Thromboprophylaxis in patients with lower limb immobilisation - review of current status

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.

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.

Venous thromboembolism in trauma patients with lower limb cast immobilization, associated risk reduction and complication using rivaroxaban

INTRODUCTION

Several studies have shown a reduction in the rate of thromboembolic events with LMWH thromboprophylaxis in patients immobilised in lower limb cast. However, the literature is limited on the use of rivaroxaban in this setting. Therefore the aim of this study was to assess the associated impact of rivaroxaban on the incidence of venous thromboembolism in trauma patients with lower limb cast immobilisation.

METHOD

Adult patients treated with lower limb cast immobilisation for different types of lower limb injuries were included in this study. One cohort of patients (n = 518) received rivaroxaban thromboprophylaxis. This was compared with a historical cohort (n = 486), who received no rivaroxaban for thromboprophylaxis.

RESULTS

The number of patients developing VTEs in the rivaroxaban group was zero, compared with 6 cases (1.2%) in the nonrivaroxaban group p = 0.013. There were no major or minor bleeding incidences; no wound complications reported in the rivaroxaban group. All the side effects reported in association with rivaroxaban use did not require further intervention.

CONCLUSION

This study has shown that rivaroxaban is associated with a significant reduction in the risk of VTEs in patients with lower limb cast immobilisation without increasing the risk of bleeding or associated untoward effect. Lower limb immobilisation is high risk factor for VTE per se. However, there is still limited data in the literature to make further recommendations.

Effects of graduated compression stockings, local vibration and their combination on popliteal venous blood velocity

Objectives

The purpose of this pilot study was to examine and compare the effects of graduated compression stockings, local vibration, and combined graduated compression stockings and local vibration on popliteal venous blood velocity.

Method

Twenty-four healthy subjects received four 15 min interventions (control, graduated compression stockings alone, local vibration alone, and combined graduated compression stockings and local vibration), while resting inactive in the prone position. Popliteal vein blood velocity was investigated before (PRE) and at the end (POST) of each intervention using Doppler ultrasound.

Results

At POST, peak velocity was reported to be 26.3 ± 53.5% ( p <  0.05) greater for local vibration than control (CONT). Peak velocity was 46.2 ± 54.6% ( p <  0.001) and 21.1 ± 37.6% ( p <  0.01) higher for graduated compression stockings than CONT and local vibration, respectively. Graduated compression stockings + local vibration presented 64.1 ± 58.0% ( p <  0.001), 38.4 ± 52.4% ( p <  0.001) and 15.0 ± 31.6% ( p <  0.05) greater values than CONT, local vibration and graduated compression stockings, respectively.

Conclusions

This study demonstrated an increase in popliteal venous blood velocity after graduated compression stockings and local vibration application. Their combination provided the greatest effects.

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.

Individual risk factors predictive of venous thromboembolism in patients with temporary lower limb immobilization due to injury: a systematic review

Essentials Thromboprophylaxis after lower limb injury is often based on complex risk stratification. Our systematic review identified variables predicting venous thromboembolism (VTE) in this group. Age and injury type were commonly reported to increase the odds of VTE (odds ratio 1.5-3.48). We found limited evidence to support the use of other risk factors within prediction models. SUMMARY: Background Patients immobilized after lower limb injury are at risk of venous thromboembolism (VTE). There is international variation in the use of thromboprophylaxis for such patients. Risk-based strategies have been adopted to aid decision making in many settings. The accuracy of these strategies is unclear. Objectives A systematic review was undertaken to identify all individual patient-identifiable risk factors linked to any VTE outcome following lower limb immobilization. Methods Several electronic databases were searched from inception to May 2017. Any studies that included a measurement of VTE as a patient outcome in adults requiring temporary immobilization (e.g. leg cast or brace in an ambulatory setting) for an isolated lower limb injury and reported risk factor variables were included. Descriptive statistics and thematic analysis were used to synthesize the evidence. Results Our database search returned 4771 citations, of which 15 studies reporting outcome data on 80 678 patients were eligible for analysis. Risk-factor associations were reported through regression analyses, non-parametric tests and descriptive statistics. All studies were assessed as at moderate or serious risk of bias using the ROBINS-I risk of bias tool. Advancing age and injury type were the only individual risk factors demonstrating a reproducible association with increased symptomatic and/or asymptomatic VTE rates. Several risk factors currently used in scoring tools did not appear to be robustly evaluated for subsequent association with VTE within these studies. Conclusions Clinicians should be aware of the limited evidence to support individual risk factors in guiding thromboprophylaxis use for this patient cohort.

