A Comparison of Two Dosing Regimens of ASA Following Total Hip and Knee Arthroplasties

Thirty day low-dose versus regular-dose aspirin for venous thromboembolism prophylaxis in primary total joint arthroplasty

BACKGROUND

The optimal dosing of aspirin (ASA) monotherapy for prophylaxis after total joint arthroplasty is debatable. The objective of this study was to compare two ASA regimens with regards to symptomatic deep venous thrombosis (DVT), pulmonary embolism (PE), bleeding, and infection 90 days after primary total hip arthroplasty (THA) and total knee arthroplasty (TKA).

METHODS

We retrospectively identified 625 primary THA and TKA surgeries in 483 patients who received ASA for 4 weeks post-op. 301 patients received 325 mg once daily (QD) and 324 patients received 81 mg twice daily (BID). Patients were excluded if they were minors, had a prior venous thromboembolism (VTE), had ASA allergy, or received other VTE prophylaxis drugs.

RESULTS

There was a significant difference in rate of bleeding and suture reactions between the two groups. Bleeding was 7.6% for 325 mg QD and 2.5% for 81 mg BID (p = .0029 Χ2, p = .004 on multivariate logistic regression analysis). Suture reactions were 3.3% for 325 mg QD and 1.2% for 81 mg BID (p = .010 Χ2, p = .027 on multivariate logistic regression analysis). Rates of VTE, symptomatic DVT, and PE were not significantly different. The incidence of VTE was 2.7% for 325 mg QD and 1.5% for 81 mg BID (p = .4056). Symptomatic DVT rates were 1.6% for 325 mg QD and 0.9% for 81 mg BID (p = .4139). Deep infection was 1.0% for 325 mg QD and 0.31% for 81 mg BID (p = .3564).

CONCLUSION

Low-dose ASA in patients with limited comorbidities undergoing primary THA and TKA is associated with significant lower rates of bleeding and suture reactions than high dose ASA. Low-dose ASA was not inferior to higher dose ASA for the prevention of VTE, wound complications, and infection 90 days postoperatively.

Low-Dose NSAIDs Efficacy in Orthopedic Applications

Non-steroidal anti-inflammatory drugs (NSAIDs) [cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) inhibitors] and COXIBs (the COX-2 selective inhibitors) may induce several potentially severe and life-threatening issues especially in elderly patients. The use of low-dose NSAIDs is associated with lower risk of side effects compared to the standard dosage. Low-dose NSAIDs could minimize the side effects of these drugs while maintaining their clinical efficacy and effectiveness. The present study evaluates the effectiveness and safety of low-dose NSAIDs in musculoskeletal applications.

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.

Morbidly Obese Patients Undergoing Primary Total Joint Arthroplasty May Experience Higher Rates of Venous Thromboembolism When Prescribed Direct Oral Anticoagulants vs Aspirin

BACKGROUND

Morbidly obese (body mass index [BMI] >40 kg/m²) patients undergoing total joint arthroplasty (TJA) are at high risk for postoperative venous thromboembolism (VTE); however, there is debate surrounding the optimal pharmacologic agent for prevention of VTE after TJA in this patient subset. Current guidelines recommend against direct-acting oral anticoagulants (DOACs) in patients of BMI >40 kg/m² due to low quality evidence justifying their use. We evaluated whether patients of BMI >40 kg/m² undergoing primary unilateral TJA would have increased risk of postoperative VTE if prescribed DOACs compared to non-DOAC agents such as aspirin.

METHODS

This retrospective study analyzed 897 patients of BMI >40 kg/m² undergoing primary unilateral TJA. Demographic and comorbidity-related variables were collected. The association between postoperative VTE and prophylactic pharmacologic agent prescribed was evaluated by multivariate logistic regression.

RESULTS

After controlling for comorbidities, we found that the sole use of DOACs, specifically apixaban, for VTE prophylaxis was associated with an increased risk of developing VTE compared to prophylaxis with aspirin alone in patients of BMI >40 kg/m² (odds ratio 2.962, P = .016). Regardless of VTE prophylactic agent, patients with BMI >40 kg/m² undergoing TKA had at least 4.5-fold increased odds of developing VTE compared to patients undergoing THA (OR 4.830, P = .019).

