Pulmonary Embolism Rates Following Total Hip Arthroplasty With Prophylactic Anticoagulation: Some Pulmonary Emboli Cannot Be Avoided

Risk Factors for Venous Thromboembolism Following Total Knee Arthroplasty: An Analysis of 3,052 Pulmonary Emboli

INTRODUCTION

Identifying risk factors for pulmonary embolism (PE) and deep vein thrombosis (DVT) following primary total knee arthroplasty (TKA) may improve risk stratification and guide surgeons in prophylaxis selection. This study aimed to identify factors associated with postoperative venous thromboembolism (VTE) following TKA.

METHODS

A national healthcare database was queried for adults who underwent primary, elective TKA from January 1, 2015 to December 31, 2020. Patients who developed PE or DVT within 90 days postoperatively were compared with patients who did not. Demographics, comorbidities, hospital factors, perioperative medications, and blood transfusion needs were assessed. A multivariate model was used to identify independent risk factors for VTE. Overall, 847,496 patients were identified, of whom 8,002 (0.94%) developed a VTE postoperatively (3,052 PE, 5,294 DVT).

RESULTS

After controlling for confounders, an elevated risk of VTE was associated with increased age (adjusted odds ratio [aOR]: 1.01, 95% confidence interval [CI] = 1.01-1.01, P < 0.001), Black patients (aOR: 1.30, 95% CI=1.28-1.47, P < 0.001), and patients enrolled in Medicare (aOR: 1.18, 95% CI = 1.13-1.24, P < 0.001) or Medicaid (aOR: 1.24, 95% CI = 1.12-1.37, P < 0.001). Independent risk factors for PE included obesity (aOR: 1.25, 95% CI = 1.16-1.35, P < 0.001), pulmonary hypertension (aOR: 3.64, 95% CI = 3.05-4.35, P < 0.001), and history of VTE (aOR: 1.71, 95% CI = 1.54-1.91, P < 0.001). Risk factors associated with an increased risk of DVT included iron deficiency anemia (aOR:1.38, 95% CI = 1.14-1.66, P < 0.001) and abnormal weight loss (aOR: 1.67, 95% CI = 1.07-2.60, P = 0.023).

CONCLUSION

Increasing age, Black race, Medicare, or Medicaid insurance were associated with increased risk of VTE. Obesity, history of VTE, and pulmonary hypertension were risk factors for both PE and DVT. These data can assist surgeons in the selection of a prophylactic regimen after TKA.

Retrospective analysis of the occurrence, potential risk factors and medical significance of pulmonary complications after total shoulder arthroplasty from the National Inpatient Sample database (2010-2019)

BACKGROUND

In USA, total shoulder arthroplasty (TSA) ranks amongst the top five surgeries that require hospitalization. As a result, the healthcare system in USA could face a considerable financial strain due to the emergence of subsequent pulmonary problems. This study aimed to conduct a thorough examination of the prevalence, influential factors and medical importance of pulmonary complications, with emphasis on pneumonia, respiratory failure and pulmonary embolism (PE) following total shoulder arthroplasty (TSA) procedures in USA.

METHODS

The National Inpatient Sample (NIS) was utilized to survey all patients who underwent primary elective TSA from 2010 to 2019. Pneumonia, respiratory failure and PE following TSA were considered to be pulmonary consequences. The inpatient expenses, length of hospitalization, death rates and patient characteristics of those with and without reported perioperative pulmonary problems were compared. The utilization of trend weights was necessary to obtain incidence estimates across USA, considering the stratified framework of the NIS database and the dependence on observed frequencies within the database. Two assessments were utilized to assess the projected annual rates of complications.

RESULTS

Between 2010 and 2019, a total of 189,695 patients were estimated to underwent primary elective TSA. Infections, such as pneumonia, respiratory failure or PE, complicated 1.4% (95% CI, 1.52%-1.64%) of TSA operations. The ailments at this period that were most likely to result in pulmonary problems were ulcer (adjusted odds ratio [AOR] = 9.43; 95% CI, 4.99-46.91), pulmonary circulation disorders (AOR = 9.01; 95% CI, 4.56- 31.92), weight loss (AOR = 4.84; 95% CI, 2.15-10.88), fluid and electrolyte disorders (AOR = 3.55; 95% CI, 2.55-4.95), alcohol abuse (AOR = 1.56; 95% CI, 1.08-2.26), congestive heart failure (AOR = 3.09; 95% CI, 1.83-5.24), chronic pulmonary disease (AOR = 2.45; 95% CI, 1.60-3.75), deficiency anaemia (AOR = 1.56; 95% CI, 1.08-2.26), depression (AOR = 1.47; 95% CI, 1.03-2.11) and obesity (AOR = 1.46; 95% CI, 1.01-2.11). A correlation was found between perioperative pulmonary problems and extended LOS (+ 3 days; 95% CI, 2-6) and increased hospitalization costs (= + 20,514 US dollars; 95% CI, 14,109-35,281).

CONCLUSIONS

This investigation primarily aimed to ascertain potential risk factors linked to pulmonary issues that may occur after TSA. The analysis revealed that the pneumonia rates decreased each year, whereas the PE rates remained relatively stable. A noticeable and consistent increase was found in respiratory failure from 2010 to 2019. The findings suggests that individuals who are older (primarily between the ages of 60 and 80 years) and female exhibit increased rates. These factors could help stratify patients and reduce the risk of potential complications. This claim is especially applicable in PE because it is associated with more significant improvements in resource utilization.

Predictors and risk factors of pulmonary embolism after total hip arthroplasty: an NSQIP study

INTRODUCTION

Pulmonary embolism (PE) is a well-known contributor to morbidity after total hip arthroplasty (THA). Considerable efforts have been invested in reducing PE occurrence through pharmacological and perioperative interventions. Nonetheless, the effectiveness of these strategies in reducing the incidence and overall mortality associated with pulmonary embolism events remains a matter of debate. Therefore, identifying risky patients has been gaining importance.

METHODS

We utilised data from the National Surgical Quality Improvement Program (NSQIP) participant usage file (PUF) database spanning the years 2016 to 2021. All preoperative parameters were analysed with chi-square afterwards, meaningful ones were run with logistic regression test.

