Almost 79% survival rate at 10-year follow-up for the patellofemoral joint arthroplasty: An Italian prosthetic registry study.

PURPOSE: The aims of the present study were (1) to evaluate the survival of patellofemoral joint (PFJ) arthroplasty in a large cohort of patients using data obtained from an Italian regional arthroplasty registry and (2) to collect clinical outcomes of a subgroup of patients, with a minimum follow-up of 4 years. The hypotheses were that PFJ arthroplasty is a procedure that had good survival and clinical outcomes, not inferior to those reported in the literature for primary total knee arthroplasty (TKA). METHODS: The Register of Orthopaedic Prosthetic Implants (RIPO) of Emilia-Romagna (ER) (Italy) database was searched for the inclusion of all PFJ arthroplasties implanted between 2003 and 2019. PFJ arthroplasties were excluded if they were implanted in patients who lived outside of the ER. The survival information was extrapolated from the RIPO considering the partial or total revision of the implant as failure; moreover, a subgroup of patients was contacted and interviewed by telephone to collect clinical outcomes. Descriptive statistics were used to summarise the data. The survival curve was calculated and plotted using the Kaplan-Meier method. RESULTS: A total of 126 arthroplasties in 114 patients were included in the final analysis (mean age at surgery 60.1 ± 11.5 years old). The main causes of patellofemoral arthroplasty were primary osteoarthritis (88%) and posttraumatic arthritis (7%). The survival was 90.4 ± 30.6 and 78.8 ± 51.5 at 5 and 10 years of follow-up, respectively. At the latest follow-up, 23 implants failed (18.3%). The main cause of revision was osteoarthrosis progression (34.8%). A total of 44 patients were contacted by telephone to collect clinical outcomes: Western Ontario and McMaster Universities Osteoarthritis Index, functional Knee Society Score, Forgotten Joint Score and Oxford Knee Score. These patients reported good to excellent scores at a medium follow-up of 10.3 ± 4.7 years. CONCLUSIONS: The PFJ showed good survival and clinical outcomes and could be considered a valuable option for patients affected by isolated patellofemoral osteoarthritis. LEVEL OF EVIDENCE: Level IV.

What Is the True Impact of Periprosthetic Joint Infection Diagnosis on Mortality?

BACKGROUND: Mortality is a quality indicator that may affect expenditures. Revisions for periprosthetic joint infection (PJI) are, on average, more expensive and exhibit higher morbidity than aseptic revisions, although reimbursement is similar. Therefore, we sought to determine (1) impact on mortality rates of revision total hip and/or knee arthroplasty performed for PJI diagnosis (septic) versus aseptic revisions, at any point in time, and (2) mortality predictors among PJI patients. METHODS: Retrospective chart review of 978 consecutive patients who underwent revision at a single institution (January 2015 to November 2020). All revisions were evaluated, and it was determined whether patients had a revision for PJI at any point in time or not. Two groups were compared: (1) patients with septic revision(s) (n = 350) and (2) patients who only underwent aseptic revision(s) (n = 628). Demographics and mortality status at latest follow-up (mean 3 years, range: 0 to 18 years, from first revision ever) were assessed. Mortality status was also separately assessed among patients who exclusively had hip revision(s), or solely knee revision(s), or both. Multivariate regression analysis (Cox) was used to determine whether PJI diagnosis was an independent mortality predictor. Among PJI patients, potential mortality predictors were evaluated. RESULTS: Overall, 65 patients died (6.6%). The septic cohort had significantly more men and American Society of Anesthesiologists (ASA) class-IV patients. Mortality rates were 10.9% and 4.3% (P < .0001) for septic and aseptic revision groups, respectively. After controlling for sex, ASA, and number of revisions, PJI diagnosis was a significant mortality predictor (hazard ratio [HR]: 2.69, 95% confidence interval [CI]: 1.5 to 4.7, P = .001). Among PJI patients, age (HR: 1.05, 95% CI: 1.01 to 1.08, P = .009) and ASA (HR: 4.02, 95% CI: 1.67 to 9.67, P = .002) were independent predictors. CONCLUSIONS: Having a revision due to PJI diagnosis was associated with 2.5 times increased mortality. Therefore, more accurate coding capturing the complexity and morbidity of revisions for PJI diagnosis is needed.

Unseen Threefold Mortality After the First Ten Days in Hemodialysis Patients Following Joint Arthroplasty: A Nationwide Retrospective Cohort Study of 1,287 Arthroplasty Patients on Hemodialysis.

BACKGROUND: The study addresses the growing number of hemodialysis (HD) patients undergoing joint arthroplasty, who are at higher risk of complications and mortality. Previous research has often overlooked deaths after discharge. This study aimed to examine early outcomes in a large nationwide cohort of patients who underwent arthroplasty for elective and fracture-related reasons. METHODS: Between 2016 and 2022, a study was conducted using the e-Nabiz database of the Türkiye Ministry of Health, focusing on patients aged 18 years and above who underwent elective or fracture-related arthroplasty. This study included 1,287 patients reliant on dialysis who underwent total hip arthroplasty, total knee arthroplasty, or hemiarthroplasty (HA), with 7.7% of them receiving dialysis for the first time. Propensity score matching was used to create an equally sized group of non-dialysis-dependent patients, ensuring demographic balance in terms of age, sex, a comorbidity index, and surgery type. The primary objective was to compare mortality rates 10, 30, and 90 days after arthroplasty. RESULTS: The first-time dialysis patients who underwent HA had significantly higher 30- and 90-day mortality rates compared to the chronic dialysis group (P = .040 and P < .001, respectively). Also, the HD patients consistently exhibited higher 90-day mortality rates across all surgery types. With total knee arthroplasty, HD patients had a mortality rate of 8.7%, in stark contrast to 0% among non-HD patients (P < .001). Similarly, with total hip arthroplasty, HD patients had a 12% mortality rate, while non-HD patients had a markedly lower rate of 2.7% (P = .008). In the case of HA, HD patients had a significantly elevated 90-day mortality rate of 31.9%, in contrast to 17.1% among non-HD patients (P < .001). CONCLUSIONS: Joint arthroplasty has higher rates of mortality and complications among HD patients. Surgical decisions must be based on patients' overall health, necessitating collaboration among specialists. These patients should be closely monitored.

