Potent anticoagulants are associated with a higher all-cause mortality rate after hip and knee arthroplasty

Incidence of Venous Thromboembolism after Primary Total Hip Arthroplasty with Mechanical Prophylaxis in Hong Kong Chinese

Purpose

The incidence of deep vein thrombosis (DVT) following total hip arthroplasty (THA) without chemoprophylaxis could be as high as 50% in Caucasians. However, according to several subsequent studies, the incidence of venous thromboembolic events (VTE) in Asians was much lower. The routine use of chemoprophylaxis, which could potentially cause increased bleeding, infection, and wound complications, has been questioned in low-incidence populations. The objective of this study is to determine the incidence of VTE after primary THA without chemoprophylaxis in an Asian population using a fast-track rehabilitation protocol and to verify the safety profile for use of 'mechanical prophylaxis alone' in patients with standard risk of VTE.

Materials and Methods

This is a retrospective cohort study of 542 Hong Kong Chinese patients who underwent primary THA without chemoprophylaxis. All patients received intermittent pneumatic compression and graduated compression stockings as mechanical prophylaxis. Multimodal pain management was applied in order to facilitate early mobilisation. Routine duplex ultrasonography was performed between the fourth and seventh postoperative day for detection of proximal DVT.

Results

All patients were Chinese (mean age, 63.0±11.9 years). Six patients developed proximal DVT (incidence rate, 1.1%). None of the patients had symptomatic or fatal pulmonary embolism.

Conclusion

The incidence of VTE after primary THA without chemical prophylaxis can be low in Asian populations when following a fast-track rehabilitation protocol. Mechanical prophylaxis alone can be regarded as a reasonably safe practice in terms of a balanced benefit-to-risk ratio for Asian patients with standard risk of VTE.

Low-Dose Aspirin Is the Safest Prophylaxis for Prevention of Venous Thromboembolism After Total Knee Arthroplasty Across All Patient Risk Profiles

BACKGROUND

The International Consensus Meeting on Venous Thromboembolism (ICM-VTE) in 2022 proclaimed low-dose aspirin as the most effective agent in patients across all risk profiles undergoing joint arthroplasty. However, data on large patient populations assessing trends in chemoprophylactic choices and related outcomes following total knee arthroplasty (TKA) remain scant. The present study was designed to characterize the clinical use of various chemoprophylactic agents in patients undergoing TKA and to determine the efficacy of aspirin compared with other agents in patient groups stratified by VTE risk profiles.

METHODS

This study utilized a national database to determine the proportion of patients undergoing TKA who received low-dose aspirin versus other chemoprophylaxis between 2012 and 2022. VTE risk profiles were determined on the basis of comorbidities established in the ICM-VTE. The odds ratios (ORs) and 95% confidence intervals (CIs) between various classes of thromboprophylaxis in patients with high and low risk of VTE were calculated. The odds of deep-vein thrombosis (DVT), pulmonary embolus (PE), bleeding events, infections, mortality, and hospitalizations were also assessed in the 90-day postoperative period for propensity-matched cohorts receiving low-dose (81 mg) aspirin only versus other prophylaxis, segregating patients by VTE risk profile.

RESULTS

A total of 126,692 patients undergoing TKA across 60 health-care organizations were included. The proportion of patients receiving low-dose aspirin increased from 7.65% to 55.29% between 2012 and 2022, whereas the proportion of patients receiving other chemoprophylaxis decreased from 96.25% to 42.98%. Low-dose-aspirin-only use increased to approximately 50% in both high-risk and low-risk populations but was more likely in low-risk populations (OR, 1.17; 95% CI, 1.15 to 1.20) relative to high-risk populations. Both low-risk and high-risk patients in the low-dose-aspirin-only cohorts had decreased odds of DVT, PE, bleeding, infections, and hospitalizations compared with other prophylaxis regimens.

CONCLUSIONS

The findings of the present study on a very large population of patients undergoing TKA support the recent ICM-VTE statement by showing that low-dose aspirin is a safe and effective method of prophylaxis in patients across various risk profiles.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Venous thromboembolism is rare after total hip and knee joint arthroplasty with long thromboprophylaxis in Finnish fast-track hospitals

INTRODUCTION

Pharmacological thromboprophylaxis effectively prevents venous thromboembolism (VTE) after total knee (TKA) and total hip arthroplasty (THA). Less is known about the influence of fast-track arthroplasty on VTE risk. We conducted a register-based study to determine the incidence of VTE after fast-track TKA and THA in Finland using long thromboprophylaxis.

MATERIALS AND METHODS

All primary TKAs and THAs operated during 2015-2016 in 3 fast-track hospitals were identified from the Finnish Arthroplasty Register. Pulmonary embolism (PE) and deep vein thrombosis (DVT) diagnosed in this patient cohort within 90 days of surgery were identified from the Finnish Hospital Discharge Register. The recommended length of thromboprophylaxis was 10 to 14 days for TKA and 28 days for THA during study period.

RESULTS

During the study period, 3 831 THAs, 4 394 TKAs and 286 bilateral TKAs (BTKAs) were performed. Of all these patients, 60% were females. Venous thromboembolism (VTE) incidence within 90 days of surgery was 0.3% (95% CI 0.2-0.4). These VTEs comprised 10 PEs and 15 DVTs. None of the VTE patients´ died within the 90-day period.

CONCLUSION

VTE incidence is low in Finnish fast-track TKA and THA patients with long thromboprophylaxis.

Incidence of Symptomatic Venous Thromboembolism (VTE) in 8,885 Elective Total Hip Arthroplasty Patients Receiving Post-operative Aspirin VTE Prophylaxis

BACKGROUND

Venous thromboembolism (VTE) is a potentially reducible cause of morbidity and mortality in patients undergoing elective hip arthroplasty surgery. The balance of post-operative VTE prophylaxis and risk of post-operative haemorrhage remains at the forefront of surgeon's mind. The National Institute for Health and Care Excellence (NICE) published updated guidelines in 2018 which recommend the use of both mechanical and pharmacological methods in patients undergoing elective total hip arthroplasty (THA).

OBJECTIVES

The aim of this study was to present the symptomatic VTE incidence in 8,885 patients who underwent THA between January 1998 and March 2018 with Aspirin as the primary agent for pharmacological thromboprophylaxis. Intermittent calf compression stockings are routinely used from the time of surgery until mobilization (usually the following day) with prophylactic doses of low molecular weight heparin (LMWH) during inpatient stay (from 2005 onwards) and then Aspirin 150mg once daily for six weeks on hospital discharge (or Aspirin only prior to 2005), with use of other therapies occasionally as required.

METHODS

Analysis of prospective data collection from consecutive patients at a single institution undergoing THA was performed with the incidence of symptomatic deep vein thrombosis (DVT) and pulmonary embolism (PE) occurring within six months of the index operation as the primary outcome measure. Ninety-day all-cause mortality of this cohort of patients was also analysed.

RESULTS

8,885 patients were reviewed. This included 7230 primary, 224 complex primary and 1431 revision cases. The overall incidence of symptomatic VTE after elective THA was 1.11% (99/8885) - with the incidence of symptomatic DVT of 0.59% (52/8885) and the incidence of symptomatic PE of 0.53% (47/8885). There was no significant difference (χ² test, p=0.239) in the symptomatic VTE incidence between primary (1.20% - 89/7230), complex primary (0.89% - 2/224) and revision cases (0.70% - 10/1431). The 90-day all-cause mortality was 0.88% (78/8885). Cardiovascular and respiratory disease were the main causes of death following surgery. Only 0.03% of deaths (n= 3) within 90 days of index surgery were due to PE. There was no significant difference (p=0.327) in length of stay (and hence amount of pharmacologic prophylaxis with LMWH received by patients before commencement of Aspirin) with the average length of stay for those patients who did not suffer a VTE of 6.8 days compared with 7.6 days for those who did suffer a VTE.

CONCLUSION

Our results support the use of aspirin as an effective form of prophylaxis against symptomatic VTE following THA in contradiction to NICE and American Academy of Orthopaedic Surgery (AAOS) recommendations. It is not associated with an increased incidence in symptomatic DVT, PE or death compared to other published studies. The fact that it is inexpensive, readily available, requires no monitoring and does not pose an increased risk of bleeding are other advantages of using aspirin for VTE prophylaxis.

Low-Dose Aspirin for Venous Thromboembolism Prophylaxis is Associated With Lower Rates of Periprosthetic Joint Infection After Total Joint Arthroplasty

BACKGROUND

Aspirin as a venous thromboembolism (VTE) prophylactic agent has been shown to have antistaphylococcal and antibiofilm roles. Optimal acetylsalicylic acid (ASA) dosage would facilitate antimicrobial effects while avoiding over-aggressive inhibition of platelet antimicrobial function. Our purpose was to determine the periprosthetic joint infection (PJI) rate after total joint arthroplasty in patients receiving low-dose ASA (81 mg twice a day), in comparison to high-dose ASA (325 mg twice a day).