CONCLUSION

In our retrospective study of a large sample size of patients with BMI >40 kg/m², we found that the use of DOACs, specifically apixaban, for VTE prophylaxis following TJA was associated with increased odds of a VTE complication compared to the use of aspirin alone.

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.

Weight-Based Aspirin Dosing May Further Reduce the Incidence of Venous Thromboembolism Following Primary Total Joint Arthroplasty

BACKGROUND

Obesity poses a challenge to thromboembolic prophylaxis following total joint arthroplasty (TJA). The purpose of this study is to evaluate a weight-based aspirin dosing regimen for prevention of venous thromboembolism (VTE) following TJA.

METHODS

This is a retrospective observational study of 2403 patients who underwent primary total hip or knee arthroplasty at one institution. A weight-based aspirin dosing regimen for VTE prophylaxis was administered to 1247 patients: patients weighing ≥120 kg received 325 mg aspirin twice daily (BID) and those weighing <120 kg received 81 mg aspirin BID for 4 weeks. In total, 1156 patients in the comparison cohort received 81 mg aspirin BID. VTE and gastrointestinal bleeding events were identified through chart review at 42 days and 6 months postoperatively. A multivariable logistic regression was performed to adjust for covariates.

RESULTS

The weight-based aspirin cohort had a significantly lesser incidence of VTE at 42 days (P = .03, relative risk [RR] 0.31, 95% confidence interval 0.12-0.82) and 6 months (P = .03, RR 0.38, 95% confidence interval 0.18-0.80). There was no difference in VTE incidence between total hip arthroplasty and total knee arthroplasty cases (P = .8). There was no difference in gastrointestinal bleeding events between the cohorts at 42 days (P = .69) or 6 months (P = .92). Subanalysis of patients weighing ≥120 kg demonstrated a significant difference between the cohorts with a VTE incidence of 3.48% and 0% in the 81 mg and weight-based cohorts, respectively (P = .02).

CONCLUSION

Patients prescribed a weight-based aspirin regimen had significantly fewer VTEs after TJA compared to historical controls with an RR reduction of 69% at 6 weeks and 62% at 6 months postoperatively. This suggests the need to factor patient weight when determining postoperative VTE prophylaxis with aspirin.

No Increased Risk of Venous Thromboembolism in High-Risk Patients Continuing Their Dose of 75 mg Aspirin Compared to Healthier Patients Given Low-Molecular-Weight Heparin

BACKGROUND

Optimum venous thromboembolism (VTE) prophylaxis for patients undergoing total hip or knee arthroplasty remains undefined. The purpose of this study is to compare complication rates among total joint arthroplasty patients using either low-dose aspirin (75 mg once daily) or low-molecular-weight heparin (LMWH; Fragmin/dalteparin 5000 U) for VTE prophylaxis.

METHODS

This is a prospective observational study. All total hip or knee arthroplasties from 2014 to 2020 were included. One thousand eighty-four patients already taking aspirin 75 mg as primary or secondary prophylaxis for cardiovascular disease continued their daily aspirin dose throughout their hospital stay and after discharge without any other kind of thromboprophylaxis. Five thousand ten patients not already taking aspirin were given LMWH for 12-14 days starting the day of surgery. Both groups consisted of patients undergoing either primary or revision total hip or knee arthroplasty. The aspirin group was older (73 ± 7.8 vs 66 ± 10.2 years, P < .01, 95% CI -7.6, -6.3) with more comorbidities but otherwise did not differ from the LMWH group. Outcome measures were recorded at 3-month follow-up and included the following complications: clinically deep venous thrombosis (DVT), pulmonary embolism (PE), deep infection, blood transfusion, and death.

RESULTS

The aspirin group had 0.28% DVT and 0.28% PE, and the LMWH group had 0.24% DVT and 0.16% PE (P = .42 and .74, respectively). No difference in deep infection, allogenic blood transfusion, or mortality was found.

CONCLUSION

No statistically significant difference in complication rates was found between aspirin 75 mg and LMWH used for VTE prophylaxis. Aspirin 75 mg daily is safe for VTE prophylaxis after total hip or knee arthroplasty.

