Venous thrombosis following lower-leg cast immobilization and knee arthroscopy: From a population-based approach to individualized therapy

Deep vein thrombosis: Implications of thromboprophylaxis after lower limb cast immobilisation

Deep vein thrombosis is a recognised complication of lower limb cast immobilisation and post operative state immobilisation. A national survey revealed that low molecular weight heparin (LMWH) is the favoured strategy for thromboprophylaxis in the latter context. However, clinicians need to be aware of the fact that the use of LMWH might incur the risk of subsequent development of heparin-induced thrombocytopenia, with its attendant life-threatening thrombotic complications. Some of the patients who develop those complications might be admitted under the care of general physicians, hence the importance of raising awareness of this issue.

Venous thromboembolism (VTE) developing after ankle sprain. Comparison with VTE after knee arthroplasty

BACKGROUND

Venous thromboembolism (VTE) is a critical complication after non-major trauma or surgery. While the risk and severity of VTE following major orthopedic surgery is well-documented, there is significant knowledge gap regarding, non-major trauma such as ankle sprains.

METHODS

We analyzed data from the RIETE registry to assess the clinical characteristics, VTE prophylaxis usage, and outcomes in patients with VTE following ankle sprain versus those post elective knee arthroplasty. We aimed to assess the risk and severity of VTE in a population traditionally considered at lower risk. Risk stratification was performed using the TRiP(cast) score.

RESULTS

Among 1,250 patients with VTE, those with ankle sprain (n = 459) were much younger than those post knee arthroplasty (n = 791), less often female, had fewer comorbidities, and received VTE prophylaxis less often (27% vs. 93 %). During anticoagulation, 26 patients developed recurrent VTE, 31 had major bleeding, and 12 died (fatal PE 3, fatal bleeding 2). There were no differences between the two groups in the rates of VTE recurrences (rate ratio (RR): 1.65; 95%CI: 0.69-3.88) or death (RR: 1.12; 95%CI: 0.33-3.46), but patients with VTE after ankle sprain had a lower rate of major bleeding (RR: 0.39; 95%CI: 0.13-0.99).

CONCLUSIONS

Ankle sprain patients are often undertreated for VTE prophylaxis and have similar severity of VTE than those undergoing elective knee surgery, indicating the need for a more customized approach to VTE management.

Evaluation of venous thromboembolism risk assessment models for hospital inpatients: the VTEAM evidence synthesis

Background

Pharmacological prophylaxis during hospital admission can reduce the risk of acquired blood clots (venous thromboembolism) but may cause complications, such as bleeding. Using a risk assessment model to predict the risk of blood clots could facilitate selection of patients for prophylaxis and optimise the balance of benefits, risks and costs.

Objectives

We aimed to identify validated risk assessment models and estimate their prognostic accuracy, evaluate the cost-effectiveness of different strategies for selecting hospitalised patients for prophylaxis, assess the feasibility of using efficient research methods and estimate key parameters for future research.

Design

We undertook a systematic review, decision-analytic modelling and observational cohort study conducted in accordance with Enhancing the QUAlity and Transparency Of health Research (EQUATOR) guidelines.

Setting

NHS hospitals, with primary data collection at four sites.

Participants

Medical and surgical hospital inpatients, excluding paediatric, critical care and pregnancy-related admissions.

Interventions

Prophylaxis for all patients, none and according to selected risk assessment models.

Main outcome measures

Model accuracy for predicting blood clots, lifetime costs and quality-adjusted life-years associated with alternative strategies, accuracy of efficient methods for identifying key outcomes and proportion of inpatients recommended prophylaxis using different models.