METHODS

We conducted a retrospective cohort study between 2008 and 2020. Eligible patients were older than 18 years, underwent primary total joint arthroplasty, both total knee arthroplasty and total hip arthroplasty, had a minimum 30-day follow-up, and received a full course ASA as VTE prophylaxis. Patients' records were reviewed for PJI, according to Musculoskeletal Infection Society criteria. Patients were excluded if they underwent revision arthroplasty, had a history of coagulopathy, or had an ASA regimen that was not completed. In total 15,825 patients were identified, 8,761 patients received low-dose ASA and 7,064 received high-dose ASA.

RESULTS

The high-dose cohort had a higher PJI rate (0.35 versus 0.10%, P = .001). This relationship was maintained when comparing subgroups comprising total knee arthroplasty (0.32 versus 0.06%, P = .019) or total hip arthroplasty (0.38 versus 0.14%, P = .035) and accounting for potentially confounding demographic and surgical variables (odds ratio = 2.59, 95% CI = 1.15-6.40, P = .028).

CONCLUSION

Comparing low-dose to high-dose ASA as a VTE prophylactic agent, low-dose ASA had a lower PJI rate. This may be attributable to a balance of anti-infective properties of ASA and antiplatelet effects.

Discontinued Use of Outpatient Portable Intermittent Pneumatic Compression Devices May Be Safe for Venous Thromboembolism Prophylaxis in Primary Total Knee Arthroplasty Using Low-Dose Aspirin

Venous thromboembolism (VTE) is a rare, but serious complication following total knee arthroplasty (TKA). Current VTE guidelines recommend pharmacologic agents with or without intermittent pneumatic compression devices (IPCDs). At our institution, both 81-mg aspirin (ASA) twice a day (BID) and portable IPCDs were previously prescribed to TKA patients at standard risk for VTE, but the IPCDs were discontinued and patients were treated with ASA alone going forward. The aim of this study is to determine if discontinued use of outpatient IPCDs is safe and does not increase the rate of VTE or any other related complications in patients following TKA. A retrospective review of 2,219 consecutive TKA cases was conducted, identifying patients with VTE, bleeding complications, infection, and mortality within 90 days postoperatively. Patients were divided into two cohorts. Patients in cohort one received outpatient IPCDs for a period of 14 days (control), while those in cohort two did not (ASA alone). All study patients received inpatient IPCDs and were maintained on 81-mg ASA BID for 28 days. A posthoc power analysis was performed using a noninferiority margin of 0.25 (α = 0.05; power = 80%), which showed that our sample size was fully powered for noninferiority for our reported deep vein thrombosis (DVT) rates, but not for pulmonary embolism (PE) rates. A total of 867 controls and 1,352 patients treated with ASA alone were identified. Only two control patients were diagnosed with a PE (0.23%), while one patient in the ASA alone group had DVT (0.07%). There was no statistical difference between these rates (p = 0.33). Furthermore, no differences were found in bleeding complications (p = 0.12), infection (p = 0.97), or 90-day mortality rates (p = 0.42) between both groups. The discontinued use of outpatient portable IPCDs is noninferior to outpatient IPCD use for DVT prophylaxis. Our findings suggest that this protocol change may be safe and does not increase the rate of VTE in standard risk patients undergoing TKA while using 81-mg ASA BID.

Time to Venous Thromboembolism Events Following Total Hip Arthroplasty: A Comparison Between Aspirin and Warfarin

BACKGROUND

The attitude and approach of orthopedic community for minimizing venous thromboembolism (VTE) has evolved over the last decade with the trend toward use of aspirin (and mechanical modalities) in lieu of aggressive anticoagulation. The optimal length of VTE prophylaxis following total hip arthroplasty (THA) still remains unknown. This study aimed to determine the timing of VTE in patients who received aspirin compared to warfarin, and determine if 30 days of prophylaxis remain adequate.

METHODS

This is a retrospective study of 18,003 patients undergoing primary and revision THA at a single institution between January 2008 and August 2020. During this time, our institution underwent a transition from the use of warfarin to aspirin as the main method for VTE prophylaxis. Symptomatic deep vein thrombosis and pulmonary embolism occurring within 90 days of surgery were identified from medical records and phone call logs. Aspirin and warfarin cohorts were matched to account for demographic and comorbidity differences. Timing of pulmonary embolism was determined based on either the date of diagnostic imaging or patient-provider phone calls confirming diagnosis.

RESULTS

The cohorts included 46 patients in the warfarin group and 46 in the aspirin group. Time to VTE was significantly shorter in the warfarin group compared to aspirin (P = .021) with a median time to VTE of 3 days (interquartile range 2-14) and 10 days (interquartile range 4-19) respectively. Over 90% of the events occurred within 32 or 30 days of surgery in the warfarin and aspirin groups respectively.

CONCLUSION

Based on the findings, a 30-day aspirin prophylaxis remains appropriate for patients undergoing THA.

Increased Morbidity With Diagnosis and Treatment of Pulmonary Embolism After Total Joint Arthroplasty: A Matched Control Analysis of 30,000 Patients

BACKGROUND

Currently, the risks associated with the diagnosis of pulmonary embolism (PE) and subsequent treatment are not well known. The purpose of our study is to quantify the specific in-hospital complications and resource utilization of patients with PE following total joint arthroplasty when compared to a matched cohort.

METHODS

The Nationwide Inpatient Sample database was used to identify patients undergoing primary hip and knee arthroplasty from January 1993 to December 2008. PE was determined using International Classification of Diseases, Ninth Revision, Clinical Modification codes. In-hospital complications, costs, and length of stay for patients with PE were compared to patients without PE, matched on the basis of age, gender, procedure (total hip arthroplasty vs total knee arthroplasty), year of surgery, morbid obesity, and all 28 comorbid-defined elements of the Elixhauser Comorbidity Index.

RESULTS

Of 8,634,038 procedures, 30,281 (0.4%) patients had a PE after total joint arthroplasty. In total, 29,917 (98%) were matched one-to-one with patients without PE. Patients with PE had a substantially higher risk of all postoperative in-hospital complications: deep vein thrombosis (odds ratio [OR] 17), peripheral vascular (OR 34), hematoma (OR 3.7), and gastrointestinal bleeding (OR 7.0) (all P < .001). Mortality was significantly higher in patients with PE compared to patients without PE (3.4% vs 0.1%, OR 30), along with total hospital costs, lengths of stay, and rates of discharge to rehabilitation facilities.

CONCLUSION

After controlling for comorbidities patients with PE have a significantly higher risk for complications including in-hospital mortality and higher hospital costs when compared to patient without PE.

Low-Dose Aspirin is Safe and Effective for Venous Thromboembolism Prevention in Patients Undergoing Revision Total Knee Arthroplasty: A Retrospective Cohort Study

Venous thromboembolism (VTE) events are rare, but serious complications of total joint replacement affect patients and health care systems due to the morbidity, mortality, and associated cost of its complications. There is currently no established universal standard of care for prophylaxis against VTE in patients undergoing revision total knee arthroplasty (rTKA). The aim of this study was to determine whether a protocol of 81-mg aspirin (ASA) bis in die (BID) is safe and/or sufficient in preventing VTE in patients undergoing rTKAs versus 325-mg ASA BID. In 2017, our institution adopted a new protocol for VTE prophylaxis for arthroplasty patients. Patients initially received 325-mg ASA BID for 1 month and then changed to a lower dose of 81-mg BID. A retrospective review from 2011 to 2019 was conducted identifying 1,438 consecutive rTKA patients and 90-day postoperative outcomes including VTE, gastrointestinal, and wound bleeding complications, acute periprosthetic joint infection, and mortality. In the 74 months prior to protocol implementation, 1,003 rTKAs were performed and nine VTE cases were diagnosed (0.90%). After 26 months of the protocol change, 435 rTKAs were performed with one VTE case identified (0.23%). There was no significant difference in rates or odds in postoperative pulmonary embolism (PE; p = 0.27), DVT (p = 0.35), and total VTE rates (p = 0.16) among patients using either protocol. There were also no differences in bleeding complications (p = 0.15) or infection rate (p = 0.36). No mortalities were observed. In the conclusion, 81-mg ASA BID is noninferior to 325-mg ASA BID in maintaining low rates of VTE and may be safe for use in patients undergoing rTKA.

Randomised comparative effectiveness trial of Pulmonary Embolism Prevention after hiP and kneE Replacement (PEPPER): the PEPPER trial protocol

INTRODUCTION

More than 1 million elective total hip and knee replacements are performed annually in the USA with 2% risk of clinical pulmonary embolism (PE), 0.1%-0.5% fatal PE, and over 1000 deaths. Antithrombotic prophylaxis is standard of care but evidence is limited and conflicting. We will compare effectiveness of three commonly used chemoprophylaxis agents to prevent all-cause mortality (ACM) and clinical venous thromboembolism (VTE) while avoiding bleeding complications.