Venous thromboembolism prophylaxis using the Caprini score

Venous thromboembolism (VTE) including pulmonary embolism (PE) and deep vein thrombosis (DVT) is one of the leading causes of preventable cardiovascular disease in the United States (US) and is the number one preventable cause of death following a surgical procedure. Post-operative VTE is associated with multiple short and long-term complications. We will focus on reviewing the many faces of VTE in detail as they represent common challenging scenarios in clinical practice.

Impact of Knee Scooter Flexion Position on Venous Flow Rate

BACKGROUND:

The knee scooter is a commonly used mobility device in the setting of unilateral below-knee immobilization. The bent-knee posture has been shown to decrease venous flow in a seated position, but the knee scooter differs as the patient is weightbearing through the affected extremity. Our goal was to investigate the effects of knee scooter positioning on popliteal venous flow.

METHODS:

Duplex ultrasonography was performed to obtain venous diameter and flow velocity of the popliteal vein on healthy subjects over the age of 18 without immobilization. Measurements were performed on the left knee of each subject while standing and with the same knee flexed on the knee scooter, by 2 physicians trained in ultrasound techniques. Mean velocity, peak velocity, vessel diameter, and volumetric flow rate were calculated and t tests were performed for each variable. A power analysis was performed, determining that 9 subjects would provide 80% power with an alpha of 0.05. A total of 13 subjects participated in the study. Mean age was 33 (range 20-56) years, with 6 females and 7 males.

RESULTS:

Measurements of subjects while standing and on the knee scooter demonstrated a significant decrease in mean velocity (6.5 vs 3.2 cm/s, P < .01) and volumetric flow rate (227.8 vs 106.2 mL/min, P < .01) while subjects were using the scooter. Vessel diameter (0.82 vs 0.78 cm, P = .15) and peak velocities (19.8 vs 14.7 cm/s, P = .19) were not significantly different between standing and kneeling positions.

CONCLUSION:

Our findings demonstrated a statistically significant decrease in volumetric flow rate in subjects using a knee scooter device with a flexed knee. Although venous stasis is a known risk factor for DVT, flow rate thresholds for increased thrombus formation are not well defined. The duration of scooter use, or flexed knee positioning, may have some effect on the degree of stasis. This finding should caution orthopedists to consider the risk attributed to the knee scooter as part of their overall patient assessment.

LEVEL OF EVIDENCE:

Level II, therapeutic, comparative study.

The effect of active toe movement (AToM) on calf pump function and deep vein thrombosis in patients with acute foot and ankle trauma treated with cast - A prospective randomized study

BACKGROUND

Patients with foot and ankle trauma treated with cast are advised to perform toe movements to prevent venous thromboembolism (VTE). Our aim was to determine the effect of active toe movement on asymptomatic deep vein thrombosis (DVT) and venous calf pump function.

METHODS

Patients aged 18-60 years with acute foot and ankle trauma requiring below knee non weight bearing cast were randomized to intervention (regular active toe movement) or control groups (n=100). Patients had bilateral lower limb venous ultrasound to assess for DVT on discharge from clinic. Patients requiring chemical thromboprophylaxis were excluded.

RESULTS

78 completed the study. 27% sustained asymptomatic DVT, with no statistically significant difference in calf pump function or DVT incidence between groups. All DVT's occurred in the injured lower limb.

CONCLUSION

Active toe movement is not a viable strategy for thromboprophylaxis in patients with acute foot and ankle trauma treated with cast.

The Efficacy and Safety of Edoxaban for VTE Prophylaxis Post-Orthopedic Surgery: A Systematic Review

BACKGROUND

Venous thromboembolism (VTE) is a common complication that manifests during and/or after hospitalization, as well as postsurgeries including orthopedic surgeries. Edoxaban is a new oral direct factor Xa inhibitor that has been recently approved for treating VTE in patients who have already been treated with a parenteral anticoagulant and for the prevention of stroke and non-central nervous system systemic embolism in patients with nonvalvular atrial fibrillation.

OBJECTIVES

The purpose of this systematic review was to evaluate the safety and efficacy of edoxaban for VTE prophylaxis after lower limb orthopedic surgery.

MATERIALS AND METHODS

A comprehensive search was conducted in Google Scholar, PubMed, MEDLINE, and ScienceDirect to identify potential records, then titles, abstracts, and full texts were screened using the inclusion criteria to filter out irrelevant studies. Moreover, the data extraction and quality assessment were undertaken using standardized tools, and the results were narratively synthesized and presented in tables.

