Deep-vein thrombosis prophylaxis in foot and ankle surgery: what is the current state of practice?

Venous Thromboembolism in Foot and Ankle Trauma

Every surgeon may have experienced a tragic event associated with death or debilitation secondary to deep vein thrombosis (DVT) or pulmonary embolism (PE) after foot and ankle trauma and surgery. Nevertheless, the prevention of such a tragic event needs to be carefully evaluated rationally with currently available epidemiologic data. With great postoperative protocols and access to care, most PE events can be prevented. There are modifiable risk factors, such as length/type of immobilization and operative trauma/time that can lower the incidence of DVT/PE. In addition, chemical prophylaxis may be warranted in certain people within the foot and ankle trauma population.

Using machine learning in the prediction of symptomatic venous thromboembolism following ankle fracture

BACKGROUND

Venous thromboembolism (VTE) is a major cause of morbidity and mortality in the trauma setting, and both prediction and prevention of VTE have long been a concern for healthcare providers in orthopedic surgery. The purpose of this study was to evaluate the use of novel statistical analysis and machine-learning in predicting the risk of VTE and the usefulness of prophylaxis following ankle fractures.

METHODS

The medical profiles of 16,421 patients with ankle fractures were screened retrospectively for symptomatic VTE. In total, 238 patients sustaining either surgical or nonsurgical treatment for ankle fracture with subsequently confirmed VTE within 180 days following the injury were placed in the case group. Alternatively, 937 patients who sustained ankle fractures managed similarly but had no documented evidence of VTE were randomly chosen as the control group. Individuals from both the case and control populations were also divided into those who had received VTE prophylaxis and those who had not. Over 110 variables were included. Conventional statistics and machine learning methods were used for data analysis.

RESULTS

Patients who had a motor vehicle accident, surgical treatment, increased hospital stay, and were on warfarin were shown to have a higher incidence of VTE, whereas patients who were on statins had a lower incidence of VTE. The highest Area Under the Receiver Operating Characteristic Curves (AUROC) showing the performance of our machine learning approach was 0.88 with 0.94 sensitivity and 0.36 specificity. The most balanced performance was seen in a model that was trained using selected variables with 0.86 AUROC, 0.75 sensitivity, and 0.85 specificity.

CONCLUSION

By using machine learning, this study successfully pinpointed several predictive factors linked to the occurrence or absence of VTE in patients who experienced an ankle fracture. Training these algorithms using larger, more granular, and multicentric data will further increase their validity and reliability and should be considered the standard for the development of such algorithms.

LEVEL OF EVIDENCE

Case-Control study - 3.

Venous Thromboembolism Prophylaxis in Foot and Ankle Surgery: A Worldwide Survey

Current recommendations on thromboprophylaxis for foot and ankle (FA) surgery are often inconsistent and generally based on weak evidence. The aim of this survey study was to evaluate the current practice among orthopedic surgeons regarding venous thromboembolism (VTE) prophylaxis following FA surgery. From February 2019 to March 2020, an online questionnaire was sent by e-mail to orthopedic societies across the world. The questionnaire was hosted by the International Society of Thrombosis and Haemostais RedCAP platform. Topics of interest were VTE rates following FA surgery, duration and type of thromboprophylaxis, bleeding complications, VTE risk factors for prophylaxis and use of risk assessment. A total of 693 FA orthopedic surgeons from all continents completed the survey of whom 392 (57%) performed more than 200 FA procedures per year. A total of 669/693 (97%) respondents stated that thromboprophylaxis is necessary in FA surgeries. When thromboprophylaxis was prescribed, half of surgeons prescribed it for the duration of immobilization. Acetylsalicylic acid, low molecular weight heparin and direct-oral anticoagulants were, in this order, the preferred choice. Acetylsalicylic acid and low molecular weight heparin were predominantly prescribed in North America and Europe, respectively. Previous deep vein thrombosis, immobility, obesity and inherited thrombophilia were considered the main risk factors indicative of thromboprophylaxis use. In this survey, most surgeons agree that thromboprophylaxis is indicated for FA surgery, but the prescription, type and duration of prophylaxis differs greatly with a large intercontinental discrepancy. These survey results could be a foundation for developing uniform guidelines to optimize thromboprophylactic strategies in FA procedures around the world.