METHODS AND ANALYSIS

Pulmonary Embolism Prevention after HiP and KneE Replacement is a large randomised pragmatic comparative effectiveness trial with non-inferiority design and target enrolment of 20 000 patients comparing aspirin (81 mg two times a day), low-intensity warfarin (INR (International Normalized Ratio) target 1.7-2.2) and rivaroxaban (10 mg/day). The primary effectiveness outcome is aggregate of VTE and ACM, primary safety outcome is clinical bleeding complications, and patient-reported outcomes are determined at 1, 3 and 6 months. Primary data analysis is per protocol, as preferred for non-inferiority trials, with secondary analyses adherent to intention-to-treat principles. All non-fatal outcomes are captured from patient and clinical reports with independent blinded adjudication. Study design and oversight are by a multidisciplinary stakeholder team including a 10-patient advisory board.

ETHICS AND DISSEMINATION

The Institutional Review Board of the Medical University of South Carolina provides central regulatory oversight. Patients aged 21 or older undergoing primary or revision hip or knee replacement are block randomised by site and procedure; those on chronic anticoagulation are excluded. Recruitment commenced at 30 North American centres in December 2016. Enrolment currently exceeds 13 500 patients, representing 33% of those eligible at participating sites, and is projected to conclude in July 2024; COVID-19 may force an extension. Results will inform antithrombotic choice by patients and other stakeholders for various risk cohorts, and will be disseminated through academic publications, meeting presentations and communications to advocacy groups and patient participants.

TRIAL REGISTRATION

NCT02810704.

Aspirina versus rivaroxabana na prevenção do tromboembolismo venoso após artroplastia total do joelho: Um ensaio clínico randomizado, controlado e duplo-cego

Objetivo A aspirina (ácido acetilsalicílico, AAS) e a rivaroxabana são anticoagulantes que vêm ganhando popularidade devido à facilidade de uso na prevenção do tromboembolismo venoso (TEV) após artroplastia total do joelho (ATJ). Este estudo teve como objetivo avaliar a eficácia do AAS em comparação com a da rivaroxabana na profilaxia de TEV em pacientes submetidos a ATJ.

Método Quarenta pacientes com osteoartrite primária do joelho, que seriam submetidos a ATJ, foram randomizados em dois grupos. No total, 20 pacientes do grupo AAS usaram aspirina oral, na dose de 300 mg/dia, para a profilaxia do TEV após ATJ; e 20 pacientes do grupo rivaroxabana receberam uma dose oral de 10 mg/dia. No 4° e 14° dias do pós-operatório, trombose venosa profunda (TVP) dos membros inferiores no lado da cirurgia foi detectada por meio de ultrassonografia duplex. Foram registradas outras complicações durante catorze dias.

Resultados Não foram detectados achados positivos de TVP com a ultrassonografia duplex nos grupos de pacientes, e não se observou a ocorrência de embolia pulmonar. No total, 4 pacientes apresentaram equimose subcutânea no 4° dia do pós-operatório (2 pacientes no grupo AAS e 2 pacientes no grupo rivaroxabana; p = 1,0), e outros 4 pacientes, no 14° dia do pós-operatório (1 paciente no grupo AAS e 3 pacientes no grupo rivaroxabana; p = 0,292). Nenhum paciente da amostra apresentou hematoma da ferida cirúrgica, sangramento de órgão importante, infecção da ferida, ou necessidade de nova cirurgia.

Conclusão A aspirina e a rivaroxabana apresentaram eficácia comparável na prevenção do TEV, sem aumentar a incidência de complicações da ferida e sangramento após ATJ.

Thirty Days of Aspirin for Venous Thromboembolism Prophylaxis Is Adequate Following Total Knee Arthroplasty, Regardless of the Dose Used

BACKGROUND

The optimal length of aspirin prophylaxis to minimize venous thromboembolism (VTE) following total knee arthroplasty (TKA) remains unknown. This study aimed to determine the timing of VTE after TKA in patients who received low and high dose aspirin, and determine if 30 days of prophylaxis remains adequate.

METHODS

We retrospectively reviewed records of 9208 patients undergoing primary TKA between 2010 and 2020 who received either low (81 mg twice daily, n = 4413) or high (325 mg twice daily, n = 4795) dose aspirin for VTE prophylaxis. Symptomatic VTEs occurring within 90 days of surgery were identified from medical records and phone call logs. Major bleeding events (MBE) within the first 30 days were also documented. Time to event was recorded.

RESULTS

Overall, 88 patients (1.0%) developed symptomatic VTE, with no significant differences in incidence between the low (n = 40, 0.9%) and high (n = 48, 1.0%) dose groups (P = .669). The median time to VTE was 8 days (interquartile range [IQR] 2-15.5), median time to deep vein thrombosis was 12 days (IQR 5-18), and median time to pulmonary embolism was 5 days (IQR 1.5-15). There was a similar distribution in time to VTE in both the low and high dose groups. Aside from a single DVT occurring at day 44, all VTE occurred within 30 days of surgery. During the prophylactic time period, 41 patients (0.4%) developed MBE, which tended to occur more frequently (0.6% vs 0.3%, P = .018) and earlier in the high dose group.

CONCLUSION

Based on the findings, a 30-day low or high dose aspirin regimen remains optimal for prevention of VTE without increasing MBE in TKA patients.

Should Insulin-dependent Diabetic Patients Be Screened for Malnutrition Before Total Joint Arthroplasty? A Cohort at Risk

INTRODUCTION

The association of malnutrition in the morbidly obese cohort has led to recommendations for preoperative screening before total joint arthroplasty (TJA). However, despite the connection between diabetes and poor nutrition, preoperative screening in the diabetic cohort has not been closely examined. This study compared malnutrition risk between diabetic patients and morbidly obese patients undergoing TJA and investigated the association of malnutrition on 30-day postoperative TJA outcomes in the diabetic cohort.

METHODS

The National Surgical Quality Improvement Program database was queried, and primary TJA patients were identified for inclusion. Patients were stratified by body mass index and diabetes, and outcomes were reported as two composite groups: complications and infections in the 30-day postoperative period. Univariate and multivariate regressions were used for the analysis.

RESULTS

Patients with insulin-dependent diabetes mellitus (IDDM) were at a high risk of being malnourished in both the morbidly obese and nonmorbidly obese populations (frequencies of 11.9% and 9.9%, respectively). Patients with IDDM, but without morbid obesity, were 1.5x more often malnourished than morbidly obese patients without diabetes mellitus (9.9% versus 6.4%, respectively, P < 0.001). In a multivariate analysis among patients with co-occurring diabetes and malnutrition, patients with IDDM were at greatest risk for postoperative complications and infection (odds ratio 2.081 [1.652, 2.621]; P < 0.001 and odds ratio 1.894 [1.231, 2.913]; P = 0.004, respectively).

DISCUSSION

Patients with IDDM are at high risk for malnutrition, and increased vigilance should be maintained in this cohort before TJA to optimize outcomes. Future studies should further investigate the utility of preoperative malnutrition screening in this cohort.

Aspirin Use for Venous Thromboembolism Prevention Is Safe and Effective in Overweight and Obese Patients Undergoing Revision Total Hip and Knee Arthroplasty

BACKGROUND

Venous thromboembolism (VTE), defined as pulmonary embolism or deep venous thrombosis, is a rare but serious complication following revision total hip arthroplasty (RTHA) and revision total knee arthroplasty (RTKA). Previous studies show that obesity may be associated with an increased risk for pulmonary embolism, wound complications, and infection. With no current universal standard of care for VTE prophylaxis, we sought to determine whether aspirin prescribed (ASA) is safe and effective in obese patients undergoing RTHA/RTKA.

METHODS

A retrospective review of 1578 consecutive RTHA/RTKA cases (751 RTHAs and 827 RTKAs) was conducted identifying patients prescribed 325 or 81 mg ASA. Ninety-day postoperative VTE rates, bleeding, wound complications, deep infections, and mortality were collected. Cohorts were stratified according to body mass index (BMI): normal (18-24.9 kg/m²), overweight (25-29.9 kg/m²), obese (30-34.9 kg/m²), severely obese (35-39.9 kg/m²), and morbidly obese (≥40 kg/m²).

RESULTS

The cohort comprised of 335 patients with a normal BMI, 511 were overweight, 408 obese, 232 severely obese, and 92 morbidly obese. Total VTE rates were statistically similar between BMI groups (0.90% vs 0.78% vs 0.74% vs 0.43% vs 0%, P = .89). There were no differences in bleeding rates (0.90% vs 0% vs 0% vs 0.43% vs 0%, P = .08), wound complications (0.30% vs 0.20% vs 0.25% vs 0% vs 0%, P = .93), infection (1.49% vs 1.57% vs 0.98% vs 1.29% vs 1.09%, P = .66), or mortality (0% vs 0.20% vs 0% vs 0% vs 0%, P = .72).

CONCLUSION

ASA is safe and effective for VTE prevention in obese patients with similar complication rates to nonobese patients undergoing RTHA/RTKA.