RESULTS

Six studies were included in this systematic review after screening 2989 records. The majority of studies demonstrated a statistically significant reduction in VTE events in the edoxaban group(s) compared to the dalteparin, placebo, or enoxaparin groups (P < .05). The differences in VTE cases in some studies reached to approximately 50% favoring edoxaban 30 mg over the comparator (P < .05). However, other studies uncovered a statistically insignificant difference between edoxaban and the comparator "enoxaparin" when used for VTE prophylaxis (P > .05). On the other hand, although edoxaban found to cause more bleeding, the differences between edoxaban and the comparator are statistically insignificant (P > .05).

CONCLUSION

This study helped to amalgamate evidence with regard to the use of edoxaban for VTE prophylaxis post-lower limb orthopedic surgery. In line with the results of the reviewed studies, edoxaban seems to be highly effective in reducing VTE post-lower limb orthopedic surgery.

A critical evaluation of venous thromboembolism risk assessment models used in patients with lower limb cast immobilisation

BACKGROUND

There is a recognised link between lower limb cast immobilisation and the development of venous thromboembolism (VTE). Our aim was to assess the diagnostic accuracy of risk assessment models (RAMs) applicable to this patient group. This has not been done before.

METHODS

A literature and guideline review identified five RAMs. They were used to retrospectively risk assess a consecutive series of patients who were diagnosed with symptomatic VTE following lower limb injury treated with a cast (Group I). A case-matched cohort who did not suffer symptomatic VTE (Group II) was also retrospectively risk assessed. The RAMs' diagnostic performance indicators were calculated.

RESULTS

Groups I and II consisted of 21 patients each. There was no significant difference in the mean age or total number of VTE risk factors between Groups I and II (p=.957 and p=.878 respectively). The Plymouth (2010) RAM achieved the highest accuracy (54.8%).

CONCLUSIONS

Each RAM demonstrated significant limitations. Two displayed very limited clinical utility. Three recommended chemical thromboprophylaxis to all patients because they weighted lower limb immobilisation as an absolute risk factor for the development of VTE. Cast immobilisation should not be considered an absolute risk factor when risk assessing patients who all have casts. Prospective evaluation with a larger patient cohort is required.

Deep Vein Thrombosis in the Lower Extremities in Comatose Elderly Patients with Acute Neurological Diseases

PURPOSE

Comatose elderly patients with acute neurological illness have a great risk of deep vein thrombosis (DVT). In this study, the incidence of DVT and the effectiveness of early initiation of treatment were evaluated in those patients.

MATERIALS AND METHODS

Total 323 patients were admitted to our ward due to neurological diseases in one year, and 43 patients, whose Glasgow Coma Scale was ≤ 11 and who was older than ≥ 60 years, were included in this study. D-dimer was measured on admission and day 7, and lower-extremity ultrasonography was performed on day 7. When DVT was positive, heparin treatment was initiated, and further evaluation of pulmonary embolism (PE) was conducted. Vena cava filter protection was inserted in PE-positive patients. Incidence of DVT and PE, alteration of D-dimer value, and effect of heparin treatment were analyzed.

RESULTS

DVT was positive in 19 (44.2%) patients, and PE was in 4 (9.3%). D-dimer was significantly higher in DVT-positive group on day 7 (p<0.01). No DVT were identified in patients with ischemic disease, while 66.7% of intracerebral hemorrhage and 53.3% of brain contusion patients were DVT positive. Surgery was a definite risk factor for DVT, with an odds ratio of 5.25. DVT and PE disappeared by treatment in all cases, and no patients were succumbed to the thrombosis.

CONCLUSION

Patients with hemorrhagic diseases or who undergo operation possess high risk of DVT, and initiation of heparin treatment in 7 days after admission is an effective prophylaxis for DVT in comatose elderly patients without causing bleeding.

