Evaluation of a Preoperative Optimization Protocol for Primary Hip and Knee Arthroplasty Patients

Non-Tobacco Nicotine Dependence and Rates of Postoperative Complications in Total Knee Arthroplasty: A Propensity-Matched Comparison

INTRODUCTION

Tobacco use elevates the incidence of postoperative complications and remains a key modifiable risk factor of perioperative surgical optimization. It remains unclear whether non-tobacco nicotine dependence confers an increased risk of surgical complications. This study evaluates postoperative complications in patients with non-tobacco nicotine dependence for total knee arthroplasty (TKA).

METHODS

We queried the TriNetX health database using Current Procedural Terminology and International Classification of Diseases, 10th Revision (ICD-10) codes and identified two cohorts for evaluation. Cohort A was defined as patients who had a TKA; had a dependence on nicotine; did not have nicotine dependence to cigarettes, chewing tobacco, other tobacco products; and were between the ages of 35 and 90 years. Cohort B was defined as patients who had a TKA but did not have a dependence on nicotine or a personal history of nicotine dependence and were between the ages of 35 and 90 years.

RESULTS

This study analyzed a total of 10,594 non-tobacco nicotine-dependent patients and 175,079 non-dependent patients who underwent TKA. In the analysis of propensity-matched cohorts, non-tobacco nicotine-dependent patients demonstrated an increased rate of various postoperative complications within 90 days. Dependent patients saw a significantly increased risk of infection after a procedure ( P < 0.001), deep vein thrombosis ( P < 0.001), pulmonary embolism ( P < 0.001), sepsis ( P = 0.0065), and prosthetic joint infection ( P = 0.0361) and a higher 3-year revision rate ( P = 0.0084).

DISCUSSION

Non-tobacco nicotine dependence demonstrated an increased associated risk of postoperative surgical complications for patients undergoing TKA. Orthopaedic surgeons should consider evaluating non-tobacco nicotine dependence within their surgical optimization protocol.

LEVEL OF EVIDENCE

Level III, Prognostic.

The Removal of Total Knee Arthroplasty From the Inpatient-Only List has Improved Patient Optimization

INTRODUCTION

On January 1, 2018, the Centers for Medicare and Medicaid Services removed total knee arthroplasty (TKA) from the inpatient-only (IPO) list, expanding outpatient TKA (oTKA) to include patients with insurance coverage through their programs. These regulatory changes reinforced the need for preoperative optimization to ensure a safe and timely discharge after surgery. This study compared modifiable preoperative optimization metrics in patients who underwent oTKA pre-IPO and post-IPO removal. The authors hypothesized that patients post-IPO removal would demonstrate improvement in the selected categories.

METHODS

Outpatient TKA in a national database was identified and stratified by surgical year (2015 to 2017 versus 2018 to 2020). Preoperative optimization thresholds were established for the following modifiable risk factors: albumin, hematocrit, sodium, smoking, and body mass index. The percentage of patients who did not meet thresholds pre-IPO and post-IPO removal were compared.

RESULTS

In total, 2,074 patients underwent oTKA from 2015 to 2017 compared with 46,480 from 2018 to 2020. Patients undergoing oTKA after IPO removal were significantly older (67.0 versus 64.4 years; P < 0.01). A lower percentage of patients in the post-IPO cohort fell outside the threshold for all modifiable risk factors. Results were significant for preoperative sodium (10.7% versus 8.8%; P < 0.01), body mass index (12.4% versus 11.0% P = 0.05), and smoking history (9.9% versus 6.6%; P < 0.01).

CONCLUSION

Outpatient TKA has increased considerably post-IPO removal. As this regulatory change has allowed older patients with increased comorbidities to undergo oTKA, the need for appropriate preoperative optimization has increased. The current data set demonstrates that surgeons have improved preoperative optimization efforts for select modifiable risk factors.

Ten Year Experience With Same Day Discharge Outpatient Total Hip Arthroplasty: Patient Demographics Changed, but Safe Outcomes Were Maintained

BACKGROUND

This study aimed to characterize changes in patient demographics and outcomes for same-day discharge total hip arthroplasty (THA) over a 10-year period at a single orthopaedic specialty hospital.

METHODS

A consecutive series of 1,654 patients between 2013 and 2022 who underwent unilateral THA and were discharged on the same calendar day were retrospectively reviewed. Patient demographics, including age, sex, body mass index (BMI), age-adjusted Charlson Comorbidity Index, and American Society of Anesthesiologists (ASA), were collected. Readmissions, complications, and unplanned visits were recorded for 90 days postoperatively. In order to compare the demographics of patients over time, patients were divided into 3 groups: Time Group A (2013 to 2016), Time Group B (2017 to 2019), and Time Group C (2020 to 2022).

RESULTS

The mean age, BMI, ASA score, and CCI increased significantly across each time group. Age increased from 57 years (range, 23 to 77) to 60 years (range, 20 to 87). The BMI increased from 28.1 (range, 18 to 41) to 29.4 (range, 18 to 47). The percentage of patients aged > 70 years almost doubled over time, as did the percentage of patients who had a BMI > 35. Overall complications increased from 3.44 to 6.82%, reflective of the changing health status of patients. Readmissions increased from 0.57 to 1.70% over time. Despite this, there were no readmissions for any patient within the first 24 hours of surgery.

CONCLUSIONS

Our study has 3 important findings. We identified a worsening patient demographic over time with an increasing percentage of patients of advanced age and higher BMI, ASA, and age-adjusted Charlson Comorbidity Index. Also, there was also an increase in readmissions, complications, and unplanned visits. In addition, despite this worsening patient demographic, there were no readmissions within 24 hours and a low rate of readmissions or unplanned visits within the first 48 hours across all time periods, suggesting that same-day discharge-THA continues to be safe in properly selected patients.

Early Versus Late Periprosthetic Joint Infection After Total Knee Arthroplasty: Do Patient Differences Exist?

BACKGROUND

Periprosthetic joint infection (PJI) is a devastating complication following total knee arthroplasty (TKA). Little evidence exists comparing those with early versus late PJI. The purpose of the study was to determine comorbidity profile differences between patients developing early and late PJI.

METHODS

There were 72,659 patients undergoing primary TKA from 2009 to 2021, who were identified from a commercial claims and encounters database. Subjects diagnosed with PJI were categorized as either 'early' (within 90 days of index procedure) or 'late' (> 2 years after index arthroplasty). Non-infected patients within these periods served as control groups following 4:1 propensity score matching on other extraneous variables. Logistic regression analyses were performed comparing comorbidities between groups.

RESULTS

Patients were significantly younger in the late compared to the early infection group (58.1 versus 62.4 years, P < .001). When compared to those with early PJI, patients who had chronic kidney disease (13.3 versus 4.1%; OR [odds ratio] 5.17, P = .002), malignancy (20.4 versus 10.5%; OR 2.53, P = .009), uncomplicated diabetes (40.8 versus 30.6%; OR 2.00, P = .01), rheumatoid arthritis (9.2 versus 3.3%; OR 2.66, P = .046), and hypertension (88.8 versus 81.6%; OR 2.17, P = .04), were all significant predictors of developing a late PJI.

CONCLUSIONS

When compared to patients diagnosed with early PJI following primary TKA, the presence of chronic kidney disease, malignancy, uncomplicated diabetes, rheumatoid arthritis, and hypertension, were independent risk factors for the development of late PJI. Younger patients who have these comorbidities may be targets for preoperative optimization interventions that minimize the risk of PJI.

Hypothyroidism Impacts Clinical and Healthcare Utilization Outcomes After Primary Total Hip Arthroplasty

BACKGROUND

Our objective was to assess the association of hypothyroidism with outcomes of primary total hip arthroplasty (THA) overall and stratified by underlying diagnosis.

METHODS

We identified patients undergoing primary THA in a national database from 2016 to 2020. We stratified them based on primary diagnoses into hip osteoarthritis (OA; N = 1,761,960), osteonecrosis (ON; N = 78,275), traumatic fracture (N = 532,910), inflammatory arthritis (IA; N = 3,520), and "other" (N = 90,550). We identified hypothyroidism and complications using secondary diagnoses. Among 2,467,215 patients undergoing primary THA, mean age was 68 years (range, 18 to 90), and 58.3% were women. Complications codes only included initial encounters. We performed time-trends analyses and multivariable-adjusted regression analyses adjusted for demographics, expected primary payer, a comorbidity score, elective versus non-elective admission, and hospital characteristic information, with clinical and healthcare utilization outcome as endpoints.

RESULTS

Overall, hypothyroidism was significantly associated with increased LOS, total charges, non-routine discharges, blood transfusions, and prosthetic fractures. In the OA cohort, hypothyroidism was associated with increased LOS, total charges, and non-routine discharges (P < .001 for each), and blood transfusions (P = .02). Hypothyroidism was associated with increased total charges (P = .001) in the ON cohort and with increased LOS, non-routine discharge, and blood transfusion (P < .05 each) in the traumatic fracture cohort.

CONCLUSIONS

Hypothyroidism was associated with blood transfusions, prosthetic fractures, and utilization outcomes in THA patients. Tailored intervention strategies for hypothyroidism should be tested for their efficacy to improve THA peri-operative outcomes.

Complication rates are not higher after outpatient compared to inpatient fast-track total hip arthroplasty: a propensity-matched prospective comparative study

PURPOSE

Concerns remain with regards to safety of fast-track (FT) and especially outpatient procedures. The purpose of this study was to compare complication rates and clinical outcomes of propensity-matched patients who received FT total hip arthroplasty (THA) in outpatient versus inpatient settings. The hypothesis was that 90-day postoperative complication rates of outpatient FT THA would not be higher than after inpatient FT THA.