Aspirin Is Safe for Venous Thromboembolism Prophylaxis for Patients With a History of Gastrointestinal Issues

BACKGROUND

The safety of acetylsalicylic acid (ASA, aspirin) in patients with prior history of gastroesophageal reflux or peptic ulcer disease remains unclear. The purpose of this study was to determine the safety of ASA for venous thromboembolism (VTE) prophylaxis after total joint arthroplasty in patients with prior history of gastrointestinal (GI) issues.

METHODS

This was an institutional, retrospective cohort study of 19,044 patients who underwent primary total hip and total knee arthroplasty from 2013 to 2019. We divided the patients into two cohorts based on the presence or absence of pre-existing GI issues. Patient demographics, VTE prophylaxis, and postoperative complications were collected. The primary outcome measure was GI bleed.

RESULTS

In our series, 3090 patients had a preoperative GI issue and 15,954 did not have a GI issue. ASA was the most common mode of VTE prophylaxis (89%), followed by Coumadin (4.7%), direct oralanticoagulants (4.2%), low-molecular-weight heparin (1.7%), and others (0.4%). In the cohort of patients given ASA, there was no significant difference in postoperative GI bleeding between those with (2/1781, 0.11%) and without preoperative GI issues (8/7,628, 0.10%, P = 1.0). In the overall cohort, history of preoperative GI issues was associated with an increased risk of postoperative GI bleeding (0.32% vs 0.11%, P = .031). In logistic regression analysis, ASA was associated with a protective effect against GI bleed (OR = 0.09, 95% CI 0.01-0.40, P = .003).

CONCLUSION

ASA is safe for VTE prophylaxis after total joint arthroplasty in patients with history of GI issues and is not associated with an increased risk of postoperative GI bleeds.

Multimodal thromboprophylaxis in low-risk patients undergoing lower limb arthroplasty: A retrospective observational cohort analysis of 1400 patients with ultrasound screening

PURPOSE

This study reports the results of a multimodal thromboprophylaxis protocol for lower limb arthroplasty involving risk stratification, intraoperative calf compression, aspirin prophylaxis and early (within 4 h) post-operative mobilisation facilitated by the use of local infiltration analgesia. The study also aimed to identify risk factors for venous thromboembolism (VTE) within a 3-month period following surgery for patients deemed not at elevated risk.

METHODS

Patients undergoing knee/hip arthroplasty or hip resurfacing were preoperatively screened for VTE risk factors, and those at standard risk were placed on a thromboprophylaxis protocol consisting of intraoperative intermittent calf compression during surgery, 300 mg/day aspirin for 6 weeks from surgery and early mobilisation. Patients were screened bilaterally for deep vein thrombosis (DVT) on post-operative days 10-14. If proximal DVT was detected, patients were anticoagulated and outcomes were recorded. Symptomatic VTE within 3 months of surgery were recorded separately. Patient notes were retrospectively collated and cross-validated against ultrasound reports.

RESULTS

At initial screening, the rate of proximal DVT was 0.54% (1.1% for knee and 0.27% for hip), and distal DVT was 6.63% (20.11% for knee and 2.31% for hip). One small, nonfatal pulmonary embolism (PE) was detected within 3 months of surgery (0.28% of total knee arthroplasty patients or 0.07% of total). All proximal DVTs were treated successfully with anticoagulants; however, one patient suffered a minor PE approximately 10 months post-operatively. Regression analysis identified knee implant and advanced age as independent risk factors for VTE in this cohort.

CONCLUSION

Although knee arthroplasty patients remained at higher risk than hip replacement/resurfacing patients, the incidence and outcomes of VTE remained positive compared with protocols involving extended immobilisation, and episodes of PE were extremely rare. Thus, we conclude that patients at standard preoperative risk of VTE may safely be taken through the post-operative recovery process with a combination of intraoperative mechanical prophylaxis, early mobilisation and post-operative aspirin, with closer attention required for older patients and those undergoing knee surgery.

Persistent Wound Drainage among Total Joint Arthroplasty Patients Receiving Aspirin vs Coumadin

BACKGROUND

Persistent wound drainage (PWD) is one of the major risk factors for periprosthetic joint infections (PJI), arguably the most dreaded complications after a total hip and knee arthroplasty (THA and TKA). The aim of this study is to identify the rates of PWD among THA and TKA patients who received aspirin (ASA) or Coumadin for postoperative venous thromboembolism (VTE) prophylaxis.

METHODS

Retrospective review of 5516 primary THA and TKA was performed. Patients with PWD were identified. Chi-square test was used to compare the incidences of PWD, 30-day VTE, and PJI at 6 months between the ASA and Coumadin groups. Multivariate regression model was used to identify independent risk factors for PWD using Charlson and Elixhauser comorbidity indexes.

RESULTS

The prevalence of PWD was 6.4% (353/5516). Patients receiving ASA had lower incidence of PWD (3.2% vs 8.5%, P < .0001) while having comparable rates of 30-day VTE (1.3% vs 1.4%, P = .722) and PJI at 6 months (1.8% vs 1.4%, P = .233) compared to those receiving Coumadin. Risk factors for PWD were diabetes (odds ratio [OR], 19.3; 95% confidence interval [CI], 11.8-23.2), rheumatoid arthritis (OR, 15.3; 95% CI, 10.8-17.2), morbid obesity (OR, 13.2; 95% CI, 9.7-17.5), chronic alcohol use (OR, 3.5; 95% CI, 1.8-5.5), hypothyroidism (OR, 1.9; 95% CI, 1.1-3.2), and Coumadin (OR, 1.7; 95% CI, 1.2-2.2).

CONCLUSION

Use of ASA is associated with significantly lower rates of PWD after THA and TKA when compared to Coumadin while being equally efficacious at preventing VTE. Coumadin was found to be an independent risk factor for PWD.

Multimodal prophylaxis in patients with a history of venous thromboembolism undergoing primary elective hip arthroplasty

Aims

We studied the safety and efficacy of multimodal thromboprophylaxis in patients with a history of venous thromboembolism (VTE) who undergo total hip arthroplasty (THA) within the first 120 postoperative days, and the mortality during the first year. Multimodal prophylaxis includes discontinuation of procoagulant medications, VTE risk stratification, regional anaesthesia, an intravenous bolus of unfractionated heparin prior to femoral preparation, rapid mobilization, the use of pneumatic compression devices, and chemoprophylaxis tailored to the patient’s risk of VTE.

Methods

Between 2004 to 2018, 257 patients with a proven history of VTE underwent 277 primary elective THA procedures by two surgeons at a single institution. The patients had a history of deep vein thrombosis (DVT) (186, 67%), pulmonary embolism (PE) (43, 15.5%), or both (48, 17.5%). Chemoprophylaxis included aspirin (38 patients), anticoagulation (215 patients), or a combination of aspirin and anticoagulation (24 patients). A total of 50 patients (18%) had a vena cava filter in situ at the time of surgery. Patients were followed for 120 days to record complications, and for one year to record mortality.

Results

Postoperative VTE was diagnosed in seven patients (2.5%): DVT in five, and PE with and without DVT in one patient each. After hospitalization, three patients required readmiss-ion for evacuation of a haematoma, one for wound drainage, and one for monitoring of an elevated international normalized ratio (INR). Seven patients died (2.5%). One patient died five months postoperatively of a PE during open thrombectomy. She had discontinued anticoagulation. One patient died of a haemorrhagic stroke while receiving Coumadin. PE or bleeding was not suspected in the remaining five fatalities.

Conclusion

Multimodal prophylaxis is safe and effective in patients with a history of VTE. Postoperative anticoagulation should be prudent as very few patients developed VTE (2.5%) or died of suspected or confirmed PE. Mortality during the first year was mostly unrelated to either VTE or bleeding. Cite this article: Bone Joint J 2020;102-B(7 Supple B):71–77.

Chemoprophylaxis in addition to mechanical prophylaxis after total knee arthroplasty surgery does not reduce the incidence of venous thromboembolism

Background

Venous thromboembolism (VTE) of the lower limbs is an important complication post total knee arthroplasty (TKA). Current guidelines recommend routine chemical prophylaxis to all patients undergoing this procedure but this is rarely done in Asia as it is believed that Asians have a lower risk of VTE. However, recent evidence suggests otherwise.

Aims

We evaluated the incidence of DVT after TKA in a multi-ethnic Asian population with and without pharmacological prophylaxis, as well as the management and outcome of patients with post-operative DVTs.

Methods

We conducted a retrospective study of consecutive patients who underwent TKA in our hospital from 1st January 2004 to 30th December 2014. All patients were on mechanical thromboprophylaxis via calf pumps after TKA with a postoperative day 3 to 5 doppler ultrasound (DUS) of bilateral lower limbs. 2258 (80.7%) patients did not receive additional chemoprophylaxis, while 540 (19.3%) received chemoprophylaxis on top of mechanical thromboprophylaxis. All patients who received chemoprophylaxis were administered the drug until they were ambulating, with a median administration duration of 6 days. Patients were followed up for a period of 3 months for recurrence of DVTs and 24 months for postoperative outcome scores.