Incidence and survival of multiply revised knee arthroplasties in Denmark 1998-2021: a nationwide register-based study.

PURPOSE: The primary aim of our study was to identify the absolute incidence and implant survival of multiply revised knee arthroplasties based on nationwide register data. The secondary aim was to determine the change in the absolute incidence and implant survival of multiply revised knee arthroplasties Methods: We performed a retrospective observational study of primary knee arthroplasties using several nationwide Danish registers. All primary knee arthroplasties performed in Denmark from 1998 to 2021 were identified. From these primary arthroplasties, revision procedures were identified. Kaplan-Meier plots were used in survival analysis to estimate the likelihood of implant survival. RESULTS: 161,384 primary knee arthroplasties and their revisions performed between 1998 and 2021 were identified; of 13,786 (8.5%) revisions there were 10,638 1st revisions, 2,148 2nd revisions, 624 3rd revisions, 223 4th revisions, and 153 procedures that had been revised more than 4 times. The 10-year revision-free survival of primary arthroplasties was 92.3% (95% confidence interval [CI] 92.2-92.5). First-time revisions had a 10-year revision-free survival of 75.9% (CI 74.9-76.9). The 10-year survival of second- and third-time revisions was 65.1% (CI 62.6-67.6) and 57.8% (CI 53.4-62.5), respectively. The 10-year implant survival probabilities of primary knee arthroplasties were 91.4% in 1998-2009 and 93.3% in 2010-2021 (difference 2.2%). The 10-year implant survival probabilities of 1st revisions were 77% in 1998-2009 and 75% in 2010-2021 (difference -2.4%). CONCLUSION: We found that 0.3% of all primary knee arthroplasties resulted in 3 or more revisions. The implant survival decreased for each consecutive revision, with almost half of the 3rd revisions being re-revised within 10 years. The 10-survival of the primary implant was higher in 2010-2021, and the 10-year survival of the 1st revision was higher in 1998-2009.

Hospital volume-outcome relationship in total knee arthroplasty: a systematic review and dose-response meta-analysis.

PURPOSE: This systematic review and dose-response meta-analysis aimed to investigate the relationship between hospital volume and outcomes for total knee arthroplasty (TKA). METHODS: MEDLINE, Embase, CENTRAL and CINAHL were searched up to February 2020 for randomised controlled trials and cohort studies that reported TKA performed in hospitals with at least two different volumes and any associated patient-relevant outcomes. The adjusted effect estimates (odds ratios, OR) were pooled using a random-effects, linear dose-response meta-analysis. Heterogeneity was quantified using the I2-statistic. ROBINS-I and the GRADE approach were used to assess the risk of bias and the confidence in the cumulative evidence, respectively. RESULTS: A total of 68 cohort studies with data from 1985 to 2018 were included. The risk of bias for all outcomes ranged from moderate to critical. Higher hospital volume may be associated with a lower rate of early revision ≤ 12 months (narrative synthesis of k = 7 studies, n = 301,378 patients) and is likely associated with lower mortality ≤ 3 months (OR = 0.91 per additional 50 TKAs/year, 95% confidence interval [0.87-0.95], k = 9, n = 2,638,996, I2 = 51%) and readmissions ≤ 3 months (OR = 0.98 [0.97-0.99], k = 3, n = 830,381, I2 = 44%). Hospital volume may not be associated with the rates of deep infections within 1-4 years, late revision (1-10 years) or adverse events ≤ 3 months. The confidence in the cumulative evidence was moderate for mortality and readmission rates; low for early revision rates; and very low for deep infection, late revision and adverse event rates. CONCLUSION: An inverse volume-outcome relationship probably exists for some TKA outcomes, including mortality and readmissions, and may exist for early revisions. Small reductions in unfavourable outcomes may be clinically relevant at the population level, supporting centralisation of TKA to high-volume hospitals. LEVEL OF EVIDENCE: III. REGISTRATION NUMBER: The study was registered in the International Prospective Register of Systematic Reviews (PROSPERO CRD42019131209 available at: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=131209 ).

Obesity and revision surgery, mortality, and patient-reported outcomes after primary knee replacement surgery in the National Joint Registry: A UK cohort study.