Results

We identified 24 validated risk assessment models, but low-quality heterogeneous data suggested weak accuracy for prediction of blood clots and generally high risk of bias in all studies. Decision-analytic modelling showed that pharmacological prophylaxis for all eligible is generally more cost-effective than model-based strategies for both medical and surgical inpatients, when valuing a quality-adjusted life-year at £20,000. The findings were more sensitive to uncertainties in the surgical population; strategies using risk assessment models were more cost-effective if the model was assumed to have a very high sensitivity, or the long-term risks of post-thrombotic complications were lower. Efficient methods using routine data did not accurately identify blood clots or bleeding events and several pre-specified feasibility criteria were not met. Theoretical prophylaxis rates across an inpatient cohort based on existing risk assessment models ranged from 13% to 91%.

Limitations

Existing studies may underestimate the accuracy of risk assessment models, leading to underestimation of their cost-effectiveness. The cost-effectiveness findings do not apply to patients with an increased risk of bleeding. Mechanical thromboprophylaxis options were excluded from the modelling. Primary data collection was predominately retrospective, risking case ascertainment bias.

Conclusions

Thromboprophylaxis for all patients appears to be generally more cost-effective than using a risk assessment model, in hospitalised patients at low risk of bleeding. To be cost-effective, any risk assessment model would need to be highly sensitive. Current evidence on risk assessment models is at high risk of bias and our findings should be interpreted in this context. We were unable to demonstrate the feasibility of using efficient methods to accurately detect relevant outcomes for future research.

Future work

Further research should evaluate routine prophylaxis strategies for all eligible hospitalised patients. Models that could accurately identify individuals at very low risk of blood clots (who could discontinue prophylaxis) warrant further evaluation.

Study registration

This study is registered as PROSPERO CRD42020165778 and Researchregistry5216.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: NIHR127454) and will be published in full in Health Technology Assessment; Vol. 28, No. 20. See the NIHR Funding and Awards website for further award information.

Targeted prophylactic anticoagulation based on the TRiP(cast) score in patients with lower limb immobilisation: a multicentre, stepped wedge, randomised implementation trial

BACKGROUND

Prophylactic anticoagulation in emergency department patients with lower limb trauma requiring immobilisation is controversial. The Thrombosis Risk Prediction for Patients with Cast Immobilisation-TRiP(cast)-score could identify a large subgroup of patients at low risk of venous thromboembolism for whom prophylactic anticoagulation can be safely withheld. We aimed to prospectively assess the safety of withholding anticoagulation for patients with lower limb trauma at low risk of venous thromboembolism, defined by a TRiP(cast) score of less than 7.

METHODS

CASTING was a stepped-wedge, multicentre, cluster-randomised trial with blinded outcome assessment. 15 emergency departments in France and Belgium were selected and randomly assigned staggered start dates for switching from the control phase (ie, anticoagulation prescription according to the physician's usual practice) to the intervention phase (ie, targeted anticoagulation according to TRiP(cast) score: no prescription if score <7 and anticoagulation if score was ≥7). Patients were included if they presented to a participating emergency department with lower limb trauma requiring immobilisation for at least 7 days and were aged 18 years or older. The primary outcome was the 3-month cumulative rate of symptomatic venous thromboembolism during the intervention phase in patients with a TRiP(cast) score of less than 7. The targeted strategy was considered safe if this rate was less than 1% with an upper 95% CI of less than 2%. The primary analysis was performed in the intention-to-treat population. This study is registered at ClinicalTrials.gov (NCT04064489).

FINDINGS

Between June 16, 2020, and Sept 15, 2021, 15 clusters and 2120 patients were included. Of the 1505 patients analysed in the intervention phase, 1159 (77·0%) had a TRiP(cast) score of less than 7 and did not receive anticoagulant treatment. The symptomatic venous thromboembolism rate was 0·7% (95% CI 0·3-1·4, n=8/1159). There was no difference between the control and the intervention phases in the cumulative rate of symptomatic venous thromboembolism or in bleeding rates.

INTERPRETATION

Patients with a TRiP(cast) score of less than 7 who are not receiving anticoagulation have a very low risk of venous thromboembolism. A large proportion of patients with lower limb trauma and immobilisation could safely avoid thromboprophylaxis.