METHODS

This is a prospective study of consecutive patients who received FT THA at various rates of outpatient and inpatient surgery by 10 senior surgeons (10 centres). The decision between outpatient and inpatient surgery was made on a case-by-case basis depending on the surgeon and patient. All patients were followed until 90 days after surgery. Complications, readmissions and reoperations were collected, and their severity was assessed according to Clavien-Dindo. Patients completed Oxford Hip Score (OHS) at the latest follow-up.

RESULTS

Compared to inpatient FT THA, patients scheduled for outpatient FT THA had no significant differences in 90-day postoperative complication rates (10.7% vs. 12.9%, p = 0.129). There were no significant differences between the 2 groups in 90-day readmission rates and reoperation rates, in severity of postoperative complications, and in time of occurrence of postoperative complications.

CONCLUSIONS

There were no differences in rates of intraoperative complications, 90-day postoperative complications, readmissions, or reoperations between outpatient and inpatient FT THA. These findings may help hesitant surgeons to move towards outpatient THA pathways as there is no greater risk of early postoperative complications that could be more difficult to manage after discharge.

Trends in Deep Vein Thrombosis Prophylaxis After Total Knee Arthroplasty: 2016 to 2021

BACKGROUND

In 2011, the American Academy of Orthopaedic Surgeons released a consensus recommending venous thromboembolism (VTE) prophylaxis after total knee arthroplasty (TKA). The purpose of our study was to examine (1) incidences of postoperative complications, including pulmonary embolism (PE), deep vein thrombosis (DVT), and transfusion rates; (2) trends from 2016 to 2021 in VTE prophylaxis; and (3) independent risk factors for 90-day total complications following TKA between aspirin, enoxaparin, rivaroxaban, and warfarin.

METHODS

Using a national, all-payer database from 2016 to 2021, we identified all patients who underwent primary TKA. Exclusions included all patients who had prescribed anticoagulants within 1 year prior to TKA, hypercoagulable states, and cancer. Data were collected on baseline demographics, including age, sex, diabetes, and a comorbidity index, in each of the VTE prophylaxis cohorts. Postoperative outcomes included rates of PE, DVT, and transfusion. Multivariable regressions were performed to determine independent risk factors for total complications at 90 days following TKA.

RESULTS

From 2016 to 2021, aspirin was the most used anticoagulant (n = 62,054), followed by rivaroxaban (n = 26,426), enoxaparin (n = 20,980), and warfarin (n = 13,305). The cohort using warfarin had the highest incidences of PE (1.8%) and DVT (5.7%), while the cohort using aspirin had the lowest incidences of PE (0.6%) and DVT (1.6%). The rates of aspirin use increased the most from 2016 to 2021 (32.1% to 70.8%), while the rates of warfarin decreased the most (19.3% to 3.0%). Enoxaparin, rivaroxaban, and warfarin were independent risk factors for total complications at 90 days.

CONCLUSIONS

An epidemiological analysis of VTE prophylaxis use from 2016 to 2021 shows an increase in aspirin following TKA compared to other anticoagulant cohorts in a nationally representative population. This approach provides more insight and a better understanding of anticoagulation trends over this time period in a nationally representative sample.

Advanced Multi-Layer Watertight Closure versus Conventional Closure in Total Hip and Knee Replacement Surgery

Background

In total joint replacement procedures, surgeons have increasingly adopted advanced multi-layer, watertight closure. The objective of the study was to compare the clinical and economic outcomes for advanced multi-layer, watertight closure patients to those with conventional closure with sutures and skin staples.

Methods

Patients aged ≥18 years were included in the study if they underwent total joint arthroplasty of the hip or knee as an elective, primary, inpatient procedure between January 2014 and March 2019. Cohorts having advanced multi-layer, watertight closure or conventional closure were compared using multivariable regression analysis of surgical site infections, length of stay, operating room time, procedure time, discharge status, readmissions, reoperations, and hospital emergency department visits.

Results

A total of 1828 patients received at least one total hip or knee replacement, of which 434 (23.7%) had advanced multi-layer, watertight closure and 1394 (76.3%) had conventional closure. Unadjusted time to readmission, when occurring, was considerably longer following advanced multi-layer, watertight closure (89.9 vs 51.1 days, p < 0.0001), and a lower proportion of the advanced multi-layer, watertight closure cohort required reoperation within 90 days (0.0% vs 2.6%, p < 0.0001). Adjusted mean hospital length of stay was approximately half of a day shorter for advanced multi-layer, watertight closure patients (1.10 vs 1.65 days; p < 0.001), and they were also more likely to be discharged to home (Odds Ratio: 4.61; p = 0.002).

Conclusion

Among patients undergoing total hip and knee arthroplasty in a highly optimized real-world clinical practice, advanced multi-layer, watertight closure was associated with significantly shorter inpatient length of stay and increased likelihood of being discharged to home compared with conventional closure. These findings suggest that advanced multi-layer, watertight closure is a valuable component of an optimal workflow for total hip or knee replacement, and may be especially valuable for high-risk patients.

Preoperative optimization of modifiable risk factors is associated with decreased superficial surgical site infections after total joint arthroplasty: a prospective case-control study

BACKGROUND AND PURPOSE

The aim of our study was to investigate change in modifiable risk factors following preoperative optimization and whether risk of superficial surgical site infection (SSI) after total joint arthroplasty (TJA) could be reduced.

METHODS

This is a prospective study of implementation of a preoperative optimization pathway for patients waiting for primary TJA. Information regarding the intervention arm was collected from January 2019 to January 2021, first at decision for operation and then at preoperative assessment 1 week prior to operation. The control arm was included between August 2018 and September 2020 after receiving conventional preoperative preparation and information gathered at preoperative assessment. Follow up occurred 6 weeks postoperatively for both groups. The primary outcome was postoperative superficial SSI.

RESULTS

The optimization effort resulted in improvement of weight, anemia, HbA1c, vitamin D, and patient engagement. At preoperative assessment the baseline characteristics of the 2 groups were similar except that the intervention group had substantially more comorbidities. Regarding superficial SSI, association was found with BMI ≥ 30 and HbA1c ≥ 42 mmol/mol in the control group but not in the intervention group. When corrected for differences in ASA classification (reflecting comorbidities), age, and sex, being in the intervention group was associated with lower odds of occurrence of superficial SSI compared with the control group (OR 0.64, 95% confidence interval 0.42-0.97).

CONCLUSION

We showed that preoperative optimization in a structured cooperation between hospital and primary care was associated with a reduced risk of superficial SSI.

Effect of Depression Interventions in Patients Undergoing Total Joint Arthroplasty Without a Formal Diagnosis of Depression: A Systematic Review

PURPOSE

Depression is a notable contributor to suboptimal outcomes after total joint arthroplasty (TJA). We conducted a systematic review of comparative studies to review the available evidence of interventions that affected depression scores and/or outcomes for patients undergoing TJA.

METHODS

EMBASE, Ovid MEDLINE, PubMed, and Scopus were reviewed systematically from inception until November 15, 2022. Studies that were relevant for this review included comparative studies between patients who received an intervention within 3 months before or after their primary total hip or knee arthroplasty procedure. The interventions included a wide range of modalities, which were grouped into psychotherapy, enhanced perioperative support, and pharmacotherapy. Other interventions included physiotherapy techniques with a psychological focus, art/music-based therapy, occupational therapy support, and educational interventions. Meta-analysis was conducted for psychotherapy and enhanced support.

RESULTS

The final systematic review consisted of 28 relevant studies, most of which were randomized controlled trials. A total of 3,702 patients, with a mean age of 66 years, were considered, of whom 59% were female. Most of the studies reported a notable reduction in depressive symptoms and/or scores based on the interventions being analyzed. At 3 months postoperatively, psychotherapy and enhanced support both resulted in markedly better depression and function scores compared with control subjects, with psychotherapy additionally improving pain scores.

CONCLUSIONS

Overall, a wide range of interventions aimed at psychological optimization of patients undergoing TJA can improve depressive symptoms, pain, and function, even in the absence of a formal diagnosis of depression. Specifically, cognitive-based psychotherapy and enhanced perioperative support had the best evidence. Routine pharmacotherapy plays a limited role, if any, in the care of TJA. Additional efforts to develop pragmatic, evidence-based, and reproducible interventions are warranted to continue to optimize outcomes in TJA patients.

The use of preoperative continuous positive airway pressure in patients with obstructive sleep apnea following total knee arthroplasty: a propensity score matched analysis

INTRODUCTION

Patients with sleep apnea, affecting up to 1 in 4 older men in the United States, may be at increased risk of postoperative complications after total knee arthroplasty (TKA), including increased thromboembolic and cerebrovascular events, as well as respiratory, cardiac, and digestive complications. However, the extent to which the use of CPAP in patients with sleep apnea has been studied in TKA is limited.

METHODS

A national, all-payer database was queried to identify all patients who underwent a primary TKA between 2010 and 2021. Patients who had any history of sleep apnea were identified and then stratified based on the use of CPAP. A propensity score match analysis was conducted to limit the influence of confounders. Medical complications, such as cardiac arrest, stroke, pulmonary embolism, transfusion, venous thromboembolism, and wound complications, were collected at 90-days, 1-year, and 2-years.