BACKGROUND: One in 10 people in the United Kingdom will need a total knee replacement (TKR) during their lifetime. Access to this life-changing operation has recently been restricted based on body mass index (BMI) due to belief that high BMI may lead to poorer outcomes. We investigated the associations between BMI and revision surgery, mortality, and pain/function using what we believe to be the world's largest joint replacement registry. METHODS AND FINDINGS: We analysed 493,710 TKRs in the National Joint Registry (NJR) for England, Wales, Northern Ireland, and the Isle of Man from 2005 to 2016 to investigate 90-day mortality and 10-year cumulative revision. Hospital Episodes Statistics (HES) and Patient Reported Outcome Measures (PROMs) databases were linked to the NJR to investigate change in Oxford Knee Score (OKS) 6 months postoperatively. After adjustment for age, sex, American Society of Anaesthesiologists (ASA) grade, indication for operation, year of primary TKR, and fixation type, patients with high BMI were more likely to undergo revision surgery within 10 years compared to those with "normal" BMI (obese class II hazard ratio (HR) 1.21, 95% CI: 1.10, 1.32 (p < 0.001) and obese class III HR 1.13, 95% CI: 1.02, 1.26 (p = 0.026)). All BMI classes had revision estimates within the recognised 10-year benchmark of 5%. Overweight and obese class I patients had lower mortality than patients with "normal" BMI (HR 0.76, 95% CI: 0.65, 0.90 (p = 0.001) and HR 0.69, 95% CI: 0.58, 0.82 (p < 0.001)). All BMI categories saw absolute increases in OKS after 6 months (range 18-20 points). The relative improvement in OKS was lower in overweight and obese patients than those with "normal" BMI, but the difference was below the minimal detectable change (MDC; 4 points). The main limitations were missing BMI particularly in the early years of data collection and a potential selection bias effect of surgeons selecting the fitter patients with raised BMI for surgery. CONCLUSIONS: Given revision estimates in all BMI groups below the recognised threshold, no evidence of increased mortality, and difference in change in OKS below the MDC, this large national registry shows no evidence of poorer outcomes in patients with high BMI. This study does not support rationing of TKR based on increased BMI.

Postoperative Morbidity and Mortality in Diabetic Patients After Fast-Track Hip and Knee Arthroplasty: A Prospective Follow-up Cohort of 36,762 Procedures.

BACKGROUND: Diabetes increases the risk of adverse outcomes in surgical procedures, including total hip and knee arthroplasty (THA/TKA), and the prevalence of diabetic patients undergoing these procedures is high, ranging from approximately 8% to 20%. However, there is still a need to clarify the role of diabetes and antihyperglycemic treatment in a fast-track THA/TKA setting, which otherwise may decrease morbidity. Consequently, we investigated the association between diabetes and antihyperglycemic treatment on length of stay (LOS) and complications following fast-track THA/TKA within a multicenter fast-track collaboration. METHODS: We used an observational study design on data from a prospective multicenter fast-track collaboration on unselected elective primary THA/TKA from 2010 to 2017. Complete follow-up (>99%) was achieved through The Danish National Patient Registry, antihyperglycemic treatment established through the Danish National Database of Reimbursed Prescriptions and types of complications leading to LOS >4 days, 90-day readmission or mortality obtained by scrutinizing health records and discharge summaries. Patients were categorized as nondiabetic and if diabetic into insulin-, orally, and dietary-treated diabetic patients. RESULTS: A total of 36,762 procedures were included, of which 837 (2.3%) had insulin-treated diabetes, 2615 (7.1%) orally treated diabetes, and 566 (1.5%) dietary-treated diabetes. Overall median LOS was 2 (interquartile range [IQR]: 1-3) days, and mean LOS was 2.4 (standard deviation [SD], 2.5) days. The proportion of patients with LOS >4 days was 6.0% for nondiabetic patients, 14.7% for insulin-treated, 9.4% for orally treated, and 9.5% for dietary-treated diabetic patients. Pharmacologically treated diabetes (versus nondiabetes) was independently associated with increased odds of LOS >4 days (insulin-treated: odds ratio [OR], 2.2 [99.6% confidence interval {CI}, 1.3-3.7], P < .001; orally treated: OR, 1.5 [99.6% CI, 1.0-2.1]; P = .002). Insulin-treated diabetes was independently associated with increased odds of "diabetes-related" morbidity (OR, 2.3 [99.6% CI, 1.2-4.2]; P < .001). Diabetic patients had increased renal complications regardless of antihyperglycemic treatment, but only insulin-treated patients suffered significantly more cardiac complications than nondiabetic patients. There was no increase in periprosthetic joint infections or mortality associated with diabetes. CONCLUSIONS: Patients with pharmacologically treated diabetes undergoing fast-track THA/TKA were at increased odds of LOS >4 days. Although complication rates were low, patients with insulin-treated diabetes were at increased odds of postoperative complications compared to nondiabetic patients and to their orally treated counterparts. Further investigation into the pathogenesis of postoperative complications differentiated by antihyperglycemic treatment is needed.

Fatal outcome and intensive care unit admission after total hip and knee arthroplasty: An analytic of preoperative frailty and comorbidities.

BACKGROUND: With increasing demand for total hip arthroplasty (THA) and total knee arthroplasty (TKA), a higher percentage of patients are identified with comorbidities that might increase the risk of complications. We aimed to elucidate the preoperative characteristics of patients with a fatal outcome or admission to the Intensive Care Unit (ICU) within 90 days after THA or TKA. We arbitrarily hypothesized that more than 50% of those patients would be frail. METHODS: This is a register based, explorative study including patients undergoing elective, unilateral, primary THA or TKA in the Capital Region of Denmark from 2010 to 2017, and who subsequently died or were admitted to the ICU within 90 days. The modified Frailty Index (mFI) was calculated from the medical records, and a score of ≥0.36 defined frailty. RESULTS: A total of 33,758 patients underwent THA or TKA, and 284 patients (0.8%) died or were admitted to the ICU within 90 days. Fifty-seven patients (20%) were frail (95% CI 16.2-25.7%). The most common comorbidities were hypertension (63%) and pulmonary diseases (32%), and 56% used walking aids. Two or more comorbidities were present in 65% of patients, and 14% had no comorbidities at all. CONCLUSION: Only 20% of patients with a fatal outcome or ICU admission after elective THA or TKA could be categorized as frail based on the mFI. Further studies with a prospective design are needed to clarify the mFI as a risk stratification tool in elderly multimorbid patients undergoing elective arthroplasty surgery.