RESULTS

A study examined factors influencing pulmonary embolism (PE) prevalence in 235,393 total hip arthroplasty patients. Univariate analysis identified significant associations between PE and female gender, diabetes, smoking, dyspnea, CHF, COPD, hypertension (HT), bleeding disorders, disseminated cancer, steroid use, and functional health status. Multivariate analysis revealed male gender as protective, while COPD, hypertension, and disseminated cancer increased PE risk. Notably, smoking appeared protective. PE patients had higher return-to-operation rates (41.7% vs. 2.2%) but similar 30-day mortality (0.2% vs. 0.04%), though mortality's odds ratio was not significant.

CONCLUSIONS

Our findings suggest that certain patient characteristics, such as COPD and metastatic malignancy, significantly influence the likelihood of PE development.

Low-versus high-dose aspirin for venous thromboembolic prophylaxis after total joint arthroplasty: a systematic review and meta-analysis

BACKGROUND

The adverse effects of aspirin are dose-dependent, and there is controversy surrounding the use of low-dose (LD) aspirin to prevent venous thromboembolism (VTE) following total joint arthroplasty (TJA). This meta-analysis sought to compare the efficacy and complication rate of low-dose (162 mg per day) versus high-dose (HD, 650 mg per day) aspirin after TJA surgery.

METHODS

In four main databases, we searched from inception until September 2024 for articles comparing the rate of VTE following TJA(TKA/THA) using only aspirin chemoprophylaxis with different dosages. We meta-analyzed and compared the VTE and complication rates of LD aspirin (162 mg per day) with HD aspirin (650 mg per day) and presented our results as odds ratio (ORs) in forest plot diagrams.

RESULTS

There were 14 eligible studies, comprising 43,518 patients in the LD group and 62,645 patients in the HD group. DVT (OR: 1.37, CI: 0.93-2.02, P = 0.11) and PE (OR: 1.86, CI: 0.73-4.72, P = 0.19) rates were similar between the groups. However, taking VTE as the total number of cases with DVT or PE, the incidence was significantly higher in the HD group than in the LD group (OR:1.53, CI: 1.17-2.00, P = 0.002). HD also had a significantly higher rate of PJI (OR:2.68 CI:1.5-4.6 P = 0.001), but gastrointestinal bleeding (GIB) was similar between the two groups (OR: 0.97, CI: 0.42-2.22, P = 0.95).

CONCLUSION

The findings suggest that LD aspirin may be a viable option for VTE chemoprophylaxis following TJA, potentially offering comparable efficacy with a lower risk of PJI compared to HD aspirin regimens.

LEVEL OF EVIDENCE

Therapeutic Level II.

Alarmingly High Rates of Deep Vein Thrombosis and Pulmonary Embolism Following Closed Reduction for Dislocated Total Hip Arthroplasty

BACKGROUND

Venous thromboembolism (VTE) and dislocation are well-described complications following total hip arthroplasty (THA). However, the relationship between THA dislocation and venous thromboembolism remains unclear. This study sought to determine the risk of deep vein thrombosis (DVT) and pulmonary embolism (PE) in patients who experience a hip dislocation and subsequent closed reduction following primary THA.

METHODS

All primary THA patients were identified in an inpatient admissions database. The THA patients who had a dislocation within 90 days of surgery who were treated with closed reduction were compared to patients who did not dislocate within 90 days of surgery. Differences in patient demographics, comorbidities, hospital characteristics, postoperative chemoprophylactic agents, and 90-day postoperative infectious rates were calculated between the cohorts. Univariate and multivariable regression were used to assess the impact of THA dislocation treated with closed reduction on 90-day DVT and PE risk.

RESULTS

There were 550,208 primary THAs identified. Of these patients, 3,700 (0.7%) experienced a dislocation within 90 days, of which 2,487 (67.2%) were treated with closed reduction. Patients who dislocated and underwent closed reduction had increased rates of PE (0.9 versus 0.3%, P < 0.001) and DVT (1.6 versus 0.5%, P < 0.001) compared to patients who did not dislocate. After controlling for confounding factors, patients in the closed reduction group had elevated risks of both DVT (adjusted odds ratio [aOR] 2.5, 95% confidence interval [CI]: 1.8 to 3.4, P < 0.001) and PE (aOR 2.2, 95% CI: 1.4 to 3.3, P < 0.001).

DISCUSSION

Patients who undergo closed reduction for dislocation following primary THA have an alarmingly high risk of DVT and PE. These findings should prompt surgeons to consider chemoprophylaxis among patients who experience a dislocation, even when treated with a closed reduction.

Venous Thromboembolism in Outpatient Elective Foot and Ankle Procedure Patients Who Is at Risk?

BACKGROUND

Venous thromboembolism (VTE) is a rare but potentially serious complication following elective foot and ankle (F&A) procedures. The absence of guidelines for thromboprophylaxis in elective procedures underscores the importance of identifying patients at risk. This study aimed to identify key risk factors of VTE in patients who underwent elective foot and ankle (F&A) operations.

METHODS

Data was collected from the IBM MarketScan Database (2009-2019) for patients >18 years old without prior VTE who underwent elective F&A procedures. Patients were divided into 3 groups based on region of operation (forefoot, mid/hindfoot, lower leg/ankle). VTE incidence (including deep vein thrombosis and/or pulmonary embolism) was recorded 30 and 90 days postprocedure. Risk factors for VTE were identified through multivariate logistic regression.

RESULTS

Among the 301 256 patients who underwent elective F&A procedures, the overall 90-day incidence of VTE was 0.95%. The findings revealed that 31.9% of VTE incidents occurred within the first 2 weeks after operation, and 29.2% still occurred after 6 weeks. Analysis of the anatomical region of operation demonstrated that the lowest rate of 90-day VTE was amongst patients undergoing forefoot procedures (0.70%). There was a higher risk for VTE in patients undergoing midfoot/hindfoot procedures (1.22%, OR = 1.81) and lower leg/ankle procedures (1.76%, OR = 2.31). Additional risk factors for VTE included thrombophilia (4.02%, OR = 3.37), male sex (1.30%, OR = 1.47), increasing age (1.02% age 65+, OR = 1.41), and a high Charlson Comorbidity Index (1.12%, OR < 0.82 for scores <5).

CONCLUSION

This study identifies the incidence and timing for VTE after elective F&A procedures. Furthermore, this study defines the risk factors associated with increased odds of VTE after elective F&A procedures. These findings are helpful in educating patients about a continued risk for VTE throughout the 90-day postoperative period and beyond. These results can also be utilized to stratify patients who need thromboprophylaxis based on the individual risk level.

