Risk of venous thrombosis after arthroscopy of the knee: results from a large population-based case-control study

Osteoarthritis: Insights into Diagnosis, Pathophysiology, Therapeutic Avenues, and the Potential of Natural Extracts

Osteoarthritis (OA) stands as a prevalent and progressively debilitating clinical condition globally, impacting joint structures and leading to their gradual deterioration through inflammatory mechanisms. While both non-modifiable and modifiable factors contribute to its onset, numerous aspects of OA pathophysiology remain elusive despite considerable research strides. Presently, diagnosis heavily relies on clinician expertise and meticulous differential diagnosis to exclude other joint-affecting conditions. Therapeutic approaches for OA predominantly focus on patient education for self-management alongside tailored exercise regimens, often complemented by various pharmacological interventions primarily targeting pain alleviation. However, pharmacological treatments typically exhibit short-term efficacy and local and/or systemic side effects, with prosthetic surgery being the ultimate resolution in severe cases. Thus, exploring the potential integration or substitution of conventional drug therapies with natural compounds and extracts emerges as a promising frontier in enhancing OA management. These alternatives offer improved safety profiles and possess the potential to target specific dysregulated pathways implicated in OA pathogenesis, thereby presenting a holistic approach to address the condition's complexities.

Risk factors for venous thromboembolism following knee arthroscopy: A systematic review and meta-analysis of observational studies

Objectives

To evaluate the risk factors for increased risk of venous thrombosis after arthroscopic knee surgery.

Methods

PubMed, EMBASE and Cochrane Library were searched from their inception to April 4, 2023. Observational studies investigated venous thrombosis following arthroscopic knee surgery were included. The Newcastle Ottawa Scale (NOS) was used to evaluate the methodological quality of included studies. The odd ratios (ORs) and 95% confidence intervals (CIs) pertaining to each risk factor were synthesized through a random effects model by STATA 14 software.

Results

The protocol this meta-analysis has been registered on PROSPERO (CRD42023410283). A total of 22 observational studies were included in the systematic review, all of which were of moderate or high methodological quality. The results of the meta-analysis revealed that several factors were significantly associated with an elevated risk of venous thrombosis following arthroscopic knee surgery. These factors included age (mean age ≥30 years) [OR = 1.08, 95%CI (1.04, 1.13), P = 0.001], overweight or obesity [OR = 1.31, 95%CI (1.13, 1.52), P＜0.001], oral contraceptive use [OR = 1.90, 95%CI (1.52, 2.37), P＜0.001], and smoking history [OR = 1.35, 95%CI (1.06, 1.71), P = 0.014]. Furthermore, the subgroup analysis indicated that patients with an average age over 50 years [OR = 3.18, 95%CI (1.17, 8.66), P = 0.001] and those who underwent surgery with a tourniquet for ≥90 min [OR = 4.79, 95%CI (1.55, 14.81), P = 0.007] were at a significantly increased risk of venous thrombosis after knee arthroscopy.

Conclusion

Age, obesity, oral contraceptives, smoking history, and prolonged tourniquet use may increase the risk of venous thrombosis after arthroscopic knee surgery. The incidence of venous thrombosis after knee arthroscopy is on a downward trend, but due to its severity, increasing awareness of risk factors and implementing effective prophylaxis are important tasks for clinicians to prevent the risk of venous thrombosis after knee arthroscopy.

Complications of Factor V Leiden in Adults Undergoing Noncardiac Surgical Procedures: A Systematic Review

Factor V Leiden is the commonest hereditary prothrombotic allele, affecting 1% to 5% of the world's population. The objective of this study was to characterize the perioperative and postoperative outcomes of patients with Factor V Leiden compared to patients without a diagnosis of hereditary thrombophilia. This was a focused systematic review of studies including adult (>18 years) patients with Factor V Leiden (heterozygous or homozygous) undergoing noncardiac surgery. Included studies were either randomized controlled trials or observational. The primary clinical outcomes of interest were thromboembolic events occurring from the perioperative period up to 1 year postoperatively, defined as deep venous thrombosis, pulmonary embolism, or other clinically significant thrombosis occurring during or after a surgical procedure. Secondary outcomes included cerebrovascular events, cardiac events, death, transplant-related outcomes, and surgery-specific morbidity. Pediatric and obstetrical patients were excluded, as were case reports and case series. Databases searched included MEDLINE and EMBASE from inception until August 2021. Study bias was assessed through the CLARITY (Collaboration of McMaster University researchers) Risk of Bias tools, and heterogeneity through analysis of study design and end points, as well as the I 2 statistic with its confidence interval and the Q statistic. A total of 5275 potentially relevant studies were identified, with 115 having full text assessed for eligibility and 32 included in the systematic review. On the whole, the literature suggests that patients with Factor V Leiden have an increased risk of perioperative and postoperative thromboembolic events compared to patients without the diagnosis. Increased risk was also seen in relation to surgery-specific morbidity and transplant-related outcomes, particularly arterial thrombotic events. The literature did not support an increased risk for mortality, cerebrovascular, or cardiac complications. Limitations of the data include predisposition toward bias due in many study designs and small sample sizes across the majority of published studies. Variable outcome definitions and durations of patient follow-up across different surgical procedures resulted in high study heterogeneity precluding the effective use of meta-analysis. Factor V Leiden status may confer additional risk for surgery-related adverse outcomes. Large, adequately powered studies are required to accurately estimate the degree of this risk by zygosity.

The efficacy and safety of low-molecular-weight heparin in patients undergoing knee arthroscopic surgery and anterior cruciate ligament reconstruction

Purpose

To inveatigate how effective LMWH was at preventing venous thromboembolism (VTE), major bleeding events, and minor bleeding events after simple knee arthroscopic surgery and anterior cruciate ligament reconstruction (ACLR).

