Incidence and time course of thromboembolic outcomes following total hip or knee arthroplasty

Direct factor Xa inhibitors versus low molecular weight heparins or vitamin K antagonists for prevention of venous thromboembolism in elective primary hip or knee replacement or hip fracture repair

BACKGROUND

People undergoing major orthopaedic surgery are at increased risk of postoperative thromboembolic events. Low molecular weight heparins (LMWHs) are recommended for thromboprophylaxis in this population. New oral anticoagulants, including direct factor Xa inhibitors, are recommended as alternatives. They may have more advantages than disadvantages compared to LMWHs and vitamin K antagonists (VKAs, another type of anticoagulant).

OBJECTIVES

To assess the benefits and harms of prophylactic anticoagulation with direct factor Xa inhibitors compared with low molecular weight heparins and vitamin K antagonists in people undergoing major orthopaedic surgery for elective total hip or knee replacement or hip fracture surgery.

SEARCH METHODS

We searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, two other databases, and two trial registers to 11 November 2023. We conducted reference checks to identify additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing the effects of direct factor Xa inhibitors to LMWHs or VKAs in people undergoing major orthopaedic surgery.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were all-cause mortality, major venous thromboembolism (VTE), symptomatic VTE, major bleeding, and serious hepatic and non-hepatic adverse events. We evaluated the risk of bias in the included studies using Cochrane's risk of bias 1 tool. We calculated estimates of treatment effects using risk ratios (RR) with 95% confidence intervals (CIs), and used GRADE criteria to assess the certainty of the evidence.

MAIN RESULTS

We included 53 RCTs (44,371 participants). Participants' average age was 64 years (range: 18 to 93 years). Only one RCT compared a VKA with direct factor Xa inhibitors. All 53 RCTs compared direct factor Xa inhibitors with LMWHs. Twenty-three studies included participants undergoing total hip replacement; 21 studies, total knee replacement; and three studies included people having hip fracture surgery. The studies' average duration was approximately 42 days (range: two to 720 days). Compared to LMWHs, direct factor Xa inhibitors may have little to no effect on all-cause mortality, but the evidence is very uncertain (RR 0.83, 95% CI 0.52 to 1.31; I2 = 0%; 28 studies, 29,698 participants; very low-certainty evidence). Direct factor Xa inhibitors may make little to no difference to major venous thromboembolic events compared to LMWHs, but the evidence is very uncertain (RR 0.51, 95% CI 0.37 to 0.71; absolute risk difference: 12 fewer major VTE events per 1000 participants, 95% CI 16 fewer to 7 fewer; I2 = 48%; 28 studies, 24,574 participants; very low-certainty evidence). Compared to LMWHs, direct factor Xa inhibitors may reduce symptomatic VTE (RR 0.64, 95% CI 0.50 to 0.83; I2 = 0%; 33 studies, 31,670 participants; low-certainty evidence). The absolute benefit of substituting factor Xa inhibitors for LMWHs may be between two and five fewer symptomatic VTE episodes per 1000 patients. In the meta-analysis with all studies pooled, direct factor Xa inhibitors appeared to make little or no difference to major bleeding compared to LMWHs, but the evidence was very uncertain (RR 1.05, 95% CI 0.86 to 1.30; I2 = 15%; 36 studies, 39,778 participants; very low certainty-evidence). • In a subgroup analysis limited to studies comparing rivaroxaban to LMWHs, people given rivaroxaban may have had more major bleeding events (RR 1.94, 95% CI 1.26 to 2.98; I2 = 0%; 17 studies, 17,630 participants; low-certainty evidence). The absolute risk of substituting rivaroxaban for LMWH may be between one and seven more major bleeding events per 1000 patients. • In a subgroup analysis limited to studies comparing direct factor Xa inhibitors other than rivaroxaban to LMWHs, people given these other direct factor Xa inhibitors may have had fewer major bleeding events, but the evidence was very uncertain (RR 0.80, 95% CI 0.63 to 1.02; absolute risk difference: 3 fewer major bleeding events per 1000 participants, 95% CI 5 fewer to 0 fewer; I2 = 0%; 19 studies, 22,148 participants; very low-certainty evidence). Direct factor Xa inhibitors may make little to no difference in serious hepatic adverse events compared to LMWHs, but the evidence is very uncertain (RR 3.01, 95% CI 0.12 to 73.93; 2 studies, 3169 participants; very low-certainty evidence). Only two studies reported this outcome, with one death in the intervention group due to hepatitis reported in one study, and no events reported in the other study. People given direct factor Xa inhibitors may have a lower risk of serious non-hepatic adverse events than those given LMWHs (RR 0.89, 95% CI 0.81 to 0.97; I2 = 18%; 15 studies, 26,246 participants; low-certainty evidence). The absolute benefit of substituting factor Xa inhibitors for LMWH may be between three and 14 fewer serious non-hepatic adverse events per 1000 patients. Only one study compared a direct factor Xa inhibitor with a VKA. It reported outcome data with imprecise results due to the small number of events. It showed no difference in the effects of the study drugs.

AUTHORS' CONCLUSIONS

Oral direct factor Xa inhibitors may have little to no effect on all-cause mortality, but the evidence is very uncertain. Oral direct factor Xa inhibitors may slightly reduce symptomatic VTE events when compared with LMWH. They may make little or no difference to major VTE events, but the evidence is very uncertain. In the evaluation of major bleeding, the evidence suggests rivaroxaban results in a slight increase in major bleeding events compared to LMWHs. The remaining oral direct factor Xa inhibitors may have little to no effect on major bleeding, but the evidence is very uncertain. Oral direct factor Xa inhibitors may reduce serious non-hepatic adverse events slightly compared to LMWHs. They may have little to no effect on serious hepatic adverse events, but the evidence is very uncertain. Due to the high rates of missing participants and selective outcome reporting, the effect estimates may be biased.

Personalized delayed anticoagulation therapy alleviates postoperative bleeding in total knee arthroplasty (TKA) patients

Purpose

Ecchymosis is one of the most common complications following total knee arthroplasty (TKA), which is closely related to postoperative bleeding. However, it is still controversial whether anticoagulation treatment should be continued for postoperative ecchymosis patients. We suppose that personalized delayed anticoagulation therapy could be beneficial for decreasing postoperative bleeding.

Methods

A total of 201 TKA patients were retrospectively included in this study, among whom ecchymosis patients received drug anticoagulation treatment 1-2 days later than usual, while nonecchymosis patients received regular drug anticoagulation treatment. The perioperative blood loss, coagulation state, fibrinolytic state and complications were collected and analyzed.

Results

Eighty-nine patients (44.3%) developed ecchymosis within 3 days after TKA. There were no differences in baseline characteristics between the two groups. In the ecchymosis group, higher K values and lower calculated coagulation index values were observed in thromboelastography, along with greater total blood loss and a more significant decrease in haemoglobin levels on postoperative Day 1 (POD1) compared to the nonecchymosis group. Additionally, the ecchymosis patients exhibited higher levels of fibrinogen degradation products and D-dimer (D-D) on POD1, with no differences noted on POD3, indicating that patients with ecchymosis are in a relatively hypocoagulable and hyperfibrinolytic state compared to those without ecchymosis. Therefore, the delayed anticoagulation treatment proved beneficial for correcting these postoperative conditions. No statistically significant differences were found between the two groups in postoperative complications, demonstrating that delayed anticoagulation treatment is safe.

Conclusion

Patients with ecchymosis exhibited a relatively hypocoagulable and hyperfibrinolytic state with a stronger tendency for postoperative bleeding. Delayed anticoagulation in ecchymosis patients could effectively prevent further exacerbation of postoperative bleeding by avoiding sustained hypocoagulable and hyperfibrinolysis states. Personalized delayed anticoagulation therapy could be beneficial for managing postoperative ecchymosis for TKA patients.

Level of Evidence

Level IV.

Venous Thromboembolism Prevention in Rehabilitation: A Review and Practice Suggestions

ABSTRACT

Venous thromboembolism is a frequent complication of acute hospital care, and this extends to inpatient rehabilitation. The timely use of appropriate thromboprophylaxis in patients who are at risk is a strong, evidence-based patient safety priority that has reduced clinically important venous thromboembolism, associated mortality and costs of care. While there has been extensive research on optimal approaches to venous thromboembolism prophylaxis in acute care, there is a paucity of high-quality evidence specific to patients in the rehabilitation setting, and there are no clinical practice guidelines that make recommendations for (or against) thromboprophylaxis across the broad spectrum of rehabilitation patients. Herein, we provide an evidence-informed review of the topic with practice suggestions. We conducted a series of literature searches to assess the risks of venous thromboembolism and its prevention related to inpatient rehabilitation as well as in major rehabilitation subgroups. Mobilization alone does not eliminate the risk of venous thromboembolism after another thrombotic insult. Low molecular weight heparins and direct oral anticoagulants are the principal current modalities of thromboprophylaxis. Based on the literature, we make suggestions for venous thromboembolism prevention and include an approach for consideration by rehabilitation units that can be aligned with local practice.

Efficacy and safety of commonly used thromboprophylaxis agents following hip and knee arthroplasty

Aims

We investigated the efficacy and safety profile of commonly used venous thromboembolism (VTE) prophylaxis agents following hip and knee arthroplasty.