FUNDING

French Ministry of Health.

Provoked vs minimally provoked vs unprovoked VTE: does it matter?

Venous thromboembolism (VTE) is a multifactorial disease, and its risk depends on exposure to risk factors and predisposing conditions. Based on their strength of association with a VTE episode, risk factors are classified as major or minor and determined using a temporal pattern to be transient or persistent. All patients with VTE should receive anticoagulant treatment for at least 3 months in the absence of an absolute contraindication. Beyond this period, selected patients may be candidates for an extended phase of anticoagulation aimed at secondary VTE prevention. The risk of recurrent VTE if anticoagulation is discontinued is probably the main driver of decision-making regarding extended treatment. The risk of recurrence after VTE associated with major risk factors is low if the risk factor is no longer present. In this case, treatment can be discontinued. If the major risk factor is persistent, anticoagulation should be continued. After VTE occurring in the absence of risk factors, anticoagulation should probably be continued indefinitely if the risk for bleeding is low and preferably with minimal effective doses of anticoagulants. VTE occurring after exposure to minor risk factors is probably the most challenging situation, especially if the clinical manifestation was acute pulmonary embolism. Understanding the actual role of minor risk factors in the occurrence of VTE helps in estimating the risk of recurrence and avoiding the dangers associated with unnecessary anticoagulation. The availability of safer strategies for anticoagulation could allow personalized strategies for secondary prevention of VTE.

The silent killer: Previously undetected pulmonary emboli that result in death after discharge

INTRODUCTION

Pulmonary embolism (PE) is a recognized cause of death in hospitalized trauma patients, yet less is known about PE after discharge.

PATIENTS & METHODS

All post-discharge, autopsy-demonstrated, fatal PE resulting from trauma within a large US county over six years were analyzed. Counts, percentages, mean values, SD, and IQR were calculated for all variables.

RESULTS

1848 trauma deaths were reviewed, of which 85% had an autopsy. Eighty-five patients died from PE after discharge from their initial injury. 53% were initially treated at non-trauma centers, and 9% did not seek medical assistance. 75% were injured by falling, and most injuries occurred in the lower extremities. 86% had an ISS <16, but 87% needed assistance or were bed-bound after injury, despite 75% having no mobility limitations before the injury. 53% died within one month of injury, and 91% within the first year. Before death, only 11% were prescribed chemical thromboprophylaxis or an antiplatelet agent, and only 8% were diagnosed with venous thromboembolism before death.

CONCLUSIONS

Fatal PE after discharge typically occurred following activity-limiting lower extremity injuries with an ISS<16.

Enhanced in vivo and ex vivo thrombin generation after lower-leg trauma, but not after knee arthroscopy

BACKGROUND

There is room for improvement of prevention of venous thromboembolism (VTE) after lower-leg cast application or knee arthroscopy. Information about the mechanism of clot formation in these patients may be useful to identify new prophylaxis targets. We aimed to study the effect of 1) lower-leg injury and 2) knee arthroscopy on thrombin generation.

METHODS

A cross-sectional study was conducted using plasma samples of POT-(K)CAST trials to measure ex vivo thrombin generation (Calibrated Automated Thrombography [CAT]) and plasma levels of prothrombin fragment 1 + 2 (F1 + 2), thrombin-antithrombin (TAT), fibrinopeptide A (FPA). Plasma was obtained shortly after lower-leg trauma or before and after (< 4 h) knee arthroscopy. Participants were randomly selected from those who did not develop VTE. For aim 1, samples of 88 patients with lower-leg injury were compared with 89 control samples (i.e., preoperative samples of arthroscopy patients). Linear regression was used to obtain mean differences (or ratios if ln-retransformed because of skewedness) adjusted for age, sex, body mass index, comorbidities. For aim 2, pre- and postoperative samples of 85 arthroscopy patients were compared, for which mean changes were obtained.