Methods

We conducted a comprehensive search of PubMed, EMBASE, Cochrane Library, and the CNKI database for potentially eligible articles. The outcomes were evaluated in terms of odds ratio (OR) and the associated 95% confidence intervals (CIs). Meta-analysis was performed using the Stata software and subgroup analyses were performed based on the surgical setting including ACLR and simple knee arthroscopic surgery.

Results

A total of eight studies with 2249 patients and 1794 controls were included in this meta-analysis. In patients undergoing simple knee arthroscopic surgery, LMWH prophylaxis did not bring a significant reduction in the risk of symptomatic deep venous thrombosis (DVT), symptomatic pulmonary embolism (PE), symptomatic VTE, and did not increase the risk of major bleeding events, but did have a higher risk of minor bleeding events (OR = 1.95, 95% CI 1.34-2.84, P = 0.000) and a lower risk of asymptomatic DVT (OR = 0.14, 95% CI 0.04-0.53, P = 0.004) in comparison with non-LMWH prophylaxis. In patients undergoing ACLR, LMWH prophylaxis did not bring a significant reduction in the risk of symptomatic DVT, symptomatic PE, symptomatic VTE, and did not increase the risk of major bleeding events and minor bleeding events, but did have a lower risk of asymptomatic DVT (OR = 0.43, 95% CI 0.23-0.78, P = 0.006).

Conclusion

When compared to a control group, this meta-analysis found that LMWH had little potential benefit in preventing major VTE (symptomatic VTE, symptomatic DVT, and symptomatic PE) after simple knee arthroscopy and ACLR. As a result, LMWH should not be considered routinely in patients undergoing knee arthroscopic surgery.

The influence of lower-leg injury and knee arthroscopy on natural anticoagulants and fibrinolysis

BACKGROUND

Patients with lower-leg injuries and those undergoing knee arthroscopy are at increased risk of developing venous thromboembolism. The mechanism is unknown, including the influence of lower-leg injury and knee arthroscopy on natural anticoagulant factors and fibrinolysis.

OBJECTIVES

To study the effect of lower-leg injury and knee arthroscopy on plasma levels of anticoagulant and fibrinolytic factors.

METHODS

We applied the following 2 designs to investigate this effect: a cross-sectional study for lower-leg trauma and a before-and-after study for knee arthroscopy. Plasma samples of POT-CAST- and POT-KAST-randomized clinical trial participants (collected shortly after lower-leg trauma or before or after arthroscopy) were analyzed for clot lysis time and levels of antithrombin, tissue factor pathway inhibitor, protein C, free protein S, plasminogen, tissue plasminogen activator, plasminogen activator inhibitor 1, antiplasmin, thrombin activatable fibrinolysis inhibitor, plasmin-antiplasmin, and D-dimer. For the effect of lower-leg injury, samples of 289 patients were compared with preoperative samples of 293 arthroscopy patients, acting as controls using linear regression and adjusting for age, sex, body mass index, comorbidities, and diurnal variation. For the effect of knee arthroscopy, mean changes were calculated for 277 patients using linear mixed models adjusted for diurnal variation. Parameters other than CLT and D-dimer were measured in smaller subsets.

RESULTS

In lower-leg injury patients, most parameters were stable, whereas D-dimer increased. After arthroscopy, most parameters decreased (especially clot lysis time, D-dimer, plasminogen, and anticoagulant factors), whereas tissue plasminogen activator and thrombin activatable fibrinolysis inhibitor slightly increased.

CONCLUSION

In contrast to lower-leg injury, knee arthroscopy was associated with decreased natural anticoagulant factor levels. Neither lower-leg injury nor knee arthroscopy affected in vivo fibrinolysis.

Perioperative Thromboprophylaxis Is Associated With Lower Risk of Venous Thromboembolism After Knee Arthroscopy

PURPOSE

To determine the rate of symptomatic venous thromboembolism (VTE) among patients undergoing arthroscopic knee procedures, risk factors associated with postoperative VTE, and current perioperative thromboprophylaxis prescription patterns associated with this population in the United States.

METHODS

Medical records for patients ≥18 years of age were queried from the Mariner database using Current Procedural Terminology codes for knee arthroscopy performed in the United States from 2010 to 2020 in this cross-sectional study. Patients who received thromboprophylaxis and those diagnosed with VTE, including deep-vein thrombosis or pulmonary embolism, within 90 days of surgery were identified using International Classification of Diseases and National Drug Codes. Two multivariable logistic regression models were used to identify VTE risk factors and likelihood of perioperative thromboprophylaxis. Covariates included procedure type, age, oral contraceptive pill (OCP) use, and medical comorbidities.

RESULTS

A total of 718,289 patients met inclusion criteria and 7,618 patients (1.06%) experienced VTE, including deep-vein thrombosis (n = 6,394, 0.9%) and/or pulmonary embolism (n = 2,211, 0.3%). A total of 10,769 patients (1.5%) filled perioperative thromboprophylaxis, including aspirin (n = 5,353, 0.7%), low-molecular-weight heparin (n = 4,563, 0.6%), and oral factor Xa inhibitors (n = 947, 0.1%). Perioperative thromboprophylaxis was associated with decreased odds of experiencing VTE (adjusted odds ratio [aOR] 0.65, 95% confidence interval [CI] 0.51-0.80). Procedure types categorized as moderate-to-greater risk were associated with increased odds of VTE (aOR 1.42, 95% CI 1.34-1.50). OCP use (aOR 1.63, 95% CI 1.38-1.91), obesity (aOR 1.17, 95% CI 1.11-1.24), renal disease (aOR 1.33, 95% CI 1.18-1.50) and congestive heart failure (aOR 1.30, 95% CI 1.13-1.50) were associated with increased odds of VTE.

CONCLUSIONS

While the overall rate of symptomatic VTE following knee arthroscopy remains low, procedure types that are more complex and generally require restrictive rehabilitation protocols, OCP use, obesity, renal disease, and congestive heart failure are associated with increased odds of postoperative VTE. Conversely, the use of perioperative thromboprophylaxis is associated with significantly lower VTE risk.

