizations for the new rule and cost implications of those compliance solutions were evaluated. Results. Hospital reimbursement averages $10,122 in an outpatient facility (includes implant, other supplies, ancillary staff, etc.) but does NOT include the physician payment. Average hospital reimbursement in the inpatient setting is $11,760. The difference in reimbursement to hospitals varies widely however due to nuances in the CMS reimbursement formula (90. th. percentile decrease, $6,725 vs 10th percentile $2,048). Physician payments are the same in both settings (avg $1,403). TKA patients not designated for in-patient admissions are not eligible for bundle payment programs thus removing the healthiest, most predictable patients from the program. Patients designated as outpatients are subject to higher out of pocket expenses. Patients may have an annual Medicare Part B Deductible ($185) and a 20% copay as well as prescription and durable medical equipment costs. A survey of AAHKS surgeons demonstrated that 44.74% were doing inpatient designation only, 17.89% were doing outpatient designation only, 25.53 % designated patients as necessary, and 10% were designated by the hospital. This survey showed that 66/374 (17.65%) of AAHKS responders had undergone a QIO audit as a result of issues with the IPO rule. An evaluation of a large academic medical center demonstrated that since January 1, 2018, 470/690 (68.1%) of CMS TKA patients left the institution in less than 2 midnights. During this time period the institution was subjected to 2 QIO audits. All CMS patients had been designated as inpatients prior to May 2019. Conclusions. There are many unintended consequences to the IPO rule application to TKA. Clearly, more study is needed to provide better guidelines to knee replacement surgeons. A well-defined outpatient TKA bundle would allow CMS and TKA surgeons to better serve their patients. For figures, tables, or references, please contact authors directly

Introduction. Rates of readmission and reoperation following primary total knee arthroplasty (TKA) are under scrutiny due to new payment models, which penalize these negative outcomes. Many prior studies have demonstrated the risk of perioperative complications among patients with obesity. However, an elevated complication rate among patients with poor nutrition, as measured by hypoalbuminemia, has also been reported. We sought to determine whether controlling for hypoalbuminemia would mitigate the effect that prior authors had identified in patients with obesity. In addition, we hoped to identify an albumin threshold above which risk of readmission and reoperation would be minimized. Materials and Methods. We reviewed the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database for the period of 2008–2016 to evaluate the rates of perioperative complications among primary TKA patients by obesity category and albumin level. Patients were divided into groups according to World Health Organization obesity category and continuous as well as dichotomous albumin level. The primary outcomes were readmission and reoperation within 30 days of surgery. Patients without BMI or albumin data were excluded, as were patients undergoing surgery for the treatment of fracture or bone tumor. Univariate logistic regression compared predictive value of body mass index and albumin on incidence of these outcomes, using the normal weight and albumin > 3.5 g/dL groups as controls. Multivariate logistic regression modeling controlled for age, gender, and comorbidity status. Receiver operator curves (ROC) were generated to determine if an albumin threshold could be determined, above which risk for these complications would be minimized. Results. Outcome data was available 108,601 patients. Overall, 3,508 patients (3.46%) were readmitted and 1,219 patients (1.19%) underwent reoperation within 30 days. Hypoalbuminemia was present in 4,327 patients (4.11%), lowest in the Overweight group (3.16%) and highest in the Obese Type III (6.72%) and Underweight (12.62%) groups (p <0.001). Readmission and reoperation rates were highest among patients categorized as Obesity Class III (4.15 and 1.73%, respectively) compared with Normal Weight (3.59 and 1.14%, respectively, p <0.001). Readmission and reoperation rates were higher among patients with hypoalbuminemia (6.10 and 1.96%, respectively) compared with normal albumin (3.34 and 1.16%, respectively, p <0.001). After controlling for covariates of interest using multivariate regression including continuous albumin, odds ratio of readmission among the highest obesity category no longer differed from the Normal Weight control group. Odds ratio of reoperation among the highest obesity category declined from 1.52 to 1.38 after controlling for albumin and other covariates (p = 0.022). A subanalysis was performed excluding all patients with albumin < 3.5 g/dL, but results did not differ significantly from the multivariate model. ROC modeling was unable to identify a threshold for continuous BMI or albumin that would adequately mitigate risk for readmission or reoperation. Discussion. Albumin and obesity remain significant independent risk factors for reoperation following primary TKA procedures. However, after controlling for hypoalbuminemia and other important covariates, readmission rates did not significantly differ between patients with Normal Weight and any other obesity category. Controlling for albumin alone does not mitigate all risk imposed by obesity on perioperative outcomes. Future studies may assess whether preoperative albumin repletion or weight loss may improve outcomes for patients with hypoalbuminemia and obesity. For figures, tables, or references, please contact authors directly