RESULTS

In patients with lower-leg injury (aim 1), endogenous thrombin potential, thrombin peak, velocity index, FPA and TAT were increased as compared with controls. In arthroscopy patients (aim 2), pre- and postoperative levels were similar for all parameters.

CONCLUSION

Lower-leg trauma increases thrombin generation both ex vivo and in vivo, in contrast to knee arthroscopy. This may imply that the pathogenesis of VTE is different in both situations.

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.

Prevention of venous thromboembolic events in patients with lower leg immobilization after trauma: Systematic review and network meta-analysis with meta-epsidemiological approach

BACKGROUND

Lower limb trauma requiring immobilization is a significant contributor to overall venous thromboembolism (VTE) burden. The clinical effectiveness of thromboprophylaxis for this indication and the optimal agent strategy are still a matter of debate. Our main objective was to assess the efficacy of pharmacological thromboprophylaxis to prevent VTE in patients with isolated temporary lower limb immobilization after trauma. We aimed to estimate and compare the clinical efficacy and the safety of the different thromboprophylactic treatments to determine the best strategy.

METHODS AND FINDINGS

We conducted a systematic review and a Bayesian network meta-analysis (NMA) including all available randomized trials comparing a pharmacological thromboprophylactic treatment to placebo or to no treatment in patients with leg immobilization after trauma. We searched Medline, Embase, and Web of Science until July 2021. Only RCT or observational studies with analysis of confounding factors including adult patients requiring temporary immobilization for an isolated lower limb injury treated conservatively or surgically and assessing pharmacological thromboprophylactic agents or placebo or no treatment were eligible for inclusion. The primary endpoint was the incidence of major VTE (proximal deep vein thrombosis, symptomatic VTE, and pulmonary embolism-related death). We extracted data according to Preferred Reporting Items for Systematic Reviews and Meta-analyses for NMA and appraised selected trials with the Cochrane review handbook. Fourteen studies were included (8,198 patients). Compared to the control group, rivaroxaban, fondaparinux, and low molecular weight heparins were associated with a significant risk reduction of major VTE with an odds ratio of 0.02 (95% credible interval (CrI) 0.00 to 0.19), 0.22 (95% CrI 0.06 to 0.65), and 0.32 (95% CrI 0.15 to 0.56), respectively. No increase of the major bleeding risk was observed with either treatment. Rivaroxaban has the highest likelihood of being ranked top in terms of efficacy and net clinical benefit. The main limitation is that the network had as many indirect comparisons as direct comparisons.

CONCLUSIONS

This NMA confirms the favorable benefit/risk ratio of thromboprophylaxis for patients with leg immobilization after trauma with the highest level of evidence for rivaroxaban.

TRIAL REGISTRATION

PROSPERO CRD42021257669.

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.

Lower-leg injury and knee arthroscopy have distinct effects on coagulation

Unlike knee arthroscopy, lower-leg injury is associated with increased plasma levels of factor VIII, von Willebrand factor, and D-dimer.

In both situations, coagulation is affected differently, which suggests that there are different pathways toward venous thromboembolism.