LEVEL OF EVIDENCE

Level III: Retrospective cohort study.

Aspirin is an Effective Prophylaxis for Venous Thromboembolism After Revision Hip and Knee Arthroplasty

BACKGROUND

Venous thromboembolism (VTE) following revision total joint arthroplasty (TJA) poses significant risks despite prophylactic measures. The optimal VTE prophylaxis agent for revision TJA remains unclear. This study aimed to compare aspirin against various anticoagulant agents regarding efficacy and safety in preventing symptomatic VTE events after revision TJA.

METHODS

A retrospective analysis included 4,575 patients undergoing revision TJA between 2008 and 2020. Of these, 2,091 received aspirin, while 2,484 received other anticoagulants. Demographic, procedural, and outcome data were collected. Logistic regression models were used to identify predictors of symptomatic VTE.

RESULTS

The aspirin group showed a significantly lower incidence of symptomatic VTE compared to the other anticoagulant group (0.53 versus 2.54%, P < .001). Logistic regression confirmed a higher risk of VTE with other anticoagulants (odds ratio: 0.2 to 0.26, P < .001), while blood transfusion (odds ratio: 2.72, P = .001) were identified as risk factors.

CONCLUSIONS

This study demonstrated that aspirin is a viable and potentially safer option than other anticoagulants, exhibiting comparable efficacy in preventing VTE events in revision TJA. Balancing effectiveness and safety is crucial, considering patient-specific risk factors and bleeding tendencies. This large cohort study demonstrated that aspirin was associated with a more effective and safer VTE prophylaxis agent, compared to other anticoagulants, in patients undergoing revision TJA.

Usefulness of Elastic Bandage Compression Compared to Calf Massage to Prevent Venous Thromboembolism-A Retrospective Evaluation

Background: Manual calf massage and passive ankle motion (CaM) can reduce the incidence of venous thromboembolism (VTE) after total hip arthroplasty (THA). However, these methods cannot be used in all patients; thus, elastic bandage (EB) compression is an alternative method. The efficacy of EB compression in preventing VTE has not yet been investigated; thus, this study aimed to compare the effects of EB compression and manual calf massage. Methods: Of the 363 patients who underwent unilateral primary THA at our hospital between 1 August 2018 and 31 October 2023, CaM without anticoagulation therapy was administered to 206 patients (CaM group) and 157 patients underwent EB without anticoagulation therapy (EB group). Duplex ultrasonography was performed 7 days postoperatively to check for deep vein thrombosis (DVT) in both legs. Results: The surgical time (122.2 min vs. 155.5 min), the incidence of DVT (4.5% vs. 4.8%) and pulmonary thromboembolism (PTE) (0% vs. 0.7%), intraoperative bleeding (305.4 mL vs. 301 mL), and estimated actual blood loss (846.6 mL vs. 811.6 mL) were not significantly different between the CaM and EB group. However, there was one case of symptomatic PTE in the EB group. Conclusions: The incidences of DVT, PTE, and intraoperative bleeding were not significantly different between the groups. Moreover, EB can be administered to patients with DVT and is considered to be a DVT prophylaxis method that can be used in a larger number of patients. Therefore, we recommend that EB be performed in all the patients undergoing THA.

Risk Factors Associated with Thromboembolic Complications After total Hip Arthroplasty: An Analysis of 1,129 Pulmonary Emboli

INTRODUCTION

Venous thromboembolism (VTE) remains a dangerous complication after total hip arthroplasty (THA), despite advances in chemoprophylactic measures. This study aimed to identify risk factors of developing pulmonary embolism (PE) and deep vein thrombosis (DVT) after THA using a modern cohort of patients reflecting contemporary practices.

METHODS

The Premier Healthcare Database was queried for primary, elective THAs from January 1st, 2015, to December 31st, 2021. Patients who developed PE or DVT within 90 days of THA were compared with patients who did not develop any postoperative VTE. Differences in patient demographics, comorbidities, hospital factors, perioperative medications, chemoprophylactic agents, and allogeneic blood transfusion were compared between cohorts. Multivariable logistic regression models were used to identify independent risk factors of PE and DVT. In total, 544,298 THAs were identified, of which 1,129 (0.21%) developed a PE and 1,799 (0.33%) developed a DVT.

RESULTS

Patients diagnosed with a PE had significantly higher rates of in-hospital death (2.6% vs 0.1%, P < 0.001) compared with those without a PE. Age (adjusted odds ratio: 1.02 per year, 95% confidence interval [CI]: 1.01 to 1.03) and Black race (aOR: 1.52, 95% CI: 1.24 to 1.87) were associated with an increased risk of PE. Comorbidities associated with increased risk of PE included chronic pulmonary disease (aOR: 1.58, 95% CI: 1.36 to 1.84), pulmonary hypertension (aOR: 2.06, 95% CI: 1.39 to 3.04), and history of VTE (aOR: 2.38, 95% CI: 1.98 to 2.86). Allogeneic blood transfusion (aOR: 2.40, 95% CI: 1.88 to 3.06) was also associated with an increased risk of PE while dexamethasone utilization was associated with a reduced risk (aOR: 0.83, 95% CI: 0.73 to 0.95).

DISCUSSION

Increasing age; Black race; allogeneic blood transfusion; and comorbidities, including chronic pulmonary disease, pulmonary hypertension, and history of VTE, were independent risk factors of PE after THA. Given the increased mortality associated with PE, patients should be carefully evaluated for these factors and managed with an appropriate chemoprophylactic regimen.

[Translated article] Risk of venous thromboembolism in thromboprophylaxis between aspirin and low molecular weight heparins after total hip arthroplasty or total knee arthroplasty: Systematic review and meta-analysis

INTRODUCTION

The aim of this study was to evaluate the efficacy of aspirin versus low molecular weight heparins (LMWH) for the prophylaxis of venous thromboembolism (VTE), deep vein thrombosis (DVT) and pulmonary embolism (PE) in patients undergoing total knee arthroplasty (TKA) and/or total hip arthroplasty (THA).

MATERIALS AND METHODS

Systematic review and meta-analysis. Sixteen studies were selected. The risk of VTE, DVT and PE were analysed. Mortality, risk of bleeding and surgical wound complications was also analysed.