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.

Utilization Patterns, Efficacy, and Complications of Venous Thromboembolism Prophylaxis Strategies in Revision Hip and Knee Arthroplasty as Reported by American Board of Orthopaedic Surgery Part II Candidates

BACKGROUND

The optimum venous thromboembolism (VTE) prophylaxis strategy to minimize risk of VTE and bleeding complications following revision total hip and knee arthroplasty (rTHA/rTKA) is controversial. The purpose of this study is to describe current VTE prophylaxis patterns following revision arthroplasty procedures to determine efficacy, complication rates, and prescribing patterns for different prophylactic strategies.

METHODS

The American Board of Orthopaedic Surgery Part II (oral) examination case list database was analyzed. Current Procedural Terminology codes for rTHA/rTKA were queried and geographic region, VTE prophylaxis strategy, and complications were obtained. Less aggressive prophylaxis patterns were defined if only aspirin and/or sequential compression devises were utilized. More aggressive VTE prophylaxis patterns were considered if any of low-molecular-weight heparin (enoxaparin), warfarin, rivaroxaban, fondaparinux, or other strategies were used.

RESULTS

In total, 6387 revision arthroplasties were included. The national rate of less aggressive VTE prophylaxis strategies was 35.3% and more aggressive in 64.7%. Use of less aggressive prophylaxis strategy was significantly associated with patients having no complications (89.8% vs 81.9%, P < .001). Use of more aggressive prophylaxis patterns was associated with higher likelihood of mild thrombotic (1.2% vs 0.3%, P < .001), mild bleeding (1.7% vs 0.6%, P < .001), moderate thrombotic (2.6% vs 0.4%, P < .001), moderate bleeding (6.2% vs 4.0%, P < .001), severe bleeding events (4.4% vs 2.4%, P < .001), infections (6.4% vs 3.8%, P < .001), and death within 90 days (3.1% vs 1.3%, P < .001). There were no significant differences in rates of fatal pulmonary embolism (0.1% vs 0.04%, P = .474). Subgroup analysis of rTHA and rTKA patients showed similar results.

CONCLUSION

The individual rationale for using a more aggressive VTE prophylaxis strategy was unknown; however, more aggressive strategies were associated with higher rates of bleeding and thrombotic complications. Less aggressive strategies were not associated with a higher rate of thrombosis.

LEVEL OF EVIDENCE

Therapeutic Level III.

A Retrospective Analysis Comparing Post-Operative Bleeding with Various Doses of Aspirin after Lower Extremity Joint Arthroplasty or Revision

STUDY OBJECTIVE

Previous studies have shown that aspirin is noninferior to other anticoagulation therapies in preventing postoperative venous thromboembolism following lower extremity arthroplasty or revision; however, its optimal dosing for this indication is less clear. This study aims to compare the odds of bleeding between different aspirin dosages following lower extremity joint arthroplasty or revision.

DESIGN

This is a 3-year retrospective multi-center cohort study across the United States and its territories.

SETTING

This study included patients admitted for total hip or knee arthroplasty or revision and were treated with prophylactic aspirin.

PATIENTS, INTERVENTION, MEASUREMENTS

Patients were assigned to groups based on a total daily aspirin dose of 81, 162, 325, or 650 mg. Data were analyzed for postsurgical bleeding and thromboembolism events occurring during the initial admission and up to 40 days following surgery. Other exploratory variables included type of surgery, hip or knee arthroplasty, length of stay, and patient demographic data.

MAIN RESULTS

Among 53,848 patients receiving aspirin, 3922 received a total daily dose of 81 mg, 19,341 received a total daily dose of 162 mg, 5256 received a total daily dose of 325 mg, and 25,329 received a total daily dose of 650 mg. Bleeding occurred in 466 (0.87%) patients and venous thromboembolism (VTE) in 209 patients (0.39%). The odds of bleeding were compared using logistic regression, with the 650-mg dose as the reference group. None were statistically significant for bleeding between all studied aspirin doses: 81 mg (OR 1.12, 95% CI 0.83-1.51, p = 0.451), 162 mg (OR 0.83, 95% CI 0.67-1.03, p = 0.097), and 325 mg (OR 0.83, 95% CI 0.59-1.13, p = 0.245). The odds of VTE were also not statistically significant: 81 mg (OR 0.71, 95% CI 0.40-1.17, p = 0.181), 162 mg (OR 0.75 95% CI 0.54-1.03, p = 0.072), and 325 mg (OR 1.00, 95% CI 0.64-1.53, p = 0.989).