RESULTS

The bivariate analysis showed inferior outcomes for sleep apnea with CPAP use compared to sleep apnea with no CPAP use, in terms of length of stay (5.9 vs. 5.2, p < 0.001), PJI (1.31% vs. 1.14%, p < 0.001), stroke (0.97% vs. 0.82%, p < 0.001), VTE (1.04% vs. 0.82, p < 0.001), and all other complications at 90-days (p < 0.001) except cardiac arrest (0.14% vs. 0.11%, p = 0.052), and aseptic revision (0.40% vs. 0.39%, p = 0.832), PJI (1.81% vs. 1.55%, p < 0.001) and aseptic revision (1.25% vs. 1.06%, p < 0.001) at 1-year, and PJI (2.07 vs. 1.77, p < 0.001) and aseptic revision (1.98 vs. 1.17, p < 0.001) at 2-years.

CONCLUSION

Patients with sleep apnea have increased postoperative complications after undergoing TKA in comparison to patients without sleep apnea. More severe sleep apnea, represented by CPAP usage in this study led to worse postoperative outcomes but further analysis is required signify the role of CPAP in this patient population. Patients with sleep apnea should be treated as a high-risk group.

Orthopaedic Nurse Navigators and Total Joint Arthroplasty Preoperative Optimization: Mental Health and Housing Status-Part Five of the Movement Is Life Special ONJ Series

Mental health and housing status have the potential to impact total joint arthroplasty (TJA) outcomes and are common TJA eligibility criteria that prevent patients from receiving surgery. Our aim was to formulate recommendations for how nurse navigators can assist patients with managing mental health and housing concerns. Through discussions with nurse navigators and a literature search across two databases, we gathered information regarding the optimization of mental health and housing status among TJA patients. We observed a lack of standardized protocols for addressing these concerns and literature supporting an increased focus on mental health and housing status, indicating the potential for greater nurse navigator involvement in developing and implementing protocols. We recommend nurse navigators use screening tools to identify mental health and housing concerns and offer the suggested resources to support patients in an effort to improve postoperative outcomes and decrease surgical risks.

The effectiveness of preoperative delirium prevention in intermediate to high-risk older surgical patients: A systematic review

BACKGROUND

Few reviews have addressed delirium prevention among intermediate to high-risk older surgical patients.

AIMS

To map preoperative delirium prevention interventions for older surgical patients at intermediate to high risk of developing delirium, assess outcomes and identify gaps in knowledge.

DESIGN

Systematic narrative review of randomised controlled trials reported following the PRISMA checklist.

METHODS

A systematic search was conducted of the literature published from 1990 to October 2022 in Medline, CINAHL and Ageline and of the grey literature in Google Scholar. Randomised controlled trials were retrieved that assessed the effectiveness of preoperative delirium prevention interventions for older surgical patients at intermediate to high risk of delirium. Data were extracted using a data extraction tool, and results were tabulated. Studies were assessed for bias using the Cochrane Collaboration Risk of Bias tool.

RESULTS

Twenty-one studies met the selection criteria including N = 5096 participants. Two studies tested cognitive training, two studies tested fascia iliaca compartment block and one study assessed femoral nerve block. Ten studies tested prophylactic medications including methylprednisolone. Five studies investigated geriatric assessment and management. One study assessed transcutaneous electrical acupoint stimulation. In the two studies testing fascia iliaca compartment block, there was a reduction in postoperative delirium for orthopaedic patients. Methylprednisolone reduced postoperative delirium in orthopaedic patients and in those undergoing gastrointestinal surgery. Results of all other interventions on the occurrence of postoperative delirium and additional outcomes including the severity and duration of delirium were inconclusive.

CONCLUSIONS

Despite the promising results for fascia iliaca compartment block and methylprednisolone, there is limited knowledge regarding evidence-based delirium prevention interventions. Most studies had small sample sizes indicating that the current evidence is exploratory. There is an urgent need for the funding and conduct of trials to test preventative interventions for older surgical patients at intermediate to high risk of developing delirium.

A Cautionary Tale: Malaligned Incentives in Total Hip and Knee Arthroplasty Payment Model Reforms Threaten Promising Innovation and Access to Care

Over the past several years, there have been notable changes and controversies involving Medicare reimbursement for total hip (THA) and total knee arthroplasty (TKA). We have seen the development and implementation of experimental bundled payment model pilot programs goals of improving quality and decreasing overall costs of care during the last decade. Many orthopaedic surgeons have embraced these programs and have demonstrated the ability to succeed in these new models by implementing strategies, such as preservice optimization, to shift care away from inpatient or postdischarge settings and reduce postoperative complications. However, these achievements have been met with continual reductions in surgeon reimbursement rates, lower bundle payment target pricings, modest increases in hospital reimbursement rates, and inappropriate valuations of THA and TKA Common Procedural Terminology (CPT) codes. These challenges have led to an organized advocacy movement and spurred research involving the methods by which improvements have been made throughout the entire episode of arthroplasty care. Collectively, these efforts have recently led to a novel application of CPT codes recognized by payers to potentially capture presurgical optimization work. In this paper, we present an overview of contemporary payment models, summarize notable events involved in the review of THA and TKA CPT codes, review recent changes to THA and TKA reimbursement, and discuss future challenges faced by arthroplasty surgeons that threaten access to high-quality THA and TKA care.

Treatment of Concurrent Depression and Its Effect on Outcomes After Total Joint Arthroplasty: A Systematic Review of Comparative Studies

PURPOSE

There is a growing body of evidence suggesting that patients with a diagnosis of depression suffer worse outcomes after total joint arthroplasty (TJA) procedures. It is unclear whether depression treatment is a modifiable risk factor that can be targeted to improve suboptimal outcomes. We conducted a systematic review to understand the role that various interventions have on outcomes of TJA in patients with diagnosed depression (PDDs).

METHODS

PubMed, Ovid MEDLINE, Scopus, and EMBASE were searched systematically from inception until November 2022. Studies of PDDs who underwent TJA that compared any intervention/treatment of depression with a control group and reported pain, functional outcomes, depression scores, and/or revision rates after TJA were relevant for this review.

RESULTS

Ten relevant studies were included in the final systematic review, with a total of 33,501 patients included. Two studies reported lower revision rates for patients receiving selective serotonin reuptake inhibitor treatment and psychotherapy. Two studies showed no difference in functional outcomes for patients receiving pharmacologic treatment. One study reported improved functional outcomes for patients receiving cognitive behavioral therapy and another reported improved postoperative functional outcomes for patients receiving alprazolam.

CONCLUSION

Interventions targeted at PDDs may improve short-term pain and functional outcomes, and there may be an association between selective serotonin reuptake inhibitor use and implant survival. The current literature is limited and inconclusive, with important gaps in understanding regarding the optimization and treatment of this modifiable risk factor. Surgeons should consider depression treatment as a method to improve outcomes in this cohort.

Orthopaedic Nurse Navigators and Total Joint Arthroplasty Preoperative Optimization: Obesity and Malnutrition-Part Four of the Movement Is Life Special ONJ Series

Obesity and malnutrition affect many patients with osteoarthritis and can predispose patients to worse outcomes after total joint arthroplasty (TJA). However, these modifiable risk factors can be addressed in preoperative optimization programs driven by nurse navigators. Our aim is to provide resources and recommendations for nurse navigators when addressing obesity and malnutrition among TJA patients. In addition to discussions with nurse navigators regarding obesity and malnutrition, a literature review was conducted to assess the current practice standards for management. Nurse navigators often had difficulty implementing long-term interventions, but interventions in the literature included medical and bariatric treatments for obesity and more targeted assessment of nutrition status. These findings are incorporated into our recommendations for nurse navigators. Addressing obesity and malnutrition in preoperative optimization can contribute to improved outcomes, as has been demonstrated in current practice and in the literature.

Trends in deep vein thrombosis prophylaxis after total hip arthroplasty: 2016 to 2021

Introduction

Venous thromboembolism (VTE) has long been acknowledged as a potential complication of total hip arthroplasty (THA) contributing to heightened patient morbidity, mortality, and substantial healthcare costs. We aimed to: 1) assess trends in VTE prophylaxis utilization between 2016 and 2021; 2) determine the incidence of postoperative VTE and transfusions; and 3) identify independent risk factors for 90-day VTE and transfusion risks following THA in relation to the use of aspirin, dabigatran, enoxaparin, rivaroxaban, and warfarin.

Methods

A national, all-payer database was queried from January 1, 2016 and December 31, 2022. Use trends for aspirin, enoxaparin, rivaroxaban, dabigatran, and warfarin as thromboprophylaxis following THA was assessed. Incidence of ninety-day postoperative outcomes assessed included rates of 90-day postoperative VTE and transfusion.

Results

From 2016 to 2021, aspirin (n = 36,346) was the most used agent for VTE prophylaxis after THA, followed by dabigatran (n = 13,065), rivaroxaban (n = 11,790), enoxaparin (n = 11,380), and warfarin (n = 6326). Independent risk factors for 90-day VTE included CKD, COPD, CHF, obesity, dabigatran, enoxaparin, rivaroxaban, and warfarin (all p < 0.05).

Conclusion

Aspirin was used with increasing frequency and demonstrated lower rates of VTE and transfusion following THA, compared to dabigatran, enoxaparin, rivaroxaban, and warfarin. These findings seem to indicate that the increasing use of aspirin in VTE prophylaxis has been accomplished in appropriately selected patients.