Methods

A systematic search of PubMed, Embase, Cochrane Library, Web of Science, and OrthoSearch was performed. Prophylaxis agents investigated were aspirin (< 325 mg and ≥ 325 mg daily), enoxaparin, dalteparin, fondaparinux, unfractionated heparin, warfarin, rivaroxaban, apixaban, and dabigatran. The primary efficacy outcome of interest was the risk of VTE, whereas the primary safety outcomes of interest were the risk of major bleeding events (MBE) and wound complications (WC). VTE was defined as the confirmed diagnosis of any deep vein thrombosis and/or pulmonary embolism. Network meta-analysis combining direct and indirect evidence was performed. Cluster rank analysis using the surface under cumulative ranking (SUCRA) was applied to compare each intervention group, weighing safety and efficacy outcomes.

Results

Of 86 studies eligible studies, cluster rank analysis showed that aspirin < 325 mg daily (SUCRA-VTE 89.3%; SUCRA-MBE 75.3%; SUCRA-WC 71.1%), enoxaparin (SUCRA-VTE 55.7%; SUCRA-MBE 49.8%; SUCRA-WC 45.2%), and dabigatran (SUCRA-VTE 44.9%; SUCRA-MBE 52.0%; SUCRA-WC 41.9%) have an overall satisfactory efficacy and safety profile.

Conclusion

We recommend the use of either aspirin < 325 mg daily, enoxaparin, or dabigatran for VTE prophylaxis following hip and knee arthroplasty.

Incidence and Time Course of Symptomatic Thromboembolic Outcomes After Lower Extremity Arthroscopic Surgery, Ankle Fracture Surgery, and Achilles Tendon Repair

BACKGROUND

The incidence and time course of acute venous thromboembolism (VTE) after ambulatory surgery for lower extremity orthopaedic conditions is not well-defined.

HYPOTHESIS

The purpose of this study was to analyze the incidence, the time course, and risk factors associated with clinically diagnosed acute deep vein thrombosis or pulmonary embolism within 3 months of surgery in patients undergoing specific operations for lower extremity injuries.

METHODS

Patients undergoing arthroscopic procedures of the knee, ankle fracture surgery, Achilles tendon repair, and ankle arthroscopy from January 1, 2005, to December 31, 2010, were identified in the California Ambulatory Surgery database with linkage to hospital discharge data, emergency department data, and a death registry. Outcomes were acute VTE and death within 90 days. Time courses were compared using Kaplan-Meier analysis, and risk factors were analyzed using proportional hazard modeling.

RESULTS

Analysis of data from 468,699 surgeries showed that the cumulative incidence of acute VTE was significantly higher after Achilles tendon repair (0.72%, P < 0.001) than ankle fracture surgery (0.33%), knee arthroscopy procedures (range, 0.29% to 0.41%), or ankle arthroscopy (0.24%). The time course of diagnosis of VTE was similar for all arthroscopic procedures (median postoperative day for diagnosis = 9 to 10; 80% by 22 to 36 days), whereas for Achilles tendon surgery, the time course was protracted (median postoperative day for diagnosis = 29 days; 80% by 51 days). Ninety-day mortality was low (<0.06%) after all procedures except ankle fracture (0.12%). Predictors of pulmonary embolism included age older than 60 years (HR, 3.1; 95% CI; 2.0 to 4.8, versus younger than 30 years), Achilles tendon repair (HR, 3.8; 95% CI; 2.8 to 5.3), and ankle fracture surgery (Hazard Ratio [HR], 2.1; 95% Confidence Interval [CI]; 1.5 to 2.8); Asian/Pacific Islander (HR, 0.3; 95% CI; 0.1 to 0.6) and Hispanic patients (HR, 0.5; 95% CI; 0.4 to 0.7) had significantly lower risk.

DISCUSSION

The incidence and time course of onset of acute VTE after lower extremity orthopaedic surgeries varies significantly depending on the surgical procedure. These findings have implications regarding the use and duration of pharmacologic thromboprophylaxis.

RANDOMIZED CLINICAL TRIAL OF ASPIRIN AS PROPHYLAXIS FOR THROMBOEMBOLISM IN HIP ARTHROPLASTY

Objective

This study aims to evaluate aspirin as a chemical prophylaxis (200 mg) in total hip arthroplasty.

Methods

the study compared two groups and used ultrasonography (USG) to screen for low-deep venous thrombosis. Group 1 received 600 mg (control), and Group 2 received 200 mg of (intervention), associated with the use of elastic compression stockings and early walking.

Results

fourteen patients were allocated to Group A (200mg), and 16 to Group B (600mg); in group A (200mg), 3 cases with thrombus below the popliteal vein were detected at the first USG examination. All of them are in the left lower limb (21.4%). In group B (600 mg), 5 cases were identified after the first exam (31.2%). All cases were asymptomatic and followed the protocol with prophylaxis only with Aspirin.

Conclusion

In the statistical data, there were no differences in the presence of thrombus between the 200- and 600 mg groups, which is credited to using low-dose aspirin in low doses (200mg). Hematimetric levels returned to baseline levels and suggested there was no chronic or acute bleeding related to the use of aspirin. The manuscript was prepared according to the CONSORT guideline 2010. Level of Evidence I; Longitudinal Randomized Comparative Clinical Study.

Effect of Knee Valgus Deformity on Symptomatic Venous Thromboembolism and Prosthesis Revision Risk after Total Knee Arthroplasty: A Multicenter Retrospective Study

OBJECTIVE

Symptomatic venous thromboembolism (VTE) and prosthesis failure are the most serious complications after total knee arthroplasty (TKA). However, whether knee valgus deformity aggravates these complications has not been fully clarified. To study the difference between perioperative symptomatic VTE and prosthesis revision rate in patients with valgus knee osteoarthritis by comparing with patients undergoing TKA for varus deformity and analyze the reasons for revision. At the same time, the distribution and radiographic features of lower extremity deep venous thrombosis were recorded.

METHODS

The data of patients who underwent TKA in two tertiary hospitals from January 2016 to December 2020 were retrospectively reviewed, and a total of 8917 patients were included. According to preoperative manifestations of knee malformations, all patients were divided into two groups: valgus group (n = 412) and varus group (n = 8505). Main indicators included the incidence of symptomatic VTE and prosthesis revision. Secondary outcomes included general information on operative time, Kellgren and Lawrence score, total hospital stay, and total costs. The patient data of the two groups were analyzed by Pearson chi-square test, Student t test, or Mann-Whitney U test. The revision was evaluated using Kaplan-Meier survival analysis.

RESULTS

The proportion of valgus knees in TKA patients was 4.62% (412/8917). The incidence of VTE was 6.23‰ (53/8505) and 16.99‰ (7/412) in the varus and valgus groups, and the results were statistically different (p = 0.009). There was no significant difference in echogenicity, number of occluded vessels, and thrombus length between the valgus group (p = 0.102; p = 0.645; p = 0.684). Patients with valgus deformity had 12.14‰ (5/412) prosthesis revision, the incidence of varus deformity was 4.82‰ (41/8505), and the revision risk of valgus group was 2.5 times higher than varus group, and the results were statistically different (p = 0.043). The operation time and hospital stay in the valgus group were longer than those in the varus group, and the results were statistically different (p = 0.018; p < 0.001).

CONCLUSIONS

Valgus deformity increases risk of symptomatic VTE and prosthesis revision after TKA. These results have guiding significance for the prevention of complications after TKA in patients with valgus deformity.

Prevalence of Venous Thromboembolism after Immediate Screening in Hip Fracture Patients

Purpose

Venous thromboembolism (VTE) is a major complication for hip fracture patients, and may exist preoperatively. This study aimed to examine the prevalence of VTE after immediate screening in hip fracture patients.

Materials and Methods

Hip fracture patients with an elevated level of D-dimer underwent screening for VTE using computed tomography (CT) angiography. Anticoagulation treatments were administered preoperatively to patients diagnosed with VTE, followed by administration of additional anticoagulation postoperatively. Medical records were reviewed to identify risk factors for preoperative VTE and determine the prognosis of the patients.

Results

Among 524 hip fracture patients, 66 patients (12.6%) were diagnosed with VTE, including 42 patients with deep vein thrombosis (DVT), 17 patients with pulmonary thromboembolism (PTE), and 7 patients with both DVT and PTE. Of the patients with VTE, 68.2% were diagnosed within 24 hours of injury, and 33.3% of these patients had PTE. VTE patients showed a tendency toward being overweight (P<0.01) and not on anticoagulant medication (P=0.02) compared to patients without VTE. The risk of VTE was higher for femur shaft fractures (odds ratio [OR] 4.83, 95% confidence interval [CI] 2.18-10.69) and overweight patients (OR 2.12, 95% CI 1.17-3.85), and lower for patients who were previously on anticoagulants (OR 0.36, 95% CI 0.18-0.74). Patients with preoperatively diagnosed VTE were asymptomatic before and after surgery.

Conclusion

Clinicians should be aware that VTE may be present within 24 hours of injury, and screening for VTE or prophylactic measures should be considered for high-risk patients.

Prior COVID-19 and Venous Thromboembolism Risk in Total Joint Arthroplasty in Patients Over 65 Years of Age

BACKGROUND

The COVID-19 pandemic has been associated with increased risks of venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE). However, there is limited literature investigating prothrombotic states and complications after total hip arthroplasty (THA) and total knee arthroplasty (TKA). We investigated (1) trends in VTE, PE, and DVT rates post-THA and TKA from 2016 to 2019 compared to 2020 to 2021 and (2) associations between prior COVID-19 diagnosis and VTE, PE, and DVT.

METHODS

A national dataset was queried for elective THA and TKA cases from 2016 to 2021. We first assessed trends in 90-day VTE prevalence between 2016 to 2019 and 2020 to 2021. Second, we investigated associations between previous COVID-19 and 90-day VTE with regression models.