CONCLUSIONS

There were no significant differences in the odds of bleeding or venous thromboembolism among all studied aspirin dosages in patients receiving aspirin for thromboprophylaxis following lower extremity joint arthroplasty or revision.

Interaction Between Low-Dose Aspirin and Nonsteroidal Anti-Inflammatory Drugs Can Compromise Aspirin's Efficacy in Preventing Venous Thrombosis Following Total Joint Arthroplasty

Total joint arthroplasty is a rapid recovery procedure with patients optimized quickly in preparation for discharge. Two significant postoperative goals are effective pain management and prevention of postoperative venous thromboembolism (VTE). Low-risk patients receive aspirin 81 mg twice daily for VTE prophylaxis; this dosing regimen has been reduced over the past few years from 325 mg to 162 mg to 81 mg twice daily. Unless contraindications exist, all patients receive multimodal pain management that includes the use of celecoxib or meloxicam. Upon reduction of the aspirin dose to 81 mg twice daily, we rapidly identified 2 patients who developed a pulmonary embolus when celecoxib or meloxicam was administered concurrently with aspirin. The interaction between nonsteroidal anti-inflammatory drugs (NSAIDs) and low-dose aspirin varies among the different NSAIDs. It is also highly dependent on numerous factors, including time of administration, dose of aspirin, and both pharmacodynamics and dose of the NSAID. Real-world outcomes of concomitant administration of NSAIDs with low-dose aspirin led to increased incidence of VTE, possibly due to competitive inhibition of aspirin at platelet receptor sites. This interaction was mitigated by altering the administration times of both agents.

Comparable efficacy of 100 mg aspirin twice daily and rivaroxaban for venous thromboembolism prophylaxis following primary total hip arthroplasty: a randomized controlled trial

Background:

Aspirin has demonstrated safety and efficacy for venous thromboembolism (VTE) prophylaxis following total hip arthroplasty (THA); however, inconsistent dose regimens have been reported in the literature. This study aimed to evaluate and compare the safety and efficacy of 100 mg aspirin twice daily with rivaroxaban in VTE prophylaxis following THA.

Methods:

Patients undergoing elective unilateral primary THA between January 2019 and January 2020 were prospectively enrolled in the study and randomly allocated to receive 5 weeks of VTE prophylaxis with either oral enteric-coated aspirin (100 mg twice daily) or rivaroxaban (10 mg once daily). Medication safety and efficacy were comprehensively evaluated through symptomatic VTE incidence, deep vein thrombosis (DVT) on Doppler ultrasonography, total blood loss (TBL), laboratory bloodwork, Harris hip score (HHS), post-operative recovery, and the incidence of other complications.

Results:

We included 70 patients in this study; 34 and 36 were allocated to receive aspirin and rivaroxaban prophylaxis, respectively. No cases of symptomatic VTE occurred in this study. The DVT rate on Doppler ultrasonography in the aspirin group was not significantly different from that in the rivaroxaban group (8.8% vs. 8.3%, χ² = 0.01, P = 0.91), confirming the non-inferiority of aspirin for DVT prophylaxis (χ² = 2.29, P = 0.01). The calculated TBL in the aspirin group (944.9 mL [658.5–1137.8 mL]) was similar to that in the rivaroxaban group (978.3 mL [747.4–1740.6mL]) (χ² = 1.55, P = 0.12). However, there were no significant inter-group differences in HHS at post-operative day (POD) 30 (Aspirin: 81.0 [78.8–83.0], Rivaroxaban: 81.0 [79.3–83.0], χ² = 0.43, P = 0.67) and POD 90 (Aspirin: 90.0 [89.0–92.0], Rivaroxaban: 91.5 [88.3–92.8], χ² = 0.77, P = 0.44), the incidence of bleeding events (2.9% vs. 8.3%, χ² = 0.96, P = 0.33), or gastrointestinal complications (2.9% vs. 5.6%, χ² = 1.13, P = 0.29).