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.

Venous thromboembolism in patients with surgically treated ankle fractures

OBJECTIVES

In patients with rotational ankle fracture, we compare the rate of venous thromboembolism development between patients who received chemoprophylaxis vs those patients that received none.

DESIGN

Retrospective cohort study.

SETTING

Level I trauma center.

PATIENTS/PARTICIPANTS

Between 2014 and 2018, we identified 483 patients with rotational ankle fracture that had no VTE risk factors, were under 70 years of age, and had an isolated injury.

INTERVENTION

Chemoprophylaxis vs no chemoprophylaxis after open reduction internal fixation of a rotational ankle fracture.

MAIN OUTCOME MEASUREMENTS

Development of VTE was the primary outcome. Secondary outcomes included wound problems, infection, hematoma, or non-union.

RESULTS

There were 313 patients that received no prophylaxis and 170 patients that received chemoprophylaxis after operative fixation of an isolated ankle fracture. Demographics including age, gender, body mass index, and ASA class were similar between groups. The rate of DVT/PE was 3.5% in those without DVT prophylaxis, and 4.1% in those on DVT prophylaxis with no significant differences found (p = 0.8). There was no significant difference in wound complication (no VTE prophylaxis-3.7% vs VTE prophylaxis-2.5%, p = 0.7) or infection rates (no VTE prophylaxis-3.8% vs VTE prophylaxis 4.1%, p = 1.0) between groups.

CONCLUSIONS

No difference was detected in the rate of symptomatic DVT or PE in patients based on chemoprophylaxis. Our results support the conclusion that the use of chemoprophylaxis may remain surgeon preference and based on patient risk factors for VTE development.

LEVEL OF EVIDENCE

Level III-retrospective cohort study.

Causes of unplanned admission after orthopedic procedures in ambulatory surgery

OBJECTIVE

Orthopaedic procedures performed in Day Surgery Units provide important advantages which disappear when patients require admission when postoperative recovery is not as expected. The aim of this study was to analyse the reasons for unplanned hospital admissions after orthopaedic procedures in a Day Surgery Unit and their relationship between variables such as patient age, anaesthetic risk and technique, procedure or duration.

METHODS

Ambispective cohort study of 5,085 patients who underwent surgical orthopaedic procedures between 1995 and 2017. Thirty-nine variables provided by the Unit's database were analysed. The database was opened on the day of admission and closed the 30th postoperative day.

RESULTS

Of the patients, 98.2% were discharged from the Unit. Seventy-four (1.5%) required overnight admission. This percentage showed significant differences in relation to the type of procedure, type of anaesthesia and duration, which conditioned overnight admission due to inadequate postoperative pain management, nausea or wound complications. Seventeen patients (0.3%) required readmission after discharge due to complications that arose at home, such as wound infection, which was the most common.

CONCLUSIONS

Unplanned admissions are more frequently related to general anaesthesia, lengthy surgeries and procedures such as arthroscopy, hallux valgus corrections or removal of osteosynthesis material. The major reasons for unplanned admissions were inadequate postoperative pain management for overnight admissions and wound infection for admissions after discharge.

Incidence of and Risk Factors for Venous Thromboembolism After Foot and Ankle Surgery