RESULTS

From 2016 to 2021, a total of 2,422,051 cases had an annual decreasing VTE prevalence from 2.2 to 1.9% (THA) and 2.5 to 2.2% (TKA). This was evident for both PE and DVT (all trend tests P < .001). After adjusting for covariates (including vaccination status), prior COVID-19 was associated with significantly increased odds of developing VTE in TKA patients (odds ratio 1.2, 95% confidence interval 1.1 to 1.4, P = .007), but not DVT or PE (P > .05). There were no significant associations between prior COVID-19 and VTE, DVT, or PE after THA (P > .05).

CONCLUSIONS

Our study suggests that a previous diagnosis of COVID-19 is associated with increased odds of VTE, but not DVT or PE, in TKA patients. Ongoing data monitoring is needed given our effect estimates, emerging COVID-19 variants, and evolving vaccination rates.

Deep Vein Thrombosis Prophylaxis in Orthopedic Surgery

Deep vein thrombosis (DVT) is a complex and multifactorial process arising from a variety of factors, including recent surgical procedures, traumatic events, and periods of prolonged immobility. The extended period of stasis post-orthopedic surgery places patients at a notably high risk of developing DVT, and DVT-related pulmonary embolism (PE) ranks as the third most common cause of death in orthopedic surgery patients. This review examines the multifaceted risk factors contributing to the development of DVT in orthopedic patients. Additionally, it addresses the importance of DVT prophylaxis in orthopedic settings, the efficacy and safety of various prophylactic methods encompassing both mechanical and pharmacological approaches, and the economic dimensions of DVT prophylaxis, including scrutiny of cost-effectiveness and the exploration of strategies for optimization.

Does rapid mobilisation as part of an enhanced recovery pathway improve length of stay, return to function and patient experience post primary total hip replacement? A randomised controlled trial feasibility study

PURPOSE

Day-zero ambulation may enable patients to recover and leave hospital quicker following total hip replacement (THR). The present randomised control feasibility study investigated the efficacy of day-zero ambulation as a physiotherapeutic intervention.

METHODS

Thirty-six non-blinded adults aged 44-85 (Mean 67.1; SD 9.6 years) undergoing primary, uncomplicated THR were block randomized to either a control group (n = 18) with standard post-operative physiotherapy or an intervention group (n = 18) incorporating walking on the same day as the operation. Outcomes were length of hospital stay (LOS), time to reach functional milestones and achieve all physiotherapy discharge criteria, post-operative pain scores, complications and patient experience.

RESULTS

Participants treated with day-zero ambulation had reduced median hospital LOS of 1 day (p = .096), and median reduced times to reaching functional milestones of 39.7 h quicker to transfer to a chair (p < .001), 24.5 h quicker to walk 10 m (p = .009) and 26.4 h quicker to independently ascend and descend stairs (p = .01). Participants in the intervention group were deemed physiotherapy ready to leave hospital significantly earlier than control group (1.04 days, p = .015).

CONCLUSIONS

Day-zero ambulation appears safe and may have clinically relevant effects in speeding patient functional recovery and facilitating earlier discharge from hospital. Implications for RehabilitationDay-zero ambulation following total hip replacement (THR) appears safe.Preliminary data suggest that day-zero mobilisation following THR could be efficacious and support the need for a fully powered randomised controlled trial.There may be a clinically relevant effect in speeding patient functional recovery and facilitating an earlier discharge from hospital.

Monocyte Tissue Factor Expression: Lipopolysaccharide Induction and Roles in Pathological Activation of Coagulation

The coagulation system is a part of the mammalian host defense system. Pathogens and pathogen components, such as bacterial lipopolysaccharide (LPS), induce tissue factor (TF) expression in circulating monocytes that then activates the coagulation protease cascade. Formation of a clot limits dissemination of pathogens, enhances the recruitment of immune cells, and facilitates killing of pathogens. However, excessive activation of coagulation can lead to thrombosis. Here, we review studies on the mechanism of LPS induction of TF expression in monocytes and its contribution to thrombosis and disseminated intravascular coagulation. Binding of LPS to Toll-like receptor 4 on monocytes induces a transient expression of TF that involves activation of intracellular signaling pathways and binding of various transcription factors, such as c-rel/p65 and c-Fos/c-Jun, to the TF promoter. Inhibition of TF in endotoxemia and sepsis models reduces activation of coagulation and improves survival. Studies with endotoxemic mice showed that hematopoietic cells and myeloid cells play major roles in the activation of coagulation. Monocyte TF expression is also increased after surgery. Activated monocytes release TF-positive extracellular vesicles (EVs) and levels of circulating TF-positive EVs are increased in endotoxemic mice and in patients with sepsis. More recently, it was shown that inflammasomes contribute to the induction of TF expression and activation of coagulation in endotoxemic mice. Taken together, these studies indicate that monocyte TF plays a major role in activation of coagulation. Selective inhibition of monocyte TF expression may reduce pathologic activation of coagulation in sepsis and other diseases without affecting hemostasis.

Increased Risk of In-Hospital Complications and Costs After Total Hip Arthroplasty for Primary and Secondary Osteonecrosis

BACKGROUND

An increasing proportion of patients are undergoing total hip arthroplasty (THA) for osteonecrosis (ON). Comorbid conditions and surgical risk factors are known to be greater in ON patients compared with patients who have osteoarthritis (OA) alone. The purpose of our study was to quantify the specific in-hospital complications and resource utilization associated with patients undergoing THA for ON versus OA.

METHODS

A large national database was queried to identify patients undergoing primary THA from January 1, 2016 to December 31, 2019. A total of 1,383,880 OA, 21,080 primary ON, and 54,335 secondary ON patients were identified. Demographics, in-hospital complications, costs, lengths of stay, and discharge dispositions for primary and secondary ON cohorts were compared to OA only. Age, race, ethnicity, comorbidities, Medicaid, and income status were controlled with binary logistic regression analyses.

RESULTS

The ON patients were often younger, African American or Hispanic, and had more comorbidities. Those undergoing THA for primary and secondary ON had a significantly higher risk of perioperative complications, including myocardial infarction, postoperative blood transfusion, and intraoperative bleeding. Total hospital costs and lengths of stay were significantly higher for both primary ON and secondary ON and both cohorts were less likely to be discharged home.

CONCLUSION

While rates of most complications have decreased over recent decades in ON patients undergoing THA, the ON patients still have worse outcomes even when controlling for comorbidity differences. Bundled payment systems and perioperative management strategies for these different patient cohorts should be considered separately.

Development and validation of a novel nomogram to predict the risk of the prolonged postoperative length of stay for lumbar spinal stenosis patients

BACKGROUND

Lumber spinal stenosis (LSS) is the increasingly reason for spine surgery for elder patients since China is facing the fastest-growing aging population. The aim of this research was to create a model to predict the probabilities of requiring a prolonged postoperative length of stay (PLOS) for lumbar spinal stenosis patients, minimizing the healthcare burden.

METHODS

A total of 540 LSS patients were enrolled in this project. The outcome was a prolonged PLOS after spine surgery, defined as hospitalizations ≥ 75th percentile for PLOS, including the day of discharge. The least absolute shrinkage and selection operator (LASSO) was used to identify independent risk variables related to prolonged PLOS. Multivariable logistic regression analysis was utilized to generate a prediction model utilizing the variables employed in the LASSO approach. The receiver operating characteristic (ROC) curve's area under the curve (AUC) and the calibration curve's respective curves were used to further validate the model's calibration with predictability and discriminative capabilities. By using decision curve analysis, the resulting model's clinical effectiveness was assessed.

RESULTS

Among 540 individuals, 344 had PLOS that was within the usual range of P75 (8 days), according to the interquartile range of PLOS, and 196 had PLOS that was above the normal range of P75 (prolonged PLOS). Four variables were incorporated into the predictive model, named: transfusion, operation duration, blood loss and involved spine segments. A great difference in clinical scores can be found between the two groups (P < 0.001). In the development set, the model's AUC for predicting prolonged PLOS was 0.812 (95% CI: 0.768-0.859), while in the validation set, it was 0.830 (95% CI: 0.753-0.881). The calibration plots for the probability showed coherence between the expected probability and the actual probability both in the development set and validation set respectively. When intervention was chosen at the potential threshold of 2%, analysis of the decision curve revealed that the model was more clinically effective.

CONCLUSIONS

The individualized prediction nomogram incorporating five common clinical features for LSS patients undergoing surgery can be suitably used to smooth early identification and improve screening of patients at higher risk of prolonged PLOS and minimize health care.

Venous Thromboembolism Prophylaxis in Major Orthopedic Surgeries and Factor XIa Inhibitors

Venous thromboembolism (VTE), comprising pulmonary embolism (PE) and deep vein thrombosis (DVT), poses a significant risk during and after hospitalization, particularly for surgical patients. Among various patient groups, those undergoing major orthopedic surgeries are considered to have a higher susceptibility to PE and DVT. Major lower-extremity orthopedic procedures carry a higher risk of symptomatic VTE compared to most other surgeries, with an estimated incidence of ~4%. The greatest risk period occurs within the first 7-14 days following surgery. Major bleeding is also more prevalent in these surgeries compared to others, with rates estimated between 2% and 4%. For patients undergoing major lower-extremity orthopedic surgery who have a low bleeding risk, it is recommended to use pharmacological thromboprophylaxis with or without mechanical devices. The choice of the initial agent depends on the specific surgery and patient comorbidities. First-line options include low-molecular-weight heparins (LMWHs), direct oral anticoagulants, and aspirin. Second-line options consist of unfractionated heparin (UFH), fondaparinux, and warfarin. For most patients undergoing knee or hip arthroplasty, the initial agents recommended for the early perioperative period are LMWHs (enoxaparin or dalteparin) or direct oral anticoagulants (rivaroxaban or apixaban). In the case of hip fracture surgery, LMWH is recommended as the preferred agent for the entire duration of prophylaxis. However, emerging factor XI(a) inhibitors, as revealed by a recent meta-analysis, have shown a substantial decrease in the occurrence of VTE and bleeding events among patients undergoing major orthopedic surgery. This discovery poses a challenge to the existing paradigm of anticoagulant therapy in this specific patient population and indicates that factor XI(a) inhibitors hold great promise as a potential strategy to be taken into serious consideration.