RESULTS

248,461 patients were included. 176,406 patients with thromboprophylaxis with LMWH and 72,055 patients with aspirin thromboprophylaxis. There were no significant differences in the risk of VTE (OR=0.93; 95% CI: 0.69-1.26; p=0.64), DVT (OR=0.72; 95% CI: 0.43-1.20; p=0.21) or PE (OR=1.13; 95% CI: 0.86-1.49; p=0.38) between both groups. No significant differences were found in mortality (p=0.30), bleeding (p=0.22), or complications in the surgical wound (p=0.85) between both groups. These same findings were found in the sub-analysis of only randomised clinical trials (p>0.05).

CONCLUSIONS

No increased risk of PE, DVT, or VTE was found among patients with aspirin thromboprophylaxis versus patients with LMWH thromboprophylaxis. There was also no greater mortality, greater bleeding, or greater complications in the surgical wound found among patients with aspirin thromboprophylaxis versus patients with LMWH thromboprophylaxis.

Risk of venous thromboembolism in thromboprophylaxis between aspirin and low molecular weight heparins after total hip arthroplasty or total knee arthroplasty: Systematic review and meta-analysis

INTRODUCTION

The aim of this study was to evaluate the efficacy of aspirin versus low molecular weight heparins (LMWH) for the prophylaxis of venous thromboembolism (VTE), deep vein thrombosis (DVT) and pulmonary embolism (PE) in patients undergoing total knee arthroplasty (TKA) and/or total hip arthroplasty (THA).

MATERIALS AND METHODS

Systematic review and meta-analysis. Sixteen studies were selected. The risk of VTE, DVT and PE were analyzed. Mortality, risk of bleeding and surgical wound complications was also analyzed.

RESULTS

248,461 patients were included. 176,406 patients with thromboprophylaxis with LMWH and 72,055 patients with aspirin thromboprophylaxis. There were no significant differences in the risk of VTE (OR = 0.93; 95% CI: 0.69-1.26; P = .64), DVT (OR = 0.72; 95% CI: 0.43-1.20; P = .21) or PE (OR = 1.13; 95% CI: 0.86-1.49; P = .38) between both groups. No significant differences were found in mortality (P = .30), bleeding (P = .22), or complications in the surgical wound (P = .85) between both groups. These same findings were found in the sub-analysis of only randomized clinical trials (P>.05).

CONCLUSIONS

No increased risk of PE, DVT, or VTE was found among patients with aspirin thromboprophylaxis versus patients with LMWH thromboprophylaxis. There was also no greater mortality, greater bleeding, or greater complications in the surgical wound found among patients with aspirin thromboprophylaxis versus patients with LMWH thromboprophylaxis.

Increased 90-Day Mortality and Morbidity Among Patients Recovering From Elective Primary Arthroplasty During the COVID-19 Pandemic in New York City

All elective procedures were stopped in March 2020 because of the coronavirus disease 2019 (COVID-19) pandemic. We report the 90-day mortality and complications of patients who underwent primary arthroplasty before the stopping of elective procedures at a single academic medical center. A retrospective cohort study was conducted including patients who underwent elective primary arthroplasty between December 2019 and mid-March 2020. Their 90-day postoperative mortality and medical complications were statistically compared with those of a historical cohort from the same operative period in 2019. The 2020 and 2019 cohorts included 372 and 410 patients, respectively. Except for the prevalence of diabetes, there was no significant difference between the two cohorts regarding baseline characteristics or preoperative health. The 2020 cohort had statistically significant higher rates of pneumonia (2.7% vs 0.7%; P=.03), readmission (9.1% vs 5.4%; P=.04), pulmonary embolism (1.6% vs 0.2%; P=.04), and 90-day mortality (1.1% vs 0%; P=.04). The 2020 cohort also had a trend for increased rates of deep venous thrombosis (1.1% vs 0.7%; P=.7) and cardiac complications (1.9% vs 0.5%; P=.07) and no change in emergency department visits (14.0% vs 11.7%; P=.3). There were 7 confirmed cases of COVID-19 in the 2020 cohort and 1 death. This study demonstrates that patients who underwent primary arthroplasty procedures at our institution close to the time of the first wave of the COVID-19 pandemic experienced a statistically significant increase in mortality, pneumonia, pulmonary embolism, and readmission compared with a historical cohort. As elective procedures have resumed during the ongoing pandemic, providers and patients should be aware of these increased risks. [Orthopedics. 2024;47(3):135-140.].

Efficacy and Safety Study of Low-Molecular-Weight Heparin and Fondaparinux Sodium After Hip Arthroplasty: A Retrospective Cohort Study

Background

Low molecular heparin(LMWH) and sodium sulfadiazine heparin(FPX) are commonly used to prevent deep vein thrombosis(DVT) after total hip arthroplasty(THA). In this study, we compared the role of these drugs in preventing DVT after THA.

Methods

Patients who underwent unilateral THA at the Sixth Affiliated Hospital of Xinjiang Medical University from April 2020 to December 2022 were retrospectively analyzed for inclusion in this study. According to the anticoagulant drugs used, the patients were divided into LMWH group (n=106) and FPX group (n=97). Changes in perioperative coagulation-related indices, hemoglobin, blood loss And the postoperative complications.

Results

The preoperative indexes of the two groups of patients, the difference was not statistically significant (P>0.05); the indexes of Intraoperative blood loss, Visible blood loss, Hidden blood loss, and Total blood loss of the two groups of patients were compared, and the difference was not significant (P>0.05); PT activity and INR in the LMWH group were significantly lower than those in the FPX group on the 1st and 5th postoperative days, and the differences were significant (P<0.05); Platelets, Hemoglobin, Hematocrit, D-dimer, and Fibrinogen were compared between the two groups on the 1st and 5th postoperative days, and the differences were not significant (P<0.05). The differences were not significant (P>0.05). The differences in blood transfusion rate and blood volume between the two groups were not significant (P>0.05); the total hospitalization cost of the LMWH group was significantly lower than that of the FPX group, and the difference was significant (P<0.05); and the differences in the incidence of postoperative complications between the two groups were not significant (P>0.05).

Conclusion

In this study, we found that the efficacy and safety of FPX and LMWH in preventing VTE after THA were basically the same, and the total cost of hospitalization in the LMWH group was significantly lower than that in the FPX group; however, due to the limited inclusion of the sample size, high-quality, large-sample, long-term follow-up clinical studies are necessary.

