Thromboprophylaxis in elective foot and ankle patients--current practice in the United Kingdom

Risk factors for symptomatic venous thromboembolism following surgery for closed ankle fractures: A case-control study

BACKGROUND

We analyzed risk factors for venous thromboembolism (VTE) within 6 months after surgery for closed ankle fractures.

METHODS

This was a case-control study based on data from chart review in a cohort of patients having open reduction and internal fixation (ORIF) for closed ankle fractures in two large general hospitals 2009-2011. Cases with symptomatic VTE (pulmonary embolism or deep venous thrombosis) were identified in the cohort, and additional cases of VTE were identified by computerized search of discharge diagnoses in the same hospitals in 2004-2008 and 2012-2016. In total, we identified 60 cases with VTE and compared with 240 randomly selected controls among 998 patients without VTE in the cohort. Risk factors were assessed using logistic regression analysis.

RESULTS

Among cases, 27 (45%) had pulmonary embolism, 33 (55%) deep venous thrombosis. Those with VTE were older, had higher BMI, had more often a family history of VTE, and more often had antibiotic prophylaxis during surgery than controls. In multivariable logistic regression analysis age/10 (OR 25.75, 95%CI 3.52-188.44, p=0.001), (age/10)² (OR 0.77, 95%CI 0.65-0.93, p=0.005), BMI (1.15 per kg/m², 95%CI 1.07-1.24, p<0.001) and Charlson comorbidity index ≥2 vs.0 (OR 0.27, 95%CI 0.08-0.92, p=0.036) and 1 vs. 0 (OR 0.27, 95%CI 0.09-0.86, p=0.026) were associated with VTE within 6 months of surgery.

CONCLUSIONS

The odds of symptomatic VTE within 6 months of ORIF increased with increasing age and BMI, but were lower with increasing comorbidity.

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.

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.

A Prospective Cohort Study of Symptomatic Venous Thromboembolic Events in Foot and Ankle Trauma: The Need for Stratification in Thromboprophylaxis?

The incidence of venous thromboembolic (VTE) events (deep vein thrombophlebitis [DVT] or pulmonary embolism [PE]) in foot and ankle trauma has been low, and the risk/benefit ratio associated with chemoprophylaxis is controversial. We compared the 90-day incidence of VTE events in 3 cohorts: group 1, tendo-Achillis (TA) ruptures managed with full weightbearing in a walker boot; group 2, ankle fractures immobilized non-weightbearing in a below-the-knee cast; and group 3, ankle fractures managed surgically, followed by non-weightbearing in a below-the-knee cast. Data were extracted from 2 prospectively collected trust databases for acute TA ruptures and ankle fractures. VTE risk was assessed using a U.K. national assessment tool. Chemoprophylaxis was prescribed for high-risk patients. The 90-day incidence of symptomatic VTE events was drawn from a trust-wide radiology database. In group 1 (n = 291), the incidence of VTE events was 4.8% (11 [3.8%] DVT, 3 [1.0%] PE) at a mean of 16.1 ± 6.8 days. In group 2 (n = 227), the incidence of VTE events was 2.2% (5 [2.2%] DVT) at a mean of 33.4 ± 11.3 days. In group 3 (n = 199), the incidence of VTE events was 3.0% (5 [2.5%] DVT, 1 [0.5%] PE) at a mean of 37.2 ± 14.2 days. Patients with symptomatic VTE events presented significantly earlier after acute TA rupture compared with after ankle fracture (p = .002). We found the overall incidence of VTE events in foot and ankle trauma was low, with a relatively greater incidence of symptomatic VTE events, which occurred earlier, in acute TA ruptures compared with ankle fractures.

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.

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.

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.

What is the evidence for chemical thromboprophylaxis in foot and ankle surgery? Systematic review of the English literature

Venous thromboembolism (VTE) is a well documented complication following lower limb trauma and surgery. The incidence of VTE in hip and knee surgery has been well studied, whereas the incidence in foot and ankle surgery is less clear. There is debate as to which cases require prophylaxis and what is the most effective means by which this is achieved. We performed a systematic review of the published English literature on VTE prophylaxis in foot and ankle surgery using MEDLINE, EMBASE, CINHAL, Cochrane Library, without date restrictions up to December 2012. From 988 citations, 25 papers fulfilled the inclusion criteria. Conclusions were drawn on the incidence (symptomatic and asymptomatic VTE), location (distal vs. proximal), associated risk factors, timing of VTE, role of mechanical and pharmacological prophylaxis and cost effectiveness of the treatment. Our review showed that the overall incidence of symptomatic VTE in foot and ankle surgery is low (0-0.55%). There is increased incidence in foot and ankle trauma patients with the highest incidence reported in tendo-achilles surgery. The reported risk factors include previous history of VTE, immobilisation, high BMI, age, co morbidities, contraceptive pill, and air-travel. There is a cumulative effect resulting in higher risk when two or more risk factors are present.