Higher Complication Rate in COVID-19 Recovered Patients Undergoing Primary Total Joint Arthroplasty

BACKGROUND

There is limited data reviewing complication risks associated with total joint arthroplasty (TJA) after recovering from COVID-19. This study evaluated complications within 90 days of TJA in patients who had a COVID-19 diagnosis at varying intervals prior to surgery vs a non-COVID-19 cohort.

METHODS

A large national database was used to identify patients diagnosed with COVID-19 in the six months prior to total hip arthroplasty (THA) or total knee arthroplasty (TKA). The incidence of complications within 90 days of surgery was recorded and compared to a COVID-19 negative control group matched 1:3 for age range in 5-year intervals, Charlson Comorbidity Index, and sex. There were 7,780 patients included in the study; 5,840 (75.1%) never diagnosed with COVID-19, 1,390 (17.9%) who had a COVID-19 diagnosis 0 to 3 months prior to surgery, and 550 (7.1%) who had a COVID-19 diagnosis 3 to 6 months prior to surgery.

RESULTS

When compared to their COVID negative controls, patients who had a COVID-19 diagnosis 0 to 3 months prior to surgery had significantly higher rates of re-admission (14.0 vs 11.1%, P=.001), pneumonia (2.2 vs 0.7%, P<.001), deep vein thrombosis (3.3 vs 1.9%, P=.001), kidney failure (2.4 vs 1.4%, P=.006), and acute respiratory distress syndrome (1.4 vs 0.7%, P=.01). Patients who had a COVID-19 diagnosis 3 to 6 months prior to surgery had significantly higher rates of pneumonia (2.0 vs 0.7%, P=.002) and deep vein thrombosis (3.6 vs 1.9%, P=.005) when compared to their COVID negative controls.

CONCLUSION

Patients diagnosed with COVID-19 within three months prior to TJA have an increased risk of 90-day postoperative complications. Risk for pneumonia and deep vein thrombosis remains elevated even when surgery was performed as far as 3 to 6 months after COVID-19 diagnosis.

Pharmacology of Heparin and Related Drugs: An Update

Heparin has been used extensively as an antithrombotic and anticoagulant for close to 100 years. This anticoagulant activity is attributed mainly to the pentasaccharide sequence, which potentiates the inhibitory action of antithrombin, a major inhibitor of the coagulation cascade. More recently it has been elucidated that heparin exhibits anti-inflammatory effect via interference of the formation of neutrophil extracellular traps and this may also contribute to heparin's antithrombotic activity. This illustrates that heparin interacts with a broad range of biomolecules, exerting both anticoagulant and nonanticoagulant actions. Since our previous review, there has been an increased interest in these nonanticoagulant effects of heparin, with the beneficial role in patients infected with SARS2-coronavirus a highly topical example. This article provides an update on our previous review with more recent developments and observations made for these novel uses of heparin and an overview of the development status of heparin-based drugs. SIGNIFICANCE STATEMENT: This state-of-the-art review covers recent developments in the use of heparin and heparin-like materials as anticoagulant, now including immunothrombosis observations, and as nonanticoagulant including a role in the treatment of SARS-coronavirus and inflammatory conditions.

Advances in Mesenchymal Stem Cell Therapy for Osteoarthritis: From Preclinical and Clinical Perspectives

The prevalence of osteoarthritis (OA), a degenerative disorder of joints, has substantially increased in recent years. Its key pathogenic hallmarks include articular cartilage destruction, synovium inflammation, and bone remodeling. However, treatment outcomes are unsatisfactory. Until recently, common therapy methods, such as analgesic and anti-inflammatory treatments, were aimed to treat symptoms that cannot be radically cured. Mesenchymal stem cells (MSCs), i.e., mesoderm non-hematopoietic cells separated from bone marrow, adipose tissue, umbilical cord blood, etc., have been intensively explored as an emerging technique for the treatment of OA over the last few decades. According to existing research, MSCs may limit cartilage degradation in OA by interfering with cellular immunity and secreting a number of active chemicals. This study aimed to examine the potential mechanism of MSCs in the treatment of OA and conduct a thorough review of both preclinical and clinical data.

Tranexamic acid is safe and effective in patients with heterozygous factor V Leiden mutation during total joint arthroplasty

INTRODUCTION

Patients with an inherent hypercoagulable state are at a higher risk of venous thromboembolism (VTE) following total joint arthroplasty (TJA). Further administration of tranexamic acid (TXA) during TJA may increase the risk of VTE in these high-risk patients. There is no study that specifically analyzes the safety and efficacy of TXA during TJA in patients with factor V Leiden (FVL) mutation; therefore, the purpose of this study was to evaluate the safety and efficacy of TXA use on the risk of VTE and bleeding in patients carrying FVL mutation.

MATERIALS AND METHODS

A total of 42 patients with FVL mutation (22 hips, 20 knees) and 40 control patients (20 hips, 20 knees) who underwent TJA were retrospectively reviewed. All patients received 1 g TXA intravenously 15 min before the skin incision and 2 g of TXA was administered locally at the surgical site as a periarticular injection. Pharmacological thromboprophylaxis (low-molecular-weight heparin) was administered to all patients. Estimated blood loss and in-hospital thromboembolic complications were compared between the groups.

RESULTS

In both total knee arthroplasty (TKA) and total hip arthroplasty (THA) patients, there was no significant difference in the amount of estimated blood loss among the groups (p = 0.980, and p = 0963, respectively). None of the patients in the THA group received a blood transfusion. The transfusion rate was similar in the TKA group (p = 0.756, one patient in each group). No VTE, myocardial infarction, or any other complications related to TXA use were observed in any of the patients.

CONCLUSIONS

The combined local and systemic administration of TXA could be safely used in patients with heterozygous FVL mutation receiving pharmacological thromboprophylaxis during TJA without increasing the risk of VTE.

Predicting prolonged postoperative length of stay risk in patients undergoing lumbar fusion surgery: Development and assessment of a novel predictive nomogram

Objective

The purpose of this study was to develop and internally validate a prediction nomogram model in patients undergoing lumbar fusion surgery.

Methods

A total of 310 patients undergoing lumbar fusion surgery were reviewed, and the median and quartile interval were used to describe postoperative length of stay (PLOS). Patients with PLOS &gt; P75 were defined as prolonged PLOS. The least absolute shrinkage and selection operator (LASSO) regression was used to filter variables for building the prolonged PLOS risk model. Multivariable logistic regression analysis was applied to build a predictive model using the variables selected in the LASSO regression model. The area under the ROC curve (AUC) of the predicting model was calculated and significant test was performed. The Kappa consistency test between the predictive model and the actual diagnosis was performed. Discrimination, calibration, and the clinical usefulness of the predicting model were assessed using the C-index, calibration plot, and decision curve analysis. Internal validation was assessed using the bootstrapping validation.

Results

According to the interquartile range of PLOS in a total of 310 patients, the PLOS of 235 patients was ≤P75 (7 days) (normal PLOS), and the PLOS of 75 patients was &gt; P75 (prolonged PLOS). The LASSO selected predictors that were used to build the prediction nomogram included BMI, diabetes, hypertension, duration of surgery, duration of anesthesia, anesthesia type, intraoperative blood loss, sufentanil for postoperative analgesia, and postoperative complication. The model displayed good discrimination with an AUC value of 0.807 (95% CI: 0.758–0.849, P &lt; 0.001), a Kappa value of 0.5186 (cutoff value, 0.2445, P &lt; 0.001), and good calibration. A high C-index value of 0.776 could still be reached in the interval validation. Decision curve analysis showed that the prolonged PLOS nomogram was clinically useful when intervention was decided at the prolonged PLOS possibility threshold of 3%.

Conclusions

This study developed a novel nomogram with a relatively good accuracy to help clinicians access the risk of prolonged PLOS in lumbar fusion surgery patients. By an estimate of individual risk, surgeons and anesthesiologists may shorten PLOS and accelerate postoperative recovery of lumbar fusion surgery through more accurate individualized treatment.

Venous and Arterial Thrombosis in Ambulatory and Discharged COVID-19 Patients: A Systematic Review and Meta-analysis

Introduction  Venous and arterial thromboses are frequently observed complications in patients with severe novel coronavirus disease 2019 (COVID-19) infection who require hospital admission. In this study, we evaluate the epidemiology of venous and arterial thrombosis events in ambulatory and postdischarge patients with COVID-19 infection.

Materials and Method  EMBASE and MEDLINE were searched up to July 21, 2021, in addition to other sources. We included studies that assessed the epidemiology of venous and arterial thrombosis events in ambulatory and postdischarge COVID-19 patients.