Bi-cruciate retaining total knee arthroplasty: a systematic literature review of clinical outcomes.

Total knee arthroplasty (TKA) has been shown to have good long-term outcomes and survivorship. Nonetheless, dissatisfied patients are frequently reported in the literature. Bi-cruciate retaining total knee prostheses (BCR TKA) were designed to address the demand for more kinematically functional implants that better reconstruct natural knee kinematics. In BCR TKA, the anterior cruciate ligament (ACL) is preserved. Improved patient-reported outcomes and satisfaction levels are expected. This review aimed to summarize indications for and clinical outcomes of BCR TKA. A systematic literature review on BCR TKA was performed. 24 articles were included for data analysis. Indications covered osteoarthritis, inflammatory arthritis and others. The degree of deformity was often but not always limited to minor axial deformity and contractures: maximum acceptable varus/valgus deformity reached 10°-30° and flexion contractures of 15°-65°. ACL intactness was macroscopically examined intraoperatively in nine studies and clinically tested in ten studies (e.g., Lachmann Test, drawer-test). Objective and patient-reported outcome scores were reported for follow-up periods of up to 22 years. Survival rates varied significantly. For first generation implants, 22-year survival reached 82% while a second generation design was associated with 13.5% revision rate at 18 months. Reasons for varying outcomes were not clear and may be attributed to the implant itself, surgical techniques and patient specific variables including changed expectations and functional demand. The literature has not shown clear indications and guidelines for the use of BCR implants. The promising results of first generation BCR TKA designs may be optimized through improved implant designs in the future. Further studies are advocated to provide the necessary evidence of second generation BCR TKA designs.

Risk of a complete exchange or failure in total knee arthroplasty and unicompartmental knee arthroplasty: a nationwide population-based cohort study from South Korea.

PURPOSE: Few large-scale studies using adjusted data from national registries have explored the risk factors of subsequent revision in patients with unicompartmental knee arthroplasty (UKA) compared to those with total knee arthroplasty (TKA). We investigated the incidence rate and risk factors of subsequent revision in patients with UKA and TKA. METHODS: We enrolled all patients who had undergone TKA or UKA as the primary surgical procedure without histories of having undergone either procedure during the preceding 2 years. Matched Cox regression models were used to compare the risks of revision between groups after propensity score matching. Revision was defined as conversion to revision TKA after primary TKA and conversion to TKA after UKA. RESULTS: The study enrolled 418,806 TKA patients and 446,009 UKA patients. The risk of revision during the entire study period was higher for patients with UKA than for patients with TKA (adjusted hazard ratio [HR] 1.22, 95% confidence interval [95% CI]: 1.10-1.36). The Kaplan-Meier 8-year survival was 98.7% in the TKA group and 96.7% in the UKA group. Patients with UKA were at an increased risk of revision in cases of advanced age (70-79 years, HR 1.40, 95% CI: 1.15-1.71), female sex (HR 1.32, 95% CI: 1.16-1.49), the presence of chronic obstructive pulmonary disease (COPD) (HR 1.27, 95% CI: 1.05-1.54), the presence of peptic ulcer disease (PUD) (HR 1.34, 95% CI: 1.11-1.61) compared to patients with TKA. In patients with hemiplegia, however, UKA were associated with a lower risk of subsequent revision (HR 0.25, 95% CI: 0.07-0.94). CONCLUSION: The risk of a complete exchange or failure was higher for patients with UKA than for patients with TKA. The most significant independent risk factors for subsequent a complete exchange or failure in patients with UKA were advanced age (70-79 years), female sex, and the presence of comorbidities such as COPD and PUD.

Pulmonary Complications After Hip and Knee Arthroplasty in the United States, 2004-2014.

BACKGROUND: Pulmonary complications after total joint arthroplasty (TJA) are uncommon but have significant cost impact. Total hip arthroplasty (THA) and total knee arthroplasty (TKA) are 2 of the 5 top procedures requiring inpatient stay within the United States. Subsequent pulmonary complications therefore may impose substantial cost burden for US health care. The purpose of this study was to describe the incidence, risk factors, and clinical implications of pulmonary complications (ie, pneumonia, respiratory failure, pulmonary embolism [PE], and aspiration) after TJA in the United States. METHODS: The National Inpatient Sample (NIS) was queried for all patients undergoing primary, elective THA and TKA between years 2004 and 2014. Pulmonary complications were defined as the occurrence of pneumonia, respiratory failure, PE, or aspiration after TJA. Demographic and clinical characteristics, inpatient cost, length of stay (LOS), and mortality were compared between patients with and without documented perioperative pulmonary complications. Given the stratified nature of the NIS database, estimates of incidence throughout the United States were made with application of trend weights to observed database frequencies. Analyses of estimated annual complication rates were made using χ tests. RESULTS: Between 2004 and 2014, an estimated 2,679,351 patients underwent elective primary THA. A total of 5,527,205 patients were estimated to have undergone elective primary TKA. THA 1.42% (95% CI, 1.37%-1.47%) and 1.71% (95% CI, 1.66%-1.76%) of TKA procedures were complicated by pneumonia, respiratory failure, PE, or aspiration. During this time, the incidence of perioperative pulmonary complications decreased from 1.57% (95% CI, 1.41%-1.73%) to 1.01% (95% CI, 0.92%-1.10%) after THA (P < .0001) and from 2.03% (95% CI, 1.88%-2.18%) to 1.33% (95% CI, 1.25%-1.42%) after TKA (P < .0001). The adjusted odds ratio (aOR) of experiencing a pulmonary complication was highest among patients with history of significant weight loss (aOR = 4.77; 99.9% CI, 3.97-5.73), fluid/electrolyte disorders (aOR = 3.33; 99.9% CI, 3.11-3.56), congestive heart failure (CHF; aOR = 3.32; 99.9% CI, 3.07-3.58), preexisting paralytic condition (aOR = 2.03; 99.9% CI, 1.57-2.61), and human immunodeficiency virus infection (aOR = 2.00; 99.9% CI, 1.06-3.78). Perioperative pulmonary complications were associated with increased LOS (THA = 3.03 days; 99.9% CI, 2.76-3.31; TKA = +2.72 days; 99.9% CI, 2.58-2.86), increased hospital costs (THA = +9163 US dollars; 99.9% CI, 8054-10,272; TKA = +7257 US dollars; 99.9% CI, 6650-7865), and increased mortality (THA: aOR = 121; 99.9% CI, 78-187; TKA: aOR = 150; 95% CI, 97-233). CONCLUSIONS: Despite a decline in overall incidence, perioperative pulmonary complications represent a significant potential source of perioperative morbidity and mortality. The current study highlights potential risk factors for pulmonary complications. Recognition of these factors may help to better stratify patients and mitigate risk of potential complications. This is particularly true of respiratory failure as it is associated with the high increases in resource utilization and mortality in this group.