Deep Venous Thrombosis and Tendon Healing

Tendon metabolism after acute Achilles tendon rupture (ATR) is associated with major complications related to immobilization, which results in reduced circulation, high risk of deep venous thrombosis (DVT), impaired healing and functional deficits.DVT has been demonstrated to occur in up to 50 % of the patients with ATR. Suffering from a DVT during tendon healing has been demonstrated as an independent predictive factor for impaired patient outcome at 1 year after ATR, suggesting that specific interventions are warranted to prevent DVT. Since pharmacological DVT prophylaxis has low or no effect during lower leg immobilization it is speculated whether adjuvant treatment with intermittent pneumatic compression (IPC) applied during lower limb immobilization can reduce the incidence of DVT.IPC, which acts through mechanical, chemical and molecular mechanisms, has been demonstrated to enhance neuro-vascular ingrowth in a tendon repair model and stimulate collagen production leading to improved maximum force during healing.Recently, a prospective randomized trial compared adjuvant IPC applied under an orthosis versus plaster cast only in ATR patients. The study found at 2 weeks post-operatively 21 % DVTs in the IPC-group compared to 37 % in the control group. Patients that received no IPC treatment exhibited an almost threefold increased odds for DVT, independently of age. Furthermore, using microdialysis technique, adjuvant IPC treatment was shown to increase the metabolic healing activity at 2 weeks post-ATR.Tendon healing is impaired by reduced circulation and DVT. The demonstration that adjuvant IPC effectively reduced DVT incidence, and also is capable of enhancing the metabolic response suggests that IPC treatment may not only be a viable means of prophylaxis against DVT, but possibly also a method of promoting healing.

Venous Thrombosis Risk after Cast Immobilization of the Lower Extremity: Derivation and Validation of a Clinical Prediction Score, L-TRiP(cast), in Three Population-Based Case-Control Studies

BACKGROUND

Guidelines and clinical practice vary considerably with respect to thrombosis prophylaxis during plaster cast immobilization of the lower extremity. Identifying patients at high risk for the development of venous thromboembolism (VTE) would provide a basis for considering individual thromboprophylaxis use and planning treatment studies. The aims of this study were (1) to investigate the predictive value of genetic and environmental risk factors, levels of coagulation factors, and other biomarkers for the occurrence of VTE after cast immobilization of the lower extremity and (2) to develop a clinical prediction tool for the prediction of VTE in plaster cast patients.

METHODS AND FINDINGS

We used data from a large population-based case-control study (MEGA study, 4,446 cases with VTE, 6,118 controls without) designed to identify risk factors for a first VTE. Cases were recruited from six anticoagulation clinics in the Netherlands between 1999 and 2004; controls were their partners or individuals identified via random digit dialing. Identification of predictor variables to be included in the model was based on reported associations in the literature or on a relative risk (odds ratio) > 1.2 and p ≤ 0.25 in the univariate analysis of all participants. Using multivariate logistic regression, a full prediction model was created. In addition to the full model (all variables), a restricted model (minimum number of predictors with a maximum predictive value) and a clinical model (environmental risk factors only, no blood draw or assays required) were created. To determine the discriminatory power in patients with cast immobilization (n = 230), the area under the curve (AUC) was calculated by means of a receiver operating characteristic. Validation was performed in two other case-control studies of the etiology of VTE: (1) the THE-VTE study, a two-center, population-based case-control study (conducted in Leiden, the Netherlands, and Cambridge, United Kingdom) with 784 cases and 523 controls included between March 2003 and December 2008 and (2) the Milan study, a population-based case-control study with 2,117 cases and 2,088 controls selected between December 1993 and December 2010 at the Thrombosis Center, Fondazione IRCCS Ca' Granda-Ospedale Maggiore Policlinico, Milan, Italy. The full model consisted of 32 predictors, including three genetic factors and six biomarkers. For this model, an AUC of 0.85 (95% CI 0.77-0.92) was found in individuals with plaster cast immobilization of the lower extremity. The AUC for the restricted model (containing 11 predictors, including two genetic factors and one biomarker) was 0.84 (95% CI 0.77-0.92). The clinical model (consisting of 14 environmental predictors) resulted in an AUC of 0.77 (95% CI 0.66-0.87). The clinical model was converted into a risk score, the L-TRiP(cast) score (Leiden-Thrombosis Risk Prediction for patients with cast immobilization score), which showed an AUC of 0.76 (95% CI 0.66-0.86). Validation in the THE-VTE study data resulted in an AUC of 0.77 (95% CI 0.58-0.96) for the L-TRiP(cast) score. Validation in the Milan study resulted in an AUC of 0.93 (95% CI 0.86-1.00) for the full model, an AUC of 0.92 (95% CI 0.76-0.87) for the restricted model, and an AUC of 0.96 (95% CI 0.92-0.99) for the clinical model. The L-TRiP(cast) score resulted in an AUC of 0.95 (95% CI 0.91-0.99). Major limitations of this study were that information on thromboprophylaxis was not available for patients who had plaster cast immobilization of the lower extremity and that blood was drawn 3 mo after the thrombotic event.