LEVEL OF EVIDENCE

III, retrospective comparative prognostic trial.

Effect of lower‐leg trauma and knee arthroscopy on procoagulant phospholipid‐dependent activity

Background

Lower-leg injury and knee arthroscopy are both associated with venous thromboembolism (VTE). The mechanism of VTE in both situations is unknown, including the role of procoagulant microparticles. This may provide useful information for individualizing thromboprophylactic treatment in both patient groups.

Objective

We aimed to study the effect of (1) lower-leg trauma and (2) knee arthroscopy on procoagulant phospholipid-dependent (PPL) activity plasma levels.

Methods

POT-(K)CAST trial participants who did not develop VTE were randomly selected for the current study. Plasma was collected shortly after lower-leg trauma or before and after knee arthroscopy. For aim 1, samples of 67 patients with lower-leg injury were compared with control samples (preoperative samples of 74 patients undergoing arthroscopy). Linear regression was used to obtain mean ratios (natural logarithm retransformed data), adjusted for age, sex, body mass index, infections, and comorbidities. For aim 2, pre- and postoperative samples of 49 patients undergoing arthroscopy were compared using paired t tests. PPL activity was measured using modified activated factor X-dependent PPL clotting assay.

Results

For aim 1, PPL activity levels were almost threefold higher in patients with lower-leg injury compared with controls, that is, mean ratio, 2.82 (95% confidence interval [CI], 1.98-4.03). For aim 2, postoperative PPL activity levels did not change significantly, that is, mean change, -0.72 mU/mL (95% CI, -2.03 to 0.59).

Conclusion

Lower-leg trauma was associated with increased plasma levels of PPL activity, in contrast to knee arthroscopy. Lower-leg trauma triggers the release of procoagulant microparticles.

Does anterior cruciate ligament reconstruction increase venous thromboembolism risk compared with knee meniscectomy under arthroscopy?

Background

This study compared the incidence of postoperative venous thromboembolism (VTE) between meniscectomy and anterior cruciate ligament reconstruction (ACLR) under arthroscopy and assessed whether ACLR increases the VTE risk compared with meniscectomy.

Methods

A retrospective study of prospectively collected clinical data, including data on 436 patients ranging in age from 18 to 60 years who underwent ACLR or meniscectomy surgery, was performed between October 2018 and October 2019 in our hospital. All patients underwent routine VTE screening by venous ultrasonography in postoperative week 2 and then clinical follow-up at 4 and 6 weeks post-surgery. The incidence of VTE was calculated, and clinical factors such as age, sex, body mass index (BMI), smoking, concomitant procedure, Caprini score, and duration of tourniquet use were evaluated in relation to the risk factors for VTE.

Results

A total of 320 patients who underwent arthroscopic ACLR or meniscectomy were available for analysis. Of these patients, 130 (40.6%) underwent ACLR, and 190 (59.4%) underwent meniscectomy. No cases of pulmonary embolism (PE) or femoral deep vein thrombosis (DVT) were reported in either group. Fourteen patients (10.8%) developed VTE in the ACLR group compared with 10 (5.3%) in the meniscectomy group, with no significant difference (p = 0.066). Among these patients, 4 (3.1%) patients in the ACL reconstruction group and 2 (1.1%) patients in the meniscectomy group had DVT confirmed by Doppler ultrasound (p > 0.05). ACLR, age, and BMI (OR = 3.129; 1.061; 1.435) tended to increase the risk of VTE, but the results were not statistically significant (p = 0.056, 0.059, 0.054).

Conclusions

The incidence of VTE after ACLR and meniscectomy within 6 weeks post-surgery was 10.8 and 5.3%, respectively. ACLR, age, and BMI had a tendency to increase the risk of VTE.

Targeted proteomics for evaluating risk of venous thrombosis following traumatic lower-leg injury or knee arthroscopy

INTRODUCTION

Patients with lower-leg cast immobilization and patients undergoing knee arthroscopy have an increased risk of venous thrombosis (VT). Guidelines are ambiguous about thromboprophylaxis use, and individual risk factors for developing VT are often ignored. To assist in VT risk stratification and guide thromboprophylaxis use, various prediction models have been developed. These models depend largely on clinical factors and provide reasonably good C-statistics of around 70%. We explored using protein levels in blood plasma measured by multiplexed quantitative targeted proteomics to predict VT. Our aim was to assess whether a VT risk prediction model based on absolute plasma protein quantification is possible.

METHODS

We used internal standards to quantify proteins in less than 10 μl plasma. We measured 270 proteins in samples from patients scheduled for knee arthroscopy or with lower-leg cast immobilization. The two prospective POT-(K)CAST trails allow complementary views of VT signature in blood, namely pre and post trauma, respectively. From approximately 3000 patients, 31 patients developed VT who were included and matched with double the number of controls.

RESULTS

Top discriminating proteins between cases and controls included APOC3, APOC4, APOC2, ATRN, F13B, and F2 in knee arthroscopy patients and APOE, SERPINF2, B2M, F13B, AFM, and C1QC in patients with lower-leg cast. A logistic regression model with cross-validation resulted in C-statistics of 88.1% (95% CI: 85.7-90.6%) and 79.6% (95% CI: 77.2-82.0%) for knee arthroscopy and cast immobilization groups respectively.

CONCLUSIONS

Promising C-statistics merit further exploration of the value of proteomic tests for predicting VT risk upon additional validation.