Results  A total of 16 studies (102,779 patients) were identified. The overall proportion of venous thromboembolic events in all patients, that is, ambulatory and postdischarge, was 0.80% (95% confidence interval [CI]: 0.44–1.28), 0.28% (95% CI: 0.07–0.64), and 1.16% (95% CI: 0.69–1.74), respectively. Arterial events occurred in 0.75% (95% CI: 0.27–1.47) of all patients, 1.45% (95% CI: 1.10–1.86) of postdischarge patients, and 0.23% (95% CI: 0.019–0.66) of ambulatory patients. The pooled incidence rate estimates per 1,000 patient-days for VTE events were 0.06 (95% CI: 0.03–0.08) and 0.12 (95% CI: 0.07–0.19) for outpatients and postdischarge, respectively, whereas for arterial events were 0.10 (95% CI: 0–0.30) and 0.26 (95% CI: 0.16–0.37).

Conclusion  This study found a low risk of venous and arterial thrombi in ambulatory and postdischarge COVID-19 patients, with a higher risk in postdischarge patients compared with ambulatory patients. This suggests that regular universal thromboprophylaxis in these patient populations is probably not necessary.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Prophylaxis for Venous Thromboembolic Events in Elective Total Hip and Total Knee Arthroplasty

Venous thromboembolism (VTE) is a serious complication after major orthopaedic operations, such as a total hip (THA) and knee (TKA) arthroplasty. Therefore, perioperative VTE prophylaxis is recommended; a multitude of modern options are available, including both pharmacologic (aspirin, unfractionated and lowmolecular-weight heparin, vitamin K antagonists, and novel oral anticoagulants) and/or mechanical interventions (early mobilization, graduated compression stockings, intermittent pneumatic compression devices, and venous foot pumps). However, because of the abundance of these possibilities, it is crucial to understand the benefits and drawbacks of each VTE prophylaxis option to ensure that the optimal treatment plan is developed for each patient. The American College of Chest Physicians (AACP) and the American Academy of Orthopaedic Surgeons (AAOS) have both published individual guidelines on VTE prophylaxis regimens, alongside numerous studies evaluating the efficacy and outcomes of the different prophylaxis modalities. The purpose of this review is to provide a summary of the evidence on VTE prophylaxis after elective total hip and knee arthroplasty based on current guidelines and highlight the major concerns and potential complications.

Total knee arthroplasty in patients with severe obesity provides value for money despite increased complications

AIMS

Access to total knee arthroplasty (TKA) is sometimes restricted for patients with severe obesity (BMI ≥ 40 kg/m²). This study compares the cost per quality-adjusted life year (QALY) associated with TKA in patients with a BMI above and below 40 kg/m² to examine whether this is supported.

METHODS

This single-centre study compared 169 consecutive patients with severe obesity (BMI ≥ 40 kg/m²) (mean age 65.2 years (40 to 87); mean BMI 44.2 kg/m² (40 to 66); 129/169 female) undergoing unilateral TKA to a propensity score matched (age, sex, preoperative Oxford Knee Score (OKS)) cohort with a BMI < 40 kg/m² in a 1:1 ratio. Demographic data, comorbidities, and complications to one year were recorded. Preoperative and one-year patient-reported outcome measures (PROMs) were completed: EuroQol five-dimension three-level questionnaire (EQ-5D-3L), OKS, pain, and satisfaction. Using national life expectancy data with obesity correction and the 2020 NHS National Tariff, QALYs (discounted at 3.5%), and direct medical costs accrued over a patient's lifetime, were calculated. Probabilistic sensitivity analysis (PSA) was used to model variation in cost/QALY for each cohort across 1,000 simulations.

RESULTS

All PROMs improved significantly (p < 0.05) in both groups without differences between groups. Early complications were higher in BMI ≥ 40 kg/m²: 34/169 versus 52/169 (p = 0.050). A total of 16 (9.5%) patients with a BMI ≥ 40 kg/m² were readmitted within one year with six reoperations (3.6%) including three (1.2%) revisions for infection. Assuming reduced life expectancy in severe obesity and revision costs, TKA in patients with a BMI ≥ 40 kg/m² costs a mean of £1,013/QALY (95% confidence interval £678 to 1,409) more over a lifetime than TKA in patients with BMI < 40 kg/m². In PSA replicates, the maximum cost/QALY was £3,921 in patients with a BMI < 40 kg/m² and £5,275 in patients with a BMI ≥ 40 kg/m².

CONCLUSION

Higher complication rates following TKA in severely obese patients result in a lifetime cost/QALY that is £1,013 greater than that for patients with BMI < 40 kg/m², suggesting that TKA remains a cost-effective use of healthcare resources in severely obese patients where the surgeon considers it appropriate. Cite this article: Bone Joint J 2022;104-B(4):452-463.

Effect of Comorbidity Burden on the Risk of Venous Thromboembolic Events After Total Knee Arthroplasty

Background

Venous thromboembolic events (VTEs) are common after total knee arthroplasty (TKA). The rate of VTEs has improved with early mobilization, mechanical prophylaxis, and appropriate chemoprophylaxis. The aim of this study was to analyze the contribution of medical comorbidities to the risk of VTE after TKA

Method

Medicare claims from 2005 to 2014 were queried. International Classification of Diseases, Ninth revision (ICD-9), and Current Procedural Terminology codes were used to identify the diagnoses, procedures, and complications. 157,200 primary TKAs were age, sex, and Elixhauser Comorbidity Index (ECI) matched with 157,200 osteoarthritis controls. First instances of deep venous thrombosis (DVT) and pulmonary embolism were tracked at 90 days and 2 years. Odds ratios (ORs), confidence intervals, and P-values (p) were calculated and used to investigate the contribution of comorbidities.

Results

90 days after TKA or OA diagnosis, comorbidities were associated with 45% of the DVT risk, 38% of the PE risk. 1 in 92 patients would be expected to be diagnosed with VTE after TKA and 1 in 136 patients after only the diagnosis of osteoarthritis. After 90 days, medical comorbidities were associated with 70% of the DVT risk, 68% of the PE risk.

Conclusion

Nearly 50% of DVTs and 40% of PEs within 90 days of TKA may be related to the baseline health of OA patients. Venous thromboembolic events after TKA are a “never” event according to Center of Medicare and services that appropriate VTE prophylaxis likely cannot be neutralized.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Efficacy and Safety of Mechanical IVC Filtration for Preventing Pulmonary Embolism in High-Risk Orthopedic Patients Undergoing Total Hip or Knee Arthroplasty

BACKGROUND

To determine the efficacy and safety of inferior vena cava (IVC) filters in preventing pulmonary embolism (PE) in high-risk patients undergoing hip or knee arthroplasty.

METHODS

2857 hip or knee arthroplasty procedures between January 2013 and December 2018 were retrospectively reviewed. Patients with a preoperative history of venous thromboembolism (VTE), either PE or deep venous thrombosis (DVT), were categorized as high-risk patients. The incidence of overall VTE, PE, and DVT were compared between patients with filters and those without. The subgroup analysis was also performed by patient risk, and filter status and the incidence of VTE, PE, and DVT were compared. Variables such as filter placement, history of hypercoagulability etcetra were evaluated as risk factors for the development of postoperative VTE.

RESULTS

In the high-risk group, the use of IVC filters was significantly associated with a lower incidence of pulmonary embolism (0.8% vs 5.5%, P = .028). When compared with the low-risk group, the high-risk group had significantly higher incidence of PE (3.8% vs 2.0%, P = .038), DVT (11.6% vs 5.3%, P < .001), and overall VTE (15.0% vs 6.8%, P < .001). The history of VTE was associated with postoperative VTE (P < .001), PE (P = .042), and DVT (P < .001). There was no significant correlation between filter placement and postoperative VTE, DVT, or PE in the low-risk group. Filter retrieval was successful in 100% (96/96) of attempted patients with no complications.

CONCLUSION

The use of IVC filters is significantly associated with a lower incidence in pulmonary embolism in high-risk arthroplasty patients. High-risk patients demonstrated an incidence of postoperative VTE over two times greater than other patients. Prophylactic placement of IVC filters in hip/knee arthroplasty is safe.

Antipsychotic Use Is Associated With Longer In-hospital Lengths of Stay and Higher Rates of Venous Thromboembolism and Costs of Care After Primary Total Knee Arthroplasty

INTRODUCTION

Studies have shown that antipsychotic medication use may lead to venous thromboembolisms (VTEs); however, this association has not been demonstrated in patients undergoing primary total knee arthroplasty (TKA). Therefore, the purpose of this study was to investigate whether patients taking antipsychotic medications at the time of their primary TKA have higher rates of in-hospital lengths of stay (LOS), VTEs, and costs of care.

METHODS

Patients taking antipsychotic medications were identified and matched to a cohort in a 1:5 ratio by age, sex, and medical comorbidities. Patients who had a history of VTEs or hypercoagulable states before their TKA were excluded. The query resulted in 439,579 patients within the study (n = 73,285) and matching cohorts (n = 366,294). Outcomes analyzed included rates of in-hospital LOS, VTEs, and costs of care. A P value less than 0.01 was considered statistically significant.

RESULTS

We found statistically significant longer in-hospital LOS for patients taking antipsychotic medications (3.27 versus 3.02 days, P < 0.0001). Study patients were also found to have a higher incidence and odds ratio of VTEs (2.37 versus 1.04%; odds ratio: 1.86, 95% confidence interval: 1.75-1.97, P < 0.0001). Ninety-day costs of care were also significantly higher in the study cohort ($17,332.70 versus $15,975.00, P < 0.0001).

CONCLUSION

After adjusting for confounders, patients taking antipsychotic medication were found to have higher rates of in-hospital LOS, VTEs, and costs of care. The study can be used by orthopaedic surgeons to counsel patients taking these medications concerning the potential complications after their procedure.

