Rivaroxaban and Acetylsalicylic Acid for Prevention of Venous Thromboembolism Following Total Knee Arthroplasty in Korean Patients

Total Knee Arthroplasty: Is It Safe? A Single-Center Study of 4,124 Patients in South Korea

Background

Although total knee arthroplasty (TKA) is considered an effective treatment for knee osteoarthritis, it carries risks of complications. With a growing number of TKAs performed on older patients, understanding the cause of mortality is crucial to enhance the safety of TKA. This study aimed to identify the major causes of short- and long-term mortality after TKA and report mortality trends for major causes of death.

Methods

A total of 4,124 patients who underwent TKA were analyzed. The average age at surgery was 70.7 years. The average follow-up time was 73.5 months. The causes of death were retrospectively collected through Korean Statistical Information Service and classified into 13 subgroups based on the International Classification of Diseases-10 code. The short- and long-term causes of death were identified within the time-to-death intervals of 30, 60, 90, 180, 180 days, and > 180 days. Standard mortality ratios (SMRs) and cumulative incidence of deaths were computed to examine mortality trends after TKA.

Results

The short-term mortality rate was 0.07% for 30 days, 0.1% for 60 days, 0.2% for 90 days, and 0.2% for 180 days. Malignant neoplasm and cardiovascular disease were the main short-term causes of death. The long-term (> 180 days) mortality rate was 6.2%. Malignant neoplasm (35%), others (11.7%), and respiratory disease (10.1%) were the major long-term causes of death. Men had a higher cumulative risk of death for respiratory, metabolic, and cardiovascular diseases. Age-adjusted mortality was significantly higher in TKA patients aged 70 years (SMR, 4.3; 95% confidence interval [CI], 3.3-5.4) and between 70 and 79 years (SMR 2.9; 95% CI, 2.5-3.5) than that in the general population.

Conclusions

The short-term mortality rate after TKA was low, and most of the causes were unrelated to TKA. The major causes of long-term death were consistent with previous findings. Our findings can be used as counseling data to understand the survival and mortality of TKA patients.

Prevention of venous thromboembolism with aspirin following knee surgery: A systematic review and meta-analysis

Venous thromboembolism (VTE) is a well-known complication following orthopaedic surgery. The incidence of this complication has decreased substantially since the introduction of routine thromboprophylaxis. However, concerns have been raised about increased bleeding complications caused by aggressive thromboprophylaxis.Attention has grown for aspirin as a safer thromboprophylactic agent following orthopaedic surgery.A systematic review using MEDLINE, Embase and Web of Science databases was undertaken to compare the effectiveness of aspirin prophylaxis following knee surgery with the current standard prophylactic agents (low molecular weight heparin [LMWH], vitamin K antagonists and factor Xa inhibitors).No significant difference in effectiveness of VTE prevention was found between aspirin, LMWH and warfarin. Factor Xa inhibitors were more effective, but increased bleeding complications were reported.As evidence is limited and of low quality with substantial heterogeneity, further research with high-quality, adequately powered trials is needed. Cite this article: EFORT Open Rev 2021;6:892-904. DOI: 10.1302/2058-5241.6.200120.

Risk factors for deep vein thrombosis even using low-molecular-weight heparin after total knee arthroplasty

Background

With an increase in deep vein thrombosis (DVT) following total knee arthroplasty (TKA) in the Asian population, most surgeons today use a form of prophylactic anticoagulant agents in patients after TKA. Nevertheless, DVT occasionally develops even in these patients with prophylaxis. The purpose of this study was to identify the risk factors for DVT after TKA in cases of postoperative low-molecular-weight heparin (LMWH) use.

Methods

We designed a retrospective study with 103 patients who underwent primary TKA. From the second postoperative day, 60 mg of LMWH was subcutaneously injected into the patients daily. On the seventh postoperative day, patients had computed tomography angiography to check whether they had DVT. Regarding risk factors, we investigated patients’ gender, age, surgical site (unilateral/bilateral), body mass index, method of anesthesia, preoperative hypertension, diabetes, hypercholesterolemia status, and prothrombin time/international normalized ratio from electronic medical records. We analyzed the statistical significance of these risk factors.

Results

Statistically significant factors in the single-variable analysis were surgical site (unilateral/bilateral), body mass index, preoperative hypertension status, and anesthesia method. Multiple logistic regression analysis with these factors revealed that the surgical site (unilateral/bilateral, p = 0.024) and anesthesia method (p = 0.039) were significant factors for the occurrence of postoperative DVT after TKA.

Conclusions

Patients undergoing simultaneous bilateral TKAs and patients undergoing TKA with general anesthesia need more attention regarding DVT even with chemoprophylaxis using LMWH after TKA.

Do We Need Chemoprophylaxis to Prevent Venous Thromboembolism following Medial Open-Wedge High Tibial Osteotomy?

The aim of this study was to investigate the overall incidence of venous thromboembolism (VTE) and to assess the efficacy of chemoprophylaxis to prevent VTE following medial open-wedge high tibial osteotomy (MOWHTO) in Asian patients. A total of 133 patients who consecutively underwent MOWHTO for the treatment of knee osteoarthritis with varus deformity were enrolled. All patients underwent preoperative ultrasonography and computed tomography venography on postoperative day 5 to detect deep vein thrombosis (DVT). Patients were divided into two groups: chemoprophylaxis group included patients (n = 66) who received 2.5 mg fondaparinux for 5 days postoperatively, whereas control group comprised patients (n = 67) who received placebo (67 patients). We evaluated the efficacy and safety outcomes of the treatment. We also assessed the predisposing factors that may affect the occurrence of VTE. The incidence of overall DVT was 14.9% in the control group and 10.6% in the chemoprophylaxis group (p > 0.05). Proximal DVT occurred in one patient in the control group. There was no symptomatic DVT or pulmonary embolism in either group. The patients with DVT had significantly higher mean body mass index (BMI) than the patients without DVT. Multivariate logistic regression showed BMI > 30 kg/m² that was significantly correlated with the development of DVT (odds ratio = 0.8; p = 0.017). There were no cases of major bleeding; however, minor bleeding episodes occurred in four patients in the chemoprophylaxis group. The current study showed that the overall incidence of VTE following MOWHTO was low in Asian patients even without chemoprophylaxis. Therefore, routine chemoprophylaxis following MOWHTO seems to be not necessary in a population with low-VTE incidence. However, selective chemoprophylaxis should be considered in patients with BMI > 30 kg/m².

Perioperative symptomatic venous thromboembolism after immediate chemoprophylaxis in patients with pelvic and lower-extremity fractures

The purpose of this study was to investigate the incidence of symptomatic venous thromboembolism (VTE) after chemoprophylaxis in patients with pelvic and lower-extremity fractures, and to identify risk factors for VTEs in this subgroup of patients. To detect VTE, multi-detector computed tomography (CT) angiography was performed. Of 363 patients assessed, the incidence of symptomatic VTE was 12.4% (45 patients), and the incidence of symptomatic PE was 5.2% (19 patients). For the risk-factor analysis, a higher Charlson comorbidity index (p = 0.037), and a history of external fixator application (p = 0.007) were associated with increased VTE risk. Among patients who had VTE, male sex (p = 0.017), and above-the-knee fractures (p = 0.035) were associated with increased pulmonary embolism (PE) risk. In conclusions, the incidence of VTE in post-traumatic patients is not low after chemoprophylaxis. Risk factors for VTE and PE are different among patients with pelvic and lower-extremity fractures.