CONCLUSIONS

These results show that information on environmental risk factors, coagulation factors, and genetic determinants in patients with plaster casts leads to high accuracy in the prediction of VTE risk. In daily practice, the clinical model may be the preferred model as its factors are most easy to determine, while the model still has good predictive performance. These results may provide guidance for thromboprophylaxis and form the basis for a management study.

Patient evaluation of outpatient venous thromboembolism prophylaxis service following lower limb injuries using a developed validated questionnaire

This paper explores patients' perceptions of a new service and protocol for managing outpatient venous thromboembolism (VTE) prophylaxis, using either subcutaneous Dalteparin or oral off-license Dabigatran in patients with lower limb injury requiring immobilisation. Establishing a patient's perspective is part of good practice as, when this is positive, it aids patient compliance and protocol dissemination. A questionnaire consisting of fifty questions was given at random to one hundred patients over a six month period when they attended the trauma clinic. Each question was scored on a five point Likert scale (1 = poor, 5 = excellent) by the patient. The internal consistency of the questionnaire (Cronbach's alpha reliability coefficient) was more than 0.9 in all domains. Qualitative analysis was done for open-ended questions. One hundred respondents completed the questionnaire, two were void due to significant amounts of incomplete data. The gender split was 54 females, 43 males, and one did not answer the question. The average age was 43 (range 18-72). Sixty seven respondents were first-time attenders, 22 were follow-up patients and nine did not complete this section. The overall average score was 4.26 (range 1-5), with 90% of the patients recommending the service. The overall patient satisfaction for a VTE prophylaxis service is high although there is room for improvement as demonstrated by the range of the scores.

Intermittent pneumatic compression reduces the risk of deep vein thrombosis during post-operative lower limb immobilisation

Deep vein thrombosis is a common complication of immobilising the lower limb after surgery. We hypothesised that intermittent pneumatic compression (IPC) therapy in outpatients who had undergone surgical repair of acute ruptures of the Achilles tendon could reduce the incidence of this problem.

A total of 150 patients who had undergone surgical repair of the Achilles tendon were randomised to either treatment with IPC for six hours per day (n = 74) under an orthosis or treatment as usual (n = 74) in a plaster cast without IPC. At two weeks post-operatively, the incidence of deep vein thrombosis was assessed using blinded, double-reported compression duplex ultrasound. At this point, IPC was discontinued and all patients were immobilised in an orthosis for a further four weeks. At six weeks post-operatively, a second compression duplex ultrasound scan was performed.

At two weeks, the incidence of deep vein thrombosis was 21% in the treated group and 37% in the control group (p = 0.042). Age over 39 years was found to be a strong risk factor for deep vein thrombosis (odds ratio (OR) = 4.84, 95% confidence interval (CI) 2.14 to 10.96). Treatment with IPC, corrected for age differences between groups, reduced the risk of deep vein thrombosis at the two-week point (OR = 2.60; 95% CI 1.15 to 5.91; p =0.022). At six weeks, the incidence of deep vein thrombosis was 52% in the treated group and 48% in the control group (OR 0.94, 95% CI 0.49 to 1.83). IPC appears to be an effective method of reducing the risk of deep vein thrombosis in the early stages of post-operative immobilisation of outpatients. Further research is necessary to elucidate whether it can confer similar benefits over longer periods of immobilisation and in a more heterogeneous group of patients.

Cite this article: Bone Joint J 2015;97-B:675–80.

Ineffective Treatment of Low-Molecular-Weight Heparin in Obese Subject with Traumatic Fractures of the Leg

American College of Chest Physicians Evidence-Based Clinical Practice Guidelines, 9th edition, 2012, suggest no prophylaxis rather than pharmacological thromboprophylaxis in management of venous thromboembolism (VTE) risk of isolated lower leg injuries distal to knee requiring leg immobilization. Low-molecular-weight heparin (LMWH) is a class of drugs commonly used as antithrombotics in surgery and in case of prolonged bed rest and hypomobility. A 35-year-old obese man with no history of health disease (height, 170 cm; weight, 95 kg; and body mass index, 32.9 kg/m²) was involved in a car accident, and as a result of the trauma he suffered the compound fracture of left tibia and fibula. Tibial intramedullary nailing was performed. The injury was near the knee, and the patient was advised long-term bed rest. For these reasons, he was treated with enoxaparin 40 mg once daily subcutaneously. On the 7th day of hospitalization, the leg became edematous and reddish. A Doppler ultrasonography evaluation was performed which showed a massive deep vein thrombosis of left leg and then a pulmonary angiotomography showed a massive pulmonary embolism. In this clinical case, there was a pharmacological treatment failure to prevent VTE after orthopedic surgery and related long-term rest using enoxaparin at prophylaxis dosage in a patient without history of health disease but at high risk of VTE for obesity, trauma, orthopedic surgery, and immobilization. Enoxaparin dosage to prevent VTE in patients with high risk should be reconsidered and especially in obese a weight-adjusted dosage can be better than a fixed dosage.