Orthopaedic Nurse Navigators and Total Joint Arthroplasty Preoperative Optimization: Substance Use

Substance use is one of the most common risk factors contributing to complications following total joint arthroplasty. Preoperative optimization programs can help patients modify or stop substance use. The purpose of this study was to provide recommendations and resources that will help nurse navigators standardize and improve preoperative optimization protocols regarding substance use. In a semistructured format, we asked nurse navigators how smoking, alcohol use, and opioid use were addressed. We conducted a literature review and combined findings with nurse navigator reports to create practice recommendations. We recommend consistently referring patients who smoke to smoking cessation programs; using validated screening tools to evaluate alcohol use and involving internists in caring for patients at risk for withdrawal; and involving pain specialists and local resources to assist patients who use opioids. There is a breadth of resources for managing substance use that nurse navigators can utilize to support stronger and more consistent preoperative optimization protocols.

Determining a preoperative international normalised ratio threshold safe for hip fracture surgery

INTRODUCTION

The purpose of this study was first, to assess the relationship between preoperative INR (international normalised ratio) and postoperative complication rates in patients with a hip fracture, and second, to establish a threshold for INR below which the risk of complications is comparable to those in patients with a normal INR.

METHODS

We retrospectively reviewed the American College of Surgeons National Surgical Quality Improvement Program and found 35,910 cases who had undergone surgery for a hip fracture between 2012 and 2018. Cases were stratified into 4 groups based on their preoperative INR levels: <1.4; ⩾1.4 and <1.6; ⩾1.6 and <1.8 and ⩾1.8. These cohorts were assessed for differences in preoperative factors, intraoperative factors, and postoperative course. Multivariate logistic regression was used to assess the risk of transfusion, 30-day mortality, cardiac complications, and wound complications adjusting for all preoperative and intraoperative factors.

RESULTS

Of the 35,910 cases, 33,484 (93.2%) had a preoperative INR < 1.4; 867 (2.4%) an INR ⩾1.4 and <1.6; 865 (2.4%) an INR ⩾ 1.6 and <1.8 and 692 (1.9%) an INR ⩾ 1.8. A preoperative INR ⩾ 1.8 was independently associated with an increased risk of bleeding requiring transfusion. A preoperative INR ⩾ 1.6 was associated with an increased risk of mortality.

CONCLUSIONS

We found that an INR of <1.6 is a safe value for patients who are to undergo surgery for a hip fracture. Below this value, patients avoid an increased risk of both transfusion and 30-day mortality seen with higher INR values. These findings may allow adjustment of preoperative protocols and improve the outcome of hip fracture surgery in this group of patients.

Orthopaedic Nurse Navigators and Total Joint Arthroplasty Preoperative Optimization: Improving Patient Access to Musculoskeletal Care

Preoperative optimization programs for total joint arthroplasty identify and address risk factors to reduce postoperative complications, thereby improving patients' ability to be safe surgical candidates. This article introduces preoperative optimization programs and describes the role of orthopaedic nurse navigators. This foundation will be used to produce an article series with recommendations for optimization of several modifiable biopsychosocial factors. We consulted orthopaedic nurse navigators across the United States and conducted a literature review regarding preoperative optimization to establish the importance of nurse navigation in preoperative optimization. The responsibilities of nurse navigators, cited resources, and structure of preoperative optimization programs varied among institutions. Optimization programs relying on nurse navigators frequently demonstrated improved outcomes. Our discussions and literature review demonstrated the integral role of nurse navigators in preoperative optimization. We will discuss specific risk factors and how nurse navigators can manage them throughout this article series.

Improved performance of machine learning models in predicting length of stay, discharge disposition, and inpatient mortality after total knee arthroplasty using patient-specific variables

BACKGROUND

This study aimed to compare the performance of ten predictive models using different machine learning (ML) algorithms and compare the performance of models developed using patient-specific vs. situational variables in predicting select outcomes after primary TKA.

METHODS

Data from 2016 to 2017 from the National Inpatient Sample were used to identify 305,577 discharges undergoing primary TKA, which were included in the training, testing, and validation of 10 ML models. 15 predictive variables consisting of 8 patient-specific and 7 situational variables were utilized to predict length of stay (LOS), discharge disposition, and mortality. Using the best performing algorithms, models trained using either 8 patient-specific and 7 situational variables were then developed and compared.

RESULTS

For models developed using all 15 variables, Linear Support Vector Machine (LSVM) was the most responsive model for predicting LOS. LSVM and XGT Boost Tree were equivalently most responsive for predicting discharge disposition. LSVM and XGT Boost Linear were equivalently most responsive for predicting mortality. Decision List, CHAID, and LSVM were the most reliable models for predicting LOS and discharge disposition, while XGT Boost Tree, Decision List, LSVM, and CHAID were most reliable for mortality. Models developed using the 8 patient-specific variables outperformed those developed using the 7 situational variables, with few exceptions.

CONCLUSION

This study revealed that performance of different models varied, ranging from poor to excellent, and demonstrated that models developed using patient-specific variables were typically better predictive of quality metrics after TKA than those developed employing situational variables.

LEVEL OF EVIDENCE

III.

Preventing the Impact of Hyperglycemia and Diabetes on Patients Undergoing Total Joint Arthroplasty

Primary and revision total joint arthroplasty (TJA) procedures have become increasingly popular worldwide. At the same time, a growing number of patients undergoing TJA are either known diabetics or exhibit evidence of hyperglycemia preoperatively. Based on extensive data, it is well-established that poor glycemic control in TJA patients is an independent risk factor for several complications, including periprosthetic joint infection and death. This article will serve as an overview of currently available evidence on how to prevent the impact of hyperglycemia and diabetes mellitus on patients undergoing TJA.

Preoperative Patient Optimization: Outcomes from Elective Total Joint Arthroplasty in a Large US Healthcare System

INTRODUCTION

Patient factors are known to affect outcomes in arthroplasty surgery. A preoperative program to address modifiable factors may aid in more appropriate patient selection. We sought to assess patient selection and 90-day postoperative outcomes for total joint arthroplasty (TJA) candidates before and after implementation of a preoperative optimization protocol.

METHODS

A retrospective time-trend study using data from an integrated healthcare system's total joint replacement registry was done. The study sample consisted of patients aged 18 years or older who underwent primary elective total hip arthroplasty (THA) and total knee arthroplasty (TKA) for osteoarthritis between 2009 and 2019. Patients were divided into two cohorts: procedures performed from 2009 to 2013 ("preoptimization protocol") and those from 2015 to 2019 ("postoptimization protocol"); 2014 was excluded because an evidence-based preoperative patient optimization protocol was progressively implemented throughout the year. Patient characteristics, optimization factors, and 90-day outcomes (including emergency department [ED] visits, readmission, all-cause revision, deep infection, venous thromboembolism, and mortality) were compared between the two cohorts using the Pearson chi-square test or Wilcoxon test.

RESULTS

The study sample included 25,925 THA and 60,484 TKA. In the THA cohort, 10,364 (40.0%) and 15,561 (60.0%) were from the preoptimization and postoptimization cohorts, respectively. The postoptimization THA cohort saw lower rates of ED visits (12.1% vs. 9.4%, P < 0.001) and readmissions (5.6% vs. 3.8%, P < 0.001). In the TKA cohort, 24,054 (39.8%) and 36,430 (60.2%) were from the preoptimization and postoptimization cohorts, respectively. The postoptimization TKA cohort saw lower rates of ED visits (13.1% vs. 11.9%, P < 0.001), readmissions (5.6% vs. 3.0%, P < 0.001), all-cause revisions (0.5% vs. 0.3%, P = 0.003), venous thromboembolism (1.3% vs. 0.9%, P < 0.001), and mortality (0.3% vs. 0.2%, P = 0.011).

DISCUSSION

An evidence-based protocol to improve patient selection based on modifiable patient factors was adopted by orthopaedic surgeons in the system and utilization of the protocol before TJA was associated with fewer postoperative complications over time.

LEVEL OF EVIDENCE

Level IV.

Metrics for Monitoring Preoperative Optimization Programs for Total Joint Arthroplasty: A Survey of Orthopaedic Nurses

Preoperative optimization programs are becoming more common for patients seeking total joint arthroplasty; yet, limited research has been conducted to monitor the long-term effects of these programs on patient outcomes. Our aim was to develop a set of metrics that programs can use to monitor the success of preoperative optimization programs. As part of a larger survey of orthopaedic nurses, we collected data regarding current monitoring techniques for preoperative optimization programs and the feasibility of collecting specific variables. Surgical factors such as length of stay and 30-day readmissions were most often used to monitor the success of preoperative optimization programs. Surgical factors were the most likely to be accessible using the electronic medical record. Surgical factors and patient characteristics are the most feasible components for programs to monitor in order to track the outcomes of patients participating in preoperative optimization programs.

Trends of Venous Thromboembolism After Total Hip Arthroplasty in the United States: Analysis From 2011 to 2019

BACKGROUND

In 2011, the American Academy of Orthopaedic Surgeons released a Clinical Practice Guideline` that recommended routine venous thromboembolism (VTE) prophylaxis after total joint arthroplasty. The purpose of this study was to examine (1) the change in the incidence of 90-day VTE, deep vein thrombosis, and pulmonary embolism, (2) the change in the utilization of antithrombotic agents; and (3) the change in the economic burden associated with VTE after total hip arthroplasty (THA) from 2011 to 2019.