Conclusion:

In terms of safety and efficacy, the prophylactic use of 100 mg aspirin twice daily was not statistically different from that of rivaroxaban in preventing VTE and reducing the risk of blood loss following elective primary THA. This supports the use of aspirin chemoprophylaxis following THA as a less expensive and more widely available option for future THAs.

Trial Registration:

Chictr.org, ChiCTR18000202894; http://www.chictr.org.cn/showproj.aspx?proj=33284

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

BACKGROUND

Currently, there is no established universal standard of care for prophylaxis against venous thromboembolism (VTE) in orthopedic patients undergoing revision total hip arthroplasty (rTHA). The aim of this study is to determine whether a protocol of 81-mg aspirin (ASA) bis in die (BID) is safe and/or effective in preventing VTE in patients undergoing rTHAs vs 325-mg ASA BID.

METHODS

In 2017, a large academic medical center adopted a new protocol for VTE prophylaxis in arthroplasty patients at standard risk. Initially, patients received 325-mg ASA BID but switched to 81-mg ASA BID. A retrospective review (2011-2019) was performed to identify 1361 consecutive rTHA patients and their associated 90-day postoperative complications such as VTE, including pulmonary embolism (PE) and/or deep vein thrombosis (DVT), as the primary outcome; and gastrointestinal and wound bleeding, acute periprosthetic joint infection, and mortality as the secondary outcome.

RESULTS

From 2011 to 2017, 973 rTHAs were performed and 13 total VTE cases were diagnosed (1.34%). From 2017 to 2019, 388 rTHAs were performed with 3 total VTE cases identified (0.77%). Chi-squared analyses and logistic regression models showed no differences in rates or odds in postoperative PE (P = .09), DVT (P = .79), PE and DVT (P = .85), and total VTE (P = .38) using either dose. There were also no differences between bleeding complications (P = .14), infection rate (P = .46), and mortality (P = .53).

CONCLUSION

Using a protocol of 81-mg of ASA BID is noninferior to 325-mg ASA BID and may be safe and effective in maintaining low rates of VTE in patients undergoing rTHA.

Gastrointestinal Complications Warranting Invasive Interventions Following Total Joint Arthroplasty

BACKGROUND

Gastrointestinal (GI) complications following total joint arthroplasty (TJA) are uncommon but can be associated with substantial morbidity and mortality. The current literature on GI complications that warrant invasive procedures after TJA is lacking. This study reviews the incidence and outcomes of GI complications after TJA that went on to require invasive procedures.

METHODS

All TJA patients at our institution between January 2012 and May 2018 who had GI complications requiring an invasive procedure within 30 days of TJA were identified and retrospectively chart reviewed. Descriptive statistics were used to evaluate these patients.

RESULTS

Of 19,090 TJAs in a 6-year period, 34 patients (0.18%) required invasive procedures for GI complications within 30 days of the index surgery. Twenty-two (64%) of the required procedures were endoscopy for suspected GI bleeding. Within this cohort, aspirin was the most common thromboprophylaxis used (63.6% of patients) and smoking was more prevalent (9.1% current smokers) (P = .28). Of the remaining 12 GI procedures required, 75% were exploratory laparotomies, 44.4% of which were performed for obstruction. Three (33.3%) of the exploratory laparotomy patients died during the study period.

CONCLUSION

GI complications necessitating surgical intervention after TJA are rare. Suspected GI bleeding is the most common indication for intervention and is typically managed endoscopically. Other complications, such as GI obstruction, often require more extensive intervention and open procedures. Though rare, GI complications following TJA can lead to detrimental outcomes, significant patient morbidity, and occasionally mortality; therefore, a heightened awareness of these complications is warranted.

Should we use dabigatran or aspirin thromboprophylaxis in total hip and knee arthroplasty? A natural experiment

Background

Despite long clinical experience some authorities recommend against the use of aspirin for perioperative VTE prophylaxis and favour alternatives such as dabigatran. A change from Dabigatran to an Aspirin based protocol in a British district general hospital created the conditions of a natural experiment.