It is unknown how lower-leg injury and knee arthroscopy, both associated with venous thromboembolism (VTE), affect coagulation. To study the effect of (1) lower-leg trauma and (2) knee arthroscopy on coagulation, plasma samples of the Prevention of Thrombosis following CAST immobilization (POT-CAST, #NCT01542762) and Prevention of Thrombosis following Knee Arthroscopy (POT-KAST, #NCT01542723) trials were used, which were collected shortly after lower-leg trauma and before/after (<4 hours) knee arthroscopy. For aim 1, 1204 lower-leg injury patients were compared with preoperative samples of 1001 controls. Mean differences/ratios (if ln-retransformed because of skewedness) were adjusted for sex, age, body mass index, comorbidity, malignancy, and oral contraceptives using linear regression. For aim 2, perioperative mean changes of 715 arthroscopy patients were calculated. Plasma levels of fibrinogen, factor (F)VIII, FIX, FXI, von Willebrand Factor (VWF), and D-dimer were measured in all individuals. Parameters of underlying mechanisms (tissue factor, interleukin-6 [IL-6], myeloperoxidase DNA, cell-free DNA) were measured in random subsets. In lower-leg injury patients, coagulation parameter levels increased, especially FVIII, VWF, and D-dimer, that is, adjusted mean differences: FVIII 26.8% (95% confidence interval [CI], 23.7-29.9), FIX 13.8% (95% CI, 11.9-15.6), FXI 5.1% (95% CI, 3.3-7.0), VWF 29.8% (95% CI, 26.0-33.6), fibrinogen 32.5 mg/dL (95% CI, 25.8-39.2), and D-dimer (mean ratio) 3.3 (95% CI, 3.1-3.6). Remaining parameters were unchanged, except for increased IL-6 levels. After arthroscopy, all parameters decreased. Lower-leg trauma is associated with increased procoagulant factor levels in contrast to knee arthroscopy. This suggests that, in both situations, different pathways are involved in development of VTE.

Effect of joint immobilization using extension splint immediately after total knee arthroplasty on post-operative knee function and pain: a randomized clinical trial

PURPOSE

Investigate the effect of semirigid extension bracing after total knee arthroplasty (TKA) on articular pain and function.

METHODS

The present randomized clinical trial included 72 patients undergoing unilateral primary TKA. Patients in the case group received eight days of post-operative semirigid extension-locked knee bracing, whereas controls did not. The outcomes assessed preoperatively and on the first, ninth, 30th day, and one year post-operatively included the knee society score (KSS), functional KSS (FKSS), VAS pain score, amount of postoperative opiate painkiller usage (tablet oxycodone 5mg), and knee ROM.

RESULTS

The case group had a significantly lower flexion ROM on postoperative day nine compared to the control group (95.3° vs. 100.8°, p=0.03), while it became significantly higher 1 month (114.1° vs. 104.7°, p=0.03) and one year post-operative (128.0° vs. 120.5°, p=0.002). Also, FKSS was significantly higher in the case group than in the controls in the one month post-operative assessment (37.0 vs. 32.6, p=0.009) but not in the one year post-operative assessment. The case group patients had a significantly lower pain than the controls on days one (5.8 vs. 7.2, p=0.02) and nine post-operative (4.1 vs. 5.2, p=0.048), but not at later assessments. The amount of one month post-operative opium (oxycodone) consumption was significantly lower in the brace group (12.4 vs. 14.1 tablets, p=0.03). The KSS were not significantly different between the groups after the surgery.

CONCLUSION

Extension-locked splinting immediately after TKA is a noninvasive, non-pharmacological, and inexpensive intervention with possible promising effects on knee ROM, short-term functional improvement, and acute post-operative pain management.

Risque thromboembolique veineux chez les patients traumatisés d’un membre inférieur nécessitant une immobilisation : vers une approche individualisée