METHODS

National, administrative claims data from 2011 to 2019 were used to identify patients who underwent primary THA for osteoarthritis. Exclusions entailed liver pathology, coagulopathy, malignancy, or those on prior prescribed blood thinners before THA. Multivariable regression was used, controlling for age and Charlson Comorbidity Index for all years, with 2011 as the reference year.

RESULTS

From 2011 to 2019, there was a significant reduction in 90-day VTE rates after THA, with a significant reduction in deep vein thrombosis and pulmonary embolism during this time frame as well. Of the antithrombotic agents prescribed after THA, the utilization of prescribed aspirin significantly increased and that of nonaspirin anticoagulants significantly decreased. Among nonaspirin anticoagulants, the utilization of direct factor Xa inhibitors and direct thrombin inhibitors significantly increased. The added reimbursements associated with VTE after THA significantly decreased during this period.

CONCLUSION

Since 2011, the incidence and economic burden associated with VTE after THA have significantly declined. In addition, there has been an increase in prescription aspirin and direct oral anticoagulants.

LEVEL OF EVIDENCE

Therapeutic, III.

A Total Knee Arthroplasty Preoperative Optimization Program Managed by an Advanced Practice Provider (Physician Assistant) Decreases Complications and Cost: A Pilot Study

BACKGROUND

Studies have shown that optimizing modifiable risk factors leads to improved outcomes, with decreased lengths of stay (LOS), readmissions, complications, and hospital costs. Our goal was to demonstrate that use of an advanced practice provider, physician assistant (PA), within an orthopaedic practice would support these outcomes.

METHODS

A preoperative optimization program managed by a PA was instituted at an academic medical center. From November 2019 to December 2022, a pilot group of fifteen (15) consecutive primary total knee arthroplasty (TKA) patients who were successfully optimized with the PA-managed program prior to TKA were matched 2:1 to a cohort of thirty (30) TKA patients who did not undergo optimization. Demographics and the modified readmission risk assessment tool score were used to match patients. Variables evaluated included LOS, emergency department visits, and hospital readmissions within 30 and 90 days after surgery, complications, and hospital costs of care.

RESULTS

Optimized patients had less complications (P = .004) and significantly shorter (P < .001) mean LOS (1.27 days vs 2.97 days) compared to nonoptimized patients. The difference of hospital cost between cohorts for the primary admission was significant (P = .049). When readmission costs were included, the average hospital cost for the nonoptimized group was significantly higher than the optimized group (P = .018).

CONCLUSIONS

Preoperative optimization led by a PA demonstrated significant reductions in LOS and the costs of care between optimized and non-optimized patients, along with decreased complications.

Relationship Between Preoperative Nutritional Status and Predicting Short-Term Complications Following Revision Total Hip Arthroplasty

BACKGROUND

The association between malnutrition and complications following primary total joint arthroplasty is well-delineated, however, nutritional status has yet to be explored specifically in revision total hip arthroplasty (THA). Therefore, our objective was to examine if a patient's nutritional status based on body mass index, diabetic status, and serum albumin predicted complications following a revision THA.

METHODS

A retrospective national database review identified 12,249 patients who underwent revision THA from 2006 to 2019. Patients were stratified based on body mass index (<18.5=underweight, 18.5 to 29.9=healthy/overweight, >30=obese), diagnosis of diabetes (no diabetes, insulin-dependent diabetes mellitus (IDDM), non-insulin-dependent diabetes mellitus (NIDDM)), and preoperative serum albumin (<3.5=malnourished, >3.5=non-malnourished). Multivariate analyses was performed using Chi-squared tests and multiple logistic regressions.

RESULTS

In all groups including underweight (1.8%), healthy/overweight (53.7%), and obese (44.5%), those without diabetes were less likely to be malnourished (p<0.001), while those with IDDM had a higher rate of malnutrition (p<0.001). Underweight patients were significantly more malnourished compared to healthy/overweight or obese patients (p<0.05). Malnourished patients had an increased risk of wound dehiscence/surgical site infections (p<0.001), urinary tract infection (p<0.001), requiring a blood transfusion (p<0.001), sepsis (p<0.001), and septic shock (p<0.001). Malnourished patients also have worse postoperative pulmonary and renal function.

CONCLUSIONS

Patients who are underweight or have IDDM are more likely to be malnourished. The risk of complications within 30 days of surgery following revision THA significantly increases with malnutrition. This study shows the utility of screening underweight and IDDM patients for malnutrition prior to revision THA to minimize complications.

Exploration of nursing students' views on the theory-practice gap in surgical nursing education and its relationship with attitudes towards the profession and evidence-based practice

AIM

The aim of this study was to explore nursing students' views on the theory-practice gap in surgical nursing education and determine its relationship with attitudes towards the profession and evidence-based practice.

BACKGROUND

In nursing education, the discrepancy between the theoretical knowledge and clinical practices is known as the "theory-practice gap". Although this problem was defined many years ago, scientific information on the subject is very limited in terms of surgical nursing.

METHOD

This descriptive-analytical and cross-sectional study was carried out in three different universities in the Black Sea Region of Türkiye. The sample consisted of 389 nursing students. The data collection was carried out in May-July 2022 through the use of the following tools: The Attitude Scale for the Nursing Profession (ASNP), the Knowledge, Attitudes and Behaviors Questionnaire for Evidence-Based Practice (KABQ-EBP) and the researchers made form to determine students' views on the theory-practice gap. The data were analysed with Student's t-test, multiple linear regression analysis.

RESULTS

72.8% of the students stated that they thought there was a discrepancy between their theoretical surgical nursing courses and clinical practice. While the total ASNP score of students who thought that there was a discrepancy between theoretical education and clinical practice was lower than that of the other students (p = 0.002), no difference was found among the students in terms of the total KABQ-EBP score (p > 0.05). In the multiple linear regression analysis, it was determined that thinking about gap (β = -0.125, p = 0.009), gender (β = -0.134, p = 0.006), willingness to choose the profession (β = 0.150, p = 0.002) and KABQ-EBP score (β = 0.247, p < 0.001) had significant effects on nursing students' attitudes towards the profession. In the model, %12 of the total variance was explained by the variables.

CONCLUSION

The study shows that the gap between theory and practice for the surgical nursing course is a problem perceived by most students. Also, students who thought that there was a theory-practice gap for the surgical nursing course had a more negative attitude towards the profession, while their attitudes towards evidence-based nursing were not different from others. The results of this study encourage further research to gain a better understanding of the impact of the gap between theory and practice on nursing students.

Hospital Readmissions After Total Joint Arthroplasty: An Updated Analysis and Implications for Value-Based Care

BACKGROUND

While risk factors have been published for readmissions following primary total joint arthroplasty, little is known about the etiology of those costly adverse events. In this study, we sought to identify the reasons for 30-day readmission following primary total joint arthroplasty in a contemporary national patient sample.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program was queried to identify 367,199 patients who underwent primary total knee (TKA) or hip arthroplasty (THA) between 2011 and 2018. The primary outcomes were the annual rates of 30-day readmissions and the causes of those readmissions.

RESULTS

The 30-day readmission rate trended downward from 4.5% in 2011 to 3.3% in 2018. Medical complications accounted for 52.6% and 38.5% of readmissions following TKA and THA, respectively. Diseases of the circulatory system, abnormal laboratory values, and diseases of the digestive system were the leading causes of medical readmissions. Surgical complications accounted for 37.7% and 50.7% of readmissions following TKA and THA, respectively. Surgical site infections/wound disruption and venous thromboembolism were the leading two causes of surgical readmissions for THA and TKA. Prosthetic complications-namely dislocations and periprosthetic fractures-were the third leading cause of surgical readmissions for THA. For TKA, musculoskeletal conditions-namely pain and hematoma-were the third leading cause of surgical readmissions.

CONCLUSION

Medical complications accounted for half of all TKA readmissions and more than a third of THA readmissions. This could penalize institutions participating in value-based payment programs or dissuade others who are considering participation in such programs.

Perception of Perioperative Risk for Arthroplasty Patients: A Poll of Australian Orthopedic Surgeons

BACKGROUND

There is growing interest in the perioperative management of patients who have indications for hip and knee arthroplasty in the setting of modifiable risk factors such as morbid obesity, poorly controlled diabetes, and smoking. A recent survey of the American Association of Hip and Knee Surgeons (AAHKS) found that 95% of respondents address modifiable risk factors prior to surgery. The aim of this study was to poll Australian arthroplasty surgeons regarding their approach to patients who have modifiable risk factors.

METHODS

The survey tool used in the AAHKS study was adapted for use in the Australian context and distributed to the membership of the Arthroplasty Society of Australia via SurveyMonkey. There were 77 responses received, representing a response rate of 64%.

RESULTS

The majority of respondents were experienced, high volume arthroplasty surgeons. Overall, 91% of respondents restricted access to arthroplasty for patients who have modifiable risk factors. There were 72% restricting access for excessive body mass index, 85% for poor diabetic control, and 46% for smoking. Most respondents made decisions based on personal experience or literature review rather than hospital or departmental pressures. While 49% of surgeons believed that current payment systems did not impair their ability to achieve good outcomes, 58% believed that certain arthroplasty patients would benefit from additional intervention, based on their socioeconomic status.

CONCLUSION

Over 90% of surgeons who responded address modifiable risk factors prior to surgery. This finding aligns with the practice patterns of AAHKS members, despite differences in healthcare systems.