Results

Two thousand nine hundred seventy-eight patients had DUS of the lower limbs with 134 diagnosed with DVT giving an incidence of 4.5%. Six of these patients had concurrent PEs. There were 26 (19.4%) proximal DVTs and 108 (80.6%) distal DVTs. After 3 months of follow up, no additional VTE occurred. None of the DVTs or PEs progressed.All DVTs with accompanying PE were proximal. 102 out of 2200 patients (4.6%) without chemoprophylaxis developed DVT as compared to 32 out of 540 patients (5.9%) with chemoprophylaxis, which was not statistically significant (p = 0.13). 19 (0.8%) proximal and 83 (3.8%) distal DVT developed in the patient group without chemoprophylaxis while 4 (0.7%) proximal and 28 (5.2%) distal DVT developed in the patient group with (p = 0.62). Comparison of the incidence of PEs between the two groups, revealed a similar incidence with 5 out of 2200 patients (0.2%) without chemoprophylaxis developing PE as compared to 1 out of 540 patients (0.2%) with chemoprophylaxis (p = 0.87).In addition, patients with chemoprophylaxis showed an association with higher post-operative outcome scores such as post op 6 months SF36 (PCS), post op 12 months SF36 (PCS), post op 12 months SF36 (MCS), post op 24 months SF36 (MCS) and post op 24 months WOMAC.

Conclusion

In one of the largest Asian studies specifically investigating the incidence of DVT after TKA, we found that the incidence is low at 4.5%. This is in contrast to recent studies that showed higher post-operative VTE rates similar to Western populations. In addition, patients who were administered chemoprophylaxis did not have a statistically significant difference in incidence of VTE although it did show a correlation with higher post-operative outcome scores which may indicate better function. This was seen in functional outcome scores such as post op 6 months SF36 (PCS), post op 12 months SF36 (PCS), post op 12 months SF36 (MCS), post op 24 months SF36 (MCS) and post op 24 months WOMAC.

No Difference Between Low- and Regular-dose Aspirin for Venous Thromboembolism Prophylaxis After THA

BACKGROUND

Aspirin is established as an effective prophylaxis for venous thromboembolism (VTE) after THA; however, there is no consensus as to whether low- or regular-dose aspirin is more effective at preventing VTE.

QUESTIONS/PURPOSES

(1) Is there a difference in the incidence of symptomatic VTE within 90 days of elective THA using low-dose aspirin compared with regular-dose aspirin? (2) Is there a difference in the risk of significant bleeding (gastrointestinal and wound bleeding) and mortality between low- and standard-dose aspirin within 90 days after surgery?

METHODS

We retrospectively evaluated 7488 patients in our database who underwent THA between September 2012 and December 2016. A total of 3936 (53%) patients received aspirin alone for VTE prophylaxis after THA. During the study period, aspirin was prescribed as a monotherapy for VTE prophylaxis after surgery in low-risk patients (no history of VTE, recent orthopaedic surgery, hypercoagulable state, history of cardiac arrhythmia requiring anticoagulation, or receiving anticoagulation for any other medical conditions before surgery). Patients were excluded if aspirin use was contraindicated because of peptic ulcer disease, intolerance, or other reasons. Patients received aspirin twice daily (BID) for 4 to 6 weeks after surgery and were grouped into two cohorts: a low-dose (81 mg BID) aspirin group (n = 1033) and a standard-dose (325 mg BID) aspirin group (n = 2903). The primary endpoint was symptomatic VTE (deep vein thrombosis [DVT] and pulmonary embolism [PE]). Secondary endpoints included significant bleeding (gastrointestinal [GI] and wound) and mortality. Exploratory univariate analyses were used to compare confounders between the study groups. Multivariate regression was used to control for confounding variables (including age, sex, body mass index, comorbidities, and surgeon) as we compared the study groups with respect to the proportion of patients who developed symptomatic VTE, bleeding (GI or wound), and mortality within 90 days of surgery.

RESULTS

The 90-day incidence of symptomatic VTE was 1.0% in the 325-mg group and 0.6% in the 81-mg group (p = 0.35). Symptomatic DVT incidence was 0.8% in the 325-mg group and 0.5% in the 81-mg group (p = 0.49), and the incidence of symptomatic PE was 0.3% in the 325-mg group and 0.2% in the 81-mg group (p = 0.45). Furthermore, bleeding was observed in 0.8% of the 325-mg group and 0.5% of the 81-mg group (p = 0.75), and 90-day mortality was not different (0.1%) between the groups (p = 0.75). After accounting for confounders, regression analyses showed no difference between aspirin doses and the 90-day incidence of symptomatic VTE (odds ratio [OR], 0.90; 95% confidence interval [CI], 0.29-2.85; p = 0.85) or symptomatic DVT (OR, 0.96; 95% CI, 0.26-3.59; p = 0.95).

CONCLUSIONS

We found no difference in the incidence of symptomatic VTE after THA with low-dose compared with standard-dose aspirin. In the absence of compelling evidence to the contrary, low-dose aspirin appears to be a reasonable option for VTE prophylaxis in otherwise healthy patients undergoing elective THA.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Aspirin: are patients actually taking it?-A quality assessment study

BACKGROUND

The purpose of the study was to assess patient adherence to an aspirin-based prophylactic deep venous thromboembolism (DVT) care management plan after total lower extremity arthroplasty.

METHODS

Using a cross-sectional study design, patients who underwent total hip or knee replacement surgery by a single senior surgeon were surveyed at their routine 6-week follow-up appointment regarding adherence to aspirin DVT prophylaxis. Postoperatively, patients were advised to take 325 mg of aspirin twice daily for 6 weeks to prevent DVT.

RESULTS

Of the 101 patients surveyed, 45 underwent total hip arthroplasty while 56 underwent total knee arthroplasty. There were 48 (48%) patients who were still taking aspirin at their routine 6-week postoperative follow-up appointment and 53 (52%) patients who were not taking aspirin (nonadherent group). Of the latter, 3 (6%) never took aspirin postoperatively, 14 (26%) discontinued within 2 weeks postoperatively, and 23 (43%) did not take it any longer for half the time prescribed. In the nonadherent group, 8 patients reported that they felt they did not need the aspirin prophylaxis, 5 experienced side effects, and 10 were unsure of how long they needed to take it. There was 1 patient with a calf DVT and no episodes of pulmonary embolism.

CONCLUSIONS

Over half of our study, patients did not finish their aspirin regimen. We suggest a consistent outline of medication duration throughout the pre/postop course and communication regarding aspirin cessation.

A dedicated anticoagulation clinic does not improve postoperative management of warfarin after total joint arthroplasty

Background

Periprosthetic joint infections (PJIs) are devastating complications. Excessive anticoagulation with warfarin is an independent risk factor for PJIs. The use of a dedicated anticoagulation clinic to improve warfarin management has not been proven.

Methods

Between 2006 and 2014, we identified 92 patients who were placed on postoperative warfarin, and later developed PJI. These patients were compared to 313 patients who underwent total joint arthroplasty placed on warfarin without developing PJI. Patients were included if they had no history of a venous thromboembolic event, were warfarin naive, and enrolled in the anticoagulation clinic. A univariate analysis compared independent variables, and statistical analysis was performed using Student's t-test and Pearson chi-square test for continuous and categorical variables.

Results

Thirty-six PJI patients and 297 control patients met the inclusion criteria. The venous thromboembolism rate was 2.1%. At discharge, 82% of all patients were subtherapeutic. Patients were within their target international normalized ratio (INR) range 26.7% of the time. The mean INR in the initial postoperative period for the PJI group was 1.46 and 1.29 in the control group (P < .001). In the acute postoperative period, 13.3% of the knee PJI group were therapeutic or supratherapeutic compared with 3.5% in the knee control group (P = .002).

Conclusions

Despite utilization of a dedicated anticoagulation clinic, patients were only within their target INR range 27% of the time. Total knee arthroplasty patients who developed a PJI were more likely to be therapeutic or supratherapeutic in the initial postoperative period. Consequently, the risks associated with warfarin as a venous thromboembolism prophylaxis may outweigh the potential benefits.

Enhanced recovery after surgery for primary hip and knee arthroplasty: a review of the evidence

Enhanced recovery after surgery (ERAS) protocols produce significant clinical and economic benefits in a range of surgical subspecialties. There is a long tradition of applying clinical pathways to the perioperative care of joint arthroplasty patients. Enhanced recovery after surgery represents the next step in the evolution of standardized care. To date, reports of full ERAS pathways for hip or knee arthroplasty are lacking. In this narrative review, we present the evidence base that can be usefully applied to constructing ERAS pathways for hip or knee arthroplasty. The history and rationale for applying ERAS to joint arthroplasty are explained. Evidence demonstrates improved outcomes after joint arthroplasty when a standardized approach to care is implemented. The efficacy of individual ERAS components in hip or knee replacement is considered, including preoperative education, intraoperative anaesthetic techniques, postoperative analgesia, and early mobilization after joint arthroplasty. Interventions lacking high-quality evidence are identified, together with recommendations for future research. Based on currently available evidence, we present a model ERAS pathway that can be applied to perioperative care of patients undergoing hip or knee arthroplasty.