How Accurate Are the Surgical Risk Preoperative Assessment System (SURPAS) Universal Calculators in Total Joint Arthroplasty?

BACKGROUND: Surgical outcome prediction models are useful for many purposes, including informed consent, shared decision making, preoperative mitigation of modifiable risk, and risk-adjusted quality measures. The recently reported Surgical Risk Preoperative Assessment System (SURPAS) universal risk calculators were developed using 2005-2012 American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP), and they demonstrated excellent overall and specialty-specific performance. However, surgeons must assess whether universal calculators are accurate for the small subset of procedures they perform. To our knowledge, SURPAS has not been tested in a subset of patients undergoing lower-extremity total joint arthroplasty (TJA). QUESTIONS/PURPOSES: How accurate are SURPAS models' predictions for patients undergoing TJA? METHODS: We identified an internal subset of patients undergoing non-emergency THA or TKA from the 2012 ACS-NSQIP, the most recent year of the SURPAS development dataset. To assess the accuracy of SURPAS prediction models, 30-day postoperative outcomes were defined as in the original SURPAS study: mortality, overall morbidity, and six complication clusters-pulmonary, infectious, cardiac or transfusion, renal, venous thromboembolic, and neurologic. We calculated predicted outcome probabilities by applying coefficients from the published SURPAS logistic regression models to the TJA cohort. Discrimination was assessed with C-indexes, and calibration was assessed with Hosmer-Lemeshow 10-group chi-square tests and decile plots. RESULTS: The 30-day postoperative mortality rate for TJA was 0.1%, substantially lower than the 1% mortality rate in the SURPAS development dataset. The most common postoperative complications for TJA were intraoperative or postoperative transfusion (16%), urinary tract infection (5%), and vein thrombosis (3%). The C-indexes for joint arthroplasty ranged from 0.56 for venous thromboembolism (95% CI 0.53 to 0.59 versus SURPAS C-index 0.78) to 0.82 for mortality (95% CI 0.76 to 0.88 versus SURPAS C-index 0.94). All joint arthroplasty C-index estimates, including CIs, were lower than those reported in the original SURPAS development study. Decile plots and Hosmer-Lemeshow tests indicated poor calibration. Observed mortality rates were lower than expected for patients in all risk deciles (lowest decile: no observed deaths, 0.0% versus expected 0.1%; highest decile: observed mortality 0.7% versus expected 2%; p < 0.001). Conversely, observed morbidity rates were higher than expected across all risk deciles (lowest decile: observed 12% versus expected 8%; highest decile: observed morbidity 32% versus expected 25%; p < 0.001) CONCLUSIONS: The universal SURPAS risk models have lower accuracy for TJA procedures than they do for the wider range of procedures in which the SURPAS models were originally developed. CLINICAL RELEVANCE: These results suggest that SURPAS model estimates must be evaluated for individual surgical procedures or within restricted groups of related procedures such as joint arthroplasty. Given substantial variation in patient populations and outcomes across numerous surgical procedures, universal perioperative risk calculators may not produce accurate and reliable results for specific procedures. Surgeons and healthcare administrators should use risk calculators developed and validated for specific procedures most relevant to each decision. Continued work is needed to assess the accuracy of universal risk calculators in more narrow procedural categories based on similarity of outcome event rates and prevalence of predictive variables across procedures.

Comorbidities rather than age affect medium-term outcome in octogenarian patients after total knee arthroplasty.

PURPOSE: As the population ages, it is important to determine whether total knee arthroplasties (TKA)s are safe and beneficial in the octogenarian population. The aims of the present study were: (1) to assess the effect of comorbidities and age on the incidence of postoperative complications following TKA and (2) to evaluate the mid-term outcome of octogenarian patients. METHODS: A retrospective matched-paired analysis by gender, BMI and duration of follow-up was conducted on 206 patients older than 80 years and younger than 75 years between 2009 and 2016, undergoing primary TKA. The mean follow-up was 5 years. Outcome measures including Oxford Knee Score (OKS), Knee Society Score (KSS), Knee Society Function Score (KSFS), postoperative complications, length of stay (LOS) and survivorship were analysed. The association between complications and comorbidities was assessed using multivariable logistic regression after adjusting for age, Deyo-Charlson Comorbidity Index (D-CCI) and the American Society of Anesthesiologist's (ASA) physical status classification. RESULTS: In the multivariable models, D-CCI class is an independent predictor for postoperative cardiac complications, delirium and transfusion rate (OR ranging from 1.2 to 69.5 in respect to D-CCI reference class 0). Being ≥ 80 years old was associated with an increased risk of transfusion (OR 3.4; 95% CI 1.7-6.8) and 1.7-day increase in LOS (p < 0.001). Both groups showed significant improvement in postoperative knee scores following TKA. CONCLUSION: Octogenarians experienced good clinical results when compared to their younger counterparts. Comorbidities, rather than age itself, are responsible for the increase in postoperative morbidity. Preoperative risk assessment has to be optimized in order to reduce complications.