Clinical factors associated with adverse outcomes in the acute period of management of submassive pulmonary embolism

The majority of patients with intermediate-to-severe submassive pulmonary embolism are hemodynamically stable upon presentation. There is a lack of evidence for the clinical relevance and safety of initially employed therapies in this population. The objective of current analysis was to determine predictors associated with adverse outcomes in submassive pulmonary embolism patients. This was a single-center, retrospective chart review identifying patient characteristics and clinical factors associated with adverse outcomes within the management of patients presenting to the emergency department for submassive pulmonary embolism. A total of 122 admissions for submassive pulmonary embolism were included. Among these patients, 41% (n = 50) of admissions had an adverse outcomes. Fluid volume was associated with adverse events in an incremental manner (odds ratio 2.1, 95% confidence interval, 1.4-3.2). These findings demonstrate a significant incidence of adverse events in patients with submassive pulmonary embolism and an incremental increase in likelihood of adverse events with each liter of fluid.

Is Apixaban Safe and Effective for Venous Thromboembolism Prophylaxis After Primary Total Hip and Total Knee Arthroplasties?

BACKGROUND

Venous thromboembolism (VTE) is a serious complication of total hip arthroplasty (THA) and total knee arthroplasty (TKA). Apixaban is approved for VTE prophylaxis. This study seeks to ascertain the risk of VTE and bleeding complications in patients undergoing primary THA and TKA receiving apixaban for postoperative VTE prophylaxis for one of the following indications: high risk for VTE, previously on apixaban, and contraindication to the use of aspirin.

METHODS

This is a retrospective cohort study of patients who underwent primary THA or TKA over a 17-month period and were prescribed apixaban for thromboprophylaxis postoperatively.

RESULTS

230 patients were included in the study, 110 TKA and 120 THA. The primary reasons for high-risk VTE status included personal and family history of VTE, and 13% were taking apixaban preoperatively for atrial fibrillation. 1 patient (0.43%) who underwent TKA had a DVT with PE. 2.6% of patients had wound complications requiring operative treatment, and 0.87% of THA patients underwent revision arthroplasty.

CONCLUSION

The use of apixaban for VTE prophylaxis after primary THA and TKA in patients at high risk for VTE, in patients previously on apixaban, and in patients with a contraindication to the use of aspirin is associated with a low risk of VTE and bleeding complications.

Effectiveness and Safety of Direct Oral Anticoagulants Versus Warfarin in Patients With Valvular Atrial Fibrillation : A Population-Based Cohort Study

BACKGROUND

Direct oral anticoagulants (DOACs) are increasingly used in place of warfarin, but evidence about their effectiveness and safety in patients with valvular atrial fibrillation (AF) remains limited.

OBJECTIVE

To assess the effectiveness and safety of DOACs compared with warfarin in patients with valvular AF.

DESIGN

New-user retrospective propensity score-matched cohort study.

SETTING

U.S.-based commercial health care database from 1 January 2010 to 30 June 2019.

PARTICIPANTS

Adults with valvular AF who were newly prescribed DOACs or warfarin.

MEASUREMENTS

The primary effectiveness outcome was a composite of ischemic stroke or systemic embolism. The primary safety outcome was a composite of intracranial or gastrointestinal bleeding.

RESULTS

Among a total of 56 336 patients with valvular AF matched on propensity score, use of DOACs (vs. warfarin) was associated with lower risk for ischemic stroke or systemic embolism (hazard ratio [HR], 0.64 [95% CI, 0.59 to 0.70]) and major bleeding events (HR, 0.67 [CI, 0.63 to 0.72]). The results for the effectiveness and safety outcomes remained consistent for apixaban (HRs, 0.54 [CI, 0.47 to 0.61] and 0.52 [CI, 0.47 to 0.57], respectively) and rivaroxaban (HRs, 0.74 [CI, 0.64 to 0.86] and 0.87 [CI, 0.79 to 0.96], respectively); with dabigatran, results were consistent for the major bleeding outcome (HR, 0.81 [CI, 0.68 to 0.97]) but not for effectiveness (HR, 1.03 [CI, 0.81 to 1.31]).

LIMITATION

Relatively short follow-up; inability to ascertain disease severity.

CONCLUSION

In this comparative effectiveness study using practice-based claims data, patients with valvular AF who were new users of DOACs had lower risks for ischemic stroke or systemic embolism and major bleeding than new users of warfarin. These data may be used to guide risk-benefit discussions regarding anticoagulant choices for patients with valvular AF.

PRIMARY FUNDING SOURCE

None.

Apixaban or enoxaparin: Which is better for thromboprophylaxis after total hip and total knee arthroplasty in Indian patients?

Both apixaban and enoxaparin are Food and Drug Administration-approved standard therapy for prophylaxis of deep-vein thrombosis; however, the superiority of one over the other is still controversial. With an objective to observe efficacy and safety outcomes of apixaban and enoxaparin in patients undergoing total hip (THA) and knee (TKA) arthroplasty, 96 patients undergoing THA/TKA (October 2018 to August 2019) were randomly allocated into 2 groups; (n = 48) apixaban; and (n = 48) enoxaparin. Efficacy outcomes and safety outcomes were recorded at 2 and 5 weeks post-TKA/THA. Follow-up functional scoring was done at 6 months postoperatively. Apixaban and enoxaparin were found to be equally efficacious in preventing venous thromboembolism; however, apixaban had a better safety profile. The apixaban group had nonsignificant higher tendency for wound discharge, atrial fibrillation and transient ischaemic attack. Enoxaparin had nonsignificant greater tendency for bleeding, wound dehiscence and pulmonary complications. Apixaban is a safe alternative to conventionally used enoxaparin for chemoprophylaxis in patients undergoing THA or TKA.

A Basic Intervention to Improve Compliance With Thromboprophylaxis in Patients With Neck of Femur Fracture

Background: Venous thromboembolism (VTE) is a significant complication following orthopedic intervention for neck of femur fracture. Our aim was to evaluate compliance with The National Institute for Health and Care Excellence guidance surrounding VTE prophylaxis before and after a brief intervention in an orthopedic department at a district general hospital. Methods: A 2-cycle quality improvement project was conducted. The primary outcome measure was whether adequate thromboprophylaxis was appropriately prescribed. For the intervention between the 2 cycles, posters were placed in key prescribing areas of all orthopedic wards. Results: In cycle 1, 63 (76.8%) patients were correctly prescribed enoxaparin, and 14 (17.1%) were prescribed other anticoagulants, leaving 5 patients (6.1%) who did not receive thromboprophylaxis for no apparent reason. In cycle 2, 56 (87.5%) patients were correctly prescribed enoxaparin, and the remaining patients were covered with alternative therapies. Conclusion: Small but basic interventions can lead to improvements in VTE prophylaxis prescribing. Future focus should be on implementing similar interventions across hospitals.

Thromboembolic disease in hypercortisolism

PURPOSE OF REVIEW

Endogenous Cushing's syndrome (CS) is associated with increased patient morbidity (hypertension, diabetes mellitus, dyslipidemia, visceral obesity, osteoporosis, cognitive alterations, and impaired quality of life). Both arterial and venous thromboembolic events (TE) due to alterations in the hemostatic system and prothrombotic state are widely reported in patients with CS, more so postoperatively. Increased mortality, if not appropriately treated, is largely due to cardiovascular events and infections.

RECENT FINDINGS

Patients with CS have markedly increased risk of thromboembolic episodes compared to the general population. The prothrombotic state is mediated by increased levels of procoagulant factors, but also by an impaired fibrinolytic capacity. All contribute to TE, atherosclerosis, and subsequent cardiovascular morbidity and mortality. Some abnormalities progressively improve after CS remission, but do not fully normalize for at least 1 year or more.

SUMMARY

Due to the additional thrombotic risk of surgery or any invasive procedure, anticoagulation prophylaxis should be at least considered in patients with CS and balanced with individual bleeding risk. However, a clear protocol of thromboprophylaxis is lacking and increased awareness regarding risks per se is needed. Large prospective trials will clarify, which patients with CS are at the highest risk and the optimal prevention protocol to minimize risks and maximize efficacy.

Postoperative thromboprophylaxis does not reduce the incidence of thromboembolic events after ACL reconstruction

INTRODUCTION

Anterior cruciate ligament (ACL) reconstructive surgery is one of the most common ligament-related surgeries performed in France. The French Society of Anesthesia & Intensive Care Medicine (SFAR) recommends the systematic use of low-molecular weight heparin postoperatively to prevent venous thromboembolisms (VTE). However, these recommendations differ from one country to another; several national societies do not recommend them. To specify the benefits of such a treatment, we did a retrospective case-control study to evaluate the incidence of symptomatic VTE after ACL reconstruction. Hypothesis We hypothesized that the rate of symptomatic VTE would be the same, whether a course of postoperative anticoagulants is prescribed or not.

METHODS

This was a retrospective, multicenter, multi-surgeon study. Of the four participating surgeons, two never prescribed thromboprophylaxis after surgery while the other two always prescribed a 10-day course of low-molecular weight heparin. All patients who underwent primary ACL reconstruction using an autologous graft between the 1st of January 2019 and the 15th of February 2020 were included. The 535 patients who had undergone ACL reconstruction were divided into two groups: (Group 1) 279 patients in the group without anticoagulants; 96% received a four-strand semi-tendinosus graft (ST4) and 4% received a quadriceps tendon (QT) graft; the mean age of these patients was 30 years (14-58); 41% of them were women and 22% of them were smokers; the mean body mass index was 24.4 (18-37); the mean tourniquet time was 37minutes. (Group 2) 256 patients in the group with anticoagulants; 81% received a semi-tendinosus/gracilis graft, 15% received a ST4 and 4% a QT; the mean age of these patients was 29 years (14-60); 38% of them were women and 21% of them were smokers; the mean body mass index was 25.0 (18-38); the mean tourniquet time was 34minutes. The two groups were comparable in all respects except for the type of graft used. All patients were contacted at a minimum interval of 3 months after their surgery, by telephone. Doppler ultrasonography was done solely when a VTE was suspected.