Perioperative Management of Orthopaedic Patients with Hematologic Disorders: A Critical Analysis Review

Perioperative management of orthopaedic patients with a hematologic disorder is a complex endeavor that requires a multidisciplinary team-based approach. A team composed of an experienced orthopaedic surgeon, an anesthesiologist, and a hematologist is necessary to achieve optimal outcomes. Patients with hemophilia and other complex hematologic disorders should be managed at, or in consultation with a hematologist at, a comprehensive hemophilia center. Bleeding disorders and inherited thrombophilia present unique challenges for the perioperative management of orthopaedic surgery. Comprehensive preoperative planning and familiarity with treatment guidelines can help to minimize these risks. Knowledge of the disease processes outlined in this article will provide orthopaedic surgeons with the requisite background knowledge that is needed to initiate safe and effective treatment strategies involving this high-risk patient population.

A rare case of pulmonary embolus after arthroscopic meniscus surgery

Although there is consensus that thromboprophylaxis is necessary for major orthopedic surgeries such a joint replacement, there is no widespread consensus on the need for thromboprophylaxis for minor arthroscopic surgery. Here, we present a case of deep vein thrombosis (DVT) and pulmonary embolism (PE) after a common arthroscopic meniscectomy in a healthy 20-year-old female collegiate athlete. The patient had no risk factors except for prior use of combined oral contraceptive pills (COCPs). Twenty hours after an uncomplicated right knee meniscectomy, patient presented to ED with right calf pain and cramping, and DVT was confirmed using ultrasound. One week later, patient presented again to ED with dyspnea and chest pain. PE was diagnosed on CT angiography. Despite the rarity of thromboembolic complications in minor arthroscopy surgery, the broadened use of thromboprophylaxis in patients with even few risk factors could prevent thromboembolic complications from occurring.

High risk of venous thromboembolism after orthopedic surgery in patients with thrombophilia

OBJECTIVE

This study aimed at evaluating the effect of thrombophilia on the risk of venous thromboembolism (VTE) in patients undergoing any type of orthopedic surgery.

BACKGROUND

Patients undergoing orthopedic surgery are at high risk for VTE. Although patients with thrombophilia have an increased risk of VTE, it is currently unclear whether there is a synergetic effect in patients with thrombophilia who undergo orthopedic surgery.

METHODS

Data from a large population-based case-control study (the Multiple Environmental and Genetic Assessment [MEGA] of risk factors for venous thrombosis study) were used. Odds ratios (ORs) with 95% confidence intervals (CIs), adjusted for age, sex, and body mass index (BMI) (ORadj) were calculated for patients undergoing any orthopedic intervention.

RESULTS

Of 4721 cases and 5638 controls, 263 cases and 94 controls underwent orthopedic surgery. Patients who had any orthopedic intervention in the year before the index date were at higher risk of VTE (ORadj 3.7; 95% CI, 2.9-4.8) than those who did not undergo any orthopedic surgery. There was an additionally increased risk in patients with factor V Leiden (OR 17.5, 95% CI, 4.1-73.6), non-O blood group (OR 11.2; 95% CI, 3.4-34.0), or elevated plasma levels of factor VIII (OR 18.6; 95% CI, 7.4-46.9) all relative to patients without these defects, not undergoing orthopedic surgery.

CONCLUSIONS

Patients with factor V Leiden, high levels of factor VIII, or blood group non-O were found to have a high risk of VTE after orthopedic surgery. Identification of these patients may enable individualized thromboprophylactic treatment to efficiently reduce VTE risk.

Venous thromboembolism after lower extremity orthopedic surgery: A population-based nationwide cohort study

BACKGROUND

Venous thromboembolism (VTE) causes morbidity and mortality in the general population. Several events occur after lower limb orthopedic surgery, but the contribution from various types of lower limb surgery is not well known.

OBJECTIVE

To investigate the postoperative incidence of VTE for all types of lower extremity orthopedic surgery compared with the background population.

METHODS

Individual-level linkage of Danish nationwide register data for all Danish residents with first-time orthopedic surgery of the lower limb (1996-2017) and, for each of these, four controls from the general population matched on age, sex, and history of VTE. Adjusted hazard ratios (HR) compared the postoperative risk of VTE to the matched controls.

RESULTS

In total 7203 of the 1 012 823 patients with a first orthopedic procedure had a VTE within 180 days after surgery, corresponding to a postoperative cumulative incidence of 0.71% (95% confidence interval [CI], 0.70-0.73). The cumulative incidence of VTE among controls was 0.11% (95% CI, 0.11-0.12). The HR of VTE within the first 30 days after surgery below knee level was 20.5 (95% CI, 17.9-23.5) compared with matched controls. The HRs of VTE after minor distal procedures (eg, meniscectomy and arthroscopies) were 2.9 (95% CI, 1.9-4.4) to 7.1 (95% CI, 6.4-8.0).

CONCLUSION

All types of lower limb orthopedic surgery including minor distal procedures were associated with higher rates of VTE compared with matched controls, in particular within the first 30 days after surgery.

Preventing venous thrombo-embolism after nonmajor orthopedic surgery

The venous thromboembolism risk is low to moderate in nonmajor orthopedic surgery. The literature is unconclusive. New emerging data are now available. The global patient risk has to be taken into account to determine the need for any prophylaxis.

Prophylaxis of Venous Thromboembolism in Ankle and Foot Surgeries

Venous thromboembolism (VTE) is among the most feared complications by orthopedists both for due to its potentially lethal outcome and the uncertainties related to its prevention. Despite the vast literature on VTE prevention in major orthopedic surgeries, little is known about it in ankle and foot procedures. In orthopedics, adequate thromboprophylaxis requires a careful assessment of the thrombotic and hemorrhagic risks based on the procedure to be performed, as well as and knowledge on anticoagulant agents. The presentis review has the goal of assessing the risk of developingdiscusses VTE risk assessment, the modalities of thromboprophylaxis modalities, and the drugs used, with an emphasis on foot and ankle surgeries.