A Comparison of the Caprini Score With an Institutional Risk Assessment Tool for Prediction of Venous Thromboembolism After Total Joint Arthroplasty at an Urban Tertiary Care Health Safety Net Hospital

Background

Patients undergoing total joint arthroplasty (TJA) are at increased risk for venous thromboembolism (VTE). Prediction tools such as the Caprini Risk Assessment Model (RAM) have been developed to identify patients at higher risk. However, studies have reported heterogeneous results when assessing its efficacy for TJA. Patients treated in an urban health safety net hospital have increased medical complexity, advanced degenerative joint disease, and severe disability prior to TJA increasing the risk of VTE. We hypothesize that use of a tool designed to account for these conditions-the Boston Medical Center (BMC) VTE score-will more accurately predict VTE in this patient population.

Methods

A retrospective case-control study was performed including subjects 18 years of age and older who underwent primary or revision TJA in an urban academic health safety net hospital. Patients with hemiarthroplasties, simultaneous bilateral TJA, and TJA after acute trauma were excluded. A total of 80 subjects were included: 40 who developed VTE after TJA (VTE+) and 40 who did not develop VTE (controls). Subjects were matched by age, gender, and surgical procedure.

Results

There was a statistically significant difference between the mean BMC VTE score for VTE+ and controls (4.40 and 3.13, respectively, P = .036). Conversely, there was no statistical difference between the mean Caprini scores for VTE+ and controls (9.50 and 9.35, respectively, P = .797).

Conclusions

In a health safety-net patient population, an institutional RAM-the BMC VTE score-was found to be more predictive of VTE than the modified Caprini RAM following TJA. The BMC-VTE score should be externally validated to confirm its reliability in VTE prediction in similar patient populations.

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.

Passive ankle motion and calf massage without anticoagulation therapy after total hip arthroplasty: A retrospective study

BACKGROUND

It has been previously reported that manual calf massage and passive ankle motion after total hip arthroplasty could reduce the incidence of venous thromboembolism. However, a combination of chemical and mechanical prophylaxes was employed. In this study, we aimed to examine the effect of mechanical prevention without pharmacological antithrombotic intervention.

METHODS

Of the 313 patients who underwent unilateral primary total hip arthroplasty and received passive ankle motion and calf massage postoperatively at our hospital between January 2015 and December 2019, 261 (58 men, 203 women; mean age 62.1 years) were included in this retrospective study. Pharmacological anticoagulation therapy was administered in 176 patients (combination group); 137 patients only underwent calf massage and passive ankle motion without anticoagulation therapy (single group). The study outcomes were operation time, the incidence of deep vein thrombosis, pulmonary thromboembolism, intraoperative bleeding, estimated actual blood loss, blood transfusion, and major bleeding.

RESULTS

No significant differences were found in sex, age, side, platelet counts, activated partial thromboplastin time, prothrombin time, prothrombin time - International Normalized Ratio, intraoperative blood loss, estimated blood loss, and operation time. Moreover, the incidence of deep vein thrombosis, pulmonary thromboembolism, and intraoperative bleeding was not significantly different between the groups (deep vein thrombosis 4.0% vs. 6.3%, p = 0.244; pulmonary thromboembolism 0.7% vs. 0%, p = 0.548; and intraoperative bleeding 394 ± 173.6 ml vs. 365.4 ± 168.5 ml, p = 0.550). However, estimated actual blood loss and postoperative bleeding differed between the groups (eABL 996.6 ± 348.3 ml vs. 858.5 ± 269.6 ml, p = 0.003; postoperative bleeding 601.8 ± 330.0 ml vs. 492.1 ± 277.1 ml, p = 0.016), and both increased in the combination group. No major bleeding was noted in the two groups.

CONCLUSION

Postoperative anticoagulant therapy does not have to be routinely used if mechanical prophylaxis is performed in patients without deep vein thrombosis before total hip arthroplasty.

Equivalent VTE rates after total joint arthroplasty using thromboprophylaxis with aspirin versus potent anticoagulants: retrospective analysis of 4562 cases across a diverse healthcare system

BACKGROUND

Guidelines support aspirin thromboprophylaxis for primary total hip and knee arthroplasty (THA and TKA) but supporting evidence has come from high volume centers and the practice remains controversial.

METHODS

We studied 4562 Medicare patients who underwent elective primary THA (1736, 38.1%) or TKA (2826, 61.9%) at 9 diverse hospitals. Thirty-day claims data were combined with data from the health system's electronic medical records to compare rates of venous thromboembolism (VTE) between patients who received prophylaxis with: (1) aspirin alone (47.3%), (2) a single, potent anticoagulant (29%), (3) antiplatelet agents other than aspirin or multiple anticoagulants (21.5%), or (4) low-dose subcutaneous unfractionated heparin or no anticoagulation (2.2%). Sub-analyses separately evaluating THA, TKA and cases from lower volume hospitals (n = 975) were performed.

RESULTS

The 30-day VTE incidence was 0.6% (29/4562). VTE rates were equal in patients receiving aspirin and those receiving a single potent anticoagulant (0.5% in both groups). Patients with VTE were significantly older than patients without VTE (mean 76.5 vs. 73.1 years, P = 0.04). VTE rate did not associate with sex or hospital case volume. On bivariate analysis considering age, aspirin did not associate with greater VTE risk compared to a single potent anticoagulant (OR = 2.1, CI = 0.7-6.3) with the numbers available. Odds of VTE were increased with use of subcutaneous heparin or no anticoagulant (OR = 6.4, CI = 1.2-35.6) and with multiple anticoagulants (OR = 3.6, CI = 1.1-11.2). THA and TKA demonstrated similar rates of VTE (0.5% vs. 0.7%, respectively, P = 0.43). Of 975 cases done at lower volume hospitals, 387 received aspirin, none of whom developed VTE.

CONCLUSIONS

This study provides further support for aspirin as an effective form of pharmacological VTE prophylaxis after total joint arthroplasty in the setting of a multi-modal regimen using 30-day outcomes. VTE occurred in 0.7% of primary joint arthroplasties. Aspirin prophylaxis did not associate with greater VTE risk compared to potent anticoagulants in the total population or at lower volume hospitals.

Venous Thromboembolic Prophylaxis After Total Hip and Knee Arthroplasty

➤

The selection of an agent for prophylaxis against venous thromboembolism (VTE) is a balance between efficacy and safety. The goal is to prevent symptomatic VTE while limiting the risk of bleeding.