Un traumatisme d’un membre inférieur nécessitant une immobilisation est une situation à risque de développement de maladie thromboembolique veineuse (MTEV). Cependant, les recommandations et les pratiques varient notablement d’un pays à un autre et d’un centre à un autre. Cette revue narrative a pour objectifs de décrire l’épidémiologie, la prévention et les algorithmes de prédiction de la MTEV chez les patients traumatisés d’un membre inférieur nécessitant une immobilisation. L’incidence de la MTEV varie selon les études du fait de la grande hétérogénéité des patients inclus (de l’entorse de cheville à une lésion chirurgicale) et du fait des différents critères d’évaluation utilisés. L’incidence des événements thromboemboliques veineux symptomatiques est estimée à 2,0 % (intervalle de confiance à 95 % : 1,3 à 2,7). L’efficacité de la thromboprophylaxie a été démontrée dans des méta-analyses récentes. Cependant, la confiance à accorder à ces résultats est médiocre, car de nombreux essais présentaient des faiblesses méthodologiques. L’étude la plus importante et la plus récente ne montre pas de bénéfice de la prévention par héparine de bas poids moléculaire sur les événements symptomatiques dans une population non ciblée. Ces résultats suggèrent d’adopter une démarche personnalisée en réservant la prophylaxie aux patients à risque. Plusieurs scores existent pour évaluer le risque thromboembolique individuel. La prise en compte des caractéristiques du patient, du traumatisme et de l’immobilisation permet d’identifier un large sous-groupe de patients chez qui la prévention ne semble pas utile et un sous-groupe de patients à haut risque où la prévention devrait être prescrite, voire renforcée. En conclusion, lors d’un traumatisme d’un membre inférieur nécessitant une immobilisation, l’indication d’une thromboprophylaxie devrait être guidée par l’évaluation individuelle du risque thrombotique.

Guidelines for the acute care of severe limb trauma patients

GOAL

To provide healthcare professionals with comprehensive multidisciplinary expert recommendations for the acute care of severe limb trauma patients, both during the prehospital phase and after admission to a Trauma Centre.

DESIGN

A consensus committee of 21 experts was formed. A formal conflict-of-interest (COI) policy was developed at the onset of the process and enforced throughout. The entire guidelines process was conducted independently of any industrial funding (i.e., pharmaceutical, medical devices). The authors were advised to follow the rules of the Grading of Recommendations Assessment, Development and Evaluation (GRADE®) system to guide assessment of the quality of evidence. The potential drawbacks of making strong recommendations in the presence of low-quality evidence were emphasised. Few recommendations remained non-graded.

METHODS

The committee addressed eleven questions relevant to the patient suffering severe limb trauma: 1) What are the key findings derived from medical history and clinical examination which lead to the patient's prompt referral to a Level 1 or Level 2 Trauma Centre? 2) What are the medical devices that must be implemented in the prehospital setting to reduce blood loss? 3) Which are the clinical findings prompting the performance of injected X-ray examinations? 4) What are the ideal timing and modalities for performing fracture fixation? 5) What are the clinical and operative findings which steer the surgical approach in case of vascular compromise and/or major musculoskeletal attrition? 6) How to best prevent infection? 7) How to best prevent thromboembolic complications? 8) What is the best strategy to precociously detect and treat limb compartment syndrome? 9) How to best and precociously detect post-traumatic rhabdomyolysis and prevent rhabdomyolysis-induced acute kidney injury? 10) What is the best strategy to reduce the incidence of fat emboli syndrome and post-traumatic systemic inflammatory response? 11) What is the best therapeutic strategy to treat acute trauma-induced pain? Every question was formulated in a PICO (Patient Intervention Comparison Outcome) format and the evidence profiles were produced. The literature review and recommendations were made according to the GRADE® methodology.

RESULTS

The experts' synthesis work and the application of the GRADE method resulted in 19 recommendations. Among the formalised recommendations, 4 had a high level of evidence (GRADE 1+/-) and 12 had a low level of evidence (GRADE 2+/-). For 3 recommendations, the GRADE method could not be applied, resulting in an expert advice. After two rounds of scoring and one amendment, strong agreement was reached on all the recommendations.

CONCLUSIONS

There was significant agreement among experts on strong recommendations to improve practices for severe limb trauma patients.

Diagnosis of venous thromboembolism using clinical pretest probability rules, D-dimer assays, and imaging techniques

ABSTRACT

Venous thromboembolism is a significant clinical entity that includes two associated medical disorders: deep vein thrombosis and pulmonary embolism. The goal of this article is to describe the optimal approach to evaluating venous thromboembolism including pretest probability clinical decision rules and appropriate testing to ensure an accurate diagnosis.

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 VTE following total hip and knee arthroplasty: Is prediction the future?