Different strategies for pharmacological thromboprophylaxis for lower-limb immobilisation after injury: systematic review and economic evaluation

BACKGROUND

Thromboprophylaxis can reduce the risk of venous thromboembolism (VTE) during lower-limb immobilisation, but it is unclear whether or not this translates into meaningful health benefit, justifies the risk of bleeding or is cost-effective. Risk assessment models (RAMs) could select higher-risk individuals for thromboprophylaxis.

OBJECTIVES

To determine the clinical effectiveness and cost-effectiveness of different strategies for providing thromboprophylaxis to people with lower-limb immobilisation caused by injury and to identify priorities for future research.

DATA SOURCES

Ten electronic databases and research registers (MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, Database of Abstracts of Review of Effects, the Cochrane Central Register of Controlled Trials, Health Technology Assessment database, NHS Economic Evaluation Database, Science Citation Index Expanded, ClinicalTrials.gov and the International Clinical Trials Registry Platform) were searched from inception to May 2017, and this was supplemented by hand-searching reference lists and contacting experts in the field.

REVIEW METHODS

Systematic reviews were undertaken to determine the effectiveness of pharmacological thromboprophylaxis in lower-limb immobilisation and to identify any study of risk factors or RAMs for VTE in lower-limb immobilisation. Study quality was assessed using appropriate tools. A network meta-analysis was undertaken for each outcome in the effectiveness review and the results of risk-prediction studies were presented descriptively. A modified Delphi survey was undertaken to identify risk predictors supported by expert consensus. Decision-analytic modelling was used to estimate the incremental cost per quality-adjusted life-year (QALY) gained of different thromboprophylaxis strategies from the perspectives of the NHS and Personal Social Services.

RESULTS

Data from 6857 participants across 13 trials were included in the meta-analysis. Thromboprophylaxis with low-molecular-weight heparin reduced the risk of any VTE [odds ratio (OR) 0.52, 95% credible interval (CrI) 0.37 to 0.71], clinically detected deep-vein thrombosis (DVT) (OR 0.40, 95% CrI 0.12 to 0.99) and pulmonary embolism (PE) (OR 0.17, 95% CrI 0.01 to 0.88). Thromboprophylaxis with fondaparinux (Arixtra®, Aspen Pharma Trading Ltd, Dublin, Ireland) reduced the risk of any VTE (OR 0.13, 95% CrI 0.05 to 0.30) and clinically detected DVT (OR 0.10, 95% CrI 0.01 to 0.94), but the effect on PE was inconclusive (OR 0.47, 95% CrI 0.01 to 9.54). Estimates of the risk of major bleeding with thromboprophylaxis were inconclusive owing to the small numbers of events. Fifteen studies of risk factors were identified, but only age (ORs 1.05 to 3.48), and injury type were consistently associated with VTE. Six studies of RAMs were identified, but only two reported prognostic accuracy data for VTE, based on small numbers of patients. Expert consensus was achieved for 13 risk predictors in lower-limb immobilisation due to injury. Modelling showed that thromboprophylaxis for all is effective (0.015 QALY gain, 95% CrI 0.004 to 0.029 QALYs) with a cost-effectiveness of £13,524 per QALY, compared with thromboprophylaxis for none. If risk-based strategies are included, it is potentially more cost-effective to limit thromboprophylaxis to patients with a Leiden thrombosis risk in plaster (cast) [L-TRiP(cast)] score of ≥ 9 (£20,000 per QALY threshold) or ≥ 8 (£30,000 per QALY threshold). An optimal threshold on the L-TRiP(cast) receiver operating characteristic curve would have sensitivity of 84-89% and specificity of 46-55%.

LIMITATIONS

Estimates of RAM prognostic accuracy are based on weak evidence. People at risk of bleeding were excluded from trials and, by implication, from modelling.

CONCLUSIONS

Thromboprophylaxis for lower-limb immobilisation due to injury is clinically effective and cost-effective compared with no thromboprophylaxis. Risk-based thromboprophylaxis is potentially optimal but the prognostic accuracy of existing RAMs is uncertain.

FUTURE WORK

Research is required to determine whether or not an appropriate RAM can accurately select higher-risk patients for thromboprophylaxis.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42017058688.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Thromboprophylactic Efficacy and Safety of Anticoagulants After Arthroscopic Knee Surgery: A Systematic Review and Meta-Analysis

To examine the efficacy and safety of anticoagulants after knee arthroscopy (KA), PubMed, EMBASE, databases of Cochrane Central Register of Controlled Trials, and Chinese National Knowledge Infrastructure were searched up to August 2019 for randomized controlled trials (RCT). Seven RCTs including 4097 patients were demonstrated eligible according to the inclusion and exclusion criteria. The efficacy and safety of thromboprophylaxis were assessed and expressed using relative risk (RR) and 95% confidence intervals (95% CIs). The analysis of pooled data showed that anticoagulants group exhibited significant lower overall incidence of symptomatic and asymptomatic venous thromboembolism (VTE; RR = 0.35, 95% CIs: 0.22-0.55, P < .00001), significant higher incidence of all bleeding events (RR = 1.42, 95% CIs: 1.08-1.86, P = .01) compared to control group. However, no significant difference was found in terms of incidence of symptomatic VTE (RR = 0.43, 95% CIs: 0.15-1.21, P = .11) and incidence of major bleeding events (RR = 1.87, 95% CIs: 0.40-8.67, P = .42). The pooled number needed to treat to prevent one symptomatic or asymptomatic VTE was 26, while the pooled number needed to harm to cause one major bleeding event was 869. These results show that anticoagulants can effectively reduce the overall risk of VTE after KA; however, the increased risk of bleeding should be fully considered. Further studies are required to address the risk–benefit calculus and cost-effectiveness of anticoagulants after KA.

Low-Molecular-Weight Heparin for the Prevention of Venous Thromboembolism in Patients Undergoing Knee Arthroscopic Surgery and Anterior Cruciate Ligament Reconstruction: A Meta-analysis of Randomized Controlled Trials

BACKGROUND

Low-molecular-weight heparin (LMWH) thromboprophylaxis is widely used for reducing the risk of thrombosis after major orthopaedic surgery. However, the effect and safety on knee arthroscopic surgery are still controversial.