➤

The optimal agent for VTE prophylaxis has not been identified. The American College of Chest Physicians guidelines recommend that, after total hip or total knee arthroplasty, patients receive at least 10 to 14 days of 1 of the following prophylaxis agents: aspirin, adjusted-dose vitamin K antagonist, apixaban, dabigatran, fondaparinux, low-molecular-weight heparin, low-dose unfractionated heparin, rivaroxaban, or portable home mechanical compression.

➤

The use of aspirin for VTE prophylaxis has increased in popularity over the past decade because it is effective, and it is an oral agent that does not require monitoring. The true efficacy of aspirin needs to be determined in multicenter randomized clinical trials.

➤

Validated risk stratification protocols are essential to identify the safest and most effective regimen for VTE prophylaxis for individual patients. There is no consensus regarding the optimal method for risk stratification; the selection of a prophylaxis agent should be determined by shared decision-making with the patient to balance the risk of thrombosis versus bleeding.

➤

Patients with atrial fibrillation being treated with chronic warfarin therapy or direct oral anticoagulants should stop the agent 3 to 5 days prior to surgery. Patients do not typically require bridging therapy prior to surgery.

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.

Bleeding and thromboembolism risk of standard antithrombotic prophylaxis after hip or knee replacement within an enhanced recovery program

INTRODUCTION

Prevention of venous thromboembolism (VTE) generally consists of low molecular weight heparin (LMWH) or direct oral anticoagulants (DOACs) after total hip arthroplasty (THA) or total knee arthroplasty (TKA). Enhanced recovery after surgery (ERAS) protocols may reduce the VTE risk after these procedures. The aim of this study was to compare the risk of VTE and the risk of bleeding complications in a non-selected population of primary THA and TKA cases done within an ERAS protocol.

HYPOTHESIS

The risk of postoperative VTE after primary THA and TKA is lower than the risk of bleeding complications within an ERAS protocol.

METHODS

This was a prospective observational study conducted on a national scale in France. All patients who underwent primary unilateral THA or TKA at one of 11 participating hospitals between October 2016 and October 2017 were enrolled and followed for 3 months. The occurrence of a VTE or major bleeding event was recorded. No patients were lost to follow-up at 3 months.

RESULTS

Of the 1110 THA cases, there were 5 VTE (0.4%) and 19 bleeding events (1.7%). Of the 893 TKA cases, there were 9 VTE (1.0%) and 14 bleeding events (1.7%). There was no significant difference in the VTE incidence and bleeding event incidence after THA and TKA. The overall incidence of bleeding complications (1.7%) was significantly greater than the overall incidence of VTE complications (0.7%) (p=0.005). This was the case after THA (p=0.004) but not after TKA.

DISCUSSION

The primary finding of this study is that bleeding complications are significantly more common than VTE complications after THA or TKA within an ERAS protocol. Based on these findings, the cost-benefit ratio of antithrombotic prophylaxis by LMWH or DOACs in this context should be reassessed.

LEVEL OF EVIDENCE

IV; Prospective cohort study without control group.

An Update on Venous Thromboembolism Rates and Prophylaxis in Hip and Knee Arthroplasty in 2020

Patients undergoing total hip and knee arthroplasty are at high risk for venous thromboembolism (VTE) with an incidence of approximately 0.6-1.5%. Given the high volume of these operations, with approximately one million performed annually in the U.S., the rate of VTE represents a large absolute number of patients. The rate of VTE after total hip arthroplasty has been stable over the past decade, although there has been a slight reduction in the rate of deep venous thrombosis (DVT), but not pulmonary embolism (PE), after total knee arthroplasty. Over this time, there has been significant research into the optimal choice of pharmacologic VTE prophylaxis for individual patients, with the objective to reduce the rate of VTE while minimizing adverse side effects such as bleeding. Recently, aspirin has emerged as a promising prophylactic agent for patients undergoing arthroplasty due to its similar efficacy and good safety profile compared to other pharmacologic agents. However, there is no evidence to date that clearly demonstrates the superiority of any given prophylactic agent. Therefore, this review discusses (1) the current prevalence and trends in VTE after total hip and knee arthroplasty and (2) provides an update on pharmacologic VTE prophylaxis in regard to aspirin usage.

The Timing of Symptomatic Pulmonary Embolism in Patients With Nonwarfarin Anticoagulants Following Elective Primary Total Joint Arthroplasty

BACKGROUND

The purpose of this study is to investigate the incidence and timing of postoperative, symptomatic pulmonary embolism (PE) in patients receiving nonwarfarin treatment following primary total joint arthroplasty (TJA), to clarify the appropriate duration of postoperative VTE prophylaxis.

METHODS

We retrospectively reviewed the medical records of 11,148 patients who underwent primary TJA, including total knee arthroplasty and total hip arthroplasty at our institution between January 2012 and March 2019. The median postoperative day of diagnosis of symptomatic PE and the interquartile range for day of diagnosis were determined. Multivariate Cox proportional hazards modeling was used to test the difference of timing for PE based on demographics and comorbidities.

RESULTS

The overall 90-day rate of symptomatic PE was 0.71%. The median day of diagnosis for symptomatic PE was 3 days postoperatively (interquartile range, 2-7 days). Factors showed statistical significance on multivariate analysis in association with earlier timing of PE occurrence in patients with atrial fibrillation, diabetes mellitus, coronary heart disease, and history of stroke.

CONCLUSION

The vast majority of symptomatic PE occurs in the early postoperative period after TJA, and atrial fibrillation, diabetes mellitus, coronary heart disease, and history of stroke were independent factors affecting the timing of symptomatic PE.

Mechanical prophylaxis, early mobilisation and risk stratification: as effective as drugs for low risk patients undergoing primary joint replacement. Results in 13,384 patients

INTRODUCTION

Current NICE Guidelines state that all patients undergoing total hip and knee arthroplasty should be given both mechanical and chemical prophylaxis. At our institution, a targeted thromboprophylaxis policy has been in place since October 1999. The aim of this study was to calculate our venous thromboembolism rates and compare these to published rates in the literature.

METHODS

All patients are pre-operatively assessed for their VTE risk. Patients are stratified into high or low risk: all patients received mechanical thromboprophylaxis and the higher risk patients now receive chemical and mechanical thromboprophylaxis post op. Patients are reviewed at 2, 6 and 52 weeks and with annual postal questionnaires and clinical and radiological review at 5 and 10yrs.