Methods

We conducted a single centre, retrospective study of 6-months using a dabigatran based protocol (THA n = 191, TKA n = 155) and 6-months using and aspirin based protocol (THA n = 165, TKA n = 136). Outcomes addressed include: VTE used, VTE events within 90-days, 30-day return to theatre (RTT) rates, and 90-day mortality.

Results

Pre-intervention, the dabigatran prescription rate was 73% (n = 139) and 78% (n = 123) with aspirin prescription post-intervention in 67% (n = 110) and 70% (n = 90) for THA and TKA respectively. We found a similar VTE rate when comparing dabigatran and aspirin groups for THA (2.2% vs. 0%, p = 0.17) and TKA (0.64% vs. 0%, p = 0.32). Similarly, no difference in the RTT rate was seen for THA (0.7% vs.2.7%, p = 0.23) or TKA (1.6% vs. 3.2%, p = 0.38).

Conclusion

No significant differences in safety were found comparing aspirin to dabigatran for VTE prophylaxis for lower limb arthroplasty which, has not been previously reported and represents significant cost saving implications.

Utilization Patterns, Efficacy, and Complications of Venous Thromboembolism Prophylaxis Strategies in Primary Hip and Knee Arthroplasty as Reported by American Board of Orthopedic Surgery Part II Candidates

BACKGROUND

Many strategies for venous thromboembolism (VTE) prophylaxis following hip and knee arthroplasty exist, with extensive controversy regarding the optimum strategy to minimize risk of VTE and bleeding complications. Data from the American Board of Orthopedic Surgery Part II (oral) Examination case list database was analyzed to determine efficacy, complication rates, and prescribing patterns for different prophylactic strategies.

METHODS

The American Board of Orthopedic Surgery case database was queried utilizing Current Procedural Terminology codes 27447 and 27130 for primary total knee and hip arthroplasty, respectively. Geographic region, patient age, gender, deep vein thrombosis prophylaxis strategy, and complications were obtained. Less aggressive prophylaxis patterns were considered if only aspirin and/or sequential compression devises were utilized. More aggressive VTE prophylaxis patterns were considered if any of low-molecular-weight heparin (enoxaparin), warfarin, rivaroxaban, fondaparinux, or other strategies was used.

RESULTS

In total, 22,072 cases of primary joint arthroplasty were analyzed from 2014 to 2016. The national rate of less aggressive VTE prophylaxis strategies was 45.4%, while more aggressive strategies were used in 54.6% of patients. Significant regional differences in prophylactic strategy patterns exist between the 6 regions. The predominant less aggressive prophylaxis pattern was aspirin with sequential compression devises at 84.8% with 14.8% receiving aspirin alone. Use of less aggressive prophylaxis strategy was significantly associated with patients having no complications (95.5% vs 93.0%). Use of more aggressive prophylaxis patterns was associated with higher likelihood of mild thrombotic (0.9% vs 0.2%), mild bleeding (1.3% vs 0.4%), moderate thrombotic (1.2% vs 0.4%), moderate bleeding (2.7% vs 2.1%), severe thrombotic (0.1% vs 0.0%), severe bleeding events (1.2% vs 0.9%), infections (1.9% vs 1.3%), and death within 90 days (0.7% vs 0.3%). Similar results were found in subgroup analysis of total hip and knee arthroplasty patients.

CONCLUSION

It was not possible to ascertain the individual rationale for use of more aggressive VTE prophylaxis strategies; however, more aggressive strategies were associated with higher rates of bleeding and thrombotic complications. Less aggressive strategies were not associated with a higher rate of thrombosis.

LEVEL OF EVIDENCE

Therapeutic Level III.

DISCLAIMER

All views expressed in the study are the sole views of the authors and do not represent the views of the American Board of Orthopedic Surgery.

Is Obesity Associated With Increased Risk of Deep Vein Thrombosis or Pulmonary Embolism After Hip and Knee Arthroplasty? A Large Database Study

BACKGROUND

Deep venous thrombosis (DVT) and pulmonary embolus (PE) remain an important cause of morbidity and mortality after THA and TKA. Prior recommendations have advocated for more aggressive prophylaxis for patients with obesity, whereas the evidence supporting these recommendations is conflicting and often based on underpowered studies.