Low-Dose Aspirin Is Safe and Effective for Venous Thromboembolism Prophylaxis Following Total Knee Arthroplasty

BACKGROUND

Aspirin is an effective prophylaxis for venous thromboembolism (VTE) after total knee arthroplasty (TKA). The optimal prophylactic aspirin dose has not been established. The study aims to compare 2 aspirin regimens with regard to the incidence of (1) symptomatic deep venous thrombosis (DVT), (2) pulmonary embolism (PE), (3) bleeding, and (4) mortality within 90 days after TKA.

METHODS

We retrospectively identified 5666 patients who received aspirin twice daily for 4 to 6 weeks after TKA. A total of 1327 patients received 81-mg BID and 4339 patients received 325-mg BID aspirin. Postoperative complications collected were VTEs (DVT and PE), bleeding (gastrointestinal or wound bleeding), and mortality.

RESULTS

The incidence of VTE was 1.5% in the 325-mg group and 0.7% in the 81-mg group (P = .02). Symptomatic DVT was 1.4% in the 325-mg aspirin compared with 0.3% for the 81-mg aspirin (P = .0009). Regression model showed no correlation between aspirin dose and VTE incidence (odds ratio [OR] = 1.03; 95% confidence interval [95% CI], 0.45-2.36; P = .94) or DVT (OR = 0.50; 95% CI, 0.16-1.55; P = .20). The incidence of PE was 0.2% in the high-aspirin group compared with 0.4% in the low-aspirin group (P = .13). Bleeding was 0.2% in the 325-mg aspirin group and 0.2% in the 81-mg aspirin group (P = .62), and 90-day mortality was similar (0.1%) between the groups (P = .56).

CONCLUSION

Low-dose aspirin was not inferior to high-dose aspirin for the prevention of VTE after TKA. Low-dose aspirin can be considered a safe and effective agent in the prevention of VTE after TKA.

Respiratory Synchronized Versus Intermittent Pneumatic Compression in Prevention of Venous Thromboembolism After Total Joint Arthroplasty: A Systematic Review and Meta-Analysis

The objective of this study was to evaluate the efficacy of respiratory synchronized compression devices (RSCDs) versus nonsynchronized intermittent pneumatic compression devices (NSIPCDs) in preventing venous thromboembolism (VTE) after total joint arthroplasty. A systematic literature review was conducted. Data regarding surgical procedure, deep vein thrombosis, pulmonary embolism, mortality, and adverse events were abstracted. Compared with control groups, the risk ratio of deep vein thrombosis development was 0.51 with NSIPCDs and 0.47 with RSCDs. This review demonstrates that RSCDs may be marginally more effective at preventing VTE events than NSIPCDs. Furthermore, the addition of mechanical prophylaxis to any chemoprophylactic regimen increases VTE prevention.

Ten-Year Trends in Medical Complications Following 540,623 Primary Total Hip Replacements from a National Database

BACKGROUND

More than 75,000 total hip replacements were performed in England and Wales in 2014, and this figure is predicted to increase. Trends in mortality and complications following total hip replacement from 2005 to 2014 were evaluated to quantify risk and to identify "at-risk" groups to better inform recommendations for patient care.

METHODS

Our primary analysis estimated 90-day inpatient mortality following total hip replacement using Hospital Episode Statistics data from 2005 to 2014. Secondary analyses explored 30-day rates of lower respiratory tract infection, renal failure, myocardial infarction, pulmonary embolism, deep-vein thrombosis, cerebrovascular accident, and Clostridium difficile. Hierarchical logistic regression was used to estimate population averages, adjusting for time and prognostic covariates.

RESULTS

From January 2005 to July 2014, a total of 540,623 total hip replacements were reported. The 90-day mortality rate dropped steadily, from 0.60% in 2005 to 0.15% in 2014. Reported postoperative complications (with the exception of lower respiratory tract infection and renal failure) reduced year-on-year, despite a steady rise in the average Charlson Comorbidity Index score. The 30-day rate of lower respiratory tract infection and renal failure increased from 0.54% to 0.84% and 0.21% to 1.09%, respectively. The risk of mortality was significantly higher for those who developed a lower respiratory tract infection (odds ratio [OR] = 42.3) or renal failure (OR = 36.5) than for those who developed pulmonary embolism (OR = 10.9) or deep-vein thrombosis (OR = 2.6).

CONCLUSIONS

Despite a population with increasing levels of comorbidity, indicators of quality of care improved from 2005 to 2014, with the exception of the rates of lower respiratory tract infection and renal failure. Postoperative care should focus on reducing the risk of lower respiratory tract infection and renal failure, both of which increased and were strongly associated with mortality. Moreover, they appeared to occur in identifiable high-risk groups; modifications to routine care should be considered for these patients.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Changes in Markers of Thrombin Generation and Interleukin-6 During Unicondylar Knee and Total Knee Arthroplasty

BACKGROUND

Total knee arthroplasty (TKA) is associated with a risk of thromboembolism requiring routine thromboprophylaxis, but there is debate about the risk with unicondylar knee arthroplasty (UKA) as it is a more minor procedure. We sought to investigate the relative risk of thromboembolism with UKA compared to TKA and one-staged bilateral TKA (BTKA) by measuring the increase in circulating biochemical markers of thrombin generation during the procedures. Degree of surgical trauma was also assessed by measuring interleukin-6, a marker of metabolic injury.

METHODS

We prospectively studied a total of 75 patients: 25 patients undergoing UKA, unilateral TKA, and BTKA, respectively. All patients had surgery performed with tourniquet and received no tranexamic acid. Blood samples were taken during surgery and assayed for circulating markers of thrombin generation: prothrombin fragment 1+2 (F1+2) and thrombin-antithrombin complexes plus interleukin-6.

RESULTS

Thrombin-antithrombin complexes, increased during all time points (P < .001) but was not significantly different between surgical treatment groups. F1+2 also rose significantly during surgery, with no significant difference between UKA and TKA. There was, however, a significant difference in F1+2 between BTKA and UKA or TKA (P < .02). Interleukin-6 rose minimally with UKA but rose significantly with TKA and BTKA (P < .001).

CONCLUSION

Based on these data of circulating biochemical markers, patients undergoing UKA are at similar risk of thromboembolism with respect to TKA despite a lower index of metabolic injury. We believe that UKA patients should receive thromboprophylaxis comparable to TKA patients.

Wound Discharge After Pharmacological Thromboprophylaxis in Lower Limb Arthroplasty

BACKGROUND

The benefits vs risk of pharmacological prophylaxis for thromboembolic disease in orthopedic patients remain controversial. Pharmacological thromboprophylaxis regimes are commonly used in this patient group. Few studies specifically examine wound complications attributable to this therapy. In this prospective trial, we investigated the effect of various regimens on postoperative wounds.

METHODS

A prospective, observational, multicenter study involving patients undergoing elective hip or knee arthroplasty was undertaken. Patients were divided into 3 groups depending on thromboprophylaxis: no anticoagulation, aspirin, or low molecular weight heparin (LMWH) (enoxaparin). Surgical wounds were evaluated for each regime using the Southampton Wound Assessment Score.

RESULTS

Over a 12-month period, 327 patients were enrolled with a mean age of 68.1 years (±11.2 years). There were 105 patients in the no anticoagulation group (32.1%), 97 patients in the aspirin group (29.7%), and 125 patients in the LMWH group (38.2%). Wound scores were evaluated for evidence and amount of discharge. The use of LMWH conferred a 4.92 times greater risk and aspirin a 3.64 times greater risk of wound discharge than no pharmacological thromboprophylaxis (P < .0001). There were no significant differences in the incidence of deep vein thrombosis or pulmonary embolus between groups either as an inpatient or postdischarge.

CONCLUSION

There is a significant increase in the risk of wound discharge when aspirin or LMWH is used in arthroplasty patients. As potential complications of wound problems are significant, a more balanced view of risk vs benefit needs to be taken when prescribing thromboprophylaxis for this patient group.

Aspirin and the prevention of venous thromboembolism following total joint arthroplasty: commonly asked questions

The number of arthroplasties being performed increases each year. Patients undergoing an arthroplasty are at risk of venous thromboembolism (VTE) and appropriate prophylaxis has been recommended. However, the optimal protocol and the best agent to minimise VTE under these circumstances are not known. Although many agents may be used, there is a difference in their efficacy and the risk of bleeding. Thus, the selection of a particular agent relies on the balance between the desire to minimise VTE and the attempt to reduce the risk of bleeding, with its undesirable, and occasionally fatal, consequences.