Venous thromboembolism (VTE) is a common complication following total hip arthroplasty (THA) and total knee arthroplasty (TKA). Many guidelines advise on the ideal pharmacological thromboprophylaxis strategy; however, despite its use, approximately 1.5% of patients still develop symptomatic VTE. Considering the large number of THAs and TKAs performed worldwide (2.5 million in total), the impact of VTE following these interventions is enormous. This paper discusses a concept how to further lower rates of VTE and bleeding complications following surgery. By stratifying patients according to their risk, we can optimize the balance between VTE and bleeding for each individual. This way, low-risk patients may be safely withheld from treatment (and avoid unnecessary bleeding complications and costs), whereas high-risk patients should receive adequate therapy (for instance, an increased thromboprophylaxis dosage and duration). An individualized strategy requires a well-functioning VTE prediction model following THA and TKA to help physicians to decide on optimal thromboprophylaxis therapy.

Thromboprophylaxis in arthroscopy: Survey of current practices in France and comparison with recommendations

INTRODUCTION

Current national and international recommendations for thromboprophylaxis after arthroscopy procedures are not very detailed and likely not well known by surgeons. The aim of this study was to compare the daily clinical practices of members of the Francophone Arthroscopy Society (SFA) with current national and international recommendations.

HYPOTHESIS

The primary hypothesis was that the procedures adopted by more than 75% of SFA members conform to the national recommendations set out by the French Anesthesia and Intensive Care Society (SFAR) in effect at the time of this study.

METHODS

A questionnaire was sent to members of the SFA asking three questions to capture their protocol (decision maker, prescriber, indication by procedure). Descriptive statistics were generated for each question. The percentage of prescription protocols conforming to each recommendation was compared to the target percentage (75% arbitrary threshold) by a Chi² test with a 5% threshold overall and for each type of procedure.

RESULTS

Thirty-five percent of the SFA members responded to the questionnaire. Overall, the compliance rate was 69%, which was significantly lower than the target (p<0.001). The compliance rate was significantly lower than the target for hip procedures, minor knee procedures and ankle procedures; each time, the prescription was excessive. The compliance rate was not different than the target for major knee procedures and upper limb procedures. The sole reason for non-compliance was a non-justified prescription.

DISCUSSION

Less than 75% of SFA members have adopted thromboprophylaxis protocols that comply with national SFAR recommendations in effect at the time of this study, with excessive prescription for procedures on the lower limb. Recent studies do not confirm that broadening of the prescription is justified. This large gap between published recommendations and current practices means that we should reconsider the relevance of current recommendations and re-evaluate the cost-benefit ratio of prescribing a drug-based thromboprophylaxis after arthroscopy surgery.

LEVEL OF EVIDENCE

Level IV.

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.

DVT and Pulmonary Embolism Following Knee Arthroscopy: The Role of Genetic Predisposition and Autoimmune Antibodies: A Report of 3 Cases

Deep vein thrombosis (DVT) after arthroscopy has been considered a rare event; however, recent studies using ultrasound and venography have shown that the incidence of DVTs is underestimated. CASES:: This report describes 3 patients with DVT and/or PE after knee arthroscopy who were attributed to a genetic predisposition of hypercoagulability unknown to the patient and surgeon. CONCLUSIONS:: Genetic predisposition and autoimmune antibodies may play a role in the development of DVT after knee arthroscopy. We recommend focused questions regarding family history be added to the standard DVT/PE preoperative questionnaire.