RESULTS

13,384 primary THA and TKAs were entered into the database. The overall rate of clinically apparent DVT and overall PE rates of 0.48% and 0.42% respectively. 86.16% of our patients were low risk, of these 23.3% of patients were on Aspirin/Clopidogrel with mechanical thromboprophylaxis and 76.7% of patients had mechanical prophylaxis alone. There was no statistical difference between the DVT or PE rates in the low risk groups.

CONCLUSION

Our results show that use of early mobilisation and mechanical prophylaxis within an Enhanced Recovery Programme results in comparable VTE rates to chemical prophylaxis for all, which is reflected in the literature. Our results question the need for chemical thromboprophylaxis or extended use of mechanical thromboprophylaxis in "lower risk" patients if a risk stratification policy is used in the context of modern surgical approaches.

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

BACKGROUND

Pulmonary complications after total joint arthroplasty (TJA) are uncommon but have significant cost impact. Total hip arthroplasty (THA) and total knee arthroplasty (TKA) are 2 of the 5 top procedures requiring inpatient stay within the United States. Subsequent pulmonary complications therefore may impose substantial cost burden for US health care. The purpose of this study was to describe the incidence, risk factors, and clinical implications of pulmonary complications (ie, pneumonia, respiratory failure, pulmonary embolism [PE], and aspiration) after TJA in the United States.

METHODS

The National Inpatient Sample (NIS) was queried for all patients undergoing primary, elective THA and TKA between years 2004 and 2014. Pulmonary complications were defined as the occurrence of pneumonia, respiratory failure, PE, or aspiration after TJA. Demographic and clinical characteristics, inpatient cost, length of stay (LOS), and mortality were compared between patients with and without documented perioperative pulmonary complications. Given the stratified nature of the NIS database, estimates of incidence throughout the United States were made with application of trend weights to observed database frequencies. Analyses of estimated annual complication rates were made using χ tests.

RESULTS

Between 2004 and 2014, an estimated 2,679,351 patients underwent elective primary THA. A total of 5,527,205 patients were estimated to have undergone elective primary TKA. THA 1.42% (95% CI, 1.37%-1.47%) and 1.71% (95% CI, 1.66%-1.76%) of TKA procedures were complicated by pneumonia, respiratory failure, PE, or aspiration. During this time, the incidence of perioperative pulmonary complications decreased from 1.57% (95% CI, 1.41%-1.73%) to 1.01% (95% CI, 0.92%-1.10%) after THA (P < .0001) and from 2.03% (95% CI, 1.88%-2.18%) to 1.33% (95% CI, 1.25%-1.42%) after TKA (P < .0001). The adjusted odds ratio (aOR) of experiencing a pulmonary complication was highest among patients with history of significant weight loss (aOR = 4.77; 99.9% CI, 3.97-5.73), fluid/electrolyte disorders (aOR = 3.33; 99.9% CI, 3.11-3.56), congestive heart failure (CHF; aOR = 3.32; 99.9% CI, 3.07-3.58), preexisting paralytic condition (aOR = 2.03; 99.9% CI, 1.57-2.61), and human immunodeficiency virus infection (aOR = 2.00; 99.9% CI, 1.06-3.78). Perioperative pulmonary complications were associated with increased LOS (THA = 3.03 days; 99.9% CI, 2.76-3.31; TKA = +2.72 days; 99.9% CI, 2.58-2.86), increased hospital costs (THA = +9163 US dollars; 99.9% CI, 8054-10,272; TKA = +7257 US dollars; 99.9% CI, 6650-7865), and increased mortality (THA: aOR = 121; 99.9% CI, 78-187; TKA: aOR = 150; 95% CI, 97-233).

CONCLUSIONS

Despite a decline in overall incidence, perioperative pulmonary complications represent a significant potential source of perioperative morbidity and mortality. The current study highlights potential risk factors for pulmonary complications. Recognition of these factors may help to better stratify patients and mitigate risk of potential complications. This is particularly true of respiratory failure as it is associated with the high increases in resource utilization and mortality in this group.

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.

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.

The self-assessment dilemma: an open-source, ethical method using Matlab to formulate multiple-choice quiz questions for online reinforcement

Student self-assessment using computer-based quizzes has been shown to increase subject memory and engagement. Some types of self-assessment quizzes can be associated with a dilemma between 1) medical students who want the self-assessment quiz to be clearly related to upcoming summative assessments or curated by the exam-setters, and 2) university administrators and ethics committees who want clear guarantees that the self-assessment quizzes are not based on the summative assessments or made by instructors familiar with the exam bank of items. An algorithm in Matlab was developed to formulate multiple-choice questions for both ion transport proteins and pharmacology. A resulting question/item subset was uploaded to the Synap online self-quiz web platform, and 48 year 1 medical students engaged with it for 3 wk. Anonymized engagement statistics for students were provided by the Synap platform, and a paper-based exit questionnaire with an 80% response rate ( n = 44) measured satisfaction. Four times as many students accessed the quiz system via laptop compared with phone/tablet. Of 391 questions/items, over 11,749 attempts were made. Greater than 80% of respondents agreed with each of the positive statements (ease of use, enjoyed, engaged more, learned more, and wanted it to be extended to other modules). Despite simplistic questions and rote memorization, the questions developed by this system were engaged with and were received positively. Students strongly supported extending the system.

Deep Vein Thrombosis Prophylaxis: State of the Art

The selection of a prophylaxis regimen to prevent symptomatic pulmonary embolism and deep vein thrombosis is a balance between efficacy and safety. The latest American Academy of Orthopaedic Surgeons guideline recommended that either chemoprophylaxis or mechanical prophylaxis be used after total joint arthroplasty but did not recommend specific agents. However, the latest evidence-based American College of Chest Physicians guideline recommended a variety of chemoprophylaxis and mechanical agents for a minimum of 10 to 14 days after total joint arthroplasty. Risk stratification is the key to the selection of the appropriate prophylaxis regimen for the individual patient, but the optimal risk stratification protocol still needs to be developed.

CT pulmonary angiography in lower limb arthroplasty

Aims

The aims of this study were to determine the indications and frequency of ordering a CT pulmonary angiography (CTPA) following primary arthroplasty of the hip and knee, and to determine the number of positive scans in these patients, the location of emboli and the outcome for patients undergoing CTPA.