QUESTIONS/PURPOSES

(1) What is the association between obesity and DVT and PE after primary and revision THA and TKA? (2) Is there a body mass index (BMI) threshold beyond which DVT and PE risk is elevated?

METHODS

We reviewed the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database from 2008 to 2016 to evaluate the reported 30-day rates of DVT, PE, and combined venous thromboembolism (VTE) after primary THA, primary TKA, revision THA, and revision TKA according to BMI as a continuous variable and a categorical variable as defined by the World Health Organization cutoffs for underweight, normal weight, overweight, and obesity. This database is risk-adjusted and designed to capture complications after surgery, thus making it ideal for this study. The diagnosis of DVT and PE is included in the ACS-NSQIP database for any DVT or PE requiring treatment. Proximal versus distal DVT is not specified within the database. Multivariate logistic regression was performed to determine if obesity was independently associated with DVT and PE risk by controlling for age, sex, race, American Society of Anesthesiologists score, diabetes, hypertension, smoking status, general anesthesia, and hypoalbuminemia.

RESULTS

After controlling for potential confounding variables such as medical comorbidities and procedure type, patients undergoing primary and revision THA and TKA with World Health Organization classification as underweight (BMI < 18.5 kg/m), overweight (BMI 25-29.9 kg/m), Class I obese (BMI 30-34.9 kg/m), Class II obese (BMI 35-39.9 kg/m), or Class III obese (BMI ≥ 40 kg/m) did not demonstrate an association with increased risk of DVT compared with patients classified as normal weight (BMI 18.5-25 kg/m). Compared with patients undergoing primary THA classified as normal weight, the risk of PE was elevated in patients with Class II obesity (odds ratio [OR], 2.36; 95% confidence interval [CI], 1.23-4.50; p = 0.009) and all heavier categories. Compared with patients undergoing TKA classified as normal weight, the risk of PE was elevated in patients classified as overweight (OR, 1.56; 95% CI, 1.03-2.36; p = 0.035) and all heavier categories.

CONCLUSIONS

This large administrative database study suggests that patient classification as overweight or obese is associated with increased risk of development of PE but not DVT after primary THA or TKA. Because aggressive pharmacologic anticoagulation regimens can decrease the DVT rate but have not been shown to affect the rate of PE or death, the data do not currently support increased anticoagulation in patients with obesity without other risk factors for VTE undergoing THA or TKA. Additional studies are required to refine VTE prophylaxis protocols to reduce PE risk while maintaining acceptable postoperative bleeding risk.

LEVEL OF EVIDENCE

Level III, therapeutic study.

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.

Evaluation of a Simplified Risk Stratification Twice-Daily Aspirin Protocol for Venous Thromboembolism Prophylaxis After Total Joint Replacement

OBJECTIVE

To determine using a simplified risk-stratified protocol to select candidates for aspirin therapy have similar death and postoperative complications as universal warfarin therapy in patients undergoing total joint replacement (TJR).

METHODS

Retrospective cohort study comparing 30-day postoperative outcomes 6 months before and after the implementation of the aspirin protocol (January 1, 2015) in patients undergoing TJR. The control group was comprised of patients using warfarin for VTE prophylaxis. The protocol group included patients who used aspirin 325 mg twice-daily or warfarin if deemed high thrombotic risk or aspirin intolerant by the criteria set forth by the aspirin protocol.

RESULTS

This study included 449 patients. No difference was found in the rates of 30-day postoperative bleeding, VTE, death, composite end point of VTE and death, and length of stay between the control and the protocol groups (all P > .05). Thirty-day postoperative surgical site infections (SSIs; 5.8% vs 1.2%; P = .02) and return to operative room (OR; 3.9% vs 0.4%; P = .03) were less frequent in the protocol group.

CONCLUSION

A simplified risk-stratified protocol used to choose patients for aspirin 325 mg twice-daily therapy is safe and effective in patients undergoing TJR, and SSI and return to OR rates may be lower when compared to universal warfarin therapy.

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.

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.