Acetylsalicylic acid (aspirin) is an agent for VTE prophylaxis following arthroplasty. Many studies have shown its efficacy in minimising VTE under these circumstances. It is inexpensive and well-tolerated, and its use does not require routine blood tests. It is also a ‘milder’ agent and unlikely to result in haematoma formation, which may increase both the risk of infection and the need for further surgery. Aspirin is also unlikely to result in persistent wound drainage, which has been shown to be associated with the use of agents such as low-molecular-weight heparin (LMWH) and other more aggressive agents.

The main objective of this review was to summarise the current evidence relating to the efficacy of aspirin as a VTE prophylaxis following arthroplasty, and to address some of the common questions about its use.

There is convincing evidence that, taking all factors into account, aspirin is an effective, inexpensive, and safe form of VTE following arthroplasty in patients without a major risk factor for VTE, such as previous VTE.

Cite this article: Bone Joint J 2017;99-B:1420–30.

Fatal pulmonary embolism following elective total knee replacement using aspirin in multi-modal prophylaxis - A 12year study

BACKGROUND

The National Institute for Health and Clinical Excellence (NICE) has issued guidelines on which thromboprophylaxis regimens are suitable following lower limb arthroplasty. Aspirin is not a recommended agent despite being accepted in orthopaedic guidelines elsewhere. We assessed the incidence of fatal pulmonary embolism (PE) and all-cause mortality following elective primary total knee replacement (TKR) with a standardised multi-modal prophylaxis regime in a large teaching district general hospital.

METHODS

We utilised a prospective audit database to identify those that had died within 42 and 90days postoperatively. Data from April 2000 to 2012 were analysed for 42 and 90day mortality rates. There were a total of 8277 elective primary TKR performed over the 12year period. The multi-modal prophylaxis regimen used unless contraindicated for all patients included 75mg aspirin once daily for four weeks. Case note review ascertained the causes of death. Where a patient had been referred to the coroner, they were contacted for post mortem results.

RESULTS

The mortality rates at 42 and 90days were 0.36 and 0.46%. There was one fatal PE within 42days of surgery (0.01%) who was taking enoxaparin because of aspirin intolerance. Two fatal PE's occurred at 48 and 57days post-operatively (0.02%). The leading cause of death was myocardial infarction (0.13%).

CONCLUSIONS

Fatal PE following elective TKR with a multi-modal prophylaxis regime is a very rare cause of mortality.

Enhanced Recovery After Surgery for Hip and Knee Replacements

BACKGROUND

Enhanced recovery after surgery (ERAS) programs or hip and knee replacements have had a significant effect on streamlining patient care with shorter stays, no increase in complications, and improved outcomes including reduced mortality.

PURPOSE

To compare outcomes following the introduction of an ERAS program for hip and knee replacements developed at our institution with a historical cohort of patients.

METHODS

ERAS protocols were developed at our institution for patients undergoing hip and knee joint replacements. Key aspects were changes in preadmission, a new education session, improved management of perioperative anemia, standardized anesthetic guidelines, day of surgery mobilization, and improved discharge planning. The results of the first 18 months (528 consecutive patients) were compared with those of a historical cohort of 507 patients from the 18 months prior to their introduction.

RESULTS

In the ERAS group, the mean age was 68.3 years for patients who underwent hip replacement and 70.4 years for patients who underwent knee replacement. Thirty-two percent of patients were ASA (American Society of Anesthesiologists) Grades III and IV. The average preoperative Oxford score was 11. The average length of stay (ALOS) fell from 5.6 to 4.3 days for patients who underwent hip replacement and from 5.7 to 4.8 days for patients who underwent knee replacement (p < .001). Ninety-six percent of patients were discharged home. The 30-day readmission rate increased from 3.2% to 5.5% (p = .065). Six-month Oxford knee scores were higher in the ERAS group (39.8 vs. 36.3, p = .03). There was no increase in mortality or early revision rate.

CONCLUSIONS

Substantial reductions in ALOS can be gained with the introduction of ERAS protocols, with high patient satisfaction and no increase in complications in a consecutive unselected group of public hospital patients. This requires a multidisciplinary approach and a strong clinical input.

Patient and Perioperative Variables Affecting 30-Day Readmission for Surgical Complications After Hip and Knee Arthroplasties: A Matched Cohort Study

BACKGROUND

Changes in reimbursement for total hip and knee arthroplasties (THA and TKA) have placed increased financial burden of early readmission on hospitals and surgeons. Our purpose was to characterize factors of 30-day readmission for surgical complications after THA and TKA at a single, high-volume orthopedic specialty hospital.

METHODS

Patients with a diagnosis of osteoarthritis and who were readmitted within 30 days of their unilateral primary THA or TKA procedure between 2010 and 2014. Readmitted patients were matched to nonreadmitted patients 1:2. Patient and perioperative variables were collected for both cohorts. A conditional logistic regression was performed to assess both the patient and perioperative factors and their predictive value toward 30-day readmission.

RESULTS

Twenty-one thousand eight hundred sixty-four arthroplasties (THA = 11,105; TKA = 10,759) were performed between 2010 and 2014 at our institution, in which 60 patients (THA = 37, TKA = 23) were readmitted during this 5-year period. The most common reasons for readmission were fracture (N = 14), infection (N = 14), and dislocation (N = 9). Thirty-day readmission for THA was associated with increased procedure time (P = .05), length of stay (LOS) shorter than 2 days (P = .04), discharge to a skilled nursing facility (P = .05), and anticoagulation use other than aspirin (P = .02). Thirty-day readmission for TKA was associated with increased tourniquet time (P = .02), LOS <3 days (P < .01), and preoperative depression (P = .02). In the combined THA/TKA model, a diagnosis of depression increased 30-day readmission (odds ratio 3.5 [1.4-8.5]; P < .01).

CONCLUSION

Risk factors for 30-day readmission for surgical complications included short LOS, discharge destination, increased procedure/tourniquet time, potent anticoagulation use, and preoperative diagnosis of depression. A focus on risk factor modification and improved risk stratification models are necessary to optimize patient care using readmission rates as a quality benchmark.

Low-Dose Aspirin Is Effective Chemoprophylaxis Against Clinically Important Venous Thromboembolism Following Total Joint Arthroplasty: A Preliminary Analysis

BACKGROUND

Aspirin is a safe and effective prophylaxis for the prevention of venous thromboembolism following total joint arthroplasty. The optimal dose of aspirin prophylaxis is unknown. Our hypothesis was that lower-dose aspirin is as effective as higher-dose aspirin for the prevention of venous thromboembolism and is associated with fewer gastrointestinal side effects.

METHODS

In a prospective, crossover study, we analyzed 4,651 primary total joint arthroplasty cases performed from July 2013 to June 2015. For 4 weeks, 3,192 patients received enteric-coated 325-mg aspirin twice daily (the 325-mg aspirin group) and 1,459 patients received 81-mg aspirin twice daily (the 81-mg aspirin group). There were no significant differences (p > 0.05) in sex, body mass index, or Charlson Comorbidity Index between the two patient populations. Recorded complications occurring within 90 days postoperatively included symptomatic venous thromboembolism (deep venous thrombosis and pulmonary embolism), gastrointestinal complications, acute periprosthetic joint infection, and death.

RESULTS

The incidence of venous thromboembolism of 0.1% (95% confidence interval [CI], 0% to 0.3%) in the 81-mg aspirin group (1 with deep venous thrombosis and 1 with pulmonary embolism) was not significantly different (p = 0.345) from 0.3% (95% CI, 0.1% to 0.6%) in the 325-mg aspirin group (7 with deep venous thrombosis and 5 with pulmonary embolism). The incidence of gastrointestinal bleeding or ulceration of 0.3% (95% CI, 0% to 0.5%) in the 81-mg aspirin group was slightly, but not significantly (p = 0.66), lower than the 0.4% (95% CI, 0.2% to 0.6%) in the 325-mg aspirin group. The incidence of acute periprosthetic joint infection was 0.2% (95% CI, 0% to 0.4%) in the 81-mg aspirin group compared with 0.5% (95% CI, 0.2% to 0.7%) in the 325-mg aspirin group (p = 0.28). The 90-day mortality rate was similar in both groups at 0.1% (95% CI, 0% to 0.2%) in the 81-mg aspirin group and 0.1% (95% CI, 0% to 0.2%) in the 325-mg aspirin group (p = 0.78).

CONCLUSIONS

Our study demonstrates that low-dose aspirin is not inferior to high-dose aspirin for venous thromboembolism prophylaxis following total joint arthroplasty. This is not unexpected, as the available literature demonstrates that low-dose aspirin is as effective as higher-dose aspirin in the prevention of acute coronary syndrome and cerebrovascular events.