Perception of Perioperative Risk for Arthroplasty Patients: A Poll of Indian Orthopedic Surgeons

BACKGROUND

A survey of the American Association of Hip and Knee Surgeons (AAHKS) reported that 95% of respondents attempted to modify risk factors prior to arthroplasty. This study investigated Indian arthroplasty surgeons' approach to patients who have modifiable risk factors.

METHODS

The AAHKS survey tool was adapted for Indian surgeons and distributed to the membership of the Indian Society of Hip and Knee Surgeons and Indian Arthroplasty Association via a Survey Monkey. A total of 92 survey responses were received, representing a response rate of 12%.

RESULTS

Overall, 87% of respondents restricted access to arthroplasty surgery for patients who have modifiable risk factors, but only 51% of respondents reported delays or restricted treatment because of risk factors. Respondents reported that financial implications were more likely to delay or restrict treatment in 97% and social/family reasons in 66%. Poor diabetic control (81%), previous infection (57%), and malnutrition/hypoalbuminemia (47%) were the most frequent modifiable risk factors. There were 82% of surgeons reporting that the patient's socioeconomic status influenced treatment including: 71% of patients who have low socioeconomic status, 57% who do not have insurance, and 45% who have limited social supports. Most surgeons (92%) reported that funding influenced the type of care provided and the choice of implants.

CONCLUSION

Over 97% of Indian arthroplasty surgeons thought socioeconomic factors impaired access to orthopaedic treatment. Only half the surgeons restricted access for comorbidities and these were more often related to infection risks and diabetes. These findings contrast dramatically to the practice patterns of American AAHKS members.

The Efficacy of Telemedicine Versus In-Person Education for High-Risk Patients Undergoing Primary Total Joint Arthroplasty

BACKGROUND

While multiple studies have demonstrated the positive impact of preoperative education on total joint arthroplasty (TJA) outcomes, the traditional method of conducting in-person individualized counseling or group education may limit access to these resources for a subset of the population. This study aimed to evaluate the use of preoperative telemedicine and in-person educational programs for primary TJA patients to determine if the utilization of telemedicine is inferior to in-person education in high-risk populations.

METHODS

A retrospective chart review of all "high-risk" patients undergoing primary unilateral TKA or THA by 1 of 10 board-certified surgeons at a single institution over 1 year was performed. Patients were prospectively classified as high-risk based on race/ethnicity, comorbidities, and socioeconomic and psychosocial factors. Demographics, comorbidities, and hospital outcomes were compared between patients receiving preoperative nurse navigator education via telemedicine versus those receiving face-to-face education.

RESULTS

When comparing the interventions, telemedicine education was noninferior to face-to-face visits. No significant differences between postoperative length of stay, discharge home, 30-day emergency department return, or 30-day readmission rates were noted. Within the telemedicine group, patients who received video consultations were found to be 6 times more likely to be discharged home after surgery (odds ratio (OR): 5.95, 95% confidence interval (CI): 2.00 to 25.49; P = .004) and less likely to have a 30-day readmission than the phone consultations (OR: 0.36, 95% CI: 0.12 to 0.94: P = .050).

CONCLUSION

This study demonstrates that telemedicine is not inferior to in-person preoperative education for patients undergoing unilateral TJA, although video-based consultation may improve outcomes over phone-only education.

Orthopaedic Nurse Navigator Involvement in Preoperative Optimization for Total Joint Arthroplasty

Patients seeking total joint arthroplasty frequently undergo preoperative optimization with the assistance of nurse navigators to facilitate interactions between patients, consulting services, and the orthopaedic surgical team. Given the enormous impact nurse navigator programs have on reducing postoperative complications, our aim is to characterize the involvement of nurse navigators in preoperative optimization programs across the country. We conducted a survey of nurse navigators identified through the National Association of Orthopaedic Nurses to assess the involvement of nurse navigators in the preoperative optimization process. Sixty-seven percent of responding nurse navigators were involved in preoperative optimization, including components such as heart disease (53%) and poorly controlled diabetes (52%). Orthopaedic nurse navigators are commonly involved in preoperative optimization programs for total joint arthroplasty but most of these involve gated yes/no checklists with limited established referral care pathways. Only some of the programs include standardized referrals for specific medical comorbidities.

Vaping Trends and Outcomes in Primary Total Joint Arthroplasty Patients: An Analysis of 21,341 Patients

INTRODUCTION

The effect of vaping on outcomes after total joint arthroplasty (TJA) and its prevalence in this patient population remain unclear. The purpose of this study was twofold: (1) to investigate the trends of vaping in TJA patients compared with patients who underwent routine physical examination and (2) to examine the influence vaping has on outcomes after TJA.

METHODS

Patients were classified as never vaped, former vape users, or whether they reported current vaping (CV). TJA patients were further classified based on whether they had no exposure to tobacco or vaping (NTNV), tobacco only (TO), both tobacco and vaping (BTV), or vaping only (VO).

RESULTS

The TJA group exhibited a steady trend of patients with CV status (P = 0.540) while patients in the routine physical examination cohort demonstrated a significant upward trend in CV status (P = 0.015). Subanalysis of TJA patients revealed that those in the VO category had significantly higher mean surgical time (P < 0.001), length of stay (P = 0.01), and rates of readmission (P = 0.001) compared with all other subgroups.

CONCLUSION

We found steady or increasing trends of electronic cigarette exposure in both groups over time. Additional efforts should be made to document electronic cigarette exposure for all patients.

Preoperative Risk Management Programs at the Top 50 Orthopaedic Institutions Frequently Enforce Strict Cutoffs for BMI and Hemoglobin A1c Which May Limit Access to Total Joint Arthroplasty and Provide Limited Resources for Smoking Cessation and Dental Care

BACKGROUND

Performing elective orthopaedic surgery on patients with high BMI, poorly controlled hyperglycemia, and who use tobacco can lead to serious complications. Some surgeons use cutoffs for BMI, hemoglobin A1c, and cigarette smoking to limit surgery to patients with lower risk profiles rather than engaging in shared decision-making with patients about those factors. Other studies have suggested this practice may discriminate against people of lower income levels and women. However, the extent to which this practice approach is used by orthopaedic surgeons at leading hospitals is unknown.

QUESTIONS/PURPOSES

(1) How often are preoperative cutoffs for hemoglobin A1c and BMI used at the top US orthopaedic institutions? (2) What services are available at the top orthopaedic institutions for weight loss, smoking cessation, and dental care? (3) What proportion of hospital-provided weight loss clinics, smoking cessation programs, and dental care clinics accept Medicaid insurance?

METHODS

To investigate preoperative cutoffs for hemoglobin A1c and BMI and patient access to nonorthopaedic specialists at the top orthopaedic hospitals in the United States, we collected data on the top 50 orthopaedic hospitals in the United States as ranked by the 2020 US News and World Report 's "Best Hospitals for Orthopedics" list. We used a surgeon-targeted email survey to ascertain information regarding the use of preoperative cutoffs for hemoglobin A1c and BMI and availability and insurance acceptance policies of weight loss and dental clinics. Surgeons were informed that the survey was designed to assess how their institution manages preoperative risk management. The survey was sent to one practicing arthroplasty surgeon, the chair of the arthroplasty service, or department chair, whenever possible, at the top 50 orthopaedic institutions. Reminder emails were sent periodically to encourage participation from nonresponding institutions. We received survey responses from 70% (35 of 50) of hospitals regarding the use of preoperative hemoglobin A1c and BMI cutoffs. There was no difference in the response rate based on hospital ranking or hospital region. Fewer responses were received regarding the availability and Medicaid acceptance of weight loss and dental clinics. We used a "secret shopper" methodology (defined as when a researcher calls a facility pretending to be a patient seeking care) to gather information from hospitals directly. The use of deception in this study was approved by our institution's institutional review board. We called the main telephone line at each institution and spoke with the telephone operator at each hospital asking standardized questions regarding the availability of medical or surgical weight loss clinics, smoking cessation programs, and dental clinics. When possible, researchers were referred directly to the relevant departments and asked phone receptionists if the clinic accepted Medicaid. We were able to contact every hospital using the main telephone number. Our first research question was answered using solely the surgeon survey responses. Our second and third research questions were addressed using a combination of the responses to the surgeon surveys and specific hospital telephone calls.

RESULTS

Preoperative hemoglobin A1c cutoffs were used at 77% (27 of 35) of responding institutions and preoperative BMI cutoffs were used at 54% (19 of 35) of responding institutions. In the secret shopper portion of our study, we found that almost all the institutions (98% [49 of 50]) had a medical weight loss clinic, surgical weight loss clinic, or combined program. Regarding smoking cessation, 52% (26 of 50) referred patients to a specific department in their institution and 18% (9 of 50) referred to a state-run smoking cessation hotline. Thirty percent (15 of 50) did not offer any internal resource or external referral for smoking cessation. Regarding dental care, 48% (24 of 50) of institutions had a dental clinic that performed presurgical check-ups and 46% (23 of 50) did not offer any internal resource or external referral for dental care. In the secret shopper portion of our study, for institutions that had internal resources, we found that 86% (42 of 49) of weight loss clinics, 88% (23 of 26) of smoking cessation programs, and 58% (14 of 24) of dental clinics accepted Medicaid insurance.

CONCLUSION

Proceeding with TJA may not be the best option for all patients; however, surgeons and patients should come to this consensus together after a thoughtful discussion of the risks and benefits for that particular patient. Future research should focus on how shared decision-making may influence patient satisfaction and a patient's ability to meet preoperative goals related to weight loss, glycemic control, smoking cessation, and dental care. Decision analyses or time trade-off analyses could be implemented in these studies to assess patients' tolerance for risk.