Background: Venous thromboembolism (VTE) is a rare but potentially lethal complication after orthopaedic foot and ankle surgery. The true incidence of VTE after orthopaedic foot and ankle surgery stratified by specific procedure has yet to be examined. The purpose of this study is to report the incidence of and identify risk factors for VTE in a large sample of patients receiving orthopaedic foot and ankle surgery. Methods: In this study, we retrospectively analyzed data from the National Surgical Quality Improvement Program 2006 to 2015 data files. The incidence of VTE was calculated for 30 specific orthopaedic foot and ankle surgeries and for 4 broad types of foot and ankle surgery. Demographic, comorbidity, and complication variables were analyzed to determine associations with development of VTE. Results: The overall incidence of VTE in our sample was 0.6%. The types of procedures with the highest frequency of VTE were ankle fractures (105/15 302 cases, 0.7%), foot pathologies (28/5466, 0.6%), and arthroscopy (2/398, 0.5%). Female gender, increasing age, obesity, inpatient status, and nonelective surgery were all significantly associated with VTE. Conclusion: Although VTE after orthopaedic foot and ankle surgery is a rare occurrence, several high-risk groups and procedures may be especially indicated for chemical thromboprophylaxis. Levels of Evidence: Level III: Retrospective, comparative study.

Incidence and Risk Factors Associated with Venous Thromboembolism After Orthopaedic Below-knee Surgery

INTRODUCTION

Among patients undergoing below-knee orthopaedic surgery, no consensus exists regarding the need for or type of postoperative prophylaxis to prevent venous thromboembolic (VTE) events. The purpose of this study was to assess the incidence and risk factors associated with symptomatic VTE among orthopaedic patients undergoing below-knee surgery who were subject to different types of pharmacologic thromboprophylactic strategies.

METHODS

A total of 20,043 adult patients who underwent surgery for a below-knee orthopaedic condition between August 2005 and August 2015 were identified. Retrospective chart review recorded patient demographics, comorbid data, and anatomic location of any procedures performed. Multivariable logistic regression analysis was used to determine factors associated with postoperative development of symptomatic VTE among patients receiving various thromboprophylactic regimens.

RESULTS

The incidence of symptomatic VTE in patients who underwent below-knee surgery was 2.5% (492/20,043). For patients who did not receive thromboprophylaxis, the incidence was 1.5% (134/9,127 patients). In this group, risk factors for developing VTE were male sex; nonwhite race; surgery performed below the knee but above the ankle; combination procedures of the forefoot/midfoot, hindfoot/ankle, and/or lower leg; history of VTE; and Charlson Comorbidity Index score greater than 2. Among patients who received an antiplatelet agent, the VTE incidence was 1.7% (33/1,992 patients). The incidence of VTE among patients who received an oral or injectable anticoagulant was 3.6% (325/8,924 patients). In this group, risk factors for developing VTE were male sex; surgery performed below the knee but above the ankle; combination procedures of the forefoot/midfoot, hindfoot/ankle, and/or lower leg; and history of VTE.

CONCLUSION

Allowing for different types of thromboprophylactic strategies, the results of this study demonstrate a higher rate of symptomatic thromboembolic disease compared with previously reported <1% VTE incidence rates among orthopaedic patients undergoing below-knee surgery. Certain patients are at higher risk for thromboembolic disease after below-knee orthopaedic surgery. This risk was not found to be lowered by thromboprophylaxis as performed in patients in this database. Future research should be directed at determining what the best thromboprophylactic strategies are for lowering this risk.

LEVEL OF EVIDENCE

Therapeutic study level III.

Venous Thromboembolism and Bleeding Adverse Events in Lower Leg, Ankle, and Foot Orthopaedic Surgery with and without Anticoagulants

BACKGROUND

Currently, there is insufficient knowledge about the benefits of anticoagulant use for primary prevention of venous thromboembolism (VTE) and its inherent risk of bleeding adverse events in patients undergoing surgery distal to the knee.

METHODS

The study included patients who had undergone an orthopaedic procedure distal to the tibial articular surface when they were 18 years of age or older. Using retrospective information from a tertiary care referral center, we compared patient demographics, clinical findings, diagnostic reports, procedures performed, and the rate of symptomatic VTE and bleeding adverse events between patients who had and those who had not received anticoagulant prophylaxis. Propensity score matching was used to minimize selection bias due to prophylactic treatment allocation.