PURPOSE

To assess the efficacy and safety of LMWH for the prevention of symptomatic venous thromboembolism (VTE) after knee arthroscopic surgery and anterior cruciate ligament reconstruction (ACLR) by conducting a meta-analysis of randomized controlled trials (RCTs).

STUDY DESIGN

Meta-analysis.

METHODS

The authors searched the electronic databases of MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), ClinicalTrials.gov , and Web of Science for all studies from inception to June 30, 2017. All selected studies were categorized into 2 subgroups: simple knee arthroscopic surgery and ACLR. The primary effect and safety endpoint were the incidence of major VTE and major bleeding events (BEs), respectively. The secondary effect and safety endpoint were the incidence of all VTE and all BEs, respectively. Relative risks (RRs) with 95% CIs were calculated using Review Manager 5.3.

RESULTS

Eight RCTs with 4113 patients were included. For patients undergoing simple knee arthroscopic surgery, LMWH prophylaxis did not bring a significant reduction in the risk of major VTE (RR, 1.00 [95% CI, 0.37-2.67]; P > .99) and all VTE (RR, 0.63 [95% CI, 0.31-1.29]; P = .21) and did not increase the risk of major BEs (RR, 0.98 [95% CI, 0.06-15.72]; P = .99) but did have a higher risk of all BEs (RR, 1.64 [95% CI, 1.18-2.28]; P = .003) in comparison with non-LMWH prophylaxis. For patients undergoing ACLR, LMWH prophylaxis was associated with a significantly lower rate of major VTE (RR, 0.23 [95% CI, 0.12-0.43]; P < .001) and all VTE (RR, 0.22 [95% CI, 0.06-0.73]; P = .01) but no increase in major BEs (RR, 1.80 [95% CI, 0.19-17.25]; P = .61) and all BEs (RR, 1.12 [95% CI, 0.72-1.74]; P = .61) in comparison with non-LMWH prophylaxis.

CONCLUSION

Compared with non-LMWH treatment, LMWH had no significant efficacy in preventing VTE in patients undergoing simple knee arthroscopic surgery but increased the risk of BEs. However, LMWH had significant efficacy in preventing VTE for patients mainly undergoing ACLR and did not increase the risk of BEs.

Symptomatic Deep Vein Thrombosis Following Elective Knee Arthroscopy Over the Age of 40

Thromboprophylaxis following arthroscopic knee surgery (AKS) is not clear in the literature. The purpose of this study was to present the incidence of symptomatic deep vein thrombosis (DVT) following elective AKS over the age of 40. The secondary purpose was to investigate risk factors associated with venous thromboembolic events (VTEs). Surgical database and outpatient clinic follow-up charts of the patients who underwent AKS for any reason were included in the study. Odds for risk factors such as previous medical history of thrombosis, any family history for clotting disorders, diabetes mellitus (DM), oral contraceptive usage, body mass index, history of malignancy, and smoking were evaluated. The incidence of DVT following AKS significantly increased in the patients older than 40 years who had a previous medical history of VTE, DM, and smoking. A variety of guidelines exist for VTE prophylaxis; however, one should focus on risk factors related to the patient’s medical history and current medical conditions. In this study, smoking, DM, and previous history of DVT increased DVT risk significantly, and thromboprophylaxis should be kept in mind for these patients.

The Importance of a Standardized Screening Tool to Identify Thromboembolic Risk Factors in Pediatric Lower Extremity Arthroscopy Patients

INTRODUCTION

Deep vein thrombosis and pulmonary embolism are major complications that can occur in common orthopaedic procedures such as knee arthroscopy. The purpose of this study is to determine the incidence of venous thromboembolism (VTE) risk factors in adolescent patients undergoing elective lower extremity arthroscopy. A second objective is to determine whether a targeted, standardized screening tool is both cost- and clinically effective in the identification of VTE risk factors in adolescents.

METHODS

A standardized VTE screening tool was prospectively administered to all elective arthroscopic procedures in a pediatric sports medicine practice. A comparison cohort that did not complete the screening tool was isolated through a retrospective chart review identifying VTE risk factors. The incidence and cost between the two cohorts were compared.

RESULTS

Of 332 subjects who did not receive a targeted screening (TS) tool, 103 risk factors were noted. One pulmonary embolism case was identified with a total incidence of 0.15% over 3 years. With TS, we identified 325 subjects with 134 identifiable risk factors. Six patients (1.8%) were noted to be very high risk, requiring consultation with hematology. No VTEs were reported. When compared with the retrospective review, TS identified 30% more risk factors. A significant increase in the identification of family history of blood clots (P < 0.001), history of previous blood clot (P = 0.059), recurrent miscarriages in the family (P = 0.010), and smoking exposure (P = 0.062) was found. Additionally, the total cost of screening was less than the cost of prophylaxis treatment with no screening ($20.98 versus $23.51 per person, respectively).

DISCUSSION

Risk factors for VTE may be present in 32.5% of elective adolescent arthroscopic patients. A TS model for VTE identified 30% more risk factors, especially a significant family history, and was shown to be a cost-effective way to safely implement a VTE prevention program.

LEVEL OF EVIDENCE

Level II.