RESULTS

In the group without anticoagulants, 249 of 279 patients were contacted, while in the group with anticoagulants, 221 of 256 were contacted. The two groups were comparable in terms of age, gender ratio, tourniquet time, body mass index and proportion of smokers. Two cases of deep vein thrombosis (all in the calf region) were found in each group with no associated pulmonary embolism. There was no difference between groups in the VTE rate.

DISCUSSION

Our hypothesis was confirmed since the incidence of symptomatic VTE was the same whether postoperative anticoagulants were prescribed or not. The incidence of symptomatic VTE after ACL reconstruction was identical whether thromboprophylaxis was used or not. This casts doubt on the need for postoperative thromboprophylaxis, especially in younger patients who do not have risk factors, and brings into question whether the recommendations in France should be changed.

LEVEL OF EVIDENCE

III (retrospective case-control study).

Venous thromboembolism prophylaxis in high-risk orthopedic and cancer surgery

Orthopedic surgery and surgery for cancer are major risk factors for venous thromboembolism (VTE). Deep vein thrombosis (DVT) can occur in up to 50% of patients after major orthopedic surgery. The rate of VTE after cancer surgery varies according to the type of surgery, with rates as high as those after orthopedic surgery in certain settings. Use of thromboprophylaxis in these high-risk settings is well established and recent studies inform the type and duration of thromboprophylaxis. With major orthopedic surgery, there has been a shift from use of low molecular weight heparins (LMWHs) to direct oral anticoagulants (DOACs) along with renewed interest in aspirin as a thromboprophylaxis agent. Recent studies have also informed optimal thromboprophylaxis strategies after nonmajor orthopedic surgery. Use of thromboprophylaxis after major cancer surgery for cancer is established and recent evidence has focused on the potential benefits of extended-duration thromboprophylaxis. This review will summarize emerging evidence for thromboprophylaxis after orthopedic and cancer surgery with a view to providing clinicians with concise and actionable guidance for best practice.

Tranexamic acid in patients with current or former cancer undergoing hip and knee arthroplasty

BACKGROUND AND OBJECTIVES

While tranexamic acid (TXA) is an excellent mechanism to reduce blood loss in arthroplasty, its safety in cancer patients-who could potentially benefit the most from blood conservation-is unknown.

METHODS

A multicenter, retrospective review of current or former cancer patients undergoing hip/knee arthroplasty from 2014 to 2019 was performed. The use of intravenous TXA, indication (oncologic/degenerative), cancer state, cancer type, surgical factors, demographics, and comorbidities were collected. The association between TXA use and 90-day/1-year complications was analyzed with multivariable logistic regressions.

RESULTS

We identified 282 patients with current (87.9%) or former (12.1%) malignancies undergoing arthroplasty (73.0% oncologic/27.0% degenerative). About 74 (26.2%) patients received TXA (52.7% had oncologic indications, 74.3% had active cancer). In adjusted analysis, TXA was not associated with increased risk of venous thromboembolism within 90-days (odds ratio [OR] 0.59; 95% confidence interval [CI] 0.16-2.16, p = 0.43) or 1-year (OR 0.47; 95%CI 0.15-1.44, p = 0.19), with a trend towards lower risk. Similar results were seen for mortality and wound complications, and when stratifying by indication.

CONCLUSION

TXA was not associated with increased complications in current or former cancer patients undergoing arthroplasty. Future randomized studies of TXA in arthroplasty should include cancer patients; in the interim, clinicians should weigh the theoretical risks of TXA with the known benefits of reduced blood loss in oncology patients.

Aspirin versus enoxaparin for the initial prevention of venous thromboembolism following elective arthroplasty of the hip or knee: A systematic review and meta-analysis

BACKGROUND

Aspirin is perceived to be non-inferior to enoxaparin, a low-molecular-weight heparin, for the prevention of venous thromboembolism (VTE) following elective arthroplasty of the hip or knee and is recommended in clinical guidelines internationally. Previous systematic reviews of aspirin as VTE prophylaxis have been limited by the inclusion of heterogenous studies where aspirin is commenced after the initial high-risk postoperative period. The purpose of this systematic review and meta-analysis was to compare the efficacy and associated harms of aspirin and enoxaparin when used as VTE prophylaxis in the initial postoperative period following elective arthroplasty of the hip or knee. We sought to: (1) to compare the use of aspirin versus enoxaparin following elective joint replacement of the hip or knee on the primary outcomes of incidence of VTE and mortality up to 3 months postoperatively and (2) assess the efficacy of aspirin with respect to secondary outcomes such as major or minor bleeding events. We hypothesised that aspirin would have equivalent efficacy for the prevention of VTE when used as initial prophylactic agent, without increasing harm from bleeding events.

PATIENTS AND METHODS

We searched Pubmed, Embase, Medline and Cochrane Central for randomized controlled trials reporting the primary outcomes of VTE incidence and mortality. Secondary outcomes included major (compromise of organ, limb or muscle function requiring unplanned re-operation) and minor bleeding events (wound ooze, minor bleed, infection). Included trials underwent a risk of bias and quality of evidence assessment using the GRADE criteria.

RESULTS

Four trials involving 1507 participants who underwent elective lower limb arthroplasty were included. We did not detect a significant difference in overall VTE rates when comparing aspirin versus enoxaparin (RR, 0.84; 95% CI: 0.41 to 1.75; p=0.65). Mortality was reported by one study and no events were recorded. There were no significant differences in the rates of all major (RR, 0.84; 95% CI: 0.08 to 9.16) or minor (RR, 0.77; 95% CI: 0.34 to 1.72) bleeding events between the aspirin and enoxaparin groups. Included trials demonstrated a significant risk of bias, and Low to Very Low quality of evidence for primary outcomes, and Moderate to Very Low for secondary outcomes.

CONCLUSION

There is currently a lack of high quality randomised controlled trials supporting the use of aspirin as VTE chemoprophylaxis in the initial postoperative period for both total hip and total knee arthroplasty. The results of this meta-analysis provide cautious endorsement for the position that aspirin is likely a safe alternative to enoxaparin for TKA patients as part of a multimodal enhanced recovery protocol, but care is advised for THA patients owing to a lack of data from trials. Current evidence from randomized controlled trials is generally of low quality, and does not estimate critical event data for VTE incidence or mortality, as well as major and minor bleeding events with sufficient certainty. PROSPERO Registration CRD42018110784.

LEVEL OF EVIDENCE

II, systematic review.

Bleeding complications of thromboprophylaxis with dabigatran, nadroparin or rivaroxaban for 6 weeks after total knee arthroplasty surgery: a randomised pilot study

OBJECTIVES

For the non-vitamin-K oral anticoagulants, data on bleeding when used for 42 days as thromboprophylaxis after total knee arthroplasty (TKA) are scarce. This pilot study assessed feasibility of a multicentre randomised clinical trial to evaluate major and clinically relevant non-major bleeding during 42-day use of dabigatran, nadroparin and rivaroxaban after TKA.

PATIENTS AND METHODS

In 70 weeks, between July 2012 and November 2013, 198 TKA patients were screened for eligibility in the Martini Hospital (Groningen, the Netherlands). Patients were randomly assigned to dabigatran (n=45), nadroparin (n=45) or rivaroxaban (n=48). The primary outcome was the combined endpoint of major bleeding and clinically relevant non-major bleeding. Secondary endpoints of this study were the occurrence of clinical venous thromboembolism (VTE) (pulmonary embolism or deep venous thrombosis), compliance, duration of hospital stay, rehospitalisation, adverse events and Knee Injury and Osteoarthritis Outcome Score (KOOS).

RESULTS

The primary outcome was observed in 33.3% (95% CI 20.0% to 49.0%), 24.4% (95% CI 12.9% to 39.5%) and 27.1% (95% CI 15.3% to 41.8%) of patients who received dabigatran, nadroparin or rivaroxaban, respectively (p=0.67). Major bleeding was found in two patients who received nadroparin (p=0.21). Clinically relevant non-major bleeding was observed in 33.3% (95% CI 20.0% to 49.0%), 22.2% (95% CI 11.2% to 37.1%) and 27.1% (95% CI 15.3% to 41.8%) for dabigatran, nadroparin and rivaroxaban, respectively (p=0.51). Wound haematoma was the most observed bleeding event. VTE was found in one patient who received dabigatran (p=0.65). The presurgery and postsurgery KOOS qQuestionnaires were available for 32 (71%), 35 (77%) and 35 (73%) patients for dabigatran, nadroparin and rivaroxaban, respectively. KOOS was highly variable, and no significant difference between treatment groups in mean improvement was observed.

CONCLUSIONS

A multicentre clinical trial may be feasible. However, investments will be substantial. No differences in major and clinically relevant non-major bleeding events were found between dabigatran, nadroparin and rivaroxaban during 42 days after TKA. KOOS may not be suitable to detect functional loss due to bleeding.

TRIAL REGISTRATION NUMBER

NCT01431456.

Delayed pulmonary embolism after unicompartmental knee arthroplasty: A case report

INTRODUCTION

Although venous thromboembolism (VTE) is relatively rare after unicompartmental knee arthroplasty (UKA), symptomatic pulmonary embolism (PE) can be fatal. Whether routine thromboprophylaxis or thrombolytic treatment is necessary for patients undergoing UKA remains unclear. Here, we present a case of delayed pulmonary embolism after UKA.