RESULTS

A total of 5,286 patients who had received anticoagulant prophylaxis for below-the-knee surgery were successfully matched with 5,286 patients who had not received anticoagulant prophylaxis for such surgery. After propensity score matching, the standardized difference between the groups was <0.1 for all baseline characteristics, indicating a negligible difference between the groups. Patients who received anticoagulant prophylaxis had a significantly lower risk of developing a VTE compared with patients who did not (39 patients [0.7%] versus 99 patients [1.9%]), with an odds ratio (OR) of 0.38 (95% confidence interval [CI], 0.25 to 0.56; p < 0.001). In contradistinction, patients who received anticoagulant prophylaxis had a significantly higher risk of developing a bleeding adverse event than those who did not (115 [2.2%] versus 55 [1.0%]; OR, 2.18 [95% CI, 1.55 to 3.09]; p < 0.001).

CONCLUSIONS

Anticoagulant prophylaxis reduced the risk of VTE after surgery distal to the tibial articular surface by 3-fold but resulted in a concomitant 2-fold increase in the risk of a bleeding adverse event. Large-scale, prospective studies are necessary to better understand the true incidence of such events, associated patient-specific risk factors, efficacy of various thromboprophylactic regimens, and patient-reported implications of such events.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Prevalence of Deep Vein Thrombosis in Low-Risk Patients After Elective Foot and Ankle Surgery

BACKGROUND:

The evidence regarding the prevalence of deep vein thrombosis (DVT) after foot and ankle surgery in elective patients that need to be 6 weeks non-weight bearing postoperatively is incomplete and has limitations.

METHODS:

The prevalence of DVT in 114 procedures involving the hindfoot and midfoot was determined using ultrasonographic surveillance at 2 and 6 weeks after surgery.

RESULTS:

The prevalence of DVT was observed to be 25.4%. The majority (68.9%) of DVTs were diagnosed at the ultrasonographic scan performed 2 weeks postoperatively. The remainder (31.1%) of DVTs were diagnosed at the 6-week postoperative ultrasonographic scan. At least 75% of the patients who had early and late DVT had no clinical symptoms or signs of DVT. The prevalence of DVT in clinically detectable patients was 6%. The average age of patients with early DVT was 62.2 years, significantly higher compared to those who had no DVT. The mean tourniquet time for patients with early DVT was 68.1 minutes, significantly higher compared to those without DVT. All DVTs detected were distal to the popliteal vein.

CONCLUSIONS:

The prevalence of clinically silent DVT was significantly higher than was previously thought. We believe this increased rate is directly attributable to the use of ultrasonographic surveillance postsurgery both at 2 and 6 weeks. The risk of DVT continued after the 2-week visit, and 30% of the DVTs were detected at the ultrasonographic scan at 6 weeks.

LEVEL OF EVIDENCE:

Level II, prospective cohort.

Incidence and Risk Factors of Symptomatic Venous Thromboembolism Following Foot and Ankle Surgery

BACKGROUND:

The incidence rate of venous thrombotic events (VTEs) following foot and ankle surgery is low. Currently, there is no consensus regarding postoperative prophylaxis or evidence to support risk stratification.

METHODS:

A 2-part study assessing the incidence and factors for the development of VTE was conducted: (1) a retrospective observational cohort study of 22 486 adults to calculate the overall incidence following foot and/or ankle surgery from January 2008 to May 2011 and (2) a retrospective matched case-control study to identify risk factors for development of VTE postsurgery. One control per VTE case matched on age and sex was randomly selected from the remaining patients.

RESULTS:

The overall incidence of VTE was 0.9%. Predictive risk factors in bivariate analyses included obesity, history of VTE, history of trauma, use of hormonal replacement or oral contraception therapy, anatomic location of surgery, procedure duration 60 minutes or more, general anesthesia, postoperative nonweightbearing immobilization greater than 2 weeks, and use of anticoagulation. When significant variables from bivariate analyses were placed into the multivariable regression model, 4 remained statistically significant: adjusted odds ratio (aOR) for obesity, 6.1; history of VTE, 15.7; use of hormone replacement therapy, 8.9; and postoperative nonweightbearing immobilization greater than 2 weeks, 9.0. The risk of VTE increased significantly with 3 or more risk factors ( P = .001).