Age and gender related differences in infection, thromboembolism, revision and death in knee arthroplasty in a Scottish population.

BACKGROUND AND AIMS: The aim of this large population based study was to investigate the effect of patient age and gender on the complication rates of knee arthroplasty surgery using data from the Scottish Arthroplasty Project joint registry. METHODS AND RESULTS: 55,636 knee arthroplasty procedures were included in the study and divided into four age categories (<55, 55-64, 65-75 and >75 years) for comparison of the 90-day deep vein thrombosis or pulmonary embolism (DVT/PE) and one-year infection rates and the mortality and revision rates up to ten-year follow up. The mean rate of DVT/PE was 1.4% with significantly higher rates in elderly patients (p = 0.0006). The mean one-year infection rate was 1.6% with a significantly increased rate of 1.9% in males (p = 0.0001). Mortality rates increased with age, the 10-year mortality in patients >75 years of age was 44.8%. Revision rates were increased in males and younger patients. CONCLUSION: Elderly patients showed higher rates of thromboembolic complications. There was no difference in infection rates between different age groups. The infection rate was higher in males. Younger patients need to be counselled about the increased risk of revision at 10 years.

Anaesthetic care of patients undergoing primary hip and knee arthroplasty: consensus recommendations from the International Consensus on Anaesthesia-Related Outcomes after Surgery group (ICAROS) based on a systematic review and meta-analysis.

BACKGROUND: Evidence-based international expert consensus regarding anaesthetic practice in hip/knee arthroplasty surgery is needed for improved healthcare outcomes. METHODS: The International Consensus on Anaesthesia-Related Outcomes after Surgery group (ICAROS) systematic review, including randomised controlled and observational studies comparing neuraxial to general anaesthesia regarding major complications, including mortality, cardiac, pulmonary, gastrointestinal, renal, genitourinary, thromboembolic, neurological, infectious, and bleeding complications. Medline, PubMed, Embase, and Cochrane Library including Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, NHS Economic Evaluation Database, from 1946 to May 17, 2018 were queried. Meta-analysis and Grading of Recommendations Assessment, Development and Evaluation approach was utilised to assess evidence quality and to develop recommendations. RESULTS: The analysis of 94 studies revealed that neuraxial anaesthesia was associated with lower odds or no difference in virtually all reported complications, except for urinary retention. Excerpt of complications for neuraxial vs general anaesthesia in hip/knee arthroplasty, respectively: mortality odds ratio (OR): 0.67, 95% confidence interval (CI): 0.57-0.80/OR: 0.83, 95% CI: 0.60-1.15; pulmonary OR: 0.65, 95% CI: 0.52-0.80/OR: 0.69, 95% CI: 0.58-0.81; acute renal failure OR: 0.69, 95% CI: 0.59-0.81/OR: 0.73, 95% CI: 0.65-0.82; deep venous thrombosis OR: 0.52, 95% CI: 0.42-0.65/OR: 0.77, 95% CI: 0.64-0.93; infections OR: 0.73, 95% CI: 0.67-0.79/OR: 0.80, 95% CI: 0.76-0.85; and blood transfusion OR: 0.85, 95% CI: 0.82-0.89/OR: 0.84, 95% CI: 0.82-0.87. CONCLUSIONS: Recommendation: primary neuraxial anaesthesia is preferred for knee arthroplasty, given several positive postoperative outcome benefits; evidence level: low, weak recommendation. RECOMMENDATION: neuraxial anaesthesia is recommended for hip arthroplasty given associated outcome benefits; evidence level: moderate-low, strong recommendation. Based on current evidence, the consensus group recommends neuraxial over general anaesthesia for hip/knee arthroplasty. TRIAL REGISTRY NUMBER: PROSPERO CRD42018099935.

Days alive and out of hospital after fast-track total hip and knee arthroplasty: an observational cohort study in 16 137 patients.

BACKGROUND: Days alive and out of hospital (DAH) has been proposed as a pragmatic outcome measure of surgical quality. However, there is a lack of procedure specific data or data within an optimised fast-track protocol. Furthermore, information about influence of follow-up duration and types of complications on DAH is limited. METHODS: Observational multicentre cohort study of patients undergoing fast-track total hip (THA) and knee arthroplasty (TKA). Prospective information on comorbidity and complete 90 days follow-up was undertaken through the Danish National Patient Register and chart review. RESULTS: For 16 137 procedures, of which 18.6% were high-risk (≥2 preoperative risk factors), the median length of stay was 2 days (inter-quartile range [IQR], 2-3), and 30- and 90-day readmission rates were 5.7% and 8.1%, respectively. Median DAH30 and DAH90 days were 27 (26-28) and 87 (85-88) vs 28 (27-28) and 88 (87-89) (P<0.001) in high-vs low-risk patients, respectively. The fraction with DAH ≤25 at 30 days and DAH ≤85 at 90 days was increased in high-vs low-risk patients: 23.3% vs 6.8% (odds ratio [OR]=4.16; 95% confidence interval [CI], 3.73-4.65) and 26.0% vs 8.6% (OR=3.75; 95% CI, 3.38-4.16). There were relatively fewer 'surgical' complications in high- vs low-risk patients with DAH30 ≤25 (14.6% vs 25.8%) (OR=0.49; 95% CI, 0.37-0.65) and DAH90 ≤85 (16.9% vs 31.89%) (OR=0.43; 95% CI, 0.34-0.56). About 2% of patients had readmissions, but DAH was >25 and >85 at 30 and 90 days after operation, respectively. CONCLUSION: Median DAH in fast-track THA/TKA patients is 28 at 30 days and 88 at 90 days after surgery. DAH in high-risk patients was only slightly reduced compared with low-risk patients, but they have relatively more 'medical' complications.