The effect of ankle joint immobilization on lower limb venous flow

BACKGROUND

Below-knee cast immobilization is associated with an increased risk of developing deep vein thrombosis secondary to venous stasis. We investigated the effect of weight-bearing in a below-knee cast or pneumatic walking boot on lower limb venous blood flow.

METHODS

Duplex ultrasonography was used to measure venous blood flow in the popliteal vein of 10 healthy volunteers. Venous blood flow was measured while at rest, ambulating non-weight-bearing, partial weight-bearing, and full weight-bearing. Measurements were performed without ankle joint immobilization, with the ankle immobilized in a neutral cast, and with the ankle immobilized in a pneumatic walking boot in both neutral and equinus.

RESULTS

There was no significant reduction in venous blood flow measurements between full weight-bearing without ankle joint immobilization and full weight-bearing in a neutral cast or neutral pneumatic walking boot. However, venous blood flow was reduced when partial weight-bearing (50%) and when full weight-bearing in a pneumatic walking boot in equinus.

CONCLUSION

These results demonstrate that venous blood flow returned to normal levels when the subjects were permitted to fully bear weight in below-knee casts or walking boots, provided that the ankle joint was not in equinus.

CLINICAL RELEVANCE

Weight-bearing status and ankle joint position should be appreciated during decisions for the provision of chemical thromboprophylaxis.

The effect of lower limb cast immobilization on calf muscle pump function: a simple strategy of exercises can maintain flow

BACKGROUND

We have investigated the role of the calf muscle pump in casted patients. An audit of venous thromboembolism (VTE) in casted patients showed that the thrombosis occurred in the casted leg; this has not been previously assessed. We postulated that local factors play a major role, and we set out to assess the calf muscle pump in casted patients and to determine whether this can be optimized despite below-knee cast immobilization.

METHODS

We measured the flow in the popliteal vein using a validated method of Doppler ultrasound measurement of peak velocity with and without a below-knee plaster cast.

RESULTS

We demonstrated that a simple strategy of toe and ankle exercises can maintain venous return despite below-knee cast immobilization.

CONCLUSION

This is the first study to examine the effect of the calf muscle pump in the presence of a plaster cast. Major muscle groups such as the flexor hallucis longus and gastrocsoleus extend beyond the field of control of the cast and can still be recruited.

CLINICAL RELEVANCE

We recommend that all patients treated with a below-knee cast be given a program of exercises that can be comfortably performed with the cast; this could provide a useful, inexpensive, and safe thromboprophylaxis strategy acting at the site of greatest risk and targeting a major cause of VTE.

Can foot compression under a plaster cast prevent deep-vein thrombosis during lower limb immobilisation?

We hypothesised that adjuvant intermittent pneumatic compression (IPC) beneath a plaster cast would reduce the risk of deep-vein thrombosis (DVT) during post-operative immobilisation of the lower limb. Of 87 patients with acute tendo Achillis (TA) rupture, 26 were prospectively randomised post-operatively after open TA repair. The treatment group (n = 14) received two weeks of IPC of the foot for at least six hours daily under a plaster cast. The control group (n = 12) had no additional treatment. At two weeks post-operatively all patients received an orthosis until follow-up at six weeks. At two and six weeks the incidence of DVT was assessed using colour duplex sonography by two ultrasonographers blinded to the treatment. Two patients withdrew from the study due to inability to tolerate IPC treatment. An interim analysis demonstrated a high incidence of DVT in both the IPC group (9 of 12, 75%) and the controls (6 of 12, 50%) (p = 0.18). No significant differences in incidence were detected at two (p = 0.33) or six weeks (p = 0.08) post-operatively. Malfunction of the IPC leading to a second plaster cast was found to correlate with an increased DVT risk at two weeks (ϕ = 0.71; p = 0.019), leading to a premature abandonment of the study. We cannot recommend adjuvant treatment with foot IPC under a plaster cast for outpatient DVT prevention during post-operative immobilisation, owing to a high incidence of DVT related to malfunctioning of this type of IPC application.