PATIENT CONCERNS

A 57-year-old women underwent cemented UKA for left localized medial knee pain. There were no risk factors of VTE besides high BMI before surgery. 2 months after surgery, the patient presented with dyspnea and palpitation, and these symptoms could not be alleviated after rest.

DIAGNOSIS

An arterial blood gas analysis showed decreased PO2, SO2 and PCO2. Pulmonary CTA showed multiple pulmonary embolism in the trunk of the right lower pulmonary artery and the branch of the left lower pulmonary arteries. The final diagnosis was delayed pulmonary embolism after UKA.

INTERVENTIONS

Urokinase thrombolysis was administered intravenously. Low molecular weight heparin and warfarin were prescribed for anticoagulation.

OUTCOMES

The patient's symptoms abated, and chest CTA showed that the pulmonary embolism had dissolved. No further thrombosis has been observed for more than 6 years.

CONCLUSIONS

We presented an unusual case of delayed pulmonary embolism after UKA. Despite the low incidence, its life-threatening nature makes it imperative for surgeons to be well-informed about thrombosis and pay more attention to its prevention strategies.

Thromboprophylaxis for orthopedic surgery; An updated meta-analysis

BACKGROUND

Venous thromboembolism (VTE) is a serious complication of orthopedic surgery. Low molecular weight heparin (LMWH) has been the standard of care for thromboprophylaxis in this population. However, direct oral anticoagulants (DOACs) are increasingly being used as alternatives.

OBJECTIVE

To assess the efficacy and safety of DOACs versus LMWH for thromboprophylaxis in orthopedic surgery.

METHODS

We searched MEDLINE, Embase, and the Cochrane Collaboration Central Register of Controlled Trials from inception until April 2020, for randomized controlled trials (RCTs) comparing DOACs with LMWH for thromboprophylaxis in orthopedic surgery.

RESULTS

Twenty-five RCTs met inclusion criteria, including 40,438 patients, with a mean age of 68 years and 50% were males. Compared to LMWH, DOACs were associated with a significant reduction of major VTE; defined as the composite events of proximal deep vein thrombosis (DVT), pulmonary embolism (PE), and VTE-related mortality (RR 0.33; 95% CI: 0.20-0.53; P<0.01), and total DVT (RR: 0.59; 95% CI: 0.48-0.73; P<0.01), but not PE (RR 0.81; 95% CI: 0.49-1.34; P=0.42). There was no statistically significant difference between both groups on the incidence of major bleeding (RR 0.99; 95% CI: 0.77-1.27; P=0.92), clinically relevant non-major bleeding (RR 1.04; 95% CI: 0.92-1.17; P=0.52), all-cause mortality (RR 1.06; 95% CI: 0.64-1.76; P=0.83), VTE-related mortality (RR 0.84; 95% CI: 0.40-1.74; P=0.64) and bleeding-related mortality (RR 1.24; 95% CI: 0.30-5.18; P=0.77).

CONCLUSION

For patients undergoing orthopedic surgery, thromboprophylaxis with DOACs is associated with a significant reduction of major VTE and DVT, compared to LMWH. Safety outcomes were not significantly different between both treatment groups.

The incidence of venous thromboembolism in total joint replacement during COVID-19 pandemic: has lockdown had an influence?

Aims

As the first wave of the COVID-19 pandemic began to dip, restarting elective orthopaedics became a challenge. Protocols including surgery at ‘green’ sites, self-isolation for 14 days, and COVID-19 testing were developed to minimize the risk of transmission. In this study, we look at risk effects of 14-day self-isolation on the incidence of venous thromboembolism (VTE) in our green site hospital among patients undergoing total joint replacement (TJR).

Methods

This retrospective cohort study included 50 patients who underwent TJR. Basic demographic data was collected including, age, sex, American Society of Anesthesiologists (ASA) grade, body mass index (BMI), type of surgery, and complications at two and four weeks. Univariate and multivariate analysis were used to identify risk factors associated with an increased risk of VTE.

Results

A total of 50 patients were included in our study, with 24 males and 26 females. The mean age was 67.86 (SD 11.803). Overall, 8% of patients suffered a VTE complication; symptomatic non-fatal pulmoary embolism was confirmed in 6% of patients (n = 3) as an inpatient, and symptomatic deep vein thrombosis was diagnosed in 2% of patients (n = 1) within two weeks of their operation. All patients were found to be female (p < 0.001), had a BMI > 30 (p = 0.317), and were immobile prior to their operation using walking aids (p = 0.016).

Conclusion

The incidence we report is much higher than the reported incidence in the literature, which we believe is related to the 14-day self-isolation period and immobility prior to their operation. We recommend that all patients undergoing TJR that require a period of self-isolation, are pre-assessed prior to self-isolation for their risk of VTE, potentially using mechanical and chemical prophylaxis to reduce the likelihood of developing VTE.

Cite this article: Bone Jt Open 2020;1-12:751–756.

Perioperative Venous Thromboembolism Prophylaxis

Venous thromboembolism (VTE) is a preventable cause of postoperative morbidity and mortality; however, audits suggest that the use of thromboprophylaxis is underused. In this review, we describe our approach to prevention of postoperative VTE and provide guidance on how to formulate an optimal VTE prophylaxis plan. We recommend that all patients undergo thrombosis- and bleeding-risk assessment as part of their preoperative evaluation. The risk of thrombosis can be estimated based on patient- and procedure-specific factors, using validated risk-assessment models such as the Caprini score. There are no validated models to predict perioperative bleeding; however, several risk factors have been proposed. Patients should ambulate early and frequently after surgery. We recommend no additional prophylaxis in patients at very low risk of VTE (Caprini score 0). Patients at low risk of VTE (Caprini 1 to 2) are recommended to receive either mechanical or pharmacological prophylaxis. Patients at moderate (Caprini 3 to 4) to high risk of VTE (Caprini ≥5) are recommended pharmacological prophylaxis either alone or combined with mechanical prophylaxis. Patients at high risk of bleeding should receive mechanical prophylaxis until their risk of bleeding is reduced and pharmacological prophylaxis can be reconsidered. Populations for which the Caprini score has not been validated (such as orthopedic surgery) are recommended prophylaxis based on individual and procedure-specific risk factors. Prophylaxis is typically continued until the patient is ambulatory or until hospital dismissal; however, longer durations can be considered in certain circumstances (high-risk patients undergoing malignant abdominopelvic operations, bariatric operations, and certain orthopedic operations).

Venous Thromboembolic Events after Total Knee Arthroplasty: Which Patients Are at a High Risk?

Venous thromboembolism (VTE; deep venous thrombosis and pulmonary embolism) is a known complication following primary total knee arthroplasty (TKA). The aim of this study was to investigate the trends of the incidence of VTE after primary TKA and identify associated risk factors for the occurrence of VTEs in a large cohort of TKA patients. We performed a retrospective study in which the Nationwide Inpatient Sample (NIS) database was used to identify all patients who underwent primary TKA over a period of 13 consecutive years (between 2002 and 2014) in the United States. The occurrence of a symptomatic VTE was identified with the use of ICD-9-CM (International Classification of Diseases, Ninth Revision, Clinical Modification) diagnosis codes. A total of 1,460,901 primary TKA procedures were identified in the NIS from 2002 to 2014, and 12,944 of these patients were recorded as having 13,855 VTEs, consisting of 7,609 deep venous thromboses (0.52%) and 6,246 pulmonary emboli (0.43%). The overall VTE incidence in patients undergoing TKA in the United States from 2002 to 2014 was 0.89%. Patient-related risk factors for VTEs include an older age (odds ratio [OR]: 1.44; 95% confidence interval [CI]: 1.31-1.59), black race (OR: 1.34; 95% CI: 1.25-1.44), and Medicare insurance (OR: 1.18; 95% CI: 1.13-1.22). Most of the comorbidities were associated with an increased risk of VTE following TKA. Particularly, cardiac arrhythmias, coagulopathy, fluid and electrolyte disorders, pulmonary circulation disorders, and weight loss increased the risk of VTE by more than twofold. After adjusting for confounders, VTE was associated with a longer hospital stay (2.81 ± 0.02 day), increased costs (US$14,212.16 ± US$255.64), and higher mortality rate (OR: 13.04; 95% CI: 11.08-15.35). This nationally representative study of inpatients in the United States identified several independent risk factors for VTE perioperatively in TKA patients and provided evidence that VTE patients after TKA are likely to have worse results than non-VTE patients with regard to the length of hospital stay, hospital costs, and inhospital mortality. This is a level III, prognostic study.

Regenerative Therapy for Osteoarthritis: A Perspective

Osteoarthritis (OA) is the most common type of arthritis and causes a significant deterioration in patients’ quality of life. The high prevalence of OA as well as the current lack of disease-modifying drugs led to a rise in regenerative medicine efforts. The hope is that this will provide a treatment modality with the ability to alter the course of OA via structural modifications of damaged articular cartilage (AC). Regenerative therapy in OA starts with the concept that administered cells may engraft to a lesion site and differentiate into chondrocytes. However, recent studies show that cells, particularly when injected in suspension, rapidly undergo apoptosis after exerting a transient paracrine effect. If the injected stem cells do not lead to structural improvements of a diseased joint, the high cost of cell therapy for OA cannot be justified, particularly when compared with other injection therapeutics such as corticosteroids and hyaluronic acid. Long-term survival of implanted cells that offer prolonged paracrine effects or possible engraftment is essential for a successful cell therapy that will offer durable structural improvements. In this perspective review, the history and current status of regenerative therapy in OA are summarized along with the conceptual strategy and future directionsfor a successful regenerative therapy that can provide structural modifications in OA.