CONCLUSION:

The overall low incidence of VTE following foot and ankle surgery does not support routine prophylaxis for all patients. Among patients with 3 or more risk factors, the use of chemoprophylaxis may be warranted.

LEVEL OF EVIDENCE:

Level III, retrospective case series.

Prevention of Deep Venous Thromboembolism in Foot and Ankle Surgery

Although rare, deep vein thrombosis (DVT) and pulmonary embolism remain a concern for foot and ankle surgeons. Most prophylactic measures against DVT formation are synthesized from orthopedic hip and knee data, and therefore the routine use of these recommendations may place patients at risk for complications associated with unnecessary prophylaxis. In this article we review and present the most current literature specific to venous thromboembolism (VTE) in foot and ankle surgery. It is clear that, given our current literature, a case-by-case approach for VTE prophylaxis should be used following foot and ankle surgery.

Routine Use of Low-Molecular-Weight Heparin For Deep Venous Thrombosis Prophylaxis After Foot and Ankle Surgery: A Cost-Effectiveness Analysis

The purpose of the present study was to determine whether certain foot/ankle surgeries would benefit from the routine use of low-molecular-weight heparin (LMWH) as postoperative deep venous thrombosis prophylaxis. We conducted a formal cost-effectiveness analysis using a decision analytic tree to explore the healthcare costs and health outcomes associated with a scenario of no prophylaxis and a scenario of routine LMWH prophylaxis for 4 weeks. The 2 scenarios were compared for 5 procedures: (1) Achilles tendon repair (ATR), (2) total ankle arthroplasty (TAA), (3) hallux valgus surgery (HVS), (4) hindfoot arthrodesis (HA), and (5) ankle fracture surgery (AFS). The outcomes assessed included short- and long-term costs, quality-adjusted life-years (QALYs), and incremental cost per QALY gained. The costs were evaluated from the healthcare system perspective and are expressed in U.S. dollars at a 2015 price base. In the short term, routine prophylaxis was always associated with greater costs compared with no prophylaxis. For ATR, TAA, HA, and AFS, prophylaxis was associated with slightly better health outcomes; however, the gain in QALYs was minimal compared with the cost of prophylaxis (incremental cost-effectiveness ratio well above $50,000/QALY threshold). For HVS, prophylaxis was associated with both worse health outcomes and greater costs. In the long term, routine prophylaxis was always associated with worse health outcomes and either cost more (HA, AFS, HVS) or saved very little (ATR, TAA). We concluded that policies encouraging the routine use of LMWH after foot/ankle surgery are unlikely to be cost-effective. Decisions to perform prophylaxis should be on a case-by-case basis and should emphasize individual patient risk factors.

VTE primary prevention, including hospitalised medical and orthopaedic surgical patients

Primary prevention is the key to managing a significant proportion of the burden of venous thromboembolism (VTE), defined as deep venous thrombosis (DVT) or pulmonary embolism (PE). This is because VTE may lead to sudden death or are often misdiagnosed and therefore treatment is not feasible. Primary prevention usually commences in hospital as VTE following hospitalisation adds to the significant disease burden worldwide. Numerous medical, surgical and other risk factors have been recognised and studied as indications for prophylaxis. The risk of VTE continues following admission to hospital with a medical or surgical condition, usually long after discharge and therefore prolonged primary prophylaxis is often recommended. Clinical and observational studies in surgical patients show this risk extends for months and perhaps more than one year, for medical patients the risk extends for at least several weeks. For the specific groups of patients at higher risk of developing VTE primary prevention, either pharmaceutical or mechanical, is recommended. The aim of this review is to describe the population at risk, the main related risk factors and the approach to thromboprophylaxis in different populations.

Chemoprophylaxis for Venous Thromboembolism in Operative Treatment of Fractures of the Tibia and Distal Bones: A Systematic Review and Meta-analysis

OBJECTIVES

Clinical practice has shifted from therapeutic anticoagulation of any lower extremity venous thromboembolism (VTE) to only thromboses with risk of proximal extension or embolization-clinically important VTE (CIVTE). Isolated operative fractures of the tibia or distal bone of the lower extremity are associated with low-to-intermediate VTE risk, and there is wide variability in the choice to anticoagulate as well as anticoagulant. We sought to evaluate the role for chemoprophylaxis of VTE and CIVTE in these injuries by meta-analysis of Level I evidence.