Patients and Methods

We analyzed the use of CTPA, as an inpatient and up to 90 days as an outpatient, in a cohort of patients and reviewed the medical records and imaging for each patient undergoing CTPA.

Results

Out of 11 249 patients, scans were requested in 229 (2.04%) and 86 (38%) were positive. No patient undergoing CTPA died within 90 days. The rate of mortality from pulmonary embolism (PE) overall was 0.08%. CTPA was performed twice as often following total knee arthroplasty (TKA) compared with total hip arthroplasty (THA), and when performed was twice as likely to be positive. Hypoxia was the main indication for a scan, being the indication in 149 scans (65%); and in 23% (11 of 47), the PE was peripheral and unilateral. Three patients suffered complications resulting from therapeutic anticoagulation for possible PE, two of whom had a negative CTPA.

Conclusion

CTPA is more likely to be performed following TKA compared with THA. Hypoxia was the main presenting feature of PE. A quarter of PEs which were diagnosed were unilateral and peripheral. Further study may indicate which patients who have a PE after lower limb arthroplasty require treatment, and which can avoid the complications associated with anticoagulation. Cite this article: Bone Joint J 2018;100-B:938–44.

What are the incidence and risk factors of in-hospital mortality after venous thromboembolism events in total hip and knee arthroplasty patients?

Background

Pulmonary embolism and deep vein thrombosis, together referred to as venous thromboembolism (VTE), are serious and potentially preventable complications after total hip arthroplasty and total knee arthroplasty. The aim of this study was to investigate the incidence of mortality after VTE events and assess the risk factors that are associated with it.

Methods

The Nationwide Inpatient Sample was used to estimate the total number of total hip arthroplasty, total knee arthroplasty, VTE events, and mortality using the International Classification of Diseases, Ninth Revision procedure codes from 2003 to 2012. Patients' demographics, Elixhauser, and Charlson comorbidity indices were used to identify the risk factors associated with in-hospital VTEs and mortality.

Results

A total of 1,805,621 THAs and TKAs were included. The overall rate of VTE was 0.93%. The in-hospital mortality rate among patients with VTEs was 7.1% vs 0.30% in patients without VTEs (P-value < .0001). The risk factors for mortality after VTE events in descending order were as follows: hypercoagulable state (odds ratio [OR]: 5.3, 95% confidence interval [CI]: 3.6-5.8), metastatic cancer (OR: 5.2, 95% CI: 3.3-5.6), myocardial infarction (OR: 4.2, 95% CI: 2.3-4.7), peripheral vascular disease (OR: 3.6, 95% CI: 3.2-4.0), cardiac arrhythmias (OR: 3.2, 95% CI: 1.6-4.3), advanced age (OR: 3.1, 95% CI: 2.3-3.7), electrolyte disorders (OR: 3.1, 95% CI: 2.2-3.6), pulmonary circulation disorders (OR: 2.9, 95% CI: 2.6-3.3), depression (OR: 2.8, 95% CI: 1.6-3.4), complicated diabetes (OR: 2.7, 95% CI: 2.1-3.2), weight loss (OR: 2.6, 95% CI: 2.2-3.3), renal failure (OR: 2.6, 95% CI: 1.7-3.5), chronic pulmonary disease (OR: 2.5, 95% CI: 1.3-3.1), valvular disease (OR: 2.4, 95% CI: 1.8-2.7), liver disease (OR: 1.7, 95% CI: 1.2-1.9), and obesity (OR: 1.6, 95% CI: 1.5-1.9).

Conclusions

In-hospital VTE has a significant in-hospital mortality rate. Several of the identified risk factors in this study are modifiable preoperatively. We strongly urge the orthopaedic community to be cognizant of these risk factors and emphasize on optimizing patients' comorbidities before an elective arthroplasty.

Persistent Pulmonary Embolism Rates Following Total Knee Arthroplasty Even With Prophylactic Anticoagulants

BACKGROUND

Symptomatic pulmonary embolism (PE), a significant and life-threatening complication following total knee arthroplasty (TKA), has been described as a "never event." Despite a number of advancements in care, PE continues to occur following TKA. This study evaluates symptomatic PE rates over time in TKA patients enrolled in multicenter randomized clinical trials assessing the efficacy of venous thromboembolism prophylaxis regimens.

METHODS

The MEDLINE and Cochrane Central Register of Controlled Trials were searched to identify clinical trials assessing prophylactic anticoagulation in patients undergoing TKA between January 1995 and December 2016. A random effect model was used to combine PE rates across studies. The pooled proportion of symptomatic PEs was calculated and heterogeneity was quantified with the I² statistic. A 95% prediction interval was constructed to examine what the expected range in the proportion of symptomatic PEs would be in future studies. Meta-regression was used to explore the effect of time on the rate of symptomatic PEs.

RESULTS

A total of 18 studies representing 27,073 patients were included in the meta-analysis. The symptomatic PE rate was 0.37% (95% confidence interval, 0.24%-0.52%). There was significant heterogeneity across studies, I² = 66%. Between 1996 and 2010, the proportion of PEs did not change in the regression analysis. The 95% prediction interval was 0.0002 to 0.0106, indicating that in similar future studies, the true proportion of symptomatic PEs would range from 0.02% to 1.06%.

CONCLUSION

Over a 14-year period, the symptomatic PE rate after TKA was relatively constant even when patients received potent anticoagulation. These results suggest that some patients may have a genetic predisposition to develop a PE and more effective risk stratification protocols need to be developed to make sure patients receive appropriate anticoagulation.

Venous Thromboembolism Prophylaxis in Total Hip Arthroplasty and Total Knee Arthroplasty Patients: From Guidelines to Practice

Venous thromboembolism (VTE) prophylaxis is recommended for all patients undergoing total hip arthroplasty or total knee arthroplasty. The selection of an appropriate prophylaxis regimen represents a balance between efficacy and safety. To help orthopaedic surgeons select an appropriate VTE prophylaxis regimen for their patients, the American Academy of Orthopaedic Surgeons and the American College of Chest Physicians have developed guidelines. These guidelines do not recommend an optimal regimen, however. Rather, an individualized prophylaxis regimen that balances efficacy and safety is recommended for each patient, based on various risk factors. Because of a paucity of data and a lack of adequately powered head-to-head trials, implementing these guidelines can be challenging for the orthopaedic surgeon. Knowledge of the prophylaxis options and the VTE risk factors is paramount for developing an effective VTE prophylaxis algorithm for the surgeon's practice.