Introduction. We designed this study to compare 30-day complications and length of hospital stay between patients undergoing total knee arthroplasty (TKA) with general anesthesia, to those undergoing TKA with spinal, epidural anesthesia, or Monitored Anesthesia Care (MAC, a combination of local anesthesia with sedation and analgesia provided by an anesthesiologist) with or without regional nerve blocks. Methods. We identified patients ≥18 years undergoing TKA between the years of 2006 and 2017 from the American College of Surgeons National Surgical Quality Improvement Program (NSQIP). We collected patient demographics, anesthesia type, 30-day complications, length of operation and hospital stay from the database. We used multivariable regression to compare complications and length of stay (LOS) between anesthesia types, while adjusting for relevant covariables. Results. We identified 265,325 TKA patients. Of these, 91 (0.03%) underwent epidural anesthesia with a nerve block, while 1,855 (0.70%) underwent epidural anesthesia with no block, 12,800 (4.82%) underwent MAC with a block, 25,643 (9.66%) underwent MAC with no block, 13,575 (5.12%) underwent spinal anesthesia with a block, 80,803 (30.45%) underwent spinal anesthesia with no block, and 130,558 (49.21%) underwent general anesthesia. The rate of complications was not associated with the presence of a block, while the unadjusted LOS was significantly lower with the use of a block in patients treated with spinal anesthesia (2.54±2.07 vs. 2.84±2.25), epidural anesthesia (2.87±1.81 vs. 3.88± 4.67), and MAC (2.51±2.14 vs. 2.68±2.11), p<0.0001. The unadjusted rate of major complications was significantly lower in patients who underwent spinal anesthesia (2.10%), and MAC (1.91%) compared to general anesthesia (2.31%), p<0.0001. Similarly, the unadjusted rate of minor complications was significantly lower for patients treated with spinal anesthesia(1.86%) and MAC (1.78%) compared to general anesthesia (2.11%), p<0.0001. The unadjusted LOS was significantly longer in patients treated with epidural (3.83±4.58), compared to general (2.94±3.64) anesthesia, p<0.0001. In contrast, the unadjusted LOS was significantly lower for patients treated with spinal anesthesia (2.80±2.23), and MAC (2.62±2.12) compared to general anesthesia, p<0.0001. Following covariable adjustment, spinal anesthesia and MAC were associated with a 0.93 (0.87–0.98), and 0.84 (0.78–0.91), odds of major complications compared to general anesthesia. Similarly, spinal anesthesia and MAC were associated with a 0.92 (0.87–0.98) and 0.89 (0.82–0.97) odds of minor complications compared to general anesthesia. Following covariable adjustment, epidural anesthesia increased the LOS by 0.25 (0.27–0.28) days compared to general, while spinal anesthesia and MAC decreased the LOS by 0.04 (95%CI 0.05–0.04), and 0.10 (0.11–0.09) days, compared to general. In patients treated with spinal anesthesia, epidural anesthesia, and MAC, the use of a block was independently associated with a decreased LOS by 0.10 (0.12–0.90), 0.24 (0.39–0.09), and 0.07 (0.08–0.05). Conclusion. Patients who undergo TKA with spinal anesthetic, and MAC appear to have superior outcomes compared to those who undergo TKA with general anesthesia. In addition, the use of a regional nerve block appears to be independently associated with a shorter LOS in patients who undergo TKA with neuraxial (spinal and epidural) anesthetic, and MAC. For figures, tables, or references, please contact authors directly

Introduction. Hypoalbuminemia has previously been identified as an independent predictor of postoperative complications following total knee arthroplasty (TKA). Given the morbidity and financial burden associated with TKA complications, significant effort has gone into identifying patients at increased risk for perioperative complications. The American Society of Anesthesiologists (ASA) physical status score has been utilized for risk stratification of surgical patients for many years and is a measure of overall health. However, it is unclear how measures like albumin compare to the prognostic ability of this type of global health measure. This study aims to elucidate the utility of preoperative albumin compared with that of the ASA score in predicting complications following TKA. Methods. Patients undergoing TKA between 2005 and 2015 were identified using the American College of Surgeons-National Surgical Quality Improvement Program (ACS-NSQIP) database. Patients were stratified based on preoperative hypoalbuminemia (<3.5 g/dL) and ASA score (≤ 2 vs. > 2). Multivariable regression analysis adjusted for age, sex, BMI, and smoking status was utilized to determine predictive potential of hypoalbuminemia and ASA score on each postoperative complication. Results. Of the 79,661 patients included in the cohort, 4.3% had preoperative hypoalbuminemia. Univariate regression analysis found significant predictive abilities of both serum albumin and ASA score on numerous postoperative complications, such as superficial infection, deep infection, MI, pneumonia, renal insufficiency, reintubation, transfusion, readmission, reoperation, and death. Interestingly, multivariable regression analysis demonstrated that hypoalbuminemia more robustly predicted postoperative deep infection than ASA. Discussion and Conclusion. Hypoalbuminemia and ASA each individually predict numerous postoperative complications following TKA. However, this study suggests that while ASA score more accurately predicts post-operative medical complications, hypoalbuminemia may be a more accurate predictor of periprosthetic infection following TKA. Ultimately, preoperative albumin should be incorporated in the pre-operative work-up routine to stratify patient risk, especially regarding postoperative infection

Aims

This study aims to determine difference in annual rate of early-onset (≤ 90 days) deep surgical site infection (SSI) following primary total knee arthroplasty (TKA) for osteoarthritis, and to identify risk factors that may be associated with infection.