DATA SOURCES

Articles in English, Chinese, French, and German in MEDLINE, Biosis, and EMBASE from 1988 to 2016.

STUDY SELECTION

Randomized controlled trials describing chemoprophylaxis of VTE after operative management of fractures of the tibia and distal bones. Independent review of 1502 citations yielded 5 studies (1181 patients) meeting inclusion criteria.

DATA EXTRACTION

Chemoprophylaxis regimen, VTE, CIVTE, and major bleeding events were recorded. Study quality was assessed with regard to randomization, outcome assessment allocation and treatment concealment, and commercial funding.

DATA SYNTHESIS

A random-effects model meta-analysis determined that chemoprophylaxis with a low-molecular-weight heparin (LMWH) compared with placebo or no intervention significantly reduced the risk of any VTE [pooled relative risk (RR) = 0.696, 95% confidence interval (0.490-0.989), P = 0.043; homogeneity P = 0.818, I = 0%]. However, chemoprophylaxis with a LMWH compared with placebo did not significantly reduce the risk of CIVTE [RR = 0.865, 95% confidence interval (pooled RR = 0.112-3.863), P = 0.790; homogeneity P = 0.718, I = 0%]. No major bleeding events occurred. Funnel plots did not suggest publication bias. The number needed to treat was 31 patients treated with chemoprophylaxis using a LMWH to prevent 1 VTE and 584 patients to prevent 1 CIVTE.

CONCLUSIONS

Meta-analysis of Level I evidence suggests that routine postoperative anticoagulation after surgical management of an isolated fracture of the tibia or distal bone in patients without risk factors for VTE is unlikely to provide a clinical benefit, based on the absence of a treatment effect for preventing VTE warranting therapeutic anticoagulation.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Venous Thromboembolic Prophylaxis in Foot and Ankle Surgery: A Review of Current Literature and Practice

Venous thromboembolism (VTE) is a well-known and feared complication following foot and ankle surgery, as it is a source of morbidity and mortality in the perioperative phase. The most recent CHEST guidelines recommended against the use of chemoprophylaxis and the majority of the literature has found a low incidence of VTE following foot and ankle surgery. Some authors prefer screening patients for risk factors and recommend the use of chemoprophylaxis on a case-by-case basis. Interestingly, studies that found high incidence of VTE were unable to determine a statistically significant difference between the prophylaxis and placebo groups. Major limitations of retrospective reviews is they are only able to study symptomatic VTE because no routine screening is typically performed. In a survey study, up to 98% of foot and ankle surgeons responded that they use prophylaxis in high-risk patients. Despite evidence-based recommendations, a significant number of foot and ankle surgeons are routinely using some form of VTE prophylaxis without taking risk factors into account.

LEVELS OF EVIDENCE

Clinical, Level IV: Review Article.

Effect of Chemical Thromboprophylaxis on the Rate of Venous Thromboembolism After Treatment of Foot and Ankle Fractures

BACKGROUND

Venous thromboembolism (VTE) is a well-documented complication in patients with lower limb fractures, but management guidelines for its prevention in isolated foot and ankle fracture patients are conflicting. The aim of this study was to conduct a multicenter, prospective cohort study to define the prevalence of VTE in patients with isolated foot and ankle fractures and determine whether routine prophylaxis is necessary in these patients.

METHODS

In a double-blind, placebo-controlled study, consecutive patients in 3 hospitals who met our criteria were enrolled. After randomization, patients received either thromboprophylaxis with low-molecular-weight heparin units (LMWH group) or placebo (placebo group) for a period of 2 weeks. All patients underwent routine ultrasonography 1 day preoperatively, 1 week postoperatively, and 1 month postoperatively. Demographic parameters were then collected and compared.