How Does Mortality Risk Change Over Time After Hip and Knee Arthroplasty?

BACKGROUND: Mortality after THA and TKA is lower than expected for several years after surgery when compared with age- and sex-adjusted population data. With long-term followup (beyond approximately 10 years), some evidence has suggested that this trend reverses, such that postsurgical mortality is higher than expected as more time passes. However, the degree to which this may be the case has not been clearly established. QUESTIONS/PURPOSES: In this large-registry study, we asked: What is the long-term mortality after THA and TKA compared with the expected mortality, adjusted for age, sex, and calendar year. METHODS: Using data on 243,057 THAs and 363,355 TKAs performed for osteoarthritis from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) from 2003 to 2016, and life tables from the Australian Bureau of Statistics the Standardised Mortality Ratio (SMR), relative mortality and excess mortality (relative to the expected mortality for people of the same sex and age in the same country) was calculated separately for hips and knees. The AOANJRR contains near-complete (98%-100%) data from all hospitals in Australia performing arthroplasty but does not include followup data on people who have left the country. Followup was from the date of surgery to 13 years, mean 5.8 years. RESULTS: We found a lower-than-expected mortality for THA and TKA in the early years after surgery. This association diminished over time and the mortality became higher than expected after 12 years for both THA and TKA. For THA, the excess mortality (per thousand people) increased from 11 fewer deaths (95% CI, 10-11 fewer) after 1 year to four more deaths (95% CI, 0-9 more) in the 13th year, and the SMR increased from 0.50 (95% CI, 0.48-0.52) after 1 year to 1.07 (95% CI, 0.99-1.14) in the 13th year. For TKA, the excess mortality (per thousand people) increased from 12 fewer deaths (95% CI, 12-13 fewer) after 1 year to five more deaths (95% CI 2-9 more) in the 13th year, and the SMR increased from 0.39 (95% CI, 0.37-0.40) after 1 year to 1.09 (95% CI, 1.03-1.15) in the 13th year. CONCLUSIONS: Mortality after hip and knee arthroplasty is lower than expected (based on population norms) in the first 8 years to 9 years but gradually increases over time, becoming higher than expected after 12 years. The lower-than-expected mortality in the early years after surgery is likely the result of patient selection with patients undergoing primary arthroplasty having better health at the time of surgery than that of the age- and sex-matched population. The increasing mortality over time cannot be regression to the mean, as late mortality is higher than expected, moving beyond the mean. It is important to understand if there are modifiable factors associated with this increased mortality. The reasons for the change are uncertain. Factors to consider in future research include determining the effect of different patient factors on late mortality. Some of these included higher obesity rates for joint replacement patients and the association or causal impact of osteoarthritis and/or its treatment to increase late mortality in a similar manner to other forms of arthritis. There is also a possibility that the arthroplasty device itself may affect late mortality. LEVEL OF EVIDENCE: Level III, therapeutic study.

No Differences in Outcomes Scores or Survivorship of Unicompartmental Knee Arthroplasty Between Patients Younger or Older than 55 Years of Age at Minimum 10-Year Followup.

BACKGROUND: Although patients who have undergone unicompartmental knee arthroplasty (UKA) report improvements in functional outcomes, orthopaedic surgeons tend to avoid UKA in younger patients due to implant survivorship concerns. As a result, few studies specifically have examined the outcomes of patients 55 years and younger. QUESTIONS/PURPOSES: Is there a difference between two cohorts of patients: those 55 years and younger and those 56 years and older who underwent UKA in terms of: (1) functional outcomes scores, (2) quality-of-life scores, and (3) implant survivorship free from all-cause revision. METHODS: Between 2004 and 2007, 100 patients 55 years and younger underwent UKA at one institution. Of those, three (3%) died, and 13 (13%) were lost to followup before the 10-year minimum required for this study, leaving 84 patients available for propensity score matching. During that same period, 343 patients older than 56 years underwent UKA; 48 (14%) died, and 59 (17%) were lost to followup before 10 years, leaving 236 patients available in that group for potential inclusion. After propensity score matching to account for confounding preoperative variables (surgeon, patient's body mass index, and sex), the patients were divided into two groups based on age: (1) 55 years and younger, (2) 56 years and older. There were 71 patients in each group, with minimum followup of 10 years. The mean age in the group of patients 55 years and younger was 52 years (range, 45-55 years) and that of the older patients was 64 years (range, 56-80 years). The mean (range) followup in both groups was 13 years (range, 11-15 years). Patient functional outcomes, quality of life scores, and implant survivorship were assessed for both groups of patients. To detect a minimum clinically important difference of 5 points in the Oxford Knee Score (OKS), a sample size of at least 68 patients in each group would be required to achieve a power of 0.95. RESULTS: With the numbers available, there were no differences between patients 55 years and younger and those 56 years and older in terms of OKS (18 ± 6 versus 20 ± 8, mean difference -1.8; 95% CI, -4.1 to 0.5; p = 0.133) and Knee Society Knee Score (84 ± 16 versus 79 ± 21, mean difference 4.7; 95% CI, -1.8 to 11.2; p = 0.157) at 10 years postoperatively. With the numbers available, there were no differences between patients 55 years and younger and those 56 years and older in terms of the physical component summary (PCS) (47 ± 10 versus 48 ± 11, mean difference -0.4; 95% CI, -4.0 to 3.2; p = 0.827) and the mental component summary (MCS) (52 ± 12 versus 51 ± 12, mean difference 1.4; 95% CI, -2.6 to 5.4; p = 0.491) of the SF-36 at 10 years postoperatively. Finally, we found no differences with the numbers available between patients 55 years and younger and those 56 years and older in terms of survivorship free from all-cause revision at a minimum of 10 years followup (both groups had the same 10-year revision-free rate of 0.96; 95% CI, 0.91-1.00). CONCLUSIONS: Because we found few differences between patients 55 years and younger and those older than that in terms of functional outcomes, quality of life, and implant survivorship after UKA, we believe that appropriately selected younger patients should not be excluded from the potential benefits of undergoing UKA, especially in the hands of high-volume surgeons. LEVEL OF EVIDENCE: Level III, therapeutic study.