Characteristics, treatment patterns and outcomes of patients presenting with venous thromboembolic events after knee arthroscopy in the RIETE Registry

Knee arthroscopy is the most common orthopedic procedure worldwide. While incidence of post-arthroscopy venous thromboembolic events (VTE) is low, treatment patterns and patient outcomes have not been described. Patients from the "Registro Informatizado Enfermedad TromboEmbolica" who had confirmed post-arthroscopy VTE were compared to patients with provoked, post bone-fracture, and to patients with unprovoked VTE. Baseline characteristics, presenting signs and symptoms, treatment and outcomes including recurrent VTE, bleeds or death were compared. A total of 101 patients with post-arthroscopy VTE and 19,218 patients with unprovoked VTE were identified. Post-arthroscopy patients were younger (49.5 vs. 66 years, P < 0.0001) and had less history of VTE [5.9% vs. 20%, OR 0.26 (0.11-0.59)]. Among patients with isolated DVT, there were fewer proximal DVT in the post-arthroscopy group [40% vs. 86%, OR 0.11 (0.06-0.19)]. Treatment duration was shorter in the post-arthroscopy group (174 ± 140 vs. 311 ± 340 days, P < 0.0001) and more often with DOAC [OR 3.67 (1.95-6.89)]. Recurrent VTE occurred in 6.18 (1.96-14.9) and 11.9 (11.0-12.8) per 100 patient years [HR 0.52 (0.16-1.26)] after treatment in the post-arthroscopy and unprovoked groups, respectively. Recurrent VTE occurred in 5.17 (1.31-14.1) per 100 patient years in a separate post bone-fracture group (n = 147), also not statistically different than the post-arthroscopy recurrence rate. After anticoagulation cessation, some patients post-knee arthroscopy develop VTE. While our small sample size precludes drawing firm conclusions, this signal should warrant further research into the optimal treatment duration for these patients, as some patients may be at increased risk for long-term recurrence.

Efficacy and safety of low-molecular-weight heparin after knee arthroscopy: A meta-analysis

Background

Venous thromboembolism (VTE) is considered a potentially serious complication of knee arthroscopy and leads to conditions such as deep venous thrombosis (DVT) and pulmonary embolism (PE). Low-molecular-weight heparin (LMWH) is widely employed in knee arthroscopy to reduce perioperative thromboembolic complications. However, the efficacy and safety of LMWH in knee arthroscopy remains unclear.

Methods

Seven randomized controlled clinical trials on LMWH in knee arthroscopy were identified and included in this meta-analysis. The main outcomes of the effectiveness (prevention of DVT and PE) and complications (death, major bleeding, and minor bleeding) of LMWH in knee arthroscopic surgery were assessed using Review Manager 5.3 software.

Results

The meta-analysis indicated that LMWH prophylaxis comprised 79% of asymptomatic DVT. No association was found in symptomatic VTE (RR: 0.90; 95% confidence interval [CI]: 0.39–2.08; P = 0.80), symptomatic DVT (RR: 0.79; 95% CI: 0.28–2.23; P = 0.66), symptomatic PE (RR: 1.36; 95% CI: 0.37–4.97; P = 0.64) and major bleeding (RR: 0.70; 95% CI: 0.12–3.95; P = 0.68) risk during LMWH prophylaxis were identified. Death was not reported in these studies. Moreover, there was a lower incidence of minor bleeding (RR: 0.64; 95% CI: 0.49 to 0.83; P = 0.001) in the control group than in the LMWH group.

Conclusion

Compared with the control group, the group treated with LMWH after knee arthroscopy was no association in reducing the symptomatic VTE rate, symptomatic DVT rate or symptomatic PE rate. The symptomatic VTE rate was 0.5% (11/2,166) in the LMWH group versus 0.6% (10/1,713) in the control group. Although the limitations of this meta-analysis cannot be ignored, the results of our study show that LMWH after knee arthroscopy is ineffective. We recommend that LMWH should not be routinely provided for knee arthroscopy.

Trial registration

ClinicalTrials.gov NCT03164746

No effectiveness of anticoagulants for thromboprophylaxis after non-major knee arthroscopy: a systemic review and meta-analysis of randomized controlled trials

Arthroscopic knee surgery is the most commonly performed orthopedic procedure worldwide and whether thromboprophylaxis should be undertaken after knee arthroscopy is still controversial. To evaluate the efficacy of thromboprophylaxis for deep venous thrombosis (DVT) and venous thromboembolism (VTE) after knee arthroscopic surgery. A meta-analysis was conducted using data from eight randomized trials (4148 patients) to compare thromboprophylaxis with placebo or no prophylactic treatment in patients undergoing knee arthroscopy. The benefits and harms of thromboprophylaxis were evaluated, including the incidence of asymptomatic DVT, symptomatic VTE, pulmonary embolism and anti-coagulation related adverse events. Thromboprophylaxis significantly decreased the incidence of DVT (95% CI 0.07-0.64, P = 0.006) and symptomatic VTE in patients undergoing knee arthroscopy (95% CI 0.23-0.76, P = 0.004), but not significantly decreased the incidence of pulmonary embolism (n.s.). Regarding to non-major knee arthroscopy surgery (simple surgical procedures without ligament reconstruction), no significant difference of the incidence of DVT or symptomatic VTE was noted between thromboprophylactic group and control group (n.s.). Thromboprophylactic treatment showed higher incidence rate of anti-coagulation related adverse events compared with the control group (95% CI 1.12-1.90, P = 0.005). There was no significant difference of the incidence of clinically relevant major bleeding between the two groups (n.s.). This meta-analysis indicates no effectiveness of thromboprophylaxis for preventing DVT or symptomatic VTE in patients undergoing non-major knee arthroscopy. Regarding to patient undergoing knee ligament construction, the thromboprophylactic strategy should mainly take into account the patient's risk factors.

Latest Innovations in the Treatment of Venous Disease

Venous disease is more common than peripheral arterial disease. Pathophysiologically, venous disease can be associated with obstruction, reflux, or both. A common feature in chronic venous disease is ambulatory venous hypertension. Inflammatory and pro-thrombotic mechanisms can be activated. The current therapies, including compression, ablation, and recanalization are discussed.