RESULTS

Of the 814 patients who met our criteria, 19 patients (2.3%, 95% confidence interval [CI], 0%-31.9%) were found to have objectively confirmed VTE, but none of the patients were symptomatic. Of the 411 patients in the LMWH group, 2 developed VTEs preoperatively and 4 postoperatively; of the 403 patients in the placebo group, 5 developed VTEs preoperatively and 8 postoperatively. The overall incidence of asymptomatic postoperative deep vein thrombosis (DVT) was 0.98% (95% CI 0%-20.3%) in the LMWH group and 2.01% (95% CI 0%-29.5%) in the placebo group without significant difference. Advanced age (odds ratio [OR] 1.050, 95% CI 1.014-1.088, P = .007) and high body mass index (OR 1.201, 95% CI 1.034-1.395, P = .016) were identified as risk factors in predicting occurrence of DVT. No fatal pulmonary emboli or major bleeding complication occurred in either group.

CONCLUSION

Routine anticoagulant prophylaxis was not found to be necessary for patients with foot and ankle fractures, although further investigation with a properly powered study design is required to definitively determine which foot and ankle patients are best served by anticoagulation and which ones are not.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

Deep vein thrombosis is accurately predicted by comprehensive analysis of the levels of microRNA-96 and plasma D-dimer

The aim of the present study was to investigate the association between platelet microRNA-96 (miR-96) expression levels and the occurrence of deep vein thrombosis (DVT) in orthopedic patients. A total of consecutive 69 orthopedic patients with DVT and 30 healthy individuals were enrolled. Ultrasonic color Doppler imaging was performed on lower limb veins after orthopedic surgery to determine the occurrence of DVT. An enzyme-linked fluorescent assay was performed to detect the levels of D-dimer in plasma. A quantitative polymerase chain reaction assay was performed to determine the expression levels of miR-96. Expression levels of platelet miR-96 were significantly increased in orthopedic patients after orthopedic surgery. miR-96 expression levels in orthopedic patients with DVT at days 1, 3 and 7 after orthopedic surgery were significantly increased when compared with those in the control group. The increased miR-96 expression levels were correlated with plasma D-dimer levels in orthopedic patients with DVT. However, for the orthopedic patients in the non-DVT group following surgery, miR-96 expression levels were correlated with plasma D-dimer levels. In summary, the present results suggest that the expression levels of miR-96 may be associated with the occurrence of DVT. The occurrence of DVT may be accurately predicted by comprehensive analysis of the levels of miR-96 and plasma D-dimer.

Diagnostic accuracy of deep vein thrombosis is increased by analysis using combined optimal cut-off values of postoperative plasma D-dimer levels

The present study aimed to evaluate the accuracy of analysis using optimal cut-off values of plasma D-dimer levels in the diagnosis of deep vein thrombosis (DVT). A total of 175 orthopedic patients with DVT and 162 patients without DVT were included in the study. Ultrasonic color Doppler imaging was performed on lower limb veins prior to and following orthopedic surgery in order to determine the types of orthopedic conditions that were present. An enzyme-linked fluorescent assay was performed to detect the expression levels of D-dimer in plasma, and receiver operating characteristic analysis was performed to predict the occurrence of DVT on the basis of the expression levels of D-dimer. After surgery, the expression levels of D-dimer in the plasma of DVT patients were significantly higher in comparison with those in orthopedic patients without DVT (P<0.05). When the patients were divided into subgroups according to the underlying orthopedic condition, the expression levels of D-dimer in the plasma of each subgroup were higher 1 day after orthopedic surgery in comparison to those prior to surgery (P<0.05). The diagnostic accuracy achieved using combined optimal cut-off values at 1 and 3 days post-surgery was significantly higher than the accuracy when using a single optimal cut-off value (P<0.05). In conclusion, detection of D-dimer expression levels at 1 day post-orthopedic surgery may be important in predicting DVT. In addition, the diagnostic accuracy of DVT is significantly increased by analysis using combined optimal cut-off values of D-dimer plasma expression levels.