Can Machine Learning Methods Produce Accurate and Easy-to-use Prediction Models of 30-day Complications and Mortality After Knee or Hip Arthroplasty?

BACKGROUND: Existing universal and procedure-specific surgical risk prediction models of death and major complications after elective total joint arthroplasty (TJA) have limitations including poor transparency, poor to modest accuracy, and insufficient validation to establish performance across diverse settings. Thus, the need remains for accurate and validated prediction models for use in preoperative management, informed consent, shared decision-making, and risk adjustment for reimbursement. QUESTIONS/PURPOSES: The purpose of this study was to use machine learning methods and large national databases to develop and validate (both internally and externally) parsimonious risk-prediction models for mortality and complications after TJA. METHODS: Preoperative demographic and clinical variables from all 107,792 nonemergent primary THAs and TKAs in the 2013 to 2014 American College of Surgeons-National Surgical Quality Improvement Program (ACS-NSQIP) were evaluated as predictors of 30-day death and major complications. The NSQIP database was chosen for its high-quality data on important outcomes and rich characterization of preoperative demographic and clinical predictors for demographically and geographically diverse patients. Least absolute shrinkage and selection operator (LASSO) regression, a type of machine learning that optimizes accuracy and parsimony, was used for model development. Tenfold validation was used to produce C-statistics, a measure of how well models discriminate patients who experience an outcome from those who do not. External validation, which evaluates the generalizability of the models to new data sources and patient groups, was accomplished using data from the Veterans Affairs Surgical Quality Improvement Program (VASQIP). Models previously developed from VASQIP data were also externally validated using NSQIP data to examine the generalizability of their performance with a different group of patients outside the VASQIP context. RESULTS: The models, developed using LASSO regression with diverse clinical (for example, American Society of Anesthesiologists classification, comorbidities) and demographic (for example, age, gender) inputs, had good accuracy in terms of discriminating the likelihood a patient would experience, within 30 days of arthroplasty, a renal complication (C-statistic, 0.78; 95% confidence interval [CI], 0.76-0.80), death (0.73; 95% CI, 0.70-0.76), or a cardiac complication (0.73; 95% CI, 0.71-0.75) from one who would not. By contrast, the models demonstrated poor accuracy for venous thromboembolism (C-statistic, 0.61; 95% CI, 0.60-0.62) and any complication (C-statistic, 0.64; 95% CI, 0.63-0.65). External validation of the NSQIP- derived models using VASQIP data found them to be robust in terms of predictions about mortality and cardiac complications, but not for predicting renal complications. Models previously developed with VASQIP data had poor accuracy when externally validated with NSQIP data, suggesting they should not be used outside the context of the Veterans Health Administration. CONCLUSIONS: Moderately accurate predictive models of 30-day mortality and cardiac complications after elective primary TJA were developed as well as internally and externally validated. To our knowledge, these are the most accurate and rigorously validated TJA-specific prediction models currently available (http://med.stanford.edu/s-spire/Resources/clinical-tools-.html). Methods to improve these models, including the addition of nonstandard inputs such as natural language processing of preoperative clinical progress notes or radiographs, should be pursued as should the development and validation of models to predict longer term improvements in pain and function. LEVEL OF EVIDENCE: Level III, diagnostic study.

Vascular injury during primary total knee arthroplasty: A nationwide study.

PURPOSE: To evaluate the incidence, risk factors, mortality, and complications of direct vascular injury (VI) in patients who underwent primary total knee arthroplasty (TKA) using data from a nationwide database. METHODS: Data were collected from the National Health Insurance Research Database of Taiwan. The study group included 111,497 patients who underwent TKA from January 2004 to December 2011. In total, 15 cases of direct VI were reported (VI group). We analyzed the incidence, risk factors, mortality, complications of direct VI and hospital stays between groups (VI group and non-VI group). RESULTS: Average incidence of VI was 13.74 per 100,000 person-years. No patient-dependent risk factors for VI were identified. Surgeons with low surgical volume highly correlated with incidence of VI (P < 0.05). 90-day mortality was significantly higher (33.3% vs. 0.37%) and length of hospital stay was significantly longer (19.43 days vs. 7.26 days) in the VI group than in the control group. In addition, incidence of periprosthetic joint infection, restenosis at the injury site, and limb loss were significantly higher in the VI group than in the control group. CONCLUSION: VI during primary TKA was associated with significantly higher incidence of periprosthetic joint infection, restenosis at the injury site, and limb loss, as well as higher 90-day mortality. Therefore, surgeons should be aware of VI during primary TKA, especially those with low surgical volume.