CLINICAL RELEVANCE

Orthopaedic surgeons should engage in shared decision-making with patients to develop realistic goals for weight loss, glycemic control, smoking cessation, and dental care that consider patient access to these services as well as the difficulties patients experience in losing weight, controlling blood glucose, and stopping smoking.

Sleep Disturbances and Disorders in Patients with Knee Osteoarthritis and Total Knee Arthroplasty

➤

There is increasing evidence that patient-reported outcomes following total knee arthroplasty (TKA) are associated with psychosocial factors and pain catastrophizing. Sleep disturbance, pain, and mental health have a complex interaction, which, if unrecognized, can be associated with impaired patient-reported outcomes and dissatisfaction following TKA.

➤

The gold standard of objective sleep assessment is polysomnography, which is not feasible to use routinely for TKA patients. Wearable devices are a validated and less costly alternative.

➤

Subjective sleep measures, such as the Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, or Patient-Reported Outcomes Measurement Information System (PROMIS) computerized adaptive test sleep domains, are simple to administer and provide additional insight into sleep disturbance. Although objective and subjective measures do not correlate precisely, they can be informative together.

➤

Sleep disturbances in the elderly population are common and multifactorial in etiology, stemming from the interplay of sleep disorders, medication side effects, and pain. Commonly prescribed medications following TKA as well as postoperative pain can exacerbate underlying sleep disturbances.

➤

Obstructive sleep apnea (OSA) is prevalent in patients seeking TKA. In the setting of OSA, postoperative opioids can cause respiratory depression, resulting in consequences as severe as death. A standardized multimodal pain protocol including anti-inflammatories and gamma-aminobutyric acid (GABA) analogues may allow for decreased reliance on opioids for pain control.

➤

Surgeons should reassure patients that postoperative sleep disturbance is common and transient, collaborate with the patient's primary care doctor to address sleep disturbance, and avoid prescription of pharmaceutical sleep aids.

The Cost-Effectiveness of Extended Oral Antibiotic Prophylaxis for Infection Prevention After Total Joint Arthroplasty in High-Risk Patients

BACKGROUND

Extended oral antibiotic prophylaxis may decrease rates of prosthetic joint infection (PJI) after total joint arthroplasty (TJA) in patients at high risk for infection. However, the cost-effectiveness of this practice is not clear. In this study, we used a break-even economic model to determine the cost-effectiveness of routine extended oral antibiotic prophylaxis for PJI prevention in high-risk TJA patients.

METHODS

Baseline PJI rates in high-risk patients, the cost of revision arthroplasty for PJI, and the costs of extended oral antibiotic prophylaxis regimens were obtained from the literature and institutional purchasing records. These variables were incorporated in a break-even economic model to calculate the absolute risk reduction (ARR) in infection rate necessary for extended oral antibiotic prophylaxis to be cost-effective. ARR was used to determine the number needed to treat (NNT).

RESULTS

Extended oral antibiotic prophylaxis with Cefadroxil in patients at high risk for PJI was cost-effective at an ARR in baseline infection rate of 0.187% (NNT = 535) and 0.151% (NNT = 662) for TKA and THA, respectively. Cost-effectiveness was preserved with varying costs of antibiotic regimens, PJI treatment costs, and infection rates.

CONCLUSION

The use of extended oral antibiotic prophylaxis may reduce PJI rates in patients at high risk for infection following TJA and appears to be cost-effective. However, the current evidence supporting this practice is limited in quality. The use of extended oral antibiotic prophylaxis should be weighed against the possible development of future antimicrobial resistance, which may change the value proposition.

Consensus Guidelines on Interventional Therapies for Knee Pain (STEP Guidelines) from the American Society of Pain and Neuroscience

Knee pain is second only to the back as the most commonly reported area of pain in the human body. With an overall prevalence of 46.2%, its impact on disability, lost productivity, and cost on healthcare cannot be overlooked. Due to the pervasiveness of knee pain in the general population, there are no shortages of treatment options available for addressing the symptoms. Ranging from physical therapy and pharmacologic agents to interventional pain procedures to surgical options, practitioners have a wide array of options to choose from - unfortunately, there is no consensus on which treatments are "better" and when they should be offered in comparison to others. While it is generally accepted that less invasive treatments should be offered before more invasive ones, there is a lack of agreement on the order in which the less invasive are to be presented. In an effort to standardize the treatment of this extremely prevalent pathology, the authors present an all-encompassing set of guidelines on the treatment of knee pain based on an extensive literature search and data grading for each of the available alternative that will allow practitioners the ability to compare and contrast each option.

Preoperative Patient Optimization in Total Joint Arthroplasty-The Paradigm Shift from Preoperative Clearance: A Narrative Review

Background: Total joint arthroplasty (TJA) is one of the most common procedures performed in the United States. Outcomes of this elective procedure may be improved via preoperative optimization of modifiable risk factors. Purposes: We sought to summarize the literature on the clinical implications of preoperative risk factors in TJA and to develop recommendations regarding preoperative optimization of these risk factors. Methods: We searched PubMed in August 2019 with an update in September 2020 for English-language, peer-reviewed publications assessing the influence on outcomes in total hip and knee replacement of 7 preoperative risk factors-obesity, malnutrition, hypoalbuminemia, diabetes, anemia, smoking, and opioid use-and recommendations to mitigate them. Results: Sixty-nine studies were identified, including 3 randomized controlled trials, 8 prospective cohort studies, 42 retrospective studies, 6 systematic reviews, 3 narrative reviews, and 7 consensus guidelines. These studies described worse outcomes associated with these 7 risk factors, including increased rates of in-hospital complications, transfusions, periprosthetic joint infections, revisions, and deaths. Recommendations for strategies to screen and address these risk factors are provided. Conclusions: Risk factors can be optimized, with evidence suggesting the following thresholds prior to surgery: a body mass index <40 kg/m², serum albumin ≥3.5 g/dL, hemoglobin A1C ≤7.5%, hemoglobin >12.0 g/dL in women and >13.0 g/dL in men, and smoking cessation and ≥50% decrease in opioid use by 4 weeks prior to surgery. Surgery should be delayed until these risk factors are adequately optimized.

Caring for Diverse and High-Risk Patients: Surgeon, Health System, and Patient Integration

Access and outcome disparities exist in hip and knee arthroplasty care. These disparities are associated with race, ethnicity, and social determinants of health such as income, housing, transportation, education, language, and health literacy. Additionally, medical comorbidities affecting postoperative outcomes are more prevalent in underresourced communities, which are more commonly communities of color. Navigating racial and ethnic differences in treating our patients undergoing hip and knee arthroplasty is necessary to reduce inequitable care. It is important to recognize our implicit biases and lessen their influence on our healthcare decision-making. Social determinants of health need to be addressed on a large scale as the current inequitable system disproportionally impacts communities of color. Patients with lower health literacy have a higher risk of postoperative complications and poor outcomes after hip and knee replacement. Low health literacy can be addressed by improving communication, reducing barriers to care, and supporting patients in their efforts to improve their own health. High-risk patients require more financial, physical, and mental resources to care for them, and hospitals, surgeons, and health insurance companies are often disincentivized to do so. By advocating for alternative payment models that adjust for the increased risk and take into account the increased perioperative work needed to care for these patients, surgeons can help reduce inequities in access to care. We have a responsibility to our patients to recognize and address social determinants of health, improve the diversity of our workforce, and advocate for improved access to care to decrease inequity and outcomes disparities in our field.

Evaluating a pre-surgical health optimisation programme: a feasibility study

Background

Health optimisation programmes are increasingly popular and aim to support patients to lose weight or stop smoking ahead of surgery, yet there is little published evidence about their impact. This study aimed to assess the feasibility of evaluating a programme introduced by a National Health Service (NHS) clinical commissioning group offering support to smokers/obese patients in an extra 3 months prior to the elective hip/knee surgery pathway.

Methods

Feasibility study mapping routinely collected data sources, availability and completeness for 502 patients referred to the hip/knee pathway in February–July 2018.

Results

Data collation across seven sources was complex. Data completeness for smoking and ethnicity was poor. While 37% (184) of patients were eligible for health optimisation, only 28% of this comparatively deprived patient group accepted referral to the support offered. Patients who accepted referral to support and completed the programme had a larger median reduction in BMI than those who did not accept referral (− 1.8 BMI points vs. − 0.5). Forty-nine per cent of patients who accepted support were subsequently referred to surgery, compared to 61% who did not accept referral to support.

Conclusions

Use of routinely collected data to evaluate health optimisation programmes is feasible though demanding. Indications of the positive effects of health optimisation interventions from this study and existing literature suggest that the challenge of programme evaluation should be prioritised; longer-term evaluation of costs and outcomes is warranted to inform health optimisation policy development.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13741-022-00255-2.