LEVEL OF EVIDENCE

Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Rate of Transfusions After Total Knee Arthroplasty in Patients Receiving Lovenox or High-Dose Aspirin

BACKGROUND

Controversy continues regarding the use of powerful anticoagulants for venous thromboembolism prophylaxis in patients undergoing total knee arthroplasty (TKA). To comply with institution-mandated guidelines and pressure from hospitalist intent on complying with conventionally recommended anticoagulation guidelines, we singularly changed our chemoprophylaxis practice from using aspirin to Lovenox and noted that transfusion rates increased substantially.

METHODS

A retrospective case review was performed to evaluate transfusion requirement differences in primary TKA patients receiving Lovenox (unilateral TKA: n = 135, bilateral TKA: n = 44) or aspirin (unilateral TKA: n = 153, bilateral TKA: n = 45) for venous thromboembolism prophylaxis. Pearson's chi-square tests were used to evaluate surgical complications and the rate of transfusions between aspirin and Lovenox groups. Independent t tests were used to evaluate the units of packed red blood cells transfused, hemoglobin drop, and hematocrit drop between aspirin and Lovenox groups.

RESULTS

Lovenox was found to significantly increase (P < .01) the rate of transfusion, units of packed red blood cells, hemoglobin drop, and hematocrit drop compared to aspirin in both unilateral and bilateral TKA patients, without significantly decreasing venous thromboembolism events (aspirin: 3 pulmonary embolisms and 4 deep venous thrombosis; Lovenox: 3 pulmonary embolisms and 2 deep venous thrombosis).

CONCLUSION

Our findings suggest that aspirin is as effective as Lovenox in preventing venous thromboembolism and that the use of Lovenox significantly increases the likelihood of requiring transfusions after surgery.

Impact of recent guideline changes on aspirin prescribing after knee arthroplasty

BACKGROUND

Prior to 2012, the American Academy of Orthopaedic Surgeons (AAOS) and American College of Chest Physicians (ACCP) differed in their recommendations for postoperative pharmacologic venous thromboembolism prophylaxis (VTEP) after total joint arthroplasty. More specifically, aspirin (ASA) monotherapy was not endorsed by the ACCP as an acceptable prophylaxis. In 2012, the ACCP supported ASA monotherapy compared with no prophylaxis. Our aim was to investigate the impact of the convergence of ACCP and AAOS recommendations on surgeon prescribing patterns after knee arthroplasty (KA).

METHODS

This is a retrospective chart review. We collected data to assess preoperative VTE risk and examined VTEP prescriptions on postoperative day 1 (POD1) and at discharge (D/C) from 7/2008 to 12/2011 (pre-period) and 1/2012 to 7/2014 (post-period). Adult patients undergoing primary and revision KA were identified by ICD-9 procedure codes. Patients on preoperative full-dose anticoagulation and with hypercoagulability disorders were excluded.

RESULTS

Of 368 records reviewed, 329 were included in the analysis. There were no differences between the two period groups for age, sex, BMI, estrogen therapy, malignancy, smoking status, prior VTE, bilateral procedures, or surgery within 3 months. On POD1, in the pre-period, 4.6 % were prescribed ASA monotherapy versus 44.4 % in the post-period (p < 0.001). On D/C, in the pre-period, 13.9 % were prescribed ASA versus 55.6 % in the post-period (p < 0.001).

CONCLUSIONS

Our results indicate a statistically significant change in orthopedist prescribing patterns after guideline convergence. Furthermore, there was no apparent change in VTE risk between the two study groups when excluding patients necessitating full anticoagulation. Prior literature has shown that the divergence in guidelines influenced physicians away from ASA and toward more potent anticoagulants in order to avoid potential litigation. Once its role in VTEP was supported by the ACCP, it appears that ASA monotherapy was readily and rapidly incorporated into clinical practice. ASA may be favored over other VTEP agents for its lower bleeding risk profile and cost. This study highlights the profound impact clinical practice guidelines have on clinician prescribing patterns. Although prospective randomized trials are needed to compare the efficacy of ASA with other VTEP agents, ASA is now a predominant part of the VTEP armamentarium after KA.

Anti-Xa bioassays for the laboratory measurement of direct Factor Xa inhibitors in plasma, in selected patients

In the past decade Direct Oral Anti-Coagulants (DOACs), targeting Thrombin or Factor Xa, have enormously facilitated the daily treatment of all relevant patients, including those requiring lifelong therapy. These DOACs have considerable advantages over the use of oral Vitamin K Antagonist (VKA) treatments, in view of having little interferences with food and other medications and also not requiring adjustment for age, gender or weight, with some well-defined exceptions. In this current What's Happening Section we focus on measurements of DiXaIs in plasma using anti-Xa assays, with the objective of providing a tribute to Professor Michel Meyer Samama, who was not only a real leader in this field but, in the past, both authors benefited from his wisdom, as a teacher who dedicated his scientific and professional life (among many other interests in hemostasis, thrombosis and fibrinolysis) to develop and promote methods and strategies for laboratory monitoring of anticoagulants. This review presents the performance characteristics of the Anti-Factor Xa assays (measuring Factor Xa inhibition by drugs), which are available for measuring Direct Factor Xa Inhibitors in plasma, and show good compliance of the results with the reference LC:MS method (which measures the mass of Direct Factor Xa Inhibitors). We also present the preparation and validation of drug specific plasma calibrators and controls which are requested for drug measurements. These assays are convenient and practical laboratory tools which can be used in any laboratory setting, and meet the requirements of regulatory bodies for making smart, quantitative, sensitive, accurate and ease of use assays for measuring DOACs when needed. The manuscript focuses mainly on the following areas of current interest: interference in coagulation assays; anti-Xa laboratory methods; development of calibrators and controls for DiXaIs; method validation and comparison with reference techniques (LC:MS); regulatory requirements and method registrations; newer clinical applications and experience on DiXaIs with Anti-Xa assays, and future perspectives.

Aspirin Is as Effective as and Safer Than Warfarin for Patients at Higher Risk of Venous Thromboembolism Undergoing Total Joint Arthroplasty

BACKGROUND

There is continued controversy regarding the optimal venous thromboembolism (VTE) prophylaxis, particularly for total joint arthroplasty (TJA) patients at higher risk. The purpose of this study was to compare the efficacy of aspirin (ASA) to warfarin in patients with higher risk of VTE.

METHODS

This retrospective study examined 30,270 patients who received ASA or warfarin for VTE prophylaxis after TJA. Using a previously developed risk stratification model, patients were classified into low or high VTE risk categories. Postoperative 90-day VTE, periprosthetic joint infection (PJI), gastrointestinal complications, and mortality were recorded.

RESULTS

The incidences of VTE, PJI, and mortality were higher in patients receiving warfarin compared to ASA. In multivariate analysis, warfarin was an independent risk factor for VTE, PJI, and mortality in the higher risk VTE patients (P < .001). There was no significant difference in gastrointestinal complications between groups.

CONCLUSION

Our study demonstrates that ASA is as effective as and safer than warfarin for VTE prophylaxis after TJA, even in patients at higher risk of VTE.

Risk-Stratified Venous Thromboembolism Prophylaxis After Total Joint Arthroplasty: Aspirin and Sequential Pneumatic Compression Devices vs Aggressive Chemoprophylaxis

BACKGROUND

Venous thromboembolism (VTE) is a major concern after total joint arthroplasty (TJA). We evaluated a risk-stratified prophylaxis protocol for patients undergoing TJA.

METHODS

A total of 2611 TJA patients were retrospectively studied. Patients treated with an aggressive VTE chemoprophylaxis protocol were compared with patients treated with a risk-stratified protocol utilizing aspirin and sequential pneumatic compression devices (SPCDs) for standard-risk patients and targeted anticoagulation for high-risk patients.

RESULTS

We found equivalence in terms of VTE prevention between the 2 cohorts. There was a decrease in adverse events and readmissions among the risk-stratified cohort, although this did not reach statistical significance. A statistically significant reduction in costs (P < .001) was experienced with the use of aspirin/SPCDs compared with aggressive anticoagulation agents within the risk-stratified cohort.

CONCLUSION

The use of aspirin/SPCDs in a risk-stratified TJA population is a safe and cost-effective method of VTE prophylaxis.

The modern, hybrid total hip arthroplasty for primary osteoarthritis at the Hospital for Special Surgery

We describe our technique and rationale using hybrid fixation for primary total hip arthroplasty (THA) at the Hospital for Special Surgery. Modern uncemented acetabular components have few screw holes, or no holes, polished inner surfaces, improved locking mechanisms, and maximised thickness and shell-liner conformity. Uncemented sockets can be combined with highly cross-linked polyethylene liners, which have demonstrated very low wear and osteolysis rates after ten to 15 years of implantation. The results of cement fixation with a smooth or polished surface finished stem have been excellent, virtually eliminating complications seen with cementless fixation like peri-operative femoral fractures and thigh pain. Although mid-term results of modern cementless stems are encouraging, the long-term data do not show reduced revision rates for cementless stems compared with cemented smooth stems. In this paper we review the conduct of a hybrid THA, with emphasis on pre-operative planning, surgical technique, hypotensive epidural anaesthesia, and intra-operative physiology.