Efficacy of Rivaroxaban for thromboprophylaxis after Knee Arthroscopy (ERIKA)

Without thromboprophylaxis, knee arthroscopy (KA) carries a low to moderate risk of venous thromboembolism. Over 5 million arthroscopies are performed worldwide yearly. It was our study objective to assess the efficacy and safety of rivaroxaban for thromboprophylaxis after therapeutic KA. Patients undergoing KA in nine Italian teaching or community hospitals were allocated to once-daily rivaroxaban (10 mg) or placebo for seven days in a phase II, multicentre, double-blind, placebo-controlled randomised trial. The primary efficacy outcome was a composite of all-cause death, symptomatic thromboembolism and asymptomatic proximal DVT at three months; major bleeding represented the primary safety outcome. All patients underwent whole-leg ultrasonography at day 7(+1), or earlier if symptomatic. A total of 241 patients were randomised (122 rivaroxaban, 119 placebo), and 234 completed the study. The primary efficacy outcome occurred in 1/120 of the rivaroxaban group and in 7/114 of the placebo group (0.8% vs 6.1%, respectively, p=0.03; absolute risk difference, −5.3%, 95% CI, −11.4 to −0.8; crude relative risk 0.14, 95% CI, 0.02 to 0.83; number-needed-to-treat=19). No major bleedings were observed. We found no association between different arthroscopic procedures and thrombotic events. Small sample size, high exclusion rate, and low number of anterior cruciate ligament reconstruction procedures are the main limitations of our study. In conclusion, a seven-day course of 10-mg rivaroxaban may be safely employed for thromboprophylaxis after KA. Whether prophylaxis after KA should be given to all patients, or to selected “high-risk” subjects, remains to be determined. A larger trial to verify our preliminary results is warranted.

An unusual case of symptomatic deep vein thrombosis and pulmonary embolism after arthroscopic meniscus surgery

Background

Although thrombosis complication is rare after arthroscopic meniscus surgery, deep vein thrombosis and pulmonary embolism can be fatal. The associated risk factors and whether anticoagulant prevention after arthroscopic knee surgery is necessary have not reach consensus. Here we present a case of deep vein thrombosis and pulmonary embolism after a common arthroscopic meniscectomy.

Case presentation

The patient had no risk factors except ipsilateral leg varicose veins. She present swell at knee and calf from postoperative 3 weeks, and developed dyspnea, palpitation, and nausea on 33th day, pulmonary embolism was confirmed with CT angiography at emergency department. After thrombolysis and anticoagulation therapy were administered, the patient improved well and discharged. And the intravenous ultrasound confirmed thrombosis of popliteal vein and small saphenous vein. Who don’t have common risk factors for venous thromboembolism.

Conclusions

Despite the low incidence of thromboembolic complications after simple arthroscopy surgery, its life-threatening and devastating property make clinicians rethink the necessity of thromboprophylaxis and importance of preoperative relative risk factors screening.

Thromboprophylaxis after Knee Arthroscopy and Lower-Leg Casting

BACKGROUND

The use of thromboprophylaxis to prevent clinically apparent venous thromboembolism after knee arthroscopy or casting of the lower leg is disputed. We compared the incidence of symptomatic venous thromboembolism after these procedures between patients who received anticoagulant therapy and those who received no anticoagulant therapy.

METHODS

We conducted two parallel, pragmatic, multicenter, randomized, controlled, open-label trials with blinded outcome evaluation: the POT-KAST trial, which included patients undergoing knee arthroscopy, and the POT-CAST trial, which included patients treated with casting of the lower leg. Patients were assigned to receive either a prophylactic dose of low-molecular-weight heparin (for the 8 days after arthroscopy in the POT-KAST trial or during the full period of immobilization due to casting in the POT-CAST trial) or no anticoagulant therapy. The primary outcomes were the cumulative incidences of symptomatic venous thromboembolism and major bleeding within 3 months after the procedure.

RESULTS

In the POT-KAST trial, 1543 patients underwent randomization, of whom 1451 were included in the intention-to-treat population. Venous thromboembolism occurred in 5 of the 731 patients (0.7%) in the treatment group and in 3 of the 720 patients (0.4%) in the control group (relative risk, 1.6; 95% confidence interval [CI], 0.4 to 6.8; absolute difference in risk, 0.3 percentage points; 95% CI, -0.6 to 1.2). Major bleeding occurred in 1 patient (0.1%) in the treatment group and in 1 (0.1%) in the control group (absolute difference in risk, 0 percentage points; 95% CI, -0.6 to 0.7). In the POT-CAST trial, 1519 patients underwent randomization, of whom 1435 were included in the intention-to-treat population. Venous thromboembolism occurred in 10 of the 719 patients (1.4%) in the treatment group and in 13 of the 716 patients (1.8%) in the control group (relative risk, 0.8; 95% CI, 0.3 to 1.7; absolute difference in risk, -0.4 percentage points; 95% CI, -1.8 to 1.0). No major bleeding events occurred. In both trials, the most common adverse event was infection.

CONCLUSIONS

The results of our trials showed that prophylaxis with low-molecular-weight heparin for the 8 days after knee arthroscopy or during the full period of immobilization due to casting was not effective for the prevention of symptomatic venous thromboembolism. (Funded by the Netherlands Organization for Health Research and Development; POT-KAST and POT-CAST ClinicalTrials.gov numbers, NCT01542723 and NCT01542762 , respectively.).

Editorial Commentary: Should the Virchow Triad Have Been a Quartet? Is High Altitude a Risk Factor for Deep Venous Thrombosis After Knee Arthroscopy?

The Virchow triad includes stasis of blood flow, endothelial injury, and hypercoagulability. It forms the physiological foundation for the development of one of our most dreaded complications: deep venous thrombosis. Although the complication rate after knee arthroscopy remains low, significant morbidity may be associated with thromboembolic events. Tyson et al. report an increased incidence of venous thromboembolism in knee operations performed at higher altitudes versus those conducted closer to sea level. Multiple acquired conditions and inherited traits have been identified as risk factors for the development of venous thromboembolism. Geographic altitude should be included within this list.