An Academic Orthopaedic Specialty Hospital Provides the Shortest Operative Times within a Single Health System for Primary and Revision Total Knee Arthroplasty

The study aimed to optimize value-based health care practices in total joint arthroplasty (TJA), and we need to understand how the surgical setting can influence efficiency of care. While this has previously been investigated, the purpose of this study was to clarify if these findings are generalizable to an institution with an orthopaedic specialty hospital. A retrospective review was conducted of 6,913 patients who underwent primary or revision total knee arthroplasty (TKA) at one of four hospitals within a single, urban, and academic health system: a high volume academic (HVA) hospital, a low volume academic (LVA) hospital, a high volume community (HVC) hospital, or a low volume community (LVC) hospital. Patient demographics were collected in an arthroplasty database, as were operating room (OR) times and several specific time points during the surgery. The HVA (orthopaedic specialty) hospital had the shortest total primary TKA OR times and the LVC that had the longest times (156.69 vs. 174.68, p < 0.0001). The HVA hospital had the shortest total revision TKA OR times, and the LVC had the longest times (158.20 vs. 184.95, p < 0.0001). In our health system, the HVA orthoapedic specialty hospital had the shortest overall OR time, even when compared with the HVC hospital. This is in contradistinction to prior findings that HVC institutions had the shortest OR times in a health system that did not have an orthopaedic specialty hospital. This provides evidence that an orthopaedic specialty hospital can be a model for efficient care, even at an academic teaching institution.

Same-Day Outpatient Lower-Extremity Joint Replacement: A Critical Analysis Review

➢ The economics of transitioning total joint arthroplasty (TJA) to standalone ambulatory surgery centers (ASCs) should not be capitalized on at the expense of patient safety in the absence of established superior patient outcomes. ➢ Proper patient selection is essential to maximizing safety and avoiding complications resulting in readmission. ➢ Ambulatory TJA programs should focus on reducing complications frequently associated with delays in discharge. ➢ The transition from hospital-based TJA to ASC-based TJA has substantial financial implications for the hospital, payer, patient, and surgeon.

Projected Prevalence of Obesity in Primary Total Hip Arthroplasty: How Big Will the Problem Get?

BACKGROUND

Obesity is associated with higher rates of adverse outcomes following primary total hip arthroplasty (THA). The purpose of this study is to utilize 3 national databases to develop projections of obesity within the general population and primary THA patients in the United States through 2029.

METHODS

Data from the National Surgical Quality Improvement Program (NSQIP), the Behavior Risk Factor Surveillance System (BRFSS), and the National Health and Nutrition Examination Survey were queried for years 1999-2019. Current Procedural Terminology code 27130 was used to identify primary THA patients in NSQIP. Individuals were categorized according to body mass index (kg/m²) by year: normal weight (≤24.9); overweight (25.0-29.9); obese (30.0-39.9); and morbidly obese (≥40). Multinomial logistic regression was used to project categorical body mass index data for years 2020-2029.

RESULTS

A total of 8,222,013 individuals were included (7,986,414 BRFSS, 235,599 NSQIP THA). From 2011 to 2019, the prevalence of normal weight and overweight individuals declined in the general population (BRFSS) and in primary THA. Prevalence of obese/morbidly obese individuals increased in the general population from 31% to 36% and in primary THA from 42% to 49%. Projection models estimate that by 2029, 46% of the general population will be obese/morbidly obese and 55% of primary THA will be obese/morbidly obese.

CONCLUSION

By 2029, we estimate ≥55% of primary THA to be obese/morbidly obese. Increased resources dedicated to care pathways and research focused on improving outcomes in obese arthroplasty patients will be necessary as this population continues to grow.

LEVEL OF EVIDENCE

Level III, Retrospective Cohort Study.

Are Morbidly Obese Patients Equally Benefitting From Care Improvements in Total Hip Arthroplasty?

BACKGROUND

Morbidly obese patients have increased rates of complications following primary total hip arthroplasty (THA) and it is not clear whether improvements in THA care pathways are equally benefitting these patients. The purpose of this study is to assess if reductions in complications have similarly improved for both morbidly obese and non-morbidly obese patients after THA.

METHODS

Patients undergoing primary THA between 2011 and 2019 were identified in the American College of Surgeons National Surgical Quality Improvement Program database. Patients were stratified by body mass index (BMI) <40 and ≥40 kg/m². Thirty-day rates of infectious complications, readmissions, reoperation, and any complication were assessed. Trends in complications were compared utilizing odds ratios and multivariate analyses.

RESULTS

In total, 234,334 patients underwent THA and 16,979 (7.8%) had BMI ≥40 kg/m². Patients with BMI ≥40 kg/m² were at significantly higher odds for readmission, reoperation, and infectious complications. Odds for any complication were lower for morbidly obese patients in 2011, not different from 2012 to 2014, and higher from 2015 to 2019 compared to lower BMI patients. Odds for any non-transfusion complication were higher for morbidly obese patients and there was no improvement for either group over the study period. There were improvements in rates of readmission and reoperation for patients with BMI <40 kg/m² and readmission for BMI >40 kg/m².

CONCLUSION

Odds for readmission and reoperation for non-morbidly obese patients and readmission for morbidly obese patients improved from 2011 to 2019. Reductions in transfusions are largely responsible for improvements in overall complication rates. Although morbidly obese patients remain at higher risk for complications, there does not appear to be a growing disparity in outcomes between morbidly obese and non-morbidly obese patients.

Racial disparities in outcomes of arthroscopic rotator cuff repair: A propensity score matched analysis using multiple national data sets

BACKGROUND

Disparities in access, utilization and outcomes exist throughout the healthcare system for minority groups, including racial and ethnic minorities; these disparities have wide-reaching implications for individuals as well as the healthcare system as a whole. This study will examine the impact of race on short and medium term outcomes for patients undergoing rotator cuff repair (RCR) using matched cohorts.

METHODS

Patients undergoing arthroscopic rotator cuff repair from 2016 to 2018 were extracted from two national databases: the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) and TriNetX Research Network. Using the ACS-NSQIP database, univariate analysis was performed to identify differences in comorbidities between white and minority patients. Patients were propensity score matched based on significant differences between groups and 30-day postoperative outcomes were assessed. These comorbidities were then used to propensity score match white and minority patients in the TriNetX database and two-year postoperative outcomes were evaluated.

RESULTS

Following propensity score matching, 3716 patients remained in each group from the ACS-NSQIP database and 4185 patients remained in each group from the TriNetX database. The OR time for minority patients was longer than white patient in the ACS-NSQIP database (92.2 vs. 87.6 min, p < .001). There was no difference in medium-term outcomes for repeat RCR, infection or frozen shoulder between white and minority patients in the TriNetX database.

CONCLUSION

After propensity score matching the only significant short-term outcome between white and minority patients undergoing RCR was a difference in OR time; there were no differences in medium-term outcomes. This may indicate that the source of racial disparities is one of access to healthcare rather than an innate difference in the patients' outcomes. Further study is needed to elucidate this issue.

Recent Increases in Outpatient Total Hip Arthroplasty Have Not Increased Early Complications

BACKGROUND

Outpatient total hip arthroplasty (THA) has increased in recent years. Recent regulatory changes may allow and incentivize outpatient THA in more patients; however, there are concerns regarding safety. The purpose of this study is to assess early complications in outpatient THA compared to longer hospitalization.

METHODS

We identified patients undergoing primary THA in the National Surgical Quality Improvement Program database between 2015 and 2018. Patients were stratified by length of stay (LOS): 0 days (LOS 0), 1-2 days, and ≥3 days. Thirty-day rates of any complication, wound complications, readmissions, and reoperation were assessed. Multivariate analysis was performed.

RESULTS

In total, 4813 (4%) patients underwent outpatient THA, 84,627 (64%) had LOS of 1-2 days, and 42,293 (32%) had LOS ≥3 days. LOS 0 patients were younger, had lower body mass index, and less medical comorbidities compared to those with postsurgical hospitalization. Any complication was experienced in 3.2% of the LOS 0 group, 5.3% of the LOS 1-2 group, and 15.6% for the LOS ≥3 group (P < .0001). Readmission rates were 1.6%, 2.6%, and 4.7% for the 3 groups, respectively (P < .0001). After controlling for confounding variables, patients with LOS 1-2 days had higher odds for any complication (odds ratio 1.56 [1.32-1.83) and readmission (odds ratio 1.41 [1.12-1.78]) compared to LOS 0 days. Patients with LOS ≥3 days had higher odds for complications compared to LOS 0 or 1-2 days.

CONCLUSION

Outpatient THA had lower odds for readmission or complications compared to LOS 1-2 days. Despite increased outpatient surgery, many patients had postsurgical hospitalization and, due to patient factors, this remains an integral patient of post-THA care.

Does Risk Mitigation Reduce 90-Day Complications in Patients Undergoing Total Knee Arthroplasty? A Cohort Study

Background

With ever-increasing demand for total knee arthroplasty (TKA), most healthcare systems around the world are concerned about its socioeconomic burden. Most centers have universally adopted well-defined clinical care pathways to minimize adverse outcomes, maximize volume, and limit costs. However, there are no prospective comparative trials reporting benefits of these risk mitigation (RM) strategies.

Methods

This is a prospective cohort study comparing post-TKA 90-day complications between patients undergoing RM before surgery and those following a standard protocol (SP). In the RM group, we used a 20-point checklist to screen for modifiable risk factors and evaluate the need for optimizing non-modifiable comorbidities. Only when optimization goals were achieved, patients were offered TKA.

Results

TKA was performed in 811 patients in the SP group and in 829 in the RM group, 40% of which were simultaneous bilateral TKA. In both groups, hypertension was the most prevalent comorbidity (48%), followed by diabetes (20%). A total of 43 (5.3%) procedure-related complications were seen over the 90-day postoperative period in the SP group, which was significantly greater than 26 (3.1%) seen in the RM group (p = 0.039). The commonest complication was pulmonary thromboembolic, 6 in each group. Blood transfusion rate was higher in the SP group (6%) than in the RM group (< 1%).

Conclusions

Screening and RM can reduce 90-day complications in patients undergoing TKA.