Aims

In-hospital length of stay (LOS) and discharge dispositions following arthroplasty could act as surrogate measures for improvement in patient pathways, and have major cost saving implications for healthcare providers. With the ever-growing adoption of robotic technology in arthroplasty, it is imperative to evaluate its impact on LOS. The objectives of this study were to compare LOS and discharge dispositions following robotic arm-assisted total knee arthroplasty (RO TKA) and unicompartmental arthroplasty (RO UKA) versus conventional technique (CO TKA and UKA).

Introduction. This study was designed to evaluate the effect of discharge timing on 30-day major and minor complications in patients undergoing total knee arthroplasty (TKA) while adjusting for other variables. Methods. Patients 18 years and older undergoing TKA between the years of 2005 and 2016 were identified from the American College of Surgeons National Surgical Quality Improvement Program (NSQIP). Patients whose length of stay (LOS) was >4 days were excluded. Patient demographics, anesthesia type, length of operation and hospital stay, as well as 30-day major and minor complications were collected from the database. Chi square tests were utilized to compare the unadjusted rates of complications between patients whose LOS was 0, 1, 2, and 3–4 days. Multivariable regression was utilized to evaluate the effect of LOS on complication rates, while adjusting for age, American Society of Anesthesiologist (ASA) class, type of anaesthesia, functional status, comorbidities, sex, steroid/immunosuppressant use, body mass index (BMI), diabetes, length of operation and smoking status. Results. A total of 198,191 TKA patients were identified (average age 66 ± 10 years). Average LOS was 2.5 ± 0.81 days. Of these patients, 1,667 (0.84%) were discharged the day of surgery, while 16,186 (8.17%) were discharged one-day post-surgery, 63,540 (32.06%) were discharged on day two, and 115,471 (58.25%) were discharged between 3 and 4 days post-surgery. Unadjusted rates of complications were significantly higher for patients who were discharged on the day of surgery (2.64%), or those whose LOS was 3–4 days (2.78%) compared to those whose LOS was 1 (1.40%) or 2 days (1.67%). After adjusting for all relevant covariables, discharge on the day of surgery increased the risk of major complications by 1.8 (95% Confidence interval [95%CI] 1.2–2.8), and minor complications by 1.6 (95%CI 1.2 – 2.2) compared to patients whose LOS was 2 days. A LOS of 1 day did not affect the risk of major complications compared to a LOS of 2 days, while a LOS of 3–4 days increased the risk of major complications by 1.4 (95%CI 1.3 – 1.6), and minor complications by 1.6 (95%CI 1.4 – 1.7). Regarding specific complications, same-day discharge remained an independent predictor of myocardial infarction (MI), cardiac arrest, pulmonary embolism (PE), unplanned reintubation, >48 hours on ventilator, pneumonia and renal insufficiency, while a LOS of 3–4 days remained an independent predictor of MI, cardiac arrest, sepsis, acute renal failure, PE, unplanned reintubation, >48 hours on ventilator, stroke, deep vein thrombosis, pneumonia, urinary tract infection, renal insufficiency, deep and superficial surgical site infection, and wound disruption compared to patients whose LOS was 2 days (p<0.01). Conclusion. Discharge on days 1–2 postoperatively following TKA appears to have superior outcomes compared to discharge on the day of surgery, or on days 3–4. Prospective clinical data is required to confirm the effect of discharge timing on postoperative outcomes following TKA

Aims

Despite recent literature questioning their use, vancomycin and clindamycin often substitute cefazolin as the preoperative antibiotic prophylaxis in primary total knee arthroplasty (TKA), especially in the setting of documented allergy to penicillin. Topical povidone-iodine lavage and vancomycin powder (VIP) are adjuncts that may further broaden antimicrobial coverage, and have shown some promise in recent investigations. The purpose of this study, therefore, is to compare the risk of acute periprosthetic joint infection (PJI) in primary TKA patients who received cefazolin and VIP to those who received a non-cephalosporin alternative and VIP.

Aims

To compare rates of serious adverse events in patients undergoing revision knee arthroplasty with consideration of the indication for revision (urgent versus elective indications), and compare these with primary arthroplasty and re-revision arthroplasty.

Aims

It has been shown that the preoperative modification of risk factors associated with obesity may reduce complications after total knee arthroplasty (TKA). However, the optimal method of doing so remains unclear. The aim of this study was to investigate whether a preoperative Risk Stratification Tool (RST) devised in our institution could reduce unexpected intensive care unit (ICU) transfers and 90-day emergency department (ED) visits, readmissions, and reoperations after TKA in obese patients.