What's new in VTE risk and prevention in orthopedic surgery

A State of the Art lecture titled "What's New in VTE Risk and Prevention in Orthopedic Surgery" was presented at the ISTH congress in 2019. Patients undergoing orthopedic surgery have long been recognized to be at increased risk of venous thromboembolism (VTE) and were among the first patient groups to be studied in VTE prophylaxis trials. From the late 1950s to 2010s, prophylaxis trials in major orthopedic surgery tended to focus on venographic deep vein thrombosis and assessed thromboprophylaxis in all patients based on a population approach. In general, anticoagulants were favored over mechanical prophylaxis or aspirin, and longer-duration prophylaxis was favored over shorter durations. As discussed in this paper, more recently, orthopedic prophylaxis has started to become more nuanced and individualized. Modern trials are focusing on symptomatic VTE as outcomes; there has been a resurgence in interest in aspirin for prophylaxis, and there has been a slow move to studying ways to evaluate VTE risk in patients undergoing orthopedic surgery and recommending thromboprophylaxis to patients based on individual attributes, in whom risk stratification and weighing of benefit versus risk of thromboprophylaxis is becoming key. We also touch on VTE risk and guideline recommendations to prevent VTE in 2 other commonly encountered orthopedic populations: patients undergoing knee arthroscopy and those with distal leg fractures. Finally, we summarize relevant new data on this topic presented during the 2019 ISTH annual congress in Melbourne.

Pharmacological thromboprophylaxis to prevent venous thromboembolism in patients with temporary lower limb immobilization after injury: systematic review and network meta-analysis

BACKGROUND

Thromboprophylaxis has the potential to reduce venous thromboembolism (VTE) following lower limb immobilization resulting from injury.

OBJECTIVES

We aimed to estimate the effectiveness of thromboprophylaxis, compare different agents, and identify any factors associated with effectiveness.

METHODS

We undertook a systematic review and network meta-analysis (NMA) of randomized trials reporting VTE or bleeding outcomes that compared thromboprophylactic agents with each other or to no pharmacological prophylaxis, for this indication. An NMA was undertaken for each outcome or agent used, and a series of study-level network meta-regressions examined whether population characteristics, type of injury, treatment of injury, or duration of thromboprophylaxis were associated with treatment effect.

RESULTS

Data from 6857 participants across 13 randomized trials showed that, compared with no treatment, low molecular weight heparin (LMWH) reduced the risk of any VTE (odds ratio [OR]: 0.52; 95% credible interval [CrI]: 0.37-0.71), clinically detected deep vein thrombosis (DVT) (OR: 0.39; 95% CrI: 0.12-0.94) and pulmonary embolism (PE) (OR: 0.16; 95% CrI: 0.01-0.74), whereas fondaparinux reduced the risk of any VTE (OR: 0.13; 95% CrI: 0.05-0.30) and clinically detected DVT (OR: 0.10; 95% CrI: 0.01-0.86), with inconclusive results for PE (OR: 0.40; 95% CrI: 0.01-7.53).

CONCLUSIONS

Thromboprophylaxis with either fondaparinux or LMWH appears to reduce the odds of both asymptomatic and clinically detected VTE in people with temporary lower limb immobilization following an injury. Treatment effects vary by outcome and are not always conclusive. We were unable to identify any treatment effect modifiers other than thromboprophylactic agent used.

Thromboprophylaxis in lower limb immobilisation after injury (TiLLI)

Venous thromboembolic disease is a major global cause of morbidity and mortality. An estimated 10 million episodes are diagnosed yearly; over half of these episodes are provoked by hospital admission/procedures and result in significant loss of disability adjusted life years. Temporary lower limb immobilisation after injury is a significant contributor to the overall burden of venous thromboembolism (VTE). Existing evidence suggests that pharmacological prophylaxis could reduce overall VTE event rates in these patients, but the proportional reduction of symptomatic events remains unclear. Recent studies have used different pharmacological agents, dosing regimens and outcome measures. Consequently, there is wide variation in thromboprophylaxis strategies, and international guidelines continue to offer conflicting advice for clinicians. In this review, we provide a summary of recent evidence assessing both the clinical and cost effectiveness of thromboprophylaxis in patients with temporary immobilisation after injury. We also examine the evidence supporting stratified thromboprophylaxis and the validity of widely used risk assessment methods.