Comparison of fondaparinux with low molecular weight heparin for venous thromboembolism prevention in patients requiring rigid or semi-rigid immobilization for isolated non-surgical below-knee injury

BACKGROUND

In several small studies, anticoagulant therapy reduced the incidence of venous thromboembolism (VTE) in patients with isolated lower-limb injuries.

OBJECTIVES

To compare the efficacy and safety of fondaparinux 2.5 mg (1.5 mg in patients with a creatinine clearance between 30 and 50 mL min(-1) ) over nadroparin 2850 anti-factor Xa IU.

PATIENTS AND METHODS

In this international, multicenter, randomized, open-label study, patients with an isolated non-surgical unilateral below-knee injury having at least one additional major risk factor for VTE and requiring, in the Investigator's opinion, rigid or semi-rigid immobilization for 21-45 days with thromboprophylaxis up to complete mobilization received subcutaneously once-daily either fondaparinux or nadroparin. The primary efficacy outcome was the composite of VTE (symptomatic or ultrasonographically detected asymptomatic deep vein thrombosis of the lower limb or symptomatic pulmonary embolism) and death up to complete mobilization. The main safety outcome was major bleeding.

RESULTS

We randomized 1349 patients (mean age 46 years): 88.7% had a bone fracture, and 83.8% had a plaster cast fitted (mean duration of immobilization, 34 days). The primary efficacy outcome occurred in 15 of 584 patients (2.6%) in the fondaparinux group and 48 of 586 patients (8.2%) in the nadroparin group (odds ratio, 0.30; 95% confidence interval [CI], 0.15-0.54; P < 0.001). A single major bleed was experienced by fondaparinux-treated patients and none by nadroparin-treated patients. These results were maintained up to the end of follow-up.

CONCLUSIONS

Fondaparinux 2.5 mg day(-1) may be a valuable therapeutic option over nadroparin 2850 anti-FXa IU day(-1) for preventing VTE after below-knee injury requiring prolonged immobilization in patients with additional risk factors.

The cost of outpatient venous thromboembolism prophylaxis following lower limb injuries

This paper reports the cost of outpatient venous thromboembolism (VTE) prophylaxis following 388 injuries of the lower limb requiring immobilisation in our institution, from a total of 7408 new patients presenting between May and November 2011. Prophylaxis was by either self-administered subcutaneous dalteparin (n = 128) or oral dabigatran (n = 260). The mean duration of prophylaxis per patient was 46 days (6 to 168). The total cost (pay and non-pay) for prophylaxis with dalteparin was £107.54 and with dabigatran was £143.99. However, five patients in the dalteparin group required nurse administration (£23 per home visit), increasing the cost of dalteparin to £1142.54 per patient. The annual cost of VTE prophylaxis in a busy trauma clinic treating 12 700 new patients (2010/11), would be £92 526.33 in the context of an income for trauma of £1.82 million, which represents 5.3% of the outpatient tariff. Outpatient prophylaxis in a busy trauma clinic is achievable and affordable in the context of the clinical and financial risks involved.

II Italian intersociety consensus statement on antithrombotic prophylaxis in orthopaedics and traumatology: arthroscopy, traumatology, leg immobilization, minor orthopaedic procedures and spine surgery

Pharmacological prophylaxis for preventing venous thromboembolism (VTE) is a worldwide established procedure in hip and knee replacement surgery, as well as in the treatment of femoral neck fractures, but few data exist in other fields of orthopaedics and traumatology. Thus, no guidelines or recommendations are available in the literature except for a limited number of weak statements about knee arthroscopy and lower limb fractures. In any case, none of them are a multidisciplinary effort as the one here presented. The Italian Society for Studies on Haemostasis and Thrombosis (SISET), the Italian Society of Orthopaedics and Traumatology (SIOT), the Association of Orthopaedic Traumatology of Italian Hospitals (OTODI), together with the Italian Society of Anesthesia, Analgesia, Resuscitation and Intensive Care (SIAARTI) and the Italian Society of General Medicine (SIMG) have set down easy and quick suggestions for VTE prophylaxis in a number of surgical conditions for which only scarce evidence is available. This inter-society consensus statement aims at simplifying the approach to VTE prophylaxis in the single patient with the goal to improve its clinical application.