Low incidence of symptomatic thromboembolic events after total ankle arthroplasty without routine use of chemoprophylaxis

BACKGROUND

There is little evidence regarding the incidence of symptomatic venous thromboembolism (VTE) following total ankle arthroplasty (TAA) to allow formulation of treatment recommendations. The purpose of this study was to determine the incidence of symptomatic VTE events after TAA without use of chemoprophylaxis and to identify risk factors contributing to the occurrence of VTEs.

METHODS

We conducted a retrospective chart review of 637 patients (664 ankles) who received a TAA between May 2007 and January 2014 and had a minimum follow-up of 3 months. Chemoprophylaxis was prescribed only in the setting of a history of VTE or active coagulopathy. Patients were continued on chemoprophylactic agents if they were taking these medications preoperatively. A VTE event was defined when clinical signs and symptoms of deep venous thrombosis (DVT) were confirmed with use of Doppler ultrasonography or pulmonary embolism was confirmed with the use of a computed tomography scan. Routine screening for VTE was not performed.

RESULTS

The overall incidence of clinically detected VTE events was 0.60% (4/664), with 0.45% (3 patients) developing a DVT and 0.15% (1 patient) developing a nonfatal pulmonary embolism. Moreover, we identified a subset of 434 patients without identifiable preoperative risk factors who were not taking chemoprophylaxis preoperatively and were not prescribed chemoprophylaxis postoperatively. Two of these patients developed a DVT postoperatively (0.46%). Given the low incidence of clinically detected VTE, no significant correlation could be identified between the occurrence of VTE events and risk factors.

CONCLUSIONS

Our results suggest that clinically detectable VTE after TAA is uncommon. Patients without identifiable risk factors do not appear to require chemoprophylaxis following TAA. We recommend continuation of antiplatelet or anticoagulation therapy in patients who are taking these medications preoperatively and the initiation of chemoprophylaxis postoperatively in patients with known risk factors for VTE.

LEVEL OF EVIDENCE

Level IV, case series.

The impact of risk assessment on the implementation of venous thromboembolism prophylaxis in foot and ankle surgery

BACKGROUND

The purpose of this prospective study was to determine whether the more frequently quoted procedure and patient specific risk factors have any impact in the implementation of venous thromboembolism (VTE) prophylaxis following foot and ankle surgery.

METHODS

Two hundred and sixteen patients were included in the study. A variety of operative procedures was carried out with the common denominator being a below knee cast for at least 4 weeks and nonweightbearing for an average of 6 weeks in 130 patients. The remainder of the patients (88) had hallux surgery not requiring a cast and were allowed to weightbear. No patient received any form of thromboprophylaxis postoperatively. All patients were subjected to compression ultrasonography for deep vein thrombosis (DVT) between 2 and 6 weeks postoperatively.

RESULTS

There was a 5.09% incidence of VTE (0.9% pulmonary embolism) overall. As no VTE (neither DVT nor pulmonary embolus) developed in the hallux subgroup, i.e. patients not requiring immobilization and were allowed to weightbear, the incidence of VTE in the cast/nonweightbearing group was 8.46%. The results are descriptive and only statistically analyzed where possible, as the sample size of the VTE group was small. There was no significant difference in number of risk factors and no association between gender in the VTE and non VTE groups. 90.9% of patients in the VTE group had a total risk factor score of 5 or more and 73.7% of patients in the non VTE group had a total risk factor score of 5 or more. The average timing to the diagnosis of VTE in this current study was 33.1 days.

CONCLUSIONS

In view of the unacceptable incidence of VTE and the average total risk factor score of 5 or more (for which thromboprophylaxis is recommended) in the majority of the patients, the authors feel that the routine use of thromboprophylaxis in foot and ankle surgery requiring nonweightbearing in combination with short leg cast immobilization, is warranted. This prophylaxis should continue until the patient regains adequate mobility either by weightbearing (in or out of the cast) or removal of cast immobilization (weightbearing or nonweightbearing), usually between 28 and 42 days.