Deep venous thrombosis risk assessment,incidence, and prophylaxis in foot and ankle surgery

As discussed in this review, DVT and PE are dangerous clinical diagnoses that can occur following foot and ankle surgery. The authors have provided a clinical protocol, a risk assessment tool, and treatment guidelines for this condition that can be applied to the everyday practice of foot and ankle surgeons. Unlike recommendations in previous studies, the authors believe that podiatric and orthopedic surgeons operating on the foot and ankle should evaluate each patient carefully and consider pharmacologic prophylaxis against DVT formation when significant risk factors are present.     

Pulmonary embolism following operative treatment of ankle fractures: a report of three cases and review of the literature

The risks of thromboembolism following operative treatment of ankle fractures are deep vein thrombosis (DVT) and pulmonary embolism (PE). These are potentially life-threatening complications. Many orthopedic surgeons fail to appreciate the potential complications of thromboembolic events because of their rare and delayed occurrence in foot and ankle operations. The purpose of this report is to describe the potential for DVT and PE following ankle operations. We present three cases in which patients who underwent operative treatment of ankle fractures subsequently developed PE. We also review the literature on the prevalence of thrombosis, risk factors, methods of prophylaxis, and use of prophylaxis in surgical procedures of the lower extremity.     

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.     

Incidence of DVT following surgery of the foot and ankle

A prospective study was undertaken to establish the incidence of deep vein thrombosis (DVT) in patients who had undergone surgery of the foot and ankle. All consecutive patients who underwent foot and ankle surgery in the senior author's practice had duplex ultrasound performed of the bilateral calves at the first postoperative visit. Of 201 patients, deep calf clots were found in seven patients (3.5%), but none of these showed progression on follow-up ultrasound or extension proximal to the calf. By the authors' criteria, none of the studied patients required treatment. The authors feel that the rate and progression of DVT after foot and ankle surgery is low and does not require routine prophylaxis. Factors associated with risk of DVT formation were postoperative immobilization, hindfoot surgery, tourniquet time and advancing age.     

Thromboprophylaxis in neurosurgery and head trauma

The incidence of deep vein thrombosis (DVT) is between 20 and 35% using contrast venography, with a rate of symptomatic DVT between 2.3 and 6% in neurosurgery without any prophylaxis. The risk of DVT is poorly evaluated in head injured patients but is around 5%. Specific risk factors in neurosurgery are: a motor deficit, a meningioma or malignant tumour, a large tumour, age over 60 years, surgery lasting more than 4 hours, a chemotherapy. The benefit of mechanical methods or low molecular weight heparin (LMWH) for the prevention of DVP in neurosurgery is demonstrated (grade A). Each method decreases the risk by about 50%. A postoperative prophylaxis with a LMWH does not seem to increase the risk of intracranial bleeding (grade C). There is no demonstrated benefit to begin a prophylaxis with LMWH before the intervention. The duration of the prophylaxis is 7 to 10 days but this has not been scientifically determined.     

Current trends in thromboprophylaxis in surgery of the foot and ankle

BACKGROUND: Few studies exist to guide the best practice in thromboprophylaxis after foot and ankle surgery. A survey of foot and ankle surgeons was performed to assess current trends in thromboprophylaxis. METHODS: An email-based survey of American and British foot and ankle surgeons was conducted. Surgeons were questioned as to their use and type(s) of thromboprophylaxis as well as reasons for not using prophylaxis. Surgeons also were asked about their use of thromboprophylaxis in hip and knee arthroplasty, if they did these surgeries. RESULTS: Nearly one-fifth (19%, 27) of surgeons routinely used thromboprophylaxis in both elective and trauma foot and ankle surgery. The most common situation for use was in a postoperative patient who was immobilized and nonweightbearing. A lack of published evidence and a low rate of thromboembolism were the most commonly cited reasons for not using thromboprophylaxis. CONCLUSIONS: This survey showed a wide variability in thromboembolic prophylaxis. It suggests that despite the literature indicating to the contrary, a significant proportion of foot and ankle surgeons routinely use thromboprophylaxis. Confusion remains regarding the appropriateness of thromboprophylaxis and what type(s)(if any) should be used. This study has identified a need for more in-depth evaluation of the importance of, and possible prophylaxis against, thromboembolic problems after foot and ankle surgery.     

Venous thromboembolic events following foot and ankle surgery in the English National Health Service

Diagnostic and operative codes are routinely collected for every patient admitted to hospital in the English NHS. Data on post-operative complications following foot and ankle surgery have not previously been available in large numbers. Data on symptomatic venous thromboembolism events and mortality within 90 days were extracted for patients undergoing fixation of an ankle fracture, first metatarsal osteotomy, hindfoot fusions and total ankle replacement over a period of 42 months. For ankle fracture surgery (45 949 patients), the rates of deep-vein thrombosis (DVT), pulmonary embolism and mortality were 0.12%, 0.17% and 0.37%, respectively. For first metatarsal osteotomy (33 626 patients), DVT, pulmonary embolism and mortality rates were 0.01%, 0.02% and 0.04%, and for hindfoot fusions (7033 patients) the rates were 0.03%, 0.11% and 0.11%, respectively. The rate of pulmonary embolism in 1633 total ankle replacement patients was 0.06%, and there were no recorded DVTs and no deaths. Statistical analysis could only identify risk factors for venous thromboembolic events of increasing age and multiple comorbidities following fracture surgery. Venous thromboembolism following foot and ankle surgery is extremely rare, but this subset of fracture patients is at a higher risk. However, there is no evidence that thromboprophylaxis reduces this risk, and these national data suggest that prophylaxis is not required in most of these patients.     

Incidence of acute deep vein thrombosis and pulmonary embolism in foot and ankle trauma: analysis of the National Trauma Data Bank

The incidence of deep vein thrombosis (DVT) after foot and ankle surgery is generally believed to be low. However, little information is available regarding DVT as it specifically relates to foot and ankle trauma. The National Trauma Data Bank data set (2007 to 2009) was used to evaluate the incidence of thromboembolism in foot and ankle trauma. Also, the risk factors associated with the thromboembolic events were identified. Data regarding the demographics, comorbidities, procedures, trauma types, and complications, including DVT and pulmonary embolism (PE), were collected from the data set for analysis. The incidence of DVT and PE was 0.28% and 0.21%, respectively. The risk factors statistically significantly associated and clinically relevant for both DVT and PE in foot and ankle trauma were older age (DVT, odds ratio [OR] 1.02, 95% confidence interval [CI] 1.01 to 1.03; PE, OR 1.02, 95% CI 1.01 to 1.03), obesity (DVT, OR 2.35, 95% CI 1.33 to 4.14; PE, OR 3.06, 95% CI 1.68 to 5.59), and higher injury severity score (DVT, OR 1.22, 95% CI 1.16 to 1.28; PE, OR 1.21, 95% CI 1.14 to 1.29). Owing to the low incidence, routine pharmacologic thromboprophylaxis might be contraindicated in foot and ankle trauma. Instead, careful, individualized assessment of the risk factors associated with DVT/PE is important.     

Antithrombotic pharmacologic prophylaxis use during conservative and surgical management of foot and ankle disorders: a systematic review

The use of antithrombotic pharmacologic prophylaxis during conservative or postoperative management of foot and ankle disorders is controversial. This article presents a systematic review of the incidence of deep venous thrombosis (DVT)/pulmonary embolus (PE) during management of foot and ankle disorders in patients who did or did not receive antithrombotic pharmacologic prophylaxis. Incidence of DVT/PE in both groups was low; however, more than half of the patients in both groups received some form of antithrombotic pharmacologic prophylaxis of varying duration, making it difficult to determine the true protective effect of antithrombotic pharmacologic prophylaxis.     

A Systematic Review of Deep Venous Thrombosis Prophylaxis in Cancer Patients: Implications for Improving Quality

Introduction Deep venous thrombosis (DVT) prophylaxis is particularly important for surgical oncologists given the high rate of DVT in patients with malignancy. Additionally, DVT prophylaxis may soon be implemented by some payers as a “pay for performance” quality measure. This is a systematic review of randomized controlled trial (RCT) evidence for DVT prophylaxis in cancer patients undergoing surgery. We examine overall rates of DVT, the efficacy of high versus low-dose heparin prophylaxis, and the rate of bleeding complications. Methods The Medline database was searched for English language RCTs using key words DVT, venous thromboembolism, prophylaxis, and general surgery. Inclusion criteria were RCTs evaluating surgical oncology patients. Results Fifty-five RCTs studied DVT prophylaxis in surgery (nonorthopedic) patients. Twenty-six RCTs evaluated 7,639 cancer patients. The overall DVT rate was 12.7% for pharmacologic prophylaxis and 35.2% for controls. High-dose low-molecular weight heparin (LMWH) was more effective than low dose, lowering the DVT rate from 14.5% to 7.9% (P < 0.01). Heparin decreased the rate of proximal DVTs. Bleeding complications requiring discontinuation of prophylaxis occurred in 3% of the patients. There was no difference between LMWH and unfractionated heparin in efficacy, DVT location, or bleeding complications. Conclusion Using RCT data, this study demonstrates a greatly reduced DVT rate with pharmacologic prophylaxis in cancer patients, and higher doses appear more effective. Complication rates are low and should not prevent the use of prophylaxis in most patients. Finally, we found no difference between LMWH and unfractionated heparin in these RCTs. These results highlight the importance of routine pharmacologic prophylaxis in surgical patients with malignancy. Presented at 2006 Society of Surgical Oncology Annual Meeting, San Diego, CA.     

Mechanical prophylaxis of deep-vein thrombosis after total hip replacement a randomised clinical trial

Routine prophylaxis for venous thromboembolic disease after total hip replacement (THR) is recommended. Pneumatic compression with foot pumps seems to provide an alternative to chemical agents. However, the overall number of patients investigated in randomised clinical trials has been too small to draw evidence-based conclusions. This randomised clinical trial was carried out to compare the effectiveness and safety of mechanical versus chemical prophylaxis of DVT in patients after THR. Inclusion criteria were osteoarthritis of the hip and age less than 80 years. Exclusion criteria included a history of thromboembolic disease, heart disease, and bleeding diatheses. There were 216 consecutive patients considered for inclusion in the trial who were randomised either for management with the A-V Impulse System foot pump. We excluded 16 patients who did not tolerate continuous use of the foot pump or with low-molecular-weight heparin (LMWH). Patients were monitored for DVT using serial duplex sonography at 3, 10 and 45 days after surgery. DVT was detected in three of 100 patients in the foot-pump group and with six of 100 patients in the LMWH group (p < 0.05). The mean post-operative drainage was 259 ml in the foot-pump group and 328 ml in the LMWH group (p < 0.05). Patients in the foot-pump group had less swelling of the thigh (10 mm compared with 15 mm; p < 0.05). One patient developed heparin-induced thrombocytopenia. This study confirms the effectiveness and safety of mechanical prophylaxis of DVT in THR. Some patients cannot tolerate the foot pump.     

Thromboembolism Following Foot and Ankle Surgery: A Case Series and Literature Review

Venous thromboembolism following major orthopedic procedures of the hip and knee is well documented and patients are therefore routinely prophylaxed following these proximal lower extremity procedures. In contrast, foot and ankle surgery is considered by most health care professionals to be a low-risk procedure for the development of venous thromboembolism. As a result, pharmacologic deep venous thrombosis prophylaxis is rarely administered. This postoperative practice is supported by the literature regarding deep venous thrombosis following foot and ankle surgery. In this article, we review the risk factors and explore the occurrence of thromboembolism after foot and ankle surgery in the literature. We also present our retrospective study of patients who developed venous thromboembolism after forefoot, midfoot, hindfoot, and ankle procedures. Over the course of 1.5 years, 4 of a consecutive series of 1000 patients (0.4%) developed a deep venous thrombolism and 3 of 1000 (0.3%) developed nonfatal pulmonary emboli. In our series, each of our patients who developed venous thromboembolism had at least 2 identifiable risk factors. The incidence of venous thromboembolism following foot and ankle surgery is rare (less than 1%), and the need for routine propylaxis postoperatively is not supported by any high level of evidence studies. LEVEL OF CLINICAL EVIDENCE: 4.     

A Comparison of Two Different Prophylactic Dose Regimens of Low Molecular Weight Heparin in Bariatric Surgery

Background: Deep venous thrombosis (DVT) is a significant risk in patients undergoing surgery for morbid obesity and may be associated with significant morbidity and mortality. In a consecutive group of patients in one bariatric surgery practice, the initial group of patients who received prophylaxis for DVT was given enoxaparin 30 mg q12h while the later group was given enoxaparin 40 mg q12h. Methods: 481 patients who underwent primary and revisional bariatric surgery over 38 months (October 1997 - December 2000) were evaluated. All patients received a multi-modality DVT prophylaxis protocol that included: early ambulation, graduated compression stockings, intermittent pneumatic compression, and enoxaparin (LMWH) in two dosage groups. The first 92 patients (19%) in the series (Group I) received LMWH 30 mg q12h while the subsequent 389 patients (81%) (Group II) received LMWH 40 mg q12h. Results: Group I patients were not different from Group II patients in body mass index (BMI) (51.7 vs 50.3 kg/m²), age (43.7 vs 44.3 yrs), sex (men 20.2% vs 15.8%) or history of previous DVT (3.2% vs 3.9%). Group I patients did have significantly longer procedure times (213 vs 175 min, p<0.05) and hospital stays (5.67 d vs 3.81 d, p<0.05) than Group II. There were a total of 7 (1.4%) postoperative DVT complications. 5 DVT complications occurred in Group I (5.4%) compared with 2 DVT complications in Group II (0.6%) (p < 0.01 by Fisher Exact Test two-tailed). One patient in each group required treatment for hemorrhage. Conclusion: A multi-modality prophylaxis treatment protocol in patients undergoing bariatric surgery is feasible and achieves a low incidence of postoperative DVT complications. The use of a higher dose of enoxaparin, 40 mg q12h, may reduce the incidence of DVT complications in patients following bariatric surgery without an increase in bleeding complications.     

Practice patterns for deep vein thrombosis prophylaxis in minimal-access surgery.

BACKGROUND: There are no comprehensive evidence-based guidelines for deep vein thrombosis (DVT) prophylaxis in patients undergoing minimal-access surgery (MAS). METHODS: We completed a cross-sectional survey of general surgeons practising in Ontario, in order to establish current practice patterns for DVT prophylaxis for MAS procedures. RESULTS: The mean duration of practice of respondents was 15.4 years, with most (67.0%) practising outside an academic centre. For minor MAS, most surgeons do not give DVT prophylaxis (73.8% in laparoscopic cholecystectomy and 63.7% in laparoscopic inguinal hernia repair). For major MAS, a minority of surgeons do not give DVT prophylaxis (4.1% in laparoscopic colorectal surgery and 13.6% in laparoscopic splenectomy). However, there remains considerable variation in the mechanism (pharmacological, mechanical), approach and duration (perioperative, postoperative) of DVT prophylaxis among respondents in all case scenarios evaluated. Academic surgeons and surgeons in practice for 15 years or less are more aggressive with preoperative heparin administration. CONCLUSIONS: There is substantial and important variability in the current practice of general surgeons with respect to DVT prophylaxis for MAS. Considerable benefit will be derived from clinical trials that provide data to establish appropriate DVT prophylaxis guidelines for MAS.     

Thromboembolic prophylaxis in head trauma and multiple-trauma patients

The association between trauma and venous thromboembolism (VTE) is well recognized. VTE consists mainly of deep venous thrombosis (DVT) and pulmonary embolism, a complication that leads to mortality in nearly 50% of cases. Without thromboprophylaxis, the risk of DVT exceeds 50%, but even with routine use of prophylaxis,one third of patients may develop DVT. Despite these findings, appropriate DVT prophylaxis is often not prescribed in trauma patients, mainly because of fear that VTE prophylaxis increases bleeding in injured tissues. Pharmacological VTE prophylaxis is based on the use of low-molecular weight heparins (LMWH). Once-daily or twice-daily LMWH protocols started within 36 h of trauma and continued throughout the hospital stay, or once-daily LMWH followed by a twice-daily protocol are possible options. Mechanical VTE prophylaxis by graduated compression stockings or intermittent pneumatic compression provides suboptimal protection, and its use is recommended only in combination with LMWH prophylaxis unless active bleeding is not controlled. The routine use of VTE prophylaxis in trauma patients is a standard of care. The use of LMWH, started once primary hemostasis has been accomplished, is safe, efficacious and cost-effective in the majority of trauma patients, including TBI patients.     

Deep venous thrombosis following different isolated lower extremity fractures: what is known about prevalences, locations, risk factors and prophylaxis?

Introduction

Deep venous thrombosis (DVT) offers a high risk of morbidity and mortality, especially in case of pulmonary embolism. Precise data as to DVT after isolated lower extremity fractures (ILEFs) are rare. Even organizations like the American Academy of Orthopaedic Surgeons or the American College of Chest Physicians do not state exact recommendations as to optimal DVT prophylaxis (ppx) after ILEFs.

Prevalence

The incidence of DVT ranges from 5 to 86 % depending on the fracture whereas femur fractures offer the highest risk for clotting. The incidence seems to decrease in more distal fractures. Location: The risk to develop proximal clots is likely low, however, especially these are feared by surgeons. DVT can occur in both the injured and uninjured leg with a trend for higher incidences in the injured leg.

Risk factors

Risk factors for DVT after ILEF seem to be similar to risk factors for DVT development after orthopaedic surgery and in general. Risk factors caused by surgeons are the use of a tourniquet, prolonged operative time and a delay from injury to surgery.

Prophylaxis

Low molecular weight heparin is favoured by many authors, however, warfarin and acetylsalicylic acid are also used. Clear recommendations are still missing.

Conclusion

The rate of morbidity caused by DVT after ILEF is poorly understood so far. Exact data on prevalences are missing and optimal DVT prophylaxis still has to be defined.     

Incidence of Venous Thromboembolism in Patients Receiving Anticoagulation for Foot and Ankle Surgery

Venous thromboembolism (VTE) is a serious medical condition that can be an unfortunate complication arising from foot and ankle surgery. Many factors may predispose a patient to a VTE event including prolonged postoperative immobilization, comorbidities, extended length of tourniquet time, and higher risk surgeries. Unfortunately, there is no clinical consensus for guidelines on VTE prophylaxis following foot and ankle surgery. In this retrospective cohort study, we present our patient population who were prophylactically anticoagulated following foot and ankle surgery along with their incidence of deep vein thrombosis and pulmonary embolism (PE). Included in the study were patients who had undergone elective and traumatic foot and ankle surgery from June 2017 to December 2018. Using retrospective data obtained we compared patient demographics, surgery type, length of tourniquet time, postoperative immobilization, type of VTE prophylaxis, and comorbidities including history of smoking, peripheral vascular disease, bleeding disorders, and patients undergoing dialysis. Five of 425 (1.2%) patients were diagnosed with a deep vein thrombosis and 1 of 425 (0.2%) patients was diagnosed with a pulmonary embolism. Risks factors statistically significant for developing a VTE in our patient population included extended periods of immobilization and an increasing patient age. We were able to conclude that routine prophylaxis for elective and traumatic foot and ankle surgery is both effective and safe for especially in older patients requiring extended immobilization. It's also important to take into consideration comorbidities, smoking history, tourniquet time, and the type of surgery that is being performed.     

Prevention of deep-vein thrombosis after total knee replacement. Randomised comparison between a low-molecular-weight heparin (nadroparin) and mechanical prophylaxis with a foot-pump system.

The optimal regime of antithrombotic prophylaxis for patients undergoing total knee arthroplasty (TKA) has not been established. Many surgeons employ intermittent pneumatic compression while others use low-molecular-weight heparins (LMWH) which were primarily developed for total hip arthroplasty. We compared the efficacy and safety of these two techniques in a randomised study with blinded assessment of the endpoint by phlebography. We randomised 130 patients, scheduled for elective TKA, to receive one daily subcutaneous injection of nadroparin calcium (dosage adapted to body-weight) or continuous intermittent pneumatic compression of the foot by means of the arteriovenous impulse system. A total of 108 patients (60 in the LMWH group and 48 in the mechanical prophylaxis group) had phlebography eight to 12 days after surgery. Of the 47 with deep-vein thrombosis, 16 had received LMWH (26.7%, 95% CI 16.1 to 39.7) and 31, mechanical prophylaxis (64.6%, 95% CI 49.5 to 77.8). The difference between the two groups was highly significant (p < 0.001). Only one patient in the LMWH group had severe bleeding. We conclude that one daily subcutaneous injection of calcium nadroparin in a fixed, weight-adjusted dosage scheme is superior to intermittent pneumatic compression of the foot for thromboprophylaxis after TKA. The LMWH scheme was also safe.     

Wound infection in the management of hip fractures: a comparison between low-molecular weight heparin and mechanical prophylaxis

A review of 205 consecutive patients was carried out to determine the association of low molecular weight heparin (LMWH) and the development of wound infection in patients having undergone surgery for a femoral neck fracture: 114 patients treated with LMW Heparin (Group A) and 91 patients with mechanical prophylaxis (Group B). The wounds were assessed using the ASEPSIS Score. Deep vein thrombosis (DVT) and pulmonary embolism (PE) were also noted. Twenty-two patients (19%) in group A developed infection; 9 patients (8%) showed severe infection. Eight patients (8%) in group B developed infection; one patient (1%) showed severe infection. The differences between these two groups regarding infection (p < 0.034) and severity of the infection (p < 0.001) were statistically significant. None of the patients developed PE; however 9 patients were diagnosed with a DVT. Based on these findings, it appears that the use of LMWH for DVT prophylaxis may increase the likelihood of developing a severe wound infection.     

Routine use of LMWH prophylaxis is associated with a lower incidence of venous thromboembolic events following an ankle fracture

BackgroundVenous thromboembolic events (VTE) are well-known and serious complications following a trauma to the lower extremities. There is an ongoing debate on the benefit of low-molecular-weight heparin (LMWH) as prophylaxis following ankle fracture treatment. We examined the association between the incidence of VTE and the use of LMWH-prophylaxis following an ankle fracture, as well as factors affecting the risk of VTE.MethodsIn this retrospective cohort study, data on ankle fractures and fracture treatment from the Swedish Fracture Register was linked to data from the Swedish National Patient Register and the Swedish Prescribed Drug Register. Patients with VTE and patients who received LMWH prophylaxis were identified. The treating orthopedic departments were sent a questionnaire about their guidelines regarding the use of LMWH prophylaxis.Results222 cases of diagnosed VTE were identified among 14,954 ankle fractures. Orthopedic departments with higher-than-average use of LMWH prophylaxis among non-operatively treated ankle fractures had a lower incidence of VTE (OR 0.60, CI 0.39–0.92). Among operatively treated patients, departments with a guideline for the routine use of LMWH prophylaxis also had lower incidence of VTE (OR 0.56, CI 0.37–0.86). A later onset of VTE was seen among patients prescribed LMWH prophylaxis, with a mean of 56 days to onset (CI 44–67), compared to 39 days (CI 33–45) in patients without prescribed prophylaxis. During the first two weeks following injury, there was only one case of VTE in patients with prescribed LMWH, compared to 39 cases of VTE among patients without prescribed prophylaxis.ConclusionsRoutine use of LMWH in patients with operatively treated ankle fractures was associated with a lower incidence of VTE. A more frequent use of LMWH among patients with non-operatively treated ankle fractures were associated with a lower incidence of VTE. The onset occurred later among patients with LMWH-prophylaxis who still suffered a VTE.