[Thromboprophylaxis during immobilization of non-surgical traumatic injury in the lower limb. An outpatient perspective]

Thromboprophylaxis with low molecular weight heparin is efficient, effective and generates savings in health costs in hospitals. However, outside hospitals, there are situations of apparent risk of thrombosis, where there seems to be no such consensus. This occurs in traumatic lower limb injuries which are not undergoing surgery and need a period of immobilization. These are processes with multidisciplinary interventions (Emergency, Family Physicians and Traumatology), although during outpatient follow up it is not easy to find criteria for using thromboprophylaxis. We report a case of a pulmonary embolism, with unusual symptoms, in an ambulatory patient with a fractured fibula and metatarsal, who was being treated with Bemiparin. As we shall see, this is a rare complication, but it shows the importance of proper risk assessment of thromboembolic disease in these patients. We emphasize the accompanying tomographic images for their clarity and eloquence.

UK national survey of venous thromboembolism prophylaxis in ankle fracture patients treated with plaster casts

BACKGROUND

Ankle fractures are one of the commonest orthopaedic injuries. A substantial proportion of these are treated non-operatively at outpatient clinics with cast immobilization. We conducted this survey to assess the current practice in UK regarding thromboembolism prophylaxis in these patients.

METHODS

A telephonic survey was carried out on junior doctors within orthopaedic departments of 56 hospitals across the UK. A questionnaire was completed regarding venous thromboembolism risk assessment, prophylaxis, hospital guidelines, etc.

RESULTS

84% (n=47) hospitals did not routinely use any prophylaxis for these patients, while 7% (n=4) hospitals used chemo-prophylaxis. Only 5.3% (n=3) hospitals had DVT prophylaxis guidelines regarding these patients while other 9% (n=5) hospitals were in process of developing such guidelines. In 64% (n=36) hospitals, no formal DVT risk assessment was carried out.

CONCLUSION

A large variation exists across NHS hospitals and a poor risk assessment is being carried out in these patients. Development of local guidelines and extension of national guidelines to include high risk outpatients may improve the situation.

Venous thromboembolism in emergency department patients with rigid immobilization for lower leg injury: Incidence and risk factors

OBJECTIVES

To determine the incidence and risk factors for symptomatic venous thromboembolism (VTE) in adults who are discharged from the ED with rigid immobilization for lower limb injury.

METHODS

Eligible patients presenting between 1 December 2008 and 31 December 2010 were identified retrospectively from the Southern Health ED (Monash Medical Centre, Dandenong Hospital, Casey Hospital, all located in Melbourne, Australia) information system. Age, sex, diagnosis, type of splint and other defined potential VTE risk factors were recorded. VTE was confirmed from archived diagnostic imaging or hospital re-attendance records. Patients presenting between 1 October 2010 and 31 December 2010 were contacted to detect VTE diagnosed and treated outside of Southern Health. VTE incidence is reported, and comparison of risk factors performed.

RESULTS

VTE was initially confirmed in 33 of 1231 patients (2.7%, 95% confidence interval 1.9-3.7). VTE was reported by 3 of 174 in the contacted subgroup (1.7%, 0.4-4.6). Applying this 'missed rate' to the whole sample, the estimated VTE incidence is between 3.1% and 7.1%. Multivariate risk factor analysis found VTE risk to increase with age and a diagnosis of Achilles tendon rupture.

CONCLUSION

The estimated VTE incidence was between 3% and 7% in this ED population with age and diagnosis of Achilles tendon rupture increasing risk. Prospective research to more accurately determine incidence, severity and risk stratification is required before firm recommendations on the likely risk versus benefit profile of thromboprophylaxis can be made for this population.

Venous thromboembolism following prolonged cast immobilisation for injury to the tendo Achillis

We report an audit of 208 patients with a mean age of 39 years (16 to 65) attending the Orthopaedic Assessment Unit at the Wellington Hospital between January 2006 and December 2007 with an injury of the tendo Achillis requiring immobilisation in a cast. Information on assessment of venous thromboembolism (VTE) risk, prophylactic measures and VTE events for all patients was obtained from the medical records. A VTE risk factor was documented in the records of three (1%) patients. One of the 208 patients received aspirin prophylaxis; none received low molecular weight heparin. In all, 13 patients (6.3%, 95% confidence interval 3.4 to 10.5) developed symptomatic VTE during immobilisation in a cast, including six with a distal deep-vein thrombosis (DVT), four with a proximal DVT, and three with a confirmed pulmonary embolus. This incidence of symptomatic VTE is similar to that reported following elective hip replacement. We propose that consideration is given to VTE prophylaxis during prolonged immobilisation of the lower limbs in a cast, to ensure that the same level of protection is provided as for patients